Last data update: Apr 22, 2024. (Total: 46599 publications since 2009)
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SARS-CoV-2 shedding and evolution in patients who were immunocompromised during the omicron period: a multicentre, prospective analysis
Raglow Z , Surie D , Chappell JD , Zhu Y , Martin ET , Kwon JH , Frosch AE , Mohamed A , Gilbert J , Bendall EE , Bahr A , Halasa N , Talbot HK , Grijalva CG , Baughman A , Womack KN , Johnson C , Swan SA , Koumans E , McMorrow ML , Harcourt JL , Atherton LJ , Burroughs A , Thornburg NJ , Self WH , Lauring AS . Lancet Microbe 2024 BACKGROUND: Prolonged SARS-CoV-2 infections in people who are immunocompromised might predict or source the emergence of highly mutated variants. The types of immunosuppression placing patients at highest risk for prolonged infection have not been systematically investigated. We aimed to assess risk factors for prolonged SARS-CoV-2 infection and associated intrahost evolution. METHODS: In this multicentre, prospective analysis, participants were enrolled at five US medical centres. Eligible patients were aged 18 years or older, were SARS-CoV-2-positive in the previous 14 days, and had a moderately or severely immunocompromising condition or treatment. Nasal specimens were tested by real-time RT-PCR every 2-4 weeks until negative in consecutive specimens. Positive specimens underwent viral culture and whole genome sequencing. A Cox proportional hazards model was used to assess factors associated with duration of infection. FINDINGS: From April 11, 2022, to Oct 1, 2022, 156 patients began the enrolment process, of whom 150 were enrolled and included in the analyses. Participants had B-cell malignancy or anti-B-cell therapy (n=18), solid organ transplantation or haematopoietic stem-cell transplantation (HSCT; n=59), AIDS (n=5), non-B-cell malignancy (n=23), and autoimmune or autoinflammatory conditions (n=45). 38 (25%) participants were real-time RT-PCR-positive and 12 (8%) were culture-positive 21 days or longer after initial SARS-CoV-2 detection or illness onset. Compared with the group with autoimmune or autoinflammatory conditions, patients with B-cell dysfunction (adjusted hazard ratio 0·32 [95% CI 0·15-0·64]), solid organ transplantation or HSCT (0·60 [0·38-0·94]), and AIDS (0·28 [0·08-1·00]) had longer duration of infection, defined as time to last positive real-time RT-PCR test. There was no significant difference in the non-B-cell malignancy group (0·58 [0·31-1·09]). Consensus de novo spike mutations were identified in five individuals who were real-time RT-PCR-positive longer than 56 days; 14 (61%) of 23 were in the receptor-binding domain. Mutations shared by multiple individuals were rare (<5%) in global circulation. INTERPRETATION: In this cohort, prolonged replication-competent omicron SARS-CoV-2 infections were uncommon. Within-host evolutionary rates were similar across patients, but individuals with infections lasting longer than 56 days accumulated spike mutations, which were distinct from those seen globally. Populations at high risk should be targeted for repeated testing and treatment and monitored for the emergence of antiviral resistance. FUNDING: US Centers for Disease Control and Prevention. |
Notes from the field: Early identification of the SARS-CoV-2 Omicron BA.2.86 variant by the traveler-based genomic surveillance program - Dulles International Airport, August 2023
Bart SM , Rothstein AP , Philipson CW , Smith TC , Simen BB , Tamin A , Atherton LJ , Harcourt JL , Taylor Walker A , Payne DC , Ernst ET , Morfino RC , Ruskey I , Friedman CR . MMWR Morb Mortal Wkly Rep 2023 72 (43) 1168-1169 During August 13–14, 2023, a new SARS-CoV-2 Omicron subvariant with a large number of mutations compared with previously circulating BA.2 variants (>30 amino acid differences in its spike protein) was identified by genomic sequencing in Denmark and Israel and subsequently designated BA.2.86 (1,2). Given near-simultaneous detections in multiple countries, including the United States, further information was needed regarding geographic spread of BA.2.86. Since January 2022, submissions to SARS-CoV-2 sequence repositories have declined by 95%,* substantially decreasing global capacity to monitor new variants. To fill gaps in global surveillance, CDC’s Traveler-based Genomic Surveillance (TGS) program was developed to provide early warning of new variants entering the United States by collecting samples from arriving international travelers (3). |
Characteristics of children and antigen test performance at a SARS-CoV-2 community testing site (preprint)
Ford L , Whaley MJ , Shah MM , Salvatore PP , Segaloff HE , Delaney A , Currie DW , Boyle-Estheimer L , O'Hegarty M , Morgan CN , Meece J , Ivacic L , Thornburg NJ , Tamin A , Harcourt JL , Folster JM , Medrzycki M , Jain S , Wong P , Goffard K , Gieryn D , Kahrs J , Langolf K , Zochert T , Tate JE , Hsu CH , Kirking HL . medRxiv 2021 2021.07.06.21259792 Background Performance characteristics of SARS-CoV-2 antigen tests among children are limited despite the need for point-of-care testing in school and childcare settings. We describe children seeking SARS-CoV-2 testing at a community site and compare antigen test performance to real-time reverse transcription-polymerase chain reaction (RT-PCR) and viral culture.Methods Two anterior nasal specimens were self-collected for BinaxNOW antigen and RT-PCR testing, along with demographics, symptoms, and exposure information from individuals ≥5 years at a community testing site. Viral culture was attempted on residual antigen or RT-PCR positive specimens. Demographic and clinical characteristics, and the performance of SARS-CoV-2 antigen tests, were compared among children (<18 years) and adults.Results About one in ten included specimens were from children (225/2110); 16.4% (37/225) were RT-PCR positive. Cycle threshold values were similar among RT-PCR positive specimens from children and adults (22.5 vs 21.3, p=0.46) and among specimens from symptomatic and asymptomatic children (22.5 vs 23.2, p=0.39). Sensitivity of antigen test compared to RT-PCR was 73.0% (27/37) among specimens from children and 80.8% (240/297) among specimens from adults; among specimens from children, specificity was 100% (188/188), positive and negative predictive value were 100% (27/27) and 94.9% (188/198) respectively. Virus was isolated from 51.4% (19/37) of RT-PCR positive pediatric specimens; all 19 had positive antigen test results.Conclusions With lower sensitivity relative to RT-PCR, antigen tests may not diagnose all positive COVID-19 cases; however, antigen testing identified children with live SARS-CoV-2 virus.Competing Interest StatementThe authors have declared no competing interest.Funding StatementThis work was supported by the Centers for Disease Control and Prevention.Author DeclarationsI confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained.YesThe details of the IRB/oversight body that provided approval or exemption for the research described are given below:This activity was reviewed by CDC and was conducted consistent with applicable federal law and CDC policy. See e.g., 45 C.F.R. part 46.102(l)(2), 21 C.F.R. part 56; 42 U.S.C. 241(d); 5 U.S.C. 552a; 44 U.S.C. 3501 et seq.All necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived.YesI understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance).YesI have followed all appropriate research reporting guidelines and uploaded the relevant EQUATOR Network research reporting checklist(s) and other pertinent material as supplementary files, if applicable.YesThe datasets generated during and analyzed during the current study are available from the corresponding author on reasonable request. |
Rapid Development of Neutralizing and Diagnostic SARS-COV-2 Mouse Monoclonal Antibodies (preprint)
Chapman AP , Tang X , Lee JR , Chida A , Mercer K , Wharton RE , Kainulainen M , Harcourt JL , Martines RB , Schroeder M , Zhao L , Bryksin A , Zhou B , Bergeron E , Bollweg BC , Tamin A , Thornburg N , Wentworth DE , Petway D , Bagarozzi DA Jr , Finn MG , Goldstein JM . bioRxiv 2020 2020.10.13.338095 The need for high-affinity, SARS-CoV-2-specific monoclonal antibodies (mAbs) is critical in the face of the global COVID-19 pandemic, as such reagents can have important diagnostic, research, and therapeutic applications. Of greatest interest is the ~300 amino acid receptor binding domain (RBD) within the S1 subunit of the spike protein because of its key interaction with the human angiotensin converting enzyme 2 (hACE2) receptor present on many cell types, especially lung epithelial cells. We report here the development and functional characterization of 29 nanomolar-affinity mouse SARS-CoV-2 mAbs created by an accelerated immunization and hybridoma screening process. Differing functions, including binding of diverse protein epitopes, viral neutralization, impact on RBD-hACE2 binding, and immunohistochemical staining of infected lung tissue, were correlated with variable gene usage and sequence.Competing Interest StatementThe authors have declared no competing interest. |
Longitudinal serologic and viral testing post-SARS-CoV-2 infection and post-receipt of mRNA COVID-19 vaccine in a nursing home cohort-Georgia, October 2020-April 2021 (preprint)
Tobolowsky FA , Waltenburg MA , Moritz ED , Haile M , DaSilva JC , Schuh AJ , Thornburg NJ , Westbrook A , McKay SL , LaVoie SP , Folster JM , Harcourt JL , Tamin A , Stumpf MM , Mills L , Freeman B , Lester S , Beshearse E , Lecy KD , Brown LG , Fajardo G , Negley J , McDonald LC , Kutty PK , Brown AC , Bhatnagar A , Bryant-Genevier J , Currie DW , Campbell D , Gilbert SE , Hatfield KM , Jackson DA , Jernigan JA , Dawson JL , Hudson MJ , Joseph K , Reddy SC , Wilson MM . medRxiv 2022 01 (10) e0275718 Importance: There are limited data describing SARS-CoV-2-specific immune responses and their durability following infection and vaccination in nursing home residents. Objective(s): To evaluate the quantitative titers and durability of binding antibodies detected after SARSCoV-2 infection and subsequent COVID-19 vaccination. Design(s): A prospective longitudinal evaluation included nine visits over 150 days; visits included questionnaire administration, blood collection for serology, and paired anterior nasal specimen collection for testing by BinaxNOWTM COVID-19 Ag Card (BinaxNOW), reverse transcription polymerase chain reaction (RT-PCR), and viral culture. Setting(s): A nursing home during and after a SARS-CoV-2 outbreak. Participant(s): 11 consenting SARS-CoV-2-positive nursing home residents. Main Outcomes and Measures: SARS-CoV-2 testing (BinaxNOWTM, RT-PCR, viral culture); quantitative titers of binding SARS-CoV-2 antibodies post-infection and post-vaccination (beginning after the first dose of the primary series). Result(s): Of 10 participants with post-infection serology results, 9 (90%) had detectable Pan-Ig, IgG, and IgA antibodies and 8 (80%) had detectable IgM antibodies. At first antibody detection post-infection, two-thirds (6/9, 67%) of participants were RT-PCR-positive but none were culture positive. Ten participants received vaccination; all had detectable Pan-Ig, IgG, and IgA antibodies through their final observation <=90 days post-first dose. Post-vaccination geometric means of IgG titers were 10-200-fold higher than post-infection. Conclusions and Relevance: Nursing home residents in this cohort mounted robust immune responses to SARS-CoV-2 post-infection and post-vaccination. The augmented antibody responses post-vaccination are potential indicators of enhanced protection that vaccination may confer on previously infected nursing home residents. Copyright The copyright holder for this preprint is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. This article is a US Government work. It is not subject to copyright under 17 USC 105 and is also made available for use under a CC0 license. |
Transmission potential of vaccinated and unvaccinated persons infected with the SARS-CoV-2 Delta variant in a federal prison, July-August 2021 (preprint)
Salvatore PP , Lee CC , Sleweon S , McCormick DW , Nicolae L , Knipe K , Dixon T , Banta R , Ogle I , Young C , Dusseau C , Salmonson S , Ogden C , Godwin E , Ballom T , Ross T , Wynn NT , David E , Bessey TK , Kim G , Suppiah S , Tamin A , Harcourt JL , Sheth M , Lowe L , Browne H , Tate JE , Kirking HL , Hagan LM . medRxiv 2021 19 Background The extent to which vaccinated persons who become infected with SARS-CoV-2 contribute to transmission is unclear. During a SARS-CoV-2 Delta variant outbreak among incarcerated persons with high vaccination rates in a federal prison, we assessed markers of viral shedding in vaccinated and unvaccinated persons. Methods Consenting incarcerated persons with confirmed SARS-CoV-2 infection provided mid-turbinate nasal specimens daily for 10 consecutive days and reported symptom data via questionnaire. Real-time reverse transcription-polymerase chain reaction (RT-PCR), viral whole genome sequencing, and viral culture was performed on these nasal specimens. Duration of RT-PCR positivity and viral culture positivity was assessed using survival analysis. Results A total of 978 specimens were provided by 95 participants, of whom 78 (82%) were fully vaccinated and 17 (18%) were not fully vaccinated. No significant differences were detected in duration of RT-PCR positivity among fully vaccinated participants (median: 13 days) versus those not fully vaccinated (median: 13 days; p=0.50), or in duration of culture positivity (medians: 5 days and 5 days; p=0.29). Among fully vaccinated participants, overall duration of culture positivity was shorter among Moderna vaccine recipients versus Pfizer (p=0.048) or Janssen (p=0.003) vaccine recipients. Conclusions As this field continues to develop, clinicians and public health practitioners should consider vaccinated persons who become infected with SARS-CoV-2 to be no less infectious than unvaccinated persons. These findings are critically important, especially in congregate settings where viral transmission can lead to large outbreaks. Copyright The copyright holder for this preprint is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. This article is a US Government work. It is not subject to copyright under 17 USC 105 and is also made available for use under a CC0 license. |
Characteristics of Nursing Home Residents and Healthcare Personnel with Repeat Positive SARS-CoV-2 Tests ≥ 90 Days After Initial Infection: 4 U.S. Jurisdictions, July 2020 - March 2021.
Wilson WW , Hatfield KM , Tressler S , BickingKinsey C , Parra G , Zell R , Denson A , Williams C , Spicer KB , Kamal-Ahmed I , Abdalhamid B , Gemechu M , Folster J , Thornburg NJ , Tamin A , Harcourt JL , Queen K , Tong S , Jernigan JA , Crist M , Perkins KM , Reddy SC . Infect Control Hosp Epidemiol 2023 44 (5) 809-812 One in six nursing home residents and staff with positive SARS-CoV-2 tests 90 days after initial infection had specimen cycle thresholds (Ct) <30. Individuals with specimen Ct<30 were more likely to report symptoms but were not different from individuals with high Ct value specimens by other clinical and testing data. |
Aerosol and surface stability of HCoV-19 (SARS-CoV-2) compared to SARS-CoV-1.
van Doremalen N , Bushmaker T , Morris DH , Holbrook MG , Gamble A , Williamson BN , Tamin A , Harcourt JL , Thornburg NJ , Gerber SI , Lloyd-Smith JO , de Wit E , Munster VJ . medRxiv 2020 A novel human coronavirus, now named severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2, referred to as HCoV-19 here) that emerged in Wuhan, China in late 2019 is now causing a pandemic1. Here, we analyze the aerosol and surface stability of HCoV-19 and compare it with SARS-CoV-1, the most closely related human coronavirus.2 We evaluated the stability of HCoV-19 and SARS-CoV-1 in aerosols and on different surfaces and estimated their decay rates using a Bayesian regression model (see Supplementary Appendix). All experimental measurements are reported as mean across 3 replicates. |
Transmission potential of vaccinated and unvaccinated persons infected with the SARS-CoV-2 Delta variant in a federal prison, July-August 2021.
Salvatore PP , Lee CC , Sleweon S , McCormick DW , Nicolae L , Knipe K , Dixon T , Banta R , Ogle I , Young C , Dusseau C , Salmonson S , Ogden C , Godwin E , Ballom T , Rhodes T , Wynn NT , David E , Bessey TK , Kim G , Suppiah S , Tamin A , Harcourt JL , Sheth M , Lowe L , Browne H , Tate JE , Kirking HL , Hagan LM . Vaccine 2022 41 (11) 1808-1818 BACKGROUND: The extent to which vaccinated persons who become infected with SARS-CoV-2 contribute to transmission is unclear. During a SARS-CoV-2 Delta variant outbreak among incarcerated persons with high vaccination rates in a federal prison, we assessed markers of viral shedding in vaccinated and unvaccinated persons. METHODS: Consenting incarcerated persons with confirmed SARS-CoV-2 infection provided mid-turbinate nasal specimens daily for 10 consecutive days and reported symptom data via questionnaire. Real-time reverse transcription-polymerase chain reaction (RT-PCR), viral whole genome sequencing, and viral culture was performed on these nasal specimens. Duration of RT-PCR positivity and viral culture positivity was assessed using survival analysis. RESULTS: A total of 957 specimens were provided by 93 participants, of whom 78 (84 %) were vaccinated and 17 (16 %) were unvaccinated. No significant differences were detected in duration of RT-PCR positivity among vaccinated participants (median: 13 days) versus those unvaccinated (median: 13 days; p = 0.50), or in duration of culture positivity (medians: 5 days and 5 days; p = 0.29). Among vaccinated participants, overall duration of culture positivity was shorter among Moderna vaccine recipients versus Pfizer (p = 0.048) or Janssen (p = 0.003) vaccine recipients. In post-hoc analyses, Moderna vaccine recipients demonstrated significantly shorter duration of culture positivity compared to unvaccinated participants (p = 0.02). When restricted to participants without reported prior infection, the difference between Moderna vaccine recipients and unvaccinated participants was more pronounced (medians: 3 days and 6 days, p = 0.002). CONCLUSIONS: Infectious periods for vaccinated and unvaccinated persons who become infected with SARS-CoV-2 are similar and can be highly variable, though some vaccinated persons are likely infectious for shorter durations. These findings are critically important, especially in congregate settings where viral transmission can lead to large outbreaks. In such settings, clinicians and public health practitioners should consider vaccinated, infected persons to be no less infectious than unvaccinated, infected persons. |
Evaluation of self-administered antigen testing in a college setting.
Tinker SC , Prince-Guerra JL , Vermandere K , Gettings J , Drenzik C , Voccio G , Parrott T , Drobeniuc J , Hayden T , Briggs S , Heida D , Thornburg N , Barrios LC , Neatherlin JC , Madni S , Rasberry CN , Swanson KD , Tamin A , Harcourt JL , Lester S , Atherton L , Honein MA . Virol J 2022 19 (1) 202 BACKGROUND: The objective of our investigation was to better understand barriers to implementation of self-administered antigen screening testing for SARS-CoV-2 at institutions of higher education (IHE). METHODS: Using the Quidel QuickVue At-Home COVID-19 Test, 1347 IHE students and staff were asked to test twice weekly for seven weeks. We assessed seroconversion using baseline and endline serum specimens. Online surveys assessed acceptability. RESULTS: Participants reported 9971 self-administered antigen test results. Among participants who were not antibody positive at baseline, the median number of tests reported was eight. Among 324 participants seronegative at baseline, with endline antibody results and ≥ 1 self-administered antigen test results, there were five COVID-19 infections; only one was detected by self-administered antigen test (sensitivity = 20%). Acceptability of self-administered antigen tests was high. CONCLUSIONS: Twice-weekly serial self-administered antigen testing in a low prevalence period had low utility in this investigation. Issues of testing fatigue will be important to address in future testing strategies. |
SARS-CoV-2 viral shedding in vaccinated and unvaccinated persons: A case series.
McCormick DW , Hagan LM , Salvatore PP , Magleby R , Lee C , Sleweon S , Nicolae L , Dixon T , Banta R , Ogle I , Young C , Dusseau C , Ogden C , Browne H , Michael Metz J , Chen MH , Solano MI , Rogers S , Burgin A , Sheth M , Bankamp B , Tamin A , Harcourt JL , Tate JE , Kirking HL . Vaccine 2022 41 (11) 1769-1773 The preclinical time course of SARS-CoV-2 shedding is not well-described. Understanding this time course will help to inform risk of SARS-CoV-2 transmission. During an outbreak in a congregate setting, we collected paired mid-turbinate nasal swabs for antigen testing and reverse-transcription polymerase chain reaction (RT-PCR) every other day from all consenting infected and exposed persons. Among 12 persons tested prospectively before and during SARS-CoV-2 infection, ten of 12 participants (83%) had completed a primary COVID-19 vaccination series prior to the outbreak. We recovered SARS-CoV-2 in viral culture from 9/12 (75%) of participants. All three persons from whom we did not recover SARS-CoV-2 in viral culture had completed their primary vaccination series. We recovered SARS-CoV-2 from viral culture in 6/9 vaccinated persons and before symptom onset in 3/6 symptomatic persons. These findings underscore the need for both non-pharmaceutical interventions and vaccination to mitigate transmission. |
Longitudinal serologic and viral testing post-SARS-CoV-2 infection and post-receipt of mRNA COVID-19 vaccine in a nursing home cohort-Georgia, October 2020‒April 2021.
Tobolowsky FA , Waltenburg MA , Moritz ED , Haile M , DaSilva JC , Schuh AJ , Thornburg NJ , Westbrook A , McKay SL , LaVoie SP , Folster JM , Harcourt JL , Tamin A , Stumpf MM , Mills L , Freeman B , Lester S , Beshearse E , Lecy KD , Brown LG , Fajardo G , Negley J , McDonald LC , Kutty PK , Brown AC , Bhatnagar A , Bryant-Genevier J , Currie DW , Campbell D , Gilbert SE , Hatfield KM , Jackson DA , Jernigan JA , Dawson JL , Hudson MJ , Joseph K , Reddy SC , Wilson MM . PLoS One 2022 17 (10) e0275718 There are limited data describing SARS-CoV-2-specific immune responses and their durability following infection and vaccination in nursing home residents. We conducted a prospective longitudinal evaluation of 11 consenting SARS-CoV-2-positive nursing home residents to evaluate the quantitative titers and durability of binding antibodies detected after SARS-CoV-2 infection and subsequent COVID-19 vaccination. The evaluation included nine visits over 150 days from October 25, 2020, through April 1, 2021. Visits included questionnaire administration, blood collection for serology, and paired anterior nasal specimen collection for testing by BinaxNOW™ COVID-19 Ag Card (BinaxNOW), reverse transcription polymerase chain reaction (RT-PCR), and viral culture. We evaluated quantitative titers of binding SARS-CoV-2 antibodies post-infection and post-vaccination (beginning after the first dose of the primary series). The median age among participants was 74 years; one participant was immunocompromised. Of 10 participants with post-infection serology results, 9 (90%) had detectable Pan-Ig, IgG, and IgA antibodies, and 8 (80%) had detectable IgM antibodies. At first antibody detection post-infection, two-thirds (6/9, 67%) of participants were RT-PCR-positive, but none were culture- positive. Ten participants received vaccination; all had detectable Pan-Ig, IgG, and IgA antibodies through their final observation ≤90 days post-first dose. Post-vaccination geometric means of IgG titers were 10-200-fold higher than post-infection. Nursing home residents in this cohort mounted robust immune responses to SARS-CoV-2 post-infection and post-vaccination. The augmented antibody responses post-vaccination are potential indicators of enhanced protection that vaccination may confer on previously infected nursing home residents. |
Outbreak of Middle East Respiratory Syndrome Coronavirus in Camels and Probable Spillover Infection to Humans in Kenya.
Ngere I , Hunsperger EA , Tong S , Oyugi J , Jaoko W , Harcourt JL , Thornburg NJ , Oyas H , Muturi M , Osoro EM , Gachohi J , Ombok C , Dawa J , Tao Y , Zhang J , Mwasi L , Ochieng C , Mwatondo A , Bodha B , Langat D , Herman-Roloff A , Njenga MK , Widdowson MA , Munyua PM . Viruses 2022 14 (8) The majority of Kenya's > 3 million camels have antibodies against Middle East respiratory syndrome coronavirus (MERS-CoV), although human infection in Africa is rare. We enrolled 243 camels aged 0-24 months from 33 homesteads in Northern Kenya and followed them between April 2018 to March 2020. We collected and tested camel nasal swabs for MERS-CoV RNA by RT-PCR followed by virus isolation and whole genome sequencing of positive samples. We also documented illnesses (respiratory or other) among the camels. Human camel handlers were also swabbed, screened for respiratory signs, and samples were tested for MERS-CoV by RT-PCR. We recorded 68 illnesses among 58 camels, of which 76.5% (52/68) were respiratory signs and the majority of illnesses (73.5% or 50/68) were recorded in 2019. Overall, 124/4692 (2.6%) camel swabs collected from 83 (34.2%) calves in 15 (45.5%) homesteads between April-September 2019 screened positive, while 22 calves (26.5%) recorded reinfections (second positive swab following ≥ 2 consecutive negative tests). Sequencing revealed a distinct Clade C2 virus that lacked the signature ORF4b deletions of other Clade C viruses. Three previously reported human PCR positive cases clustered with the camel infections in time and place, strongly suggesting sporadic transmission to humans during intense camel outbreaks in Northern Kenya. |
Differential neutralization and inhibition of SARS-CoV-2 variants by antibodies elicited by COVID-19 mRNA vaccines.
Wang L , Kainulainen MH , Jiang N , Di H , Bonenfant G , Mills L , Currier M , Shrivastava-Ranjan P , Calderon BM , Sheth M , Mann BR , Hossain J , Lin X , Lester S , Pusch EA , Jones J , Cui D , Chatterjee P , Jenks MH , Morantz EK , Larson GP , Hatta M , Harcourt JL , Tamin A , Li Y , Tao Y , Zhao K , Lacek K , Burroughs A , Wang W , Wilson M , Wong T , Park SH , Tong S , Barnes JR , Tenforde MW , Self WH , Shapiro NI , Exline MC , Files DC , Gibbs KW , Hager DN , Patel M , Halpin AL , McMullan LK , Lee JS , Xia H , Xie X , Shi PY , Davis CT , Spiropoulou CF , Thornburg NJ , Oberste MS , Dugan VG , Wentworth DE , Zhou B . Nat Commun 2022 13 (1) 4350 The evolution of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has resulted in the emergence of new variant lineages that have exacerbated the COVID-19 pandemic. Some of those variants were designated as variants of concern/interest (VOC/VOI) by national or international authorities based on many factors including their potential impact on vaccine-mediated protection from disease. To ascertain and rank the risk of VOCs and VOIs, we analyze the ability of 14 variants (614G, Alpha, Beta, Gamma, Delta, Epsilon, Zeta, Eta, Theta, Iota, Kappa, Lambda, Mu, and Omicron) to escape from mRNA vaccine-induced antibodies. The variants show differential reductions in neutralization and replication by post-vaccination sera. Although the Omicron variant (BA.1, BA.1.1, and BA.2) shows the most escape from neutralization, sera collected after a third dose of vaccine (booster sera) retain moderate neutralizing activity against that variant. Therefore, vaccination remains an effective strategy during the COVID-19 pandemic. |
Comparison of Home Antigen Testing With RT-PCR and Viral Culture During the Course of SARS-CoV-2 Infection.
Chu VT , Schwartz NG , Donnelly MAP , Chuey MR , Soto R , Yousaf AR , Schmitt-Matzen EN , Sleweon S , Ruffin J , Thornburg N , Harcourt JL , Tamin A , Kim G , Folster JM , Hughes LJ , Tong S , Stringer G , Albanese BA , Totten SE , Hudziec MM , Matzinger SR , Dietrich EA , Sheldon SW , Stous S , McDonald EC , Austin B , Beatty ME , Staples JE , Killerby ME , Hsu CH , Tate JE , Kirking HL , Matanock A . JAMA Intern Med 2022 182 (7) 701-709 IMPORTANCE: As self-collected home antigen tests become widely available, a better understanding of their performance during the course of SARS-CoV-2 infection is needed. OBJECTIVE: To evaluate the diagnostic performance of home antigen tests compared with reverse transcription-polymerase chain reaction (RT-PCR) and viral culture by days from illness onset, as well as user acceptability. DESIGN, SETTING, AND PARTICIPANTS: This prospective cohort study was conducted from January to May 2021 in San Diego County, California, and metropolitan Denver, Colorado. The convenience sample included adults and children with RT-PCR-confirmed infection who used self-collected home antigen tests for 15 days and underwent at least 1 nasopharyngeal swab for RT-PCR, viral culture, and sequencing. EXPOSURES: SARS-CoV-2 infection. MAIN OUTCOMES AND MEASURES: The primary outcome was the daily sensitivity of home antigen tests to detect RT-PCR-confirmed cases. Secondary outcomes included the daily percentage of antigen test, RT-PCR, and viral culture results that were positive, and antigen test sensitivity compared with same-day RT-PCR and cultures. Antigen test use errors and acceptability were assessed for a subset of participants. RESULTS: This study enrolled 225 persons with RT-PCR-confirmed infection (median [range] age, 29 [1-83] years; 117 female participants [52%]; 10 [4%] Asian, 6 [3%] Black or African American, 50 [22%] Hispanic or Latino, 3 [1%] Native Hawaiian or Other Pacific Islander, 145 [64%] White, and 11 [5%] multiracial individuals) who completed 3044 antigen tests and 642 nasopharyngeal swabs. Antigen test sensitivity was 50% (95% CI, 45%-55%) during the infectious period, 64% (95% CI, 56%-70%) compared with same-day RT-PCR, and 84% (95% CI, 75%-90%) compared with same-day cultures. Antigen test sensitivity peaked 4 days after illness onset at 77% (95% CI, 69%-83%). Antigen test sensitivity improved with a second antigen test 1 to 2 days later, particularly early in the infection. Six days after illness onset, antigen test result positivity was 61% (95% CI, 53%-68%). Almost all (216 [96%]) surveyed individuals reported that they would be more likely to get tested for SARS-CoV-2 infection if home antigen tests were available over the counter. CONCLUSIONS AND RELEVANCE: The results of this cohort study of home antigen tests suggest that sensitivity for SARS-CoV-2 was moderate compared with RT-PCR and high compared with viral culture. The results also suggest that symptomatic individuals with an initial negative home antigen test result for SARS-CoV-2 infection should test again 1 to 2 days later because test sensitivity peaked several days after illness onset and improved with repeated testing. |
Relationship of SARS-CoV-2 Antigen and Reverse Transcription PCR Positivity for Viral Cultures.
Currie DW , Shah MM , Salvatore PP , Ford L , Whaley MJ , Meece J , Ivacic L , Thornburg NJ , Tamin A , Harcourt JL , Folster J , Medrzycki M , Jain S , Wong P , Goffard K , Gieryn D , Kahrs J , Langolf K , Zochert T , Hsu CH , Kirking HL , Tate JE . Emerg Infect Dis 2022 28 (3) 717-720 We assessed the relationship between antigen and reverse transcription PCR (RT-PCR) test positivity and successful virus isolation. We found that antigen test results were more predictive of virus recovery than RT-PCR results. However, virus was isolated from some antigen-negative and RT-PCR‒positive paired specimens, providing support for the Centers for Disease Control and Prevention antigen testing algorithm. |
Twelve-Month Follow-up of Early COVID-19 Cases in the United States: Cellular and Humoral Immune Longevity.
Shah MM , Rasheed MAU , Harcourt JL , Abedi GR , Stumpf MM , Kirking HL , Tamin A , Mills L , Armstrong M , Salvatore PP , Surasi K , Scott SE , Killerby ME , Briggs-Hagen M , Saydah S , Tate JE , Fry AM , Hall AJ , Thornburg NJ , Midgley CM . Open Forum Infect Dis 2022 9 (3) ofab664 We quantify antibody and memory B-cell responses to severe acute respiratory syndrome coronavirus 2 at 6 and 12 months postinfection among 7 unvaccinated US coronavirus disease 2019 cases. All had detectable S-specific memory B cells and immunoglobulin G at both time points, with geometric mean titers of 117.2 BAU/mL and 84.0 BAU/mL at 6 and 12 months, respectively. |
Descriptive Evaluation of Antibody Responses to SARS-CoV-2 Infection in Plasma and Gingival Crevicular Fluid in a Nursing Home Cohort-Arkansas, June-August 2020.
Brown NE , Lyons AK , Schuh AJ , Stumpf MM , Harcourt JL , Tamin A , Rasheed MAU , Mills L , Lester SN , Thornburg NJ , Nguyen K , Costantini V , Vinjé J , Huang JY , Gilbert SE , Gable P , Bollinger S , Sabour S , Beshearse E , Surie D , Biedron C , Gregory CJ , Clemmons NS , Whitaker B , Coughlin MM , Seely KA , Garner K , Gulley T , Haney T , Kothari A , Patil N , Halpin AL , McDonald LC , Kutty PK , Brown AC . Infect Control Hosp Epidemiol 2021 43 (11) 1-24 OBJECTIVE: Characterize and compare SARS-CoV-2-specific immune responses in plasma and gingival crevicular fluid (GCF) from nursing home residents during and after natural infection. DESIGN: Prospective cohort. SETTING: Nursing home. PARTICIPANTS: SARS-CoV-2-infected nursing home residents. METHODS: A convenience sample of 14 SARS-CoV-2-infected nursing home residents, enrolled 4-13 days after real-time reverse transcription polymerase chain reaction diagnosis, were followed for 42 days. Post diagnosis, plasma SARS-CoV-2-specific pan-Immunoglobulin (Ig), IgG, IgA, IgM, and neutralizing antibodies were measured at 5 timepoints and GCF SARS-CoV-2-specific IgG and IgA were measured at 4 timepoints. RESULTS: All participants demonstrated immune responses to SARS-CoV-2 infection. Among 12 phlebotomized participants, plasma was positive for pan-Ig and IgG in all 12, neutralizing antibodies in 11, IgM in 10, and IgA in 9. Among 14 participants with GCF specimens, GCF was positive for IgG in 13 and IgA in 12. Immunoglobulin responses in plasma and GCF had similar kinetics; median times to peak antibody response was similar across specimen types (4 weeks for IgG; 3 weeks for IgA). Participants with pan-Ig, IgG, and IgA detected in plasma and GCF IgG remained positive through this evaluation's end 46-55 days post-diagnosis. All participants were viral culture negative by the first detection of antibodies. CONCLUSIONS: Nursing home residents had detectable SARS-CoV-2 antibodies in plasma and GCF after infection. Kinetics of antibodies detected in GCF mirrored those from plasma. Non-invasive GCF may be useful for detecting and monitoring immunologic responses in populations unable or unwilling to be phlebotomized. |
Performance characteristics of the Abbott BinaxNOW SARS-CoV-2 antigen test in comparison to real-time RT-PCR and viral culture in community testing sites during November 2020.
Almendares O , Prince-Guerra JL , Nolen LD , Gunn JKL , Dale AP , Buono SA , Deutsch-Feldman M , Suppiah S , Hao L , Zeng Y , Stevens VA , Knipe K , Pompey J , Atherstone C , Bui DP , Powell T , Tamin A , Harcourt JL , Petway M , Bohannon C , Folster JM , MacNeil A , Salerno R , Kuhnert-Tallman W , Tate JE , Thornburg N , Kirking HL , Villanueva JM , Rose DA , Neatherlin JC , Anderson M , Rota PA , Honein MA , Bower WA . J Clin Microbiol 2021 60 (1) Jcm0174221 Point-of-care antigen tests are an important tool for SARS-CoV-2 detection. Antigen tests are less sensitive than real-time reverse-transcriptase PCR (rRT-PCR). Data on the performance of the BinaxNOW antigen test compared to rRT-PCR and viral culture by symptom and known exposure status, timing during disease or exposure period and demographic variables are limited. During November 3(rd)-17(th), 2020, we collected paired upper respiratory swab specimens to test for SARS-CoV-2 by rRT-PCR and Abbott BinaxNOW (BinaxNOW) antigen test at two community testing sites in Pima County, Arizona. We administered a questionnaire to capture symptoms, known exposure status and previous SARS-CoV-2 test results. Specimens positive by either test were analyzed by viral culture. Previously we showed overall BinaxNOW sensitivity was 52.5%. Here we showed BinaxNOW sensitivity increased to 65.7% among currently symptomatic individuals reporting a known exposure. BinaxNOW sensitivity was lower among participants with a known exposure and previously symptomatic (32.4%) or never symptomatic (47.1%) within 14 days of testing. Sensitivity was 71.1% in participants within a week of symptom onset. In participants with a known exposure, sensitivity was highest 8-10 days post-exposure (75%). The positive predictive value for recovery of virus in cell culture was 56.7% for BinaxNOW-positive and 35.4% for rRT-PCR-positive specimens. Result reporting time was 2.5 hours for BinaxNOW and 26 hours for rRT-PCR. Point-of-care antigen tests have a shorter turn-around time compared to laboratory-based nucleic acid amplification tests, which allows for more rapid identification of infected individuals. Antigen test sensitivity limitations are important to consider when developing a testing program. |
Outbreak of SARS-CoV-2 B.1.617.2 (Delta) Variant Infections Among Incarcerated Persons in a Federal Prison - Texas, July-August 2021.
Hagan LM , McCormick DW , Lee C , Sleweon S , Nicolae L , Dixon T , Banta R , Ogle I , Young C , Dusseau C , Salmonson S , Ogden C , Godwin E , Ballom T , Ross T , Browne H , Harcourt JL , Tamin A , Thornburg NJ , Kirking HL , Salvatore PP , Tate JE . MMWR Morb Mortal Wkly Rep 2021 70 (38) 1349-1354 Incarcerated populations have experienced disproportionately higher rates of COVID-19-related illness and death compared with the general U.S. population, due in part to congregate living environments that can facilitate rapid transmission of SARS-CoV-2, the virus that causes COVID-19, and the high prevalence of underlying medical conditions associated with severe COVID-19 (1,2). The SARS-CoV-2 B.1.617.2 (Delta) variant has caused outbreaks among vaccinated and unvaccinated persons in congregate settings and large public gatherings (3,4). During July 2021, a COVID-19 outbreak involving the Delta variant was identified in a federal prison in Texas, infecting 172 of 233 (74%) incarcerated persons in two housing units. The Federal Bureau of Prisons (BOP) partnered with CDC to investigate. CDC analyzed data on infection status, symptom onset date, hospitalizations, and deaths among incarcerated persons. The attack rate was higher among unvaccinated versus fully vaccinated persons (39 of 42, 93% versus 129 of 185, 70%; p = 0.002).(†) Four persons were hospitalized, three of whom were unvaccinated, and one person died, who was unvaccinated. Among a subset of 70 persons consenting to an embedded serial swabbing protocol, the median interval between symptom onset and last positive reverse transcription-polymerase chain reaction (RT-PCR) test result in fully vaccinated versus unvaccinated persons was similar (9 versus 11 days, p = 0.37). One or more specimens were culture-positive from five of 12 (42%) unvaccinated and 14 of 37 (38%) fully vaccinated persons for whom viral culture was attempted. In settings where physical distancing is challenging, including correctional and detention facilities, vaccination and implementation of multicomponent prevention strategies (e.g., testing, medical isolation, quarantine, and masking) are critical to limiting SARS-CoV-2 transmission (5). |
Antigen Test Performance Among Children and Adults at a SARS-CoV-2 Community Testing Site.
Ford L , Whaley MJ , Shah MM , Salvatore PP , Segaloff HE , Delaney A , Currie DW , Boyle-Estheimer L , O'Hegarty M , Morgan CN , Meece J , Ivacic L , Thornburg NJ , Tamin A , Harcourt JL , Folster JM , Medrzycki M , Jain S , Wong P , Goffard K , Gieryn D , Kahrs J , Langolf K , Zochert T , Tate JE , Hsu CH , Kirking HL . J Pediatric Infect Dis Soc 2021 10 (12) 1052-1061 BACKGROUND: Performance characteristics of SARS-CoV-2 antigen tests among children are limited despite the need for point-of-care testing in school and childcare settings. We describe children seeking SARS-CoV-2 testing at a community site and compare antigen test performance to real-time reverse transcription-polymerase chain reaction (RT-PCR) and viral culture. METHODS: Two anterior nasal specimens were self-collected for BinaxNOW antigen and RT-PCR testing, along with demographics, symptoms, and exposure information from individuals ≥5 years at a community testing site. Viral culture was attempted on residual antigen or RT-PCR-positive specimens. Demographic and clinical characteristics, and the performance of SARS-CoV-2 antigen tests, were compared among children (<18 years) and adults. RESULTS: About 1 in 10 included specimens were from children (225/2110); 16.4% (37/225) were RT-PCR-positive. Cycle threshold values were similar among RT-PCR-positive specimens from children and adults (22.5 vs 21.3, P = .46) and among specimens from symptomatic and asymptomatic children (22.5 vs 23.2, P = .39). Sensitivity of antigen test compared to RT-PCR was 73.0% (27/37) among specimens from children and 80.8% (240/297) among specimens from adults; among specimens from children, specificity was 100% (188/188), positive and negative predictive values were 100% (27/27) and 94.9% (188/198), respectively. Virus was isolated from 51.4% (19/37) of RT-PCR-positive pediatric specimens; all 19 had positive antigen test results. CONCLUSIONS: With lower sensitivity relative to RT-PCR, antigen tests may not diagnose all positive COVID-19 cases; however, antigen testing identified children with live SARS-CoV-2 virus. |
Repeated Antigen Testing Among SARS-CoV-2-Positive Nursing Home Residents.
Moritz ED , McKay SL , Tobolowsky FA , LaVoie SP , Waltenburg MA , Lecy KD , Thornburg NJ , Harcourt JL , Tamin A , Folster JM , Negley J , Brown AC , McDonald LC , Kutty PK . Infect Control Hosp Epidemiol 2021 43 (12) 1-10 Repeated antigen testing of 12 SARS-CoV-2-positive nursing home residents using Abbott BinaxNOW™ identified 9/9 (100%) culture-positive specimens up to 6 days after initial positive test. Antigen positivity lasted 2-24 days. Antigen positivity might last beyond the infectious period, but was reliable in residents with evidence of early infection. |
Point-of-Care Antigen Test for SARS-CoV-2 in Asymptomatic College Students.
Tinker SC , Szablewski CM , Litvintseva AP , Folster J , Shewmaker PL , Medrzycki M , Bowen MD , Bohannon C , Bagarozzi D Jr , Petway M , Rota PA , Kuhnert-Tallman W , Thornburg N , Prince-Guerra JL , Barrios LC , Tamin A , Harcourt JL , Honein MA . Emerg Infect Dis 2021 27 (10) 2662-2665 We used the BinaxNOW COVID-19 Ag Card to screen 1,540 asymptomatic college students for severe acute respiratory syndrome coronavirus 2 in a low-prevalence setting. Compared with reverse transcription PCR, BinaxNOW showed 20% overall sensitivity; among participants with culturable virus, sensitivity was 60%. BinaxNOW provides point-of-care screening but misses many infections. |
Detection of SARS-CoV-2 on Surfaces in Households of Persons with COVID-19.
Marcenac P , Park GW , Duca LM , Lewis NM , Dietrich EA , Barclay L , Tamin A , Harcourt JL , Thornburg NJ , Rispens J , Matanock A , Kiphibane T , Christensen K , Pawloski LC , Fry AM , Hall AJ , Tate JE , Vinjé J , Kirking HL , Pevzner E . Int J Environ Res Public Health 2021 18 (15) SARS-CoV-2 transmission from contaminated surfaces, or fomites, has been a concern during the COVID-19 pandemic. Households have been important sites of transmission throughout the COVID-19 pandemic, but there is limited information on SARS-CoV-2 contamination of surfaces in these settings. We describe environmental detection of SARS-CoV-2 in households of persons with COVID-19 to better characterize the potential risks of fomite transmission. Ten households with ≥1 person with laboratory-confirmed COVID-19 and with ≥2 members total were enrolled in Utah, U.S.A. Nasopharyngeal and anterior nasal swabs were collected from members and tested for the presence of SARS-CoV-2 by RT-PCR. Fifteen surfaces were sampled in each household and tested for presence and viability of SARS-CoV-2. SARS-CoV-2 RNA was detected in 23 (15%) of 150 environmental swab samples, most frequently on nightstands (4/6; 67%), pillows (4/23; 17%), and light switches (3/21; 14%). Viable SARS-CoV-2 was cultured from one sample. All households with SARS-CoV-2-positive surfaces had ≥1 person who first tested positive for SARS-CoV-2 ≤ 6 days prior to environmental sampling. SARS-CoV-2 surface contamination occurred early in the course of infection when respiratory transmission is most likely, notably on surfaces in close, prolonged contact with persons with COVID-19. While fomite transmission might be possible, risk is low. |
Epidemiologic, immunologic, and virus characteristics in patients with paired SARS-CoV-2 serology and reverse transcription polymerase chain reaction testing.
Shragai T , Smith-Jeffcoat SE , Koh M , Schechter MC , Rebolledo PA , Kasinathan V , Wang Y , Hoffman A , Miller H , Tejada-Strop A , Jain S , Tamin A , Harcourt JL , Thornburg NJ , Wong P , Medrzycki M , Folster JM , Semenova V , Steward-Clark E , Drobenuic J , Biedron C , Stewart RJ , da Silva J , Kirking HL , Tate JE . J Infect Dis 2021 225 (2) 229-237 BACKGROUND: The natural history and clinical progression of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections can be better understood using combined serological and reverse transcription polymerase chain reaction (RT-PCR) testing. METHODS: Nasopharyngeal swabs and serum were collected at a single time-point from patients at an urban, public hospital August - November 2020 and tested for SARS-CoV-2 using RT-PCR, viral culture, and anti-Spike pan-Ig antibody testing. Participant demographics and symptoms were collected through interview. Chi-squared and Fisher's exact tests were used to identify associations between RT-PCR and serology results with presence of viable virus and frequency of symptoms. RESULTS: Among 592 participants, 129 (21.8%) had evidence of SARS-CoV-2 infection by RT-PCR or serology. Presence of SARS-CoV-2 antibodies was strongly associated with lack of viable virus (p-value=0.016). COVID-19 symptom frequency was similar for patients testing RT-PCR positive/seronegative and patients testing RT-PCR positive/seropositive. Patients testing RT-PCR positive/seronegative reported headaches, fatigue, diarrhea and vomiting at rates not statistically significantly different from those testing RT-PCR negative/seropositive. CONCLUSIONS: While patients testing SARS-CoV-2 seropositive were unlikely to test positive for viable virus and were therefore low-risk for forward transmission, COVID-19 symptoms were common. Paired SARS-CoV-2 RT-PCR and antibody testing provides more nuanced understanding of patients' COVID-19 status. |
Evaluating the Presence of Replication-Competent SARS-CoV-2 from Nursing Home Residents with Persistently Positive RT-PCR Results.
Lutgring JD , Tobolowsky FA , Hatfield KM , Lehnertz NB , Sullivan MM , Martin KG , Keaton A , Sexton DJ , Tamin A , Harcourt JL , Thornburg NJ , Reddy SC , Jernigan JA . Clin Infect Dis 2021 74 (3) 525-528 Replication-competent virus has not been detected in individuals with mild to moderate COVID-19 more than 10 days after symptom onset. It is unknown whether these findings apply to nursing home residents. Of 273 specimens collected from nursing home residents >10 days from the initial positive test, none were culture positive. |
Rapid development of neutralizing and diagnostic SARS-COV-2 mouse monoclonal antibodies.
Chapman AP , Tang X , Lee JR , Chida A , Mercer K , Wharton RE , Kainulainen M , Harcourt JL , Martines RB , Schroeder M , Zhao L , Bryksin A , Zhou B , Bergeron E , Bollweg BC , Tamin A , Thornburg N , Wentworth DE , Petway D , Bagarozzi DA Jr , Finn MG , Goldstein JM . Sci Rep 2021 11 (1) 9682 The need for high-affinity, SARS-CoV-2-specific monoclonal antibodies (mAbs) is critical in the face of the global COVID-19 pandemic, as such reagents can have important diagnostic, research, and therapeutic applications. Of greatest interest is the ~ 300 amino acid receptor binding domain (RBD) within the S1 subunit of the spike protein because of its key interaction with the human angiotensin converting enzyme 2 (hACE2) receptor present on many cell types, especially lung epithelial cells. We report here the development and functional characterization of 29 nM-affinity mouse SARS-CoV-2 mAbs created by an accelerated immunization and hybridoma screening process. Differing functions, including binding of diverse protein epitopes, viral neutralization, impact on RBD-hACE2 binding, and immunohistochemical staining of infected lung tissue, were correlated with variable gene usage and sequence. |
SARS-CoV-2 detection on self-collected saliva or anterior nasal specimens compared with healthcare personnel-collected nasopharyngeal specimens.
Marx GE , Biggerstaff BJ , Nawrocki CC , Totten SE , Travanty EA , Burakoff AW , Scott T , De Hey JC , Carlson JJ , Wendel KA , Harcourt JL , Tamin A , Thomas JD , Rowan SE . Clin Infect Dis 2021 73 S65-S73 BACKGROUND: Nasopharyngeal specimens (NPS) are commonly used for SARS-CoV-2 testing but can be uncomfortable for patients. Self-collected saliva or anterior nasal specimens (ANS) for SARS-CoV-2 detection are less invasive but the sensitivity of these specimen types has not been thoroughly evaluated. METHODS: During September-November 2020, 730 adults undergoing SARS-CoV-2 testing at community testing events and homeless shelters in Denver provided self-collected saliva and ANS specimens before NPS collection and answered a short survey about symptoms and specimen preference. Specimens were tested for SARS-CoV-2 by rRT-PCR; viral culture was performed on a subset of specimens positive by rRT-PCR. Sensitivity of saliva and ANS for SARS-CoV-2 detection by rRT-PCR was measured against NPS. Subgroup analyses included test outcomes by symptom status and culture results. RESULTS: Sensitivity for SARS-CoV-2 detection by rRT-PCR appeared higher for saliva than for ANS (85% vs. 80%) and among symptomatic participants than among those without symptoms (94% vs. 29% for saliva; 87% vs. 50% for ANS). Among participants with culture-positive SARS-CoV-2 by any specimen type, sensitivity of saliva and ANS by rRT-PCR was 94% and 100%, respectively. Saliva and ANS were equally preferred by participants; most would undergo NPS again despite being least preferred. CONCLUSIONS: Saliva was slightly more sensitive than ANS for SARS-CoV-2 detection by rRT-PCR. Both saliva and ANS reliably detected SARS-CoV-2 among participants with symptoms. Self-collected saliva and ANS offer practical advantages, are preferred by patients, and might be most useful for testing people with COVID-19 symptoms. |
Epidemiologic characteristics associated with SARS-CoV-2 antigen-based test results, rRT-PCR cycle threshold values, subgenomic RNA, and viral culture results from university testing.
Ford L , Lee C , Pray IW , Cole D , Bigouette JP , Abedi GR , Bushman D , Delahoy MJ , Currie DW , Cherney B , Kirby M , Fajardo G , Caudill M , Langolf K , Kahrs J , Zochert T , Kelly P , Pitts C , Lim A , Aulik N , Tamin A , Harcourt JL , Queen K , Zhang J , Whitaker B , Browne H , Medrzycki M , Shewmaker P , Bonenfant G , Zhou B , Folster J , Bankamp B , Bowen MD , Thornburg NJ , Goffard K , Limbago B , Bateman A , Tate JE , Gieryn D , Kirking HL , Westergaard R , Killerby M . Clin Infect Dis 2021 73 (6) e1348-e1355 BACKGROUND: Real-time reverse transcription polymerase chain reaction (rRT-PCR) and antigen tests are important diagnostics for SARS-CoV-2. Sensitivity of antigen tests has been shown to be lower than that of rRT-PCR; however, data to evaluate epidemiologic characteristics that affect test performance are limited. METHODS: Paired mid-turbinate nasal swabs were collected from university students and staff and tested for SARS-CoV-2 using both Quidel Sofia SARS Antigen Fluorescent Immunoassay (FIA) and rRT-PCR assay. Specimens positive by either rRT-PCR or antigen FIA were placed in viral culture and tested for subgenomic RNA (sgRNA). Logistic regression models were used to evaluate characteristics associated with antigen results, rRT-PCR cycle threshold (Ct) values, sgRNA, and viral culture. RESULTS: Antigen FIA sensitivity was 78.9% and 43.8% among symptomatic and asymptomatic participants respectively. Among rRT-PCR positive participants, negative antigen results were more likely among asymptomatic participants (OR 4.6, CI:1.3-15.4) and less likely among participants reporting nasal congestion (OR 0.1, CI:0.03-0.8). rRT-PCR-positive specimens with higher Ct values (OR 0.5, CI:0.4-0.8) were less likely, and specimens positive for sgRNA (OR 10.2, CI:1.6-65.0) more likely, to yield positive virus isolation. Antigen testing was >90% positive in specimens with Ct values <29. Positive predictive value of antigen test for positive viral culture (57.7%) was similar to that of rRT-PCR (59.3%). CONCLUSIONS: SARS-CoV-2 antigen test advantages include low cost, wide availability and rapid turnaround time, making them important screening tests. The performance of antigen tests may vary with patient characteristics, so performance characteristics should be accounted for when designing testing strategies and interpreting results. |
Infectious Period of Severe Acute Respiratory Syndrome Coronavirus 2 in 17 Nursing Home Residents-Arkansas, June-August 2020.
Surie D , Huang JY , Brown AC , Gable P , Biedron C , Gilbert SE , Garner K , Bollinger S , Gulley T , Haney T , Lyons AK , Beshearse E , Gregory CJ , Sabour S , Clemmons NS , James AE , Tamin A , Reese N , Perry-Dow KA , Brown R , Harcourt JL , Campbell D , Houston H , Chakravorty R , Paulick A , Whitaker B , Murdoch J , Spicer L , Stumpf MM , Mills L , Coughlin MM , Higdem P , Rasheed MAU , Lonsway D , Bhatnagar A , Kothari A , Anderson K , Thornburg NJ , Breaker E , Adamczyk M , McAllister GA , Halpin AL , Seely KA , Patil N , McDonald LC , Kutty PK . Open Forum Infect Dis 2021 8 (3) ofab048 BACKGROUND: To estimate the infectious period of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in older adults with underlying conditions, we assessed duration of coronavirus disease 2019 (COVID-19) symptoms, reverse-transcription polymerase chain reaction (RT-PCR) positivity, and culture positivity among nursing home residents. METHODS: We enrolled residents within 15 days of their first positive SARS-CoV-2 test (diagnosis) at an Arkansas facility from July 7 to 15, 2020 and instead them for 42 days. Every 3 days for 21 days and then weekly, we assessed COVID-19 symptoms, collected specimens (oropharyngeal, anterior nares, and saliva), and reviewed medical charts. Blood for serology was collected on days 0, 6, 12, 21, and 42. Infectivity was defined by positive culture. Duration of culture positivity was compared with duration of COVID-19 symptoms and RT-PCR positivity. Data were summarized using measures of central tendency, frequencies, and proportions. RESULTS: We enrolled 17 of 39 (44%) eligible residents. Median participant age was 82 years (range, 58-97 years). All had ≥3 underlying conditions. Median duration of RT-PCR positivity was 22 days (interquartile range [IQR], 8-31 days) from diagnosis; median duration of symptoms was 42 days (IQR, 28-49 days). Of 9 (53%) participants with any culture-positive specimens, 1 (11%) severely immunocompromised participant remained culture-positive 19 days from diagnosis; 8 of 9 (89%) were culture-positive ≤8 days from diagnosis. Seroconversion occurred in 12 of 12 (100%) surviving participants with ≥1 blood specimen; all participants were culture-negative before seroconversion. CONCLUSIONS: Duration of infectivity was considerably shorter than duration of symptoms and RT-PCR positivity. Severe immunocompromise may prolong SARS-CoV-2 infectivity. Seroconversion indicated noninfectivity in this cohort. |
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