Hybrid immunity, as a result of infection and vaccination to SARS-CoV-2, has been well studied in adults but limited evidence is available in children. We evaluated the antibody responses to primary SARS-CoV-2 infection among vaccinated and unvaccinated children aged ≥ 5 years. METHODS: A longitudinal cohort study of children aged ≥ 5 was conducted during August 2021-August 2022, at sites in Arizona, Texas, Utah, and Florida. Children submitted weekly nasal swabs for PCR testing and provided sera 14-59 days after PCR-confirmed SARS-CoV-2 infection. Antibodies were measured by ELISA against the receptor-binding domain (RBD) and S2 domain of ancestral Spike (WA1), in addition to Omicron (BA.2) RBD, following infection in children, with and without prior monovalent ancestral mRNA COVID-19 vaccination. RESULTS: Among the 257 participants aged 5 to 18 years, 166 (65%) had received at least two mRNA COVID-19 vaccine doses ≥ 14 days prior to infection. Of these, 53 occurred during Delta predominance, with 37 (70%) unvaccinated at the time of infection. The remaining 204 infections occurred during Omicron predominance, with 53 (26%) participants unvaccinated. After adjusting for weight, age, symptomatic infection, and gender, significantly higher mean RBD AUC values were observed among the vaccinated group compared to the unvaccinated group for both WA1 and Omicron (p < 0.0001). A smaller percentage of vaccinated children reported fever during illness, with 55 (33%) reporting fever compared to 44 (48%) unvaccinated children reporting fever (p = 0.021). CONCLUSIONS: Children with vaccine-induced immunity at the time of SARS-CoV-2 infection had higher antibody levels during convalescence and experienced less fever compared to unvaccinated children during infection.

BACKGROUND: The kinetics and durability of T-cell responses to SARS-CoV-2 in children are not well-characterized. We studied a cohort of children aged 6 months to 20 years with COVID-19 in whom peripheral blood mononuclear cells (PBMC) and sera were archived at approximately 1, 6, and 12 months post-symptom onset. METHODS: We compared antibody (N = 85) and T-cell responses (N = 26) to nucleocapsid (N) and spike (S) glycoprotein over time across four age strata: 6 months to 5 years, 5-9, 10-14, and 15-20 years. RESULTS: N-specific antibody responses declined over time, becoming undetectable in 26/32 (81%) children by approximately one year post-infection. Functional breadth of anti-N CD4+ T-cell responses also declined over time and were positively correlated with N-antibody responses (Pearson's r = 0.31, p = 0.008). CD4+ T-cell responses to S displayed greater functional breadth than N in unvaccinated children, and, along with neutralization titers, were stable over time and similar across age strata. Functional profiles of CD4+ T-cell responses against S were not significantly modulated by vaccination. CONCLUSIONS: Our data reveal durable, age-independent T-cell immunity to SARS-CoV-2 structural proteins in children over time following COVID-19 infection as well as S-Ab responses overall, in comparison to declining antibody responses to N.

IMPORTANCE: Access to COVID-19 testing is critical to reducing transmission and supporting early treatment decisions; when made accessible, the timeliness of testing may also be an important metric in mitigating community spread of the infection. While disparities in transmission and outcomes of COVID-19 have been well documented, the extent of timeliness of testing and the association with demographic factors is unclear. OBJECTIVES: To evaluate demographic factors associated with delayed COVID-19 testing among health care personnel (HCP) during the COVID-19 pandemic. DESIGN, SETTING, AND PARTICIPANTS: This cross-sectional study used data from the Preventing Emerging Infections Through Vaccine Effectiveness Testing study, a multicenter, test-negative, case-control vaccine effectiveness study that enrolled HCP who had COVID-19 symptoms and testing between December 2020 and April 2022. Data analysis was conducted from March 2022 to Junne 2023. EXPOSURE: Displaying COVID-19-like symptoms and polymerase chain reaction testing occurring from the first day symptoms occurred up to 14 days after symptoms occurred. MAIN OUTCOMES AND MEASURES: Variables of interest included patient demographics (sex, age, and clinical comorbidities) and COVID-19 characteristics (vaccination status and COVID-19 wave). The primary outcome was time from symptom onset to COVID-19 testing, which was defined as early testing (≤2 days) or delayed testing (≥3 days). Associations of demographic characteristics with delayed testing were measured while adjusting for clinical comorbidities, COVID-19 characteristics, and test site using multivariable modeling to estimate relative risks and 95% CIs. RESULTS: A total of 5551 HCP (4859 female [82.9%]; 1954 aged 25-34 years [35.2%]; 4233 non-Hispanic White [76.3%], 370 non-Hispanic Black [6.7%], and 324 non-Hispanic Asian [5.8%]) were included in the final analysis. Overall, 2060 participants (37.1%) reported delayed testing and 3491 (62.9%) reported early testing. Compared with non-Hispanic White HCP, delayed testing was higher among non-Hispanic Black HCP (adjusted risk ratio, 1.18; 95%CI, 1.10-1.27) and for non-Hispanic HCP of other races (adjusted risk ratio, 1.17; 95% CI, 1.03-1.33). Sex and age were not associated with delayed testing. Compared with clinical HCP with graduate degrees, all other professional and educational groups had significantly delayed testing. CONCLUSIONS AND RELEVANCE: In this cross-sectional study of HCP, compared with non-Hispanic White HCP and clinical HCP with graduate degrees, non-Hispanic Black HCP, non-Hispanic HCP of other races, and HCP all other professional and education backgrounds were more likely to have delayed COVID-19 testing. These findings suggest that time to testing may serve as a valuable metric in evaluating sociodemographic disparities in the response to COVID-19 and future health mitigation strategies.

INTRODUCTION: Since March 2020, Hispanic and Black/African American persons have made up a disproportionate number of COVID-19 cases, hospitalizations, and deaths. However, little is known about whether the prevalence of postacute sequelae or post-COVID conditions differs by race/ethnicity. METHODS: This study used cross-sectional survey data collected by Porter Novelli Public Services to determine the prevalence of ≥1 ongoing symptom lasting ≥4 weeks by SARS-CoV-2 test status and racial/ethnic groups among 2,890 adults in the U.S. RESULTS: Overall, 57% (95% CI=54%, 60%) of respondents with positive SARS-CoV-2 tests reported ≥1 ongoing symptom, compared with 22% (95% CI=20%, 24%) of respondents who tested negative. Among those with positive SARS-CoV-2 tests, Hispanic respondents had higher AORs of experiencing ≥1 ongoing symptom (AOR=1.79, 95% CI=1.27, 2.53) than non-Hispanic White respondents. In addition, Hispanic respondents had significantly higher ORs of experiencing 2 or more ongoing symptoms (AOR=2.03, 95% CI=1.45, 2.86), respiratory/cardiac symptoms (AOR=1.47, 95% CI=1.03, 2.07), neurologic symptoms (AOR=1.77, 95% CI=1.26, 2.48), and other symptoms (AOR=1.53, 95% CI=1.09, 2.14) than non-Hispanic White respondents. Non-Hispanic other respondents who reported at least 1 positive SARS-CoV-2 test had significantly higher ORs of experiencing gastrointestinal symptoms (AOR=4.06, 95% CI=1.78, 8.89) than non-Hispanic White respondents. CONCLUSIONS: These results highlight potential disparities in ongoing symptoms, even after accounting for demographic differences, and reinforce the need for culturally appropriate and targeted strategies to increase access to health care and reduce SARS-CoV-2 infections.

In the United States, asthma and chronic obstructive pulmonary disease (COPD) affect approximately 8% and 6% of people, respectively.1,2 Certain populations are disproportionately affected. For instance, asthma prevalence is higher among people who are non-Hispanic (NH) Black or have lower incomes3; COPD is more prevalent among individuals with less than a high school education.2 | | Early in the COVID-19 pandemic, National Syndromic Surveillance Program data showed reduced overall, asthma-, and COPD-related emergency department (ED) visits in 2020 compared with 2019.1 Less is known about how decreases in asthma- and COPD–related emergency healthcare use (eg, ED visits, hospitalizations) varied across communities by demographics including race, ethnicity, and income.

Although reinfections with SARS-CoV-2 have occurred in the United States with increasing frequency, U.S. epidemiologic trends in reinfections and associated severe outcomes have not been characterized. Weekly counts of SARS-CoV-2 reinfections, total infections, and associated hospitalizations and deaths reported by 18 U.S. jurisdictions during September 5, 2021-December 31, 2022, were analyzed overall, by age group, and by five periods of SARS-CoV-2 variant predominance (Delta and Omicron [BA.1, BA.2, BA.4/BA.5, and BQ.1/BQ.1.1]). Among reported reinfections, weekly trends in the median intervals between infections and frequencies of predominant variants during previous infections were calculated. As a percentage of all infections, reinfections increased substantially from the Delta (2.7%) to the Omicron BQ.1/BQ.1.1 (28.8%) periods; during the same periods, increases in the percentages of reinfections among COVID-19-associated hospitalizations (from 1.9% [Delta] to 17.0% [Omicron BQ.1/BQ.1.1]) and deaths (from 1.2% [Delta] to 12.3% [Omicron BQ.1/BQ.1.1]) were also substantial. Percentages of all COVID-19 cases, hospitalizations, and deaths that were reinfections were consistently higher across variant periods among adults aged 18-49 years compared with those among adults aged ≥50 years. The median interval between infections ranged from 269 to 411 days by week, with a steep decline at the start of the BA.4/BA.5 period, when >50% of reinfections occurred among persons previously infected during the Alpha variant period or later. To prevent severe COVID-19 outcomes, including those following reinfection, CDC recommends staying up to date with COVID-19 vaccination and receiving timely antiviral treatments, when eligible.

Nirmatrelvir-ritonavir (Paxlovid), an oral antiviral treatment, is authorized for adults with mild-to-moderate COVID-19 who are at increased risk for progression to severe illness. However, real-world evidence on the benefit of Paxlovid, according to vaccination status, age group, and underlying health conditions, is limited. To examine the benefit of Paxlovid in adults aged ≥18 years in the United States, a large electronic health record (EHR) data set (Cosmos(†)) was analyzed to assess the association between receiving a prescription for Paxlovid and hospitalization with a COVID-19 diagnosis in the ensuing 30 days. A Cox proportional hazards model was used to estimate this association, adjusted for demographic characteristics, geographic location, vaccination, previous infection, and number of underlying health conditions. Among 699,848 adults aged ≥18 years eligible for Paxlovid during April-August 2022, 28.4% received a Paxlovid prescription within 5 days of COVID-19 diagnosis. Being prescribed Paxlovid was associated with a lower hospitalization rate among the overall study population (adjusted hazard ratio [aHR] = 0.49), among those who had received ≥3 mRNA COVID-19 vaccines (aHR = 0.50), and across age groups (18-49 years: aHR = 0.59; 50-64 years: aHR = 0.40; and ≥65 years: aHR = 0.53). Paxlovid should be prescribed to eligible adults to reduce the risk of COVID-19-associated hospitalization.

Previous infection with SARS-CoV-2, the virus that causes COVID-19, has been estimated to confer up to 90% protection against reinfection, although this protection was lower against the Omicron variant compared with that against other SARS-CoV-2 variants (1-3). A test-negative design was used to estimate effectiveness of COVID-19 mRNA vaccines in preventing subsequent COVID-19-associated hospitalization among adults aged ≥18 years with a previous positive nucleic acid amplification test (NAAT) or diagnosis of COVID-19.(†) The analysis used data from Cosmos, an electronic health record (EHR)-aggregated data set (4), and compared vaccination status of 3,761 case-patients (positive NAAT result associated with hospitalization) with 7,522 matched control-patients (negative NAAT result). After previous SARS-CoV-2 infection, estimated vaccine effectiveness (VE) against COVID-19-associated hospitalization was 47.5% (95% CI = 38.8%-54.9%) after 2 vaccine doses and 57.8% (95% CI = 32.1%-73.8%) after a booster dose during the Delta-predominant period (June 20-December 18, 2021), and 34.6% (95% CI = 25.5%-42.5%) after 2 doses and 67.6% (95% CI = 61.4%-72.8%) after a booster dose during the Omicron-predominant period (December 19, 2021-February 24, 2022). Vaccination provides protection against COVID-19-associated hospitalization among adults with previous SARS-CoV-2 infection, with the highest level of protection conferred by a booster dose. All eligible persons, including those with previous SARS-CoV-2 infection, should stay up to date with vaccination to prevent COVID-19-associated hospitalization.

Isolation is recommended during acute infection with SARS-CoV-2, the virus that causes COVID-19, but the duration of infectiousness varies among individual persons. Rapid antigen test results have been correlated with detection of viable virus (1-3) and might inform isolation guidance, but data are limited for the recently emerged SARS-CoV-2 B.1.1.529 (Omicron) variant. On January 5, 2022, the Yukon-Kuskokwim Health Corporation (YKHC) recommended that persons with SARS-CoV-2 infection isolate for 10 days after symptom onset (or, for asymptomatic persons, 10 days after a positive nucleic acid amplification or antigen test result). However, isolation could end after 5-9 days if symptoms were resolving or absent, fever was absent for 24 hours without fever-reducing medications, and an Abbott BinaxNOW COVID-19 Ag (BinaxNOW) rapid antigen test result was negative. Antigen test results and associated individual characteristics were analyzed among 3,502 infections reported to YKHC during January 1-February 9, 2022. After 5-9 days, 396 of 729 persons evaluated (54.3%) had a positive antigen test result, with a declining percentage positive over time. In a multivariable model, a positive antigen test result was more likely after 5 days compared with 9 days (adjusted odds ratio [aOR]=6.39) or after symptomatic infection (aOR=9.63), and less likely after previous infection (aOR=0.30), receipt of a primary COVID-19 vaccination series (aOR=0.60), or after both previous infection and receipt of a primary COVID-19 vaccination series (aOR=0.17). Antigen tests might be a useful tool to guide recommendations for isolation after SARS-CoV-2 infection. During the 10 days after infection, persons might be infectious to others and are recommended to wear a well-fitting mask when around others, even if ending isolation after 5 days.

BACKGROUND: Introduction of tenofovir (TDF) plus lamivudine (3TC) and dolutegravir (DTG) in first- and second-line HIV treatment regimens in South Africa warrants characterization of acquired HIV-1 drug resistance (ADR) mutations that could impact DTG-based antiretroviral therapy (ART). In this study, we sought to determine prevalence of ADR mutations and their potential impact on susceptibility to drugs used in combination with DTG among HIV-positive adults (≥ 18 years) accessing routine care at a selected ART facility in KwaZulu-Natal, South Africa. METHODS: We enrolled adult participants in a cross-sectional study between May and September 2019. Eligible participants had a most recent documented viral load (VL) ≥ 1000 copies/mL after at least 6 months on ART. We genotyped HIV-1 reverse transcriptase and protease genes by Sanger sequencing and assessed ADR. We characterized the effect of ADR mutations on the predicted susceptibility to drugs used in combination with DTG. RESULTS: From 143 participants enrolled, we obtained sequence data for 115 (80%), and 92.2% (95% CI 85.7-96.4) had ADR. The proportion with ADR was similar for participants on first-line ART (65/70, 92.9%, 95% CI 84.1-97.6) and those on second-line ART (40/44, 90.9%, 95% CI 78.3-97.5), and was present for the single participant on third-line ART. Approximately 89% (62/70) of those on first-line ART had dual class NRTI and NNRTI resistance and only six (13.6%) of those on second-line ART had major PI mutations. Most participants (82%) with first-line viraemia maintained susceptibility to Zidovudine (AZT), and the majority of them had lost susceptibility to TDF (71%) and 3TC (84%). Approximately two in every five TDF-treated individuals had thymidine analogue mutations (TAMs). CONCLUSIONS: Susceptibility to AZT among most participants with first-line viraemia suggests that a new second-line regimen of AZT + 3TC + DTG could be effective. However, atypical occurrence of TAMs in TDF-treated individuals suggests a less effective AZT + 3TC + DTG regimen in a subpopulation of patients. As most patients with first-line viraemia had at least low-level resistance to TDF and 3TC, identifying viraemia before switch to TDF + 3TC + DTG is important to avoid DTG functional monotherapy. These findings highlight a need for close monitoring of outcomes on new standardized treatment regimens.