BACKGROUND: Indoor residual spraying (IRS) is a malaria control strategy implemented before the rainy season. Nchelenge District, Zambia is a holoendemic setting where IRS has been conducted since 2008 with little impact on malaria incidence or parasite prevalence. Pre-rainy season IRS may not reduce the post-rainy season peak abundance of the major vector, Anopheles funestus. METHODS: A controlled, pre-post, prospective cohort study assessed the impact of late-rainy season IRS on malaria prevalence, incidence, hazard, and vector abundance. Three hundred eighty-two individuals were enrolled across four household clusters, of which two were sprayed in April 2022 toward the end of the rainy season. Monthly household and individual surveys and indoor overnight vector collections were conducted through August 2022. Multivariate regression and time-to-event analyses estimated the impact of IRS on outcomes measured by rapid diagnostic tests, microscopy, and quantitative polymerase chain reaction. RESULTS: Seventy two percent of participants tested positive by rapid diagnostic test at least once and incidence by microscopy was 3.4 infections per person-year. Residing in a household in a sprayed area was associated with a 52% reduction in infection hazard (hazards ratio: 0.48, 95% confidence interval [0.29, 0.78]) but not with changes in incidence, prevalence, or vector abundance. The study-wide entomological inoculation rate was 34 infectious bites per person per year. CONCLUSION: Monthly tracking of incidence and prevalence did not demonstrate meaningful changes in holoendemic transmission intensity. However, hazard of infection, which provides greater power for detecting changes in transmission, demonstrated that late rainy season IRS reduced malaria risk.

Multiplex-based serological surveillance is a valuable but underutilized tool to understand gaps in population-level exposure, susceptibility, and immunity to infectious diseases. Assays for which blood samples can be tested for antibodies against several pathogens simultaneously, such as multiplex bead immunoassays, can more efficiently integrate public health surveillance in low- and middle-income countries. On March 7-8, 2023 a group of experts representing research institutions, multilateral organizations, private industry, and country partners met to discuss experiences, identify challenges and solutions, and create a community of practice for integrated, multi-pathogen serosurveillance using multiplex bead assay technologies. Participants were divided into six working groups: 1) supply chain; 2) laboratory assays; 3) seroepidemiology; 4) data analytics; 5) sustainable implementation; and 6) use case scenarios. These working groups discussed experiences, challenges, solutions, and research needs to facilitate integrated, multi-pathogen serosurveillance for public health. Several solutions were proposed to address challenges that cut across working groups.

The elimination of hepatitis C is a national priority (https://www.hhs.gov/sites/default/files/Viral-Hepatitis-National-Strategic-Plan-2021-2025.pdf). During 2010-2021, hepatitis C virus (HCV) acute and chronic infections (hereinafter referred to as HCV infections) increased in the United States, consequences of which include cirrhosis, liver cancer, and death. Rates of acute infections more than tripled among reproductive-aged persons during this time (from 0.8 to 2.5 per 100,000 population among persons aged 20-29 years and from 0.6 to 3.5 among persons aged 30-39 years). Because acute HCV infection can lead to chronic infection, this has resulted in increasing rates of HCV infections during pregnancy. Approximately 6%-7% of perinatally exposed (i.e., exposed during pregnancy or delivery) infants and children will acquire HCV infection. Curative direct-acting antiviral therapy is approved by the Food and Drug Administration for persons aged ≥3 years. However, many perinatally infected children are not tested or linked to care. In 2020, because of continued increases in HCV infections in the United States, CDC released universal screening recommendations for adults, which included recommendations for screening for pregnant persons during each pregnancy (Schillie S, Wester C, Osborne M, Wesolowski L, Ryerson AB. CDC recommendations for hepatitis C screening among adults-United States, 2020. MMWR Recomm Rep 2020;69[No. RR-2]:1-17). This report introduces four new CDC recommendations: 1) HCV testing of all perinatally exposed infants with a nucleic acid test (NAT) for detection of HCV RNA at age 2-6 months; 2) consultation with a health care provider with expertise in pediatric hepatitis C management for all infants and children with detectable HCV RNA; 3) perinatally exposed infants and children with an undetectable HCV RNA result at or after age 2 months do not require further follow-up unless clinically warranted; and 4) a NAT for HCV RNA is recommended for perinatally exposed infants and children aged 7-17 months who previously have not been tested, and a hepatitis C virus antibody (anti-HCV) test followed by a reflex NAT for HCV RNA (when anti-HCV is reactive) is recommended for perinatally exposed children aged ≥18 months who previously have not been tested. Proper identification of perinatally infected children, referral to care, and curative treatment are critical to achieving the goal of hepatitis C elimination.

Internet-recruited gay, bisexual, and other men who have sex with men (MSM) were offered HIV self-tests (HIVSTs) after completing baseline, 3-, 6-, and 9-month follow-up surveys. The surveys asked about the use and distribution of these HIVSTs. Among 995 who reported on their distribution of HIVSTs, 667 (67.0%) distributed HIVSTs to their social network associates (SNAs), which resulted in 34 newly identified HIV infections among 2301 SNAs (1.5%). The main reasons participants reported not distributing HIVSTs included: wanting to use the HIVSTs themselves (74.9%); thinking that their SNAs would get angry or upset if offered HIVSTs (12.5%); or not knowing that they could give the HIVSTs away (11.3%). Self-testing programs can provide multiple HIVSTs and encourage the distribution of HIVST by MSM to their SNAs to increase awareness of HIV status among persons disproportionately affected by HIV.

BACKGROUND: Targeted research on residual malaria transmission is important to improve strategies in settings pursuing elimination, where transmission reductions prove challenging. This study aimed to detect and characterize spatial heterogeneity and factors associated with Plasmodium falciparum infections and exposure, P. falciparum apical membrane antigen 1 (PfAMA1) antibody (Ab) response, in the Central Highlands of Madagascar (CHL). METHODS: From May to July 2014, a cross-sectional school-based survey was carried out in 182 fokontany (villages) within 7 health districts of the CHL. Rapid diagnostic tests (RDTs) and a bead-based immunoassay including PfAMA1 antigen biomarker were used to estimate malaria prevalence and seroprevalence, respectively. Local Moran's I index was used to detect spatial "hotspots". Remotely sensed environmental data-temperature, vegetation indices, land covers, and elevation-were used in multivariable mixed-effects logistic regression models to characterize factors associated with malaria infection and cumulative exposure. RESULTS: Among 6,293 school-children ages 2-14 years surveyed, RDT prevalence was low at 0.8% (95% CI 0.6-1.1%), while PfAMA1 Ab seroprevalence was 7.0% (95% CI 6.4-7.7%). Hotspots of PfAMA1 Ab seroprevalence were observed in two districts (Ankazobe and Mandoto). Seroprevalence increased for children living > 5 km from a health centre (adjusted odds ratio (OR) = 1.6, 95% CI 1.2-2.2), and for those experiencing a fever episode in the previous 2 weeks (OR 1.7, 95% CI 1.2-2.4), but decreased at higher elevation (for each 100-m increase, OR = 0.7, 95% CI 0.6-0.8). A clear age pattern was observed whereby children 9-10 years old had an OR of 1.8 (95% CI 1.2-2.4), children 11-12 years an OR of 3.7 (95% CI 2.8-5.0), and children 13-14 years an OR of 5.7 (95% CI 4.0-8.0) for seropositivity, compared with younger children (2-8 years). CONCLUSION: The use of serology in this study provided a better understanding of malaria hotspots and associated factors, revealing a pattern of higher transmission linked to geographical barriers in health care access. The integration of antibody-assays into existing surveillance activities could improve exposure assessment, and may help to monitor the effectiveness of malaria control efforts and adapt elimination interventions.

BACKGROUND: Currently, FDA-approved HIV-1 viral load (VL) assays use venipuncture-derived plasma. The Hologic Panther system uses 0.7mL total volume for the Aptima HIV-1 Quant Assay standard (APT-Quant-std) and dilution (APT-Quant-dil) protocols. However, smaller plasma volumes from fingerstick whole blood (FSB) collected in EDTA-microtainer tubes (MCT) could provide an easier sample collection method for HIV-1 VL testing. OBJECTIVES: To evaluate the performance of the APT-Quant-std compared to the Roche CAP/CTM and Abbott m2000RT VL assays and an alternative APTQuant 1:7 dilution protocol, the latter using 100muL of MCT-derived plasma from FSB. STUDY DESIGN: Linearity was determined using commercial HIV-1 RNA plasma controls. Dilutions ranging 1.56-2.95 log10 copies/mL were prepared to determine the APT-Quant-dil Limit of Quantitation (LOQ) using Probit analysis. Specificity of APT-Quant-std was calculated using 326 HIVnegative samples. To evaluate agreement, 329 plasma specimens were tested with APT-Quant-std, CAP/CTM, and m2000RT. Forty-seven matched venipuncture and MCT-derived plasma specimens were tested with APT-Quant-std and APT-Quant-dil. RESULTS: Among the RNA controls, specificity was 99.69 % for APT-Quant-std. The R2 values were 0.988 (APT-Quant-std/CAP/CTM), 0.980 (APT-Quant-std/ m2000RT), and 0.997 (APT-Quant-std/APT-Quant-dil). The APT-Quant-dil LOQ was estimated at 2.7 log10 copies/mL (500 copies/mL) (95 %CI 2.62-2.87). At 2.3 log10 copies/mL (200 copies/mL), the overall agreement was 91.0 % for APT-Quant-std/CAP/CTM, 85.7 % for APT-Quant-std/m2000RT, and 82.9 % for APT-Quant-std/APT-Quant-dil. Quantified APT-Quant-std results were on average 0.2 log10 copies/mL higher than CAP/CTM and m2000RT and 0.14 log10 copies/mL higher than APT-Quant-dil. CONCLUSION: APT-Quant showed similar performance compared to the CAP/CTM and m2000RT assays and remains sensitive and accurate using the dilution protocol.

BACKGROUND: Geenius HIV 1/2 Supplemental Assay (Geenius; Bio-Rad Laboratories) is the only Food and Drug Administration-approved HIV-1/HIV-2 antibody differentiation test for the second step in the HIV laboratory testing algorithm. We characterized the occurrence of true HIV-1 and HIV-2 infections as well as false results in 6 US clinical laboratories using Geenius. METHODS: We examined routine HIV testing outcome data from the time the laboratories began using the algorithm with Geenius until September 30, 2017. We calculated the positive predictive value for Geenius HIV-1 and HIV-2 reactivity separately. RESULTS: Of 5,046,684 specimens tested, 41,791 had reactive antigen/antibody test results. Most specimens with reactive antigen/antibody results were HIV-1 antibody-positive established infections (n = 32,421), 1,865 of which also had indeterminate HIV-2 bands present. Ninety-three specimens were HIV-2 antibody positive or untypable for HIV-1/HIV-2 antibody. Acute HIV-1 infections were found in 528 specimens; 881 specimens lacked the nucleic acid test to determine the possibility of acute HIV-1 infection. False-positive antigen/antibody test results were present in 7505 specimens. Few specimens (n = 363) had false-positive antigen/antibody results with indeterminate Geenius and negative HIV-1 nucleic acid test results. The positive predictive values of Geenius reactivity were 99.4% for HIV-1 and 4.3% for HIV-2. CONCLUSIONS: Routine testing using the laboratory testing algorithm with Geenius resulted in most specimens resolving as HIV negative or HIV-1 positive. The occurrence of indeterminate HIV-2 bands with a Geenius final assay interpretation of HIV-1 positive was more common than true HIV-2 infections. Reporting indeterminate HIV-2 results in this situation may cause confusion with interpreting HIV infection status.

Hepatitis C virus (HCV) infection is a major source of morbidity and mortality in the United States. HCV is transmitted primarily through parenteral exposures to infectious blood or body fluids that contain blood, most commonly through injection drug use. No vaccine against hepatitis C exists and no effective pre- or postexposure prophylaxis is available. More than half of persons who become infected with HCV will develop chronic infection. Direct-acting antiviral treatment can result in a virologic cure in most persons with 8-12 weeks of all-oral medication regimens. This report augments (i.e., updates and summarizes) previously published recommendations from CDC regarding testing for HCV infection in the United States (Smith BD, Morgan RL, Beckett GA, et al. Recommendations for the identification of chronic hepatitis C virus infection among persons born during 1945-1965. MMWR Recomm Rec 2012;61[No. RR-4]). CDC is augmenting previous guidance with two new recommendations: 1) hepatitis C screening at least once in a lifetime for all adults aged >/=18 years, except in settings where the prevalence of HCV infection is <0.1% and 2) hepatitis C screening for all pregnant women during each pregnancy, except in settings where the prevalence of HCV infection is <0.1%. The recommendation for HCV testing that remains unchanged is regardless of age or setting prevalence, all persons with risk factors should be tested for hepatitis C, with periodic testing while risk factors persist. Any person who requests hepatitis C testing should receive it, regardless of disclosure of risk, because many persons might be reluctant to disclose stigmatizing risks.

BACKGROUND: HIV testing guidelines provided by the Centers for Disease Control and Prevention (CDC) are continually changing to reflect advancements in new testing technology. Evaluation of existing and new point-of-care (POC) HIV tests is crucial to inform testing guidelines and provide information to clinicians and other HIV test providers. Characterizing the performance of POC HIV tests using unprocessed specimens can provide estimates for the window period of detection, or the time from HIV acquisition to test positivity, which allows clinicians and other HIV providers to select the appropriate POC HIV tests for persons who may be recently infected with HIV. OBJECTIVE: This paper describes the protocols and procedures used to evaluate the performance of the newest POC tests and determine their sensitivity during early HIV infection. METHODS: Project DETECT is a CDC-funded study that is evaluating POC HIV test performance. Part 1 is a cross-sectional, retrospective study comparing behavioral characteristics and HIV prevalence of the overall population of the Public Health-Seattle & King County (PHSKC) Sexually Transmitted Disease (STD) Clinic to Project DETECT participants enrolled in part 2. Part 2 is a cross-sectional, prospective study evaluating POC HIV tests in real time using unprocessed whole blood and oral fluid specimens. A POC nucleic acid test (NAT) was added to the panel of HIV tests in June 2018. Part 3 is a longitudinal, prospective study evaluating seroconversion sensitivity of POC HIV tests through serial follow-up testing. For comparison, HIV-1 RNA and HIV-1/HIV-2 antigen/antibody tests are also performed for participants enrolled in part 2 or 3. A behavioral survey that collects information about demographics, history of HIV testing, STD history, symptoms of acute HIV infection, substance use, sexual behaviors in the aggregate and with recent partners, and use of pre-exposure prophylaxis and antiretroviral therapy is completed at each part 2 or 3 visit. RESULTS: Between September 2015 and March 2019, there were 14,990 Project DETECT-eligible visits (part 1) to the PHSKC STD Clinic resulting in 1819 part 2 Project DETECT study visits. The longitudinal study within Project DETECT (part 3) enrolled 27 participants with discordant POC test results from their part 2 visit, and 10 (37%) were followed until they had fully seroconverted with concordant positive POC test results. Behavioral survey data and HIV test results, sensitivity, and specificity will be presented elsewhere. CONCLUSIONS: Studies such as Project DETECT are critical for evaluating POC HIV test devices as well as describing characteristics of persons at risk for HIV acquisition in the United States. HIV tests in development, including POC NATs, will provide new opportunities for HIV testing programs. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): RR1-10.2196/16332.

BACKGROUND: The performance of recently approved point-of-care (POC) HIV tests should be assessed using unprocessed specimens. OBJECTIVE: To evaluate the sensitivity and specificity of four POC HIV tests using whole blood (WB) and two using oral fluid (OF) among persons recruited from health clinics in Seattle, Washington, during September 2015-September 2017. STUDY DESIGN: Participants were tested with the POC tests, additional plasma and serum were collected for laboratory testing, and participant- reported use of antiretroviral therapy (ART) or pre-exposure prophylaxis (PrEP) was recorded. Participants testing negative on all tests could reenroll every 90 days. Specimens from persons previously diagnosed with HIV infection as well as from those who were newly diagnosed during the study were included in the sensitivity estimate. Sensitivity and specificity were calculated based on HIV status determined by laboratory testing. RESULTS: Of 1,256 visits, 179 were from persons with HIV infection; 120 of these were taking ART. Among 1,077 visits from participants not diagnosed with HIV, PrEP use was reported at 155 (14.4%) visits. Sensitivity was similar among POC WB tests (95.53%-97.21%; p>0.05). Among participants on ART, sensitivity was lower for the same test performed on OF compared to WB (p<0.003). Specificity was high for all tests (99.44%- 100.00%); we did not detect specificity differences with PrEP use. CONCLUSIONS: These POC tests displayed relatively high sensitivity and specificity using unprocessed specimens, suggesting their effectiveness in identifying HIV infections whenever laboratory-based testing is not feasible. Nonetheless, clients with recent risk should retest to rule out the possibility of a false-negative result.

BACKGROUND: There is benefit to early HIV-1 diagnosis and treatment, but there is no FDA-approved quantitative assay with a diagnostic claim. We compared the performance of the Hologic Aptima HIV-1 Quant (APT-Quant) and Aptima HIV-1 Qual (APT-Qual) assays for diagnostic use and the performance of a diagnostic algorithm consisting of Bio-Rad BioPlex 2200 HIV Ag-Ab assay (BPC) followed by APT-Quant (two-test) compare to BPC followed by Geenius HIV-1/2 supplemental assay (Geenius) with reflex to APT-Qual (three-test). METHODS: 524 plasma, which included 419 longitudinal specimens from HIV-1 seroconverters (78 were after initiating antiretroviral therapy (ART)) and 105 from ART-naive persons with established HIV-1 infections, were used to evaluate APT-Quant performance for diagnostic use. Specimens from 200 HIV-negative persons were used to measure specificity. For the algorithm comparison, BPC-reactive specimens were evaluated with the two-test or three-test algorithm. McNemar's test was used to compare performance. RESULTS: APT-Quant detected more samples early in infection compared with APT-Qual. APT-Quant specificity was 99.8%. Before ART initiation, the algorithms performed similarly among samples from different stages of infection. After ART initiation, the three-test algorithm performed significantly better (p=0.0233). CONCLUSIONS: APT-Quant has excellent performance for diagnostic use. The two-test algorithm works well in ART-naive samples, but its performance decreases after the IgG response is elicited and with ART-induced suppressed viremia. Providing confirmation and VL with one test result could be advantageous for patient care. However, additional factors and challenges associated with the implementation of this two-test algorithm such as cost, specimen type and collection need further evaluation.

Since 2014, the recommended laboratory testing algorithm for diagnosing human immunodeficiency virus (HIV) infection has included a supplemental HIV-1/HIV-2 differentiation test to confirm infection type on the basis of the presence of type-specific antibodies (1). Correctly identifying HIV-1 and HIV-2 infections is vital because their epidemiology and clinical management differ. To describe the percentage of diagnoses for which an HIV-1/HIV-2 differentiation test result was reported and to categorize HIV type based on laboratory test results, 2010-2017 data from CDC's National HIV Surveillance System (NHSS) were analyzed. During 2010-2017, a substantial increase in the number of HIV-1/HIV-2 differentiation test results were reported to NHSS, consistent with implementation of the HIV laboratory-based testing algorithm recommended in 2014. However, >99.9% of all HIV infections identified in the United States were categorized as HIV-1, and the number of HIV-2 diagnoses (mono-infection or dual-infection) remained extremely low (<0.03% of all HIV infections). In addition, the overall number of false positive HIV-2 test results produced by the HIV-1/HIV-2 differentiation increased. The diagnostic value of a confirmatory antibody differentiation test in a setting with sensitive and specific screening tests and few HIV-2 infections might be limited. Evaluation and consideration of other HIV tests approved by the Food and Drug Administration (FDA) that might increase efficiencies in the CDC and Association of Public Health Laboratories-recommended HIV testing algorithm are warranted.

BACKGROUND: In 2016, HIV-2 nucleic acid testing (NAT) was added to a shared service program that conducts HIV-1 NAT for public health laboratories performing the recommended algorithm for diagnosing HIV. Here we evaluate the usefulness of HIV-2 NAT in this program as compared to HIV-1 NAT. METHODS: Specimens eligible for HIV-1 NAT were reactive on an HIV-1/2 antibody or antigen/antibody initial test and non-reactive or indeterminate on a supplemental antibody test or were reactive for HIV-1 antigen-only on an HIV-1/2 antigen/antibody initial test. Specimens eligible for HIV-2 NAT were reactive on an initial test, HIV-2 indeterminate or HIV indeterminate on a supplemental antibody test and had no detectable HIV-1 RNA or were reactive for HIV-2 antibody on an HIV-1/2 antigen/antibody test and this reactivity was not confirmed with a supplemental antibody assay. All specimens were tested in a reference laboratory using APTIMA HIV-1 qualitative RNA and/or a validated qualitative HIV-2 RNA real-time PCR assay. RESULTS: During 2016-2019, HIV-1 RNA was detected in 234/1731 (14%) specimens tested. HIV-2 RNA was not detected in 52 specimens tested. Median time from specimen collection to reporting of HIV-1 and HIV-2 NAT results by year ranged from 9-10 days and 22-27 days, respectively. Two specimens with HIV-2 indeterminate results on a supplemental antibody test had detectable HIV-1 RNA. CONCLUSIONS: A shared service model for HIV-1 NAT is both feasible and beneficial for public health laboratories. However, because no HIV-2 infections were detected, our data suggest that this program should reconsider the usefulness of HIV-2 NAT testing.

BACKGROUND: Cepheid's Xpert HIV-1 Viral Load (Xpert VL), a simplified, automated, single-use quantitative assay used with the GeneXpert System, is not FDA approved. OBJECTIVES: Using stored plasma, we conducted a study to assess the ability of Xpert VL to quantify viral load relative to the Roche COBAS AmpliPrep/COBAS TaqMan HIV-1 (Cobas VL) and to examine the use of the Xpert VL as a qualitative diagnostic test. STUDY DESIGN: Following HIV-1 viral stock dilutions, we conducted a probit analysis to identify the concentration where 95 % of specimens had quantified VLs. We also examined Xpert and Cobas log VL correlation in linearity panels; compared the proportion of 220 seroconverter specimens with virus detected using McNemar's test; and tested specimens from persons with untreated, established HIV-1 infection (n=149) and uninfected persons (n=497). Furthermore, we examined Xpert VL as a qualitative test in seroconverter specimens with early (n=20) and later (n=68) acute infections. RESULTS: At 1.80 log10 copies/mL, 95 % of specimens had quantifiable virus using Xpert VL. Xpert and Cobas VLs were highly correlated (R(2)=0.994). The proportion of seroconverter specimens with virus detected using Cobas and with Xpert VL was not statistically different (p=0.0578). Xpert VL detected 97.9 % of established infections, and specificity was 99.80 % (95 % CI 98.87%-99.99%). Xpert VL detected 90 % and 98.5 % of early and later acute infections, respectively. CONCLUSIONS: If approved, Xpert VL could allow U.S. laboratories that cannot bring on large, complex testing platforms to conduct HIV monitoring. An approval for diagnostic use may provide timely identification of HIV infections.

BACKGROUND: Since 2014, the recommended algorithm for laboratory diagnosis of HIV infection in the United States has consisted of an HIV-1/2 antigen/antibody (Ag/Ab) test followed by an HIV-1/2 antibody (Ab) differentiation test and, if necessary, a diagnostic HIV-1 nucleic acid test (NAT) to resolve discordant or indeterminate results. METHODS: Using stored specimens from persons seeking HIV testing who had not received a previous diagnosis or treatment, we compared the performance of a three-step alternative algorithm consisting of an Ag/Ab test followed by a quantitative HIV-1 RNA viral load assay and, if viral load is not detected, an Ab differentiation test, to that of the recommended algorithm. We calculated the sensitivity and specificity of five Ag/Ab tests and the proportion of specimens correctly classified by the alternative algorithm compared to the recommended algorithm. Results were examined separately for specimens classified as early infection, established infection, and false-reactive screening RESULTS: Sensitivity and specificity were similar among all Ag/Ab tests. Viral load quantification correctly classified all specimens from early infection, all false-reactive screening specimens, and the majority of specimens from established infection. CONCLUSIONS: Although cost, regulatory barriers, test availability, and the ability to differentiate early from established infection must be considered, this alternative algorithm can potentially decrease the total number of tests performed and reduce turnaround time, thereby streamlining HIV diagnosis and initiation of treatment.

Since 2005, the HIV Diagnostics Conference has served as a central platform for fostering collaborations and partnerships among attendees who are involved in all aspects of HIV testing. The conference provides an open forum where attendees present and exchange ideas, review data on newer test technologies and algorithms, preview innovative testing methodologies and technologies, and present best practices related to testing, including how it relates to linkage to care, treatment, and prevention services. This approach has proven to be effective to encourage the advancement of HIV testing technology and strategies used in the US.

Due to worldwide increased human mobility, air-transportation data and mathematical models have been widely used to measure risks of global dispersal of pathogens. However, the seasonal and interannual risks of pathogens importation and onward transmission from endemic countries have rarely been quantified and validated. We constructed a modelling framework, integrating air travel, epidemiological, demographical, entomological and meteorological data, to measure the seasonal probability of dengue introduction from endemic countries. This framework has been applied retrospectively to elucidate spatiotemporal patterns and increasing seasonal risk of dengue importation from South-East Asia into China via air travel in multiple populations, Chinese travelers and local residents, over a decade of 2005-15. We found that the volume of airline travelers from South-East Asia into China has quadrupled from 2005 to 2015 with Chinese travelers increased rapidly. Following the growth of air traffic, the probability of dengue importation from South-East Asia into China has increased dramatically from 2005 to 2015. This study also revealed seasonal asymmetries of transmission routes: Sri Lanka and Maldives have emerged as origins; neglected cities at central and coastal China have been increasingly vulnerable to dengue importation and onward transmission. Compared to the monthly occurrence of dengue reported in China, our model performed robustly for importation and onward transmission risk estimates. The approach and evidence could facilitate to understand and mitigate the changing seasonal threat of arbovirus from endemic regions.

HIV-positive men who have sex with men (MSM) were recruited on www.Facebook.com and www.Poz.com to give HIV self-tests to their contacts. Study participants completed a baseline survey, were given two self-tests, and completed a survey 2 months later. Of 133 eligible men, 40 (30%) completed both surveys. Most participants were 30-54 years old and non-Hispanic white. Some had a detectable viral load (n = 4), had condomless anal sex with male partners of negative or unknown status (n = 17), and had met anal sex partners at gay dating websites (n = 23). Of 80 self-tests given to participants, 59 (74%) were distributed, primarily to non-Hispanic white MSM, 30-54 years old who were friends. Participants reported results from 31 distributed tests; 2 sex partners of participants had positive results. Participants indicated these two persons were unaware of their infections. Expanding recruitment websites might reach non-white MSM. Unrecognized infections were identified through online recruitment and self-test distribution via HIV-positive persons.

The Centers for Disease Control and Prevention recommends annual HIV tests for men who have sex with men (MSM), yet some have never tested. We analyzed data from the MSM Testing Initiative. Of 68,185 HIV tests, 8% were with MSM who never previously tested ("first-time testers"). Among tests with first-time testers, 70.7% were with MSM from racial or ethnic minorities; 66.5% were with MSM younger than 30 years. Tests with MSM who reported female partners only during the past year (compared to male partners only) or were recruited for at-home testing (compared to venue-based recruitment) were 4 times (prevalence ratio [PR] 3.62, 95% CI 3.15-4.15) and 5 times as likely (PR 4.69, 95% CI 4.22-5.21) to be associated with first-time testing. At-home testing and focusing on MSM who have sex with women may be effective methods for reaching MSM who are first-time testers.

BACKGROUND: The capacity of HIV Antigen/Antibody (Ag/Ab) immunoassays (IA) to detect HIV-1 p24 antigen has resulted in improved detection of HIV-1 infections in comparison to Ab-only screening assays. Since its introduction in the US, studies have shown that the Determine HIV-1/2 Ag/Ab Combo assay (Determine Ag/Ab) detects HIV infection earlier than laboratory-based IgM/IgG-sensitive IAs, but its sensitivity for HIV-1 p24 Ag detection is reduced compared to laboratory-based Ag/Ab assays. However, further evaluation is needed to assess its capacity to detect acute HIV-1 infection. OBJECTIVE: To assess the performance of Determine Ag/Ab in serum from acute HIV-1 infections. STUDY DESIGN: Select serum specimens that screened reactive on a laboratory-based Ag/Ab IA or IgM/IgG Ab-only IA, with a negative or indeterminate supplemental antibody test and detectable HIV-1 RNA were retrospectively tested with Determine Ag/Ab. Results were compared with those of the primary screening immunoassay to evaluate concordance within this set of algorithm-defined acute infections. RESULTS: Of 159 algorithm-defined acute HIV-1 specimens, Determine Ag/Ab was reactive for 105 resulting in 66.0% concordance. Of 125 that were initially detected by a laboratory-based Ag/Ab IA, 81 (64.8%) were reactive by Determine Ag/Ab. A total of 34 acute specimens were initially detected by a laboratory-based IgM/IgG Ab-only IA and 24 (70.6%) of those were reactive by Determine Ag/Ab. CONCLUSIONS: Due to their enhanced sensitivity, laboratory-based Ag/Ab IAs continue to be preferred over the Determine Ag/Ab as the screening method used by laboratories conducting HIV diagnostic testing on serum and plasma specimens.

HIV testing is a key component of HIV prevention. It is this critical clinical encounter that serves as the starting point for diagnosing and treating persons who are infected and delivering preventive services to those who are uninfected. Because HIV testing is so important to prevention strategies for controlling the HIV epidemic in the United States, we read with great interest the article by Hurt and colleagues1 in this issue, which provides an excellent overview of the current options available for HIV testing in clinical, nonclinical, and research settings. Their update highlights recent changes to nomenclature, updated data—particularly on the window period of HIV tests—and updates to the laboratory algorithm for diagnosis of HIV infection, at a time when this information is changing rapidly. | Hurt et al. refer to changes in the “official nomenclature” of HIV tests. Although the Centers for Disease Control and Prevention (CDC) does not determine official nomenclature for HIV test types, the CDC Division of HIV/AIDS Prevention has recently made changes to Web sites and other documents that refer to the different types of HIV tests. As discussed at the 2016 HIV Diagnostics Conference,2,3 the term “generations” began to appear in the literature shortly after HIV tests that used recombinant peptides instead of viral lysate antigens (the “2nd generation”) were developed.4–6 However, the “official” nomenclature likely gained traction when Owen et al.7 published an article including a discussion of generations, and CDC and others largely adopted the term for use in presentations, Web pages, and other documents. Indeed, a complete description of test generations appears in both the updated Clinical & Laboratory Standards Institute standards8 and the CDC/Association of Public Health Laboratories (APHL) guidelines for the laboratory diagnosis of HIV infection.9 However, as new HIV tests continued to become available, the lines between generations began to blur. In the 2008 article,7 the term generation was reserved for laboratory-based, instrumented immunoassays. As Hurt et al. reviewed, single-use, point-of-care rapid tests use different technology and probably should be considered separately. Nevertheless, both test manufacturers and authors evaluating these tests began to use the term generations to describe rapid tests. Originally, the generations described incremental improvements in test sensitivity and specificity. However, some of the newer tests within the same generation have different sensitivity for early infection.10 These differences can largely be explained by other aspects of test design, for example, whether they are lateral flow or immunconcentrating rapid tests, reagents used for detection of analytes, or the volume of sample required to perform the test.1 In addition, there are also IgG-sensitive rapid tests that differentiate HIV-1 from HIV-2, and new tests that differentiate p24-antigen detection from antibody detection, but have the same sensitivity during early infection as tests that report only one signal as “reactive for p24-antigen and/or HIV antibody.”1,3,10 As a result, in the article documenting seroconversion sensitivity on plasma specimens that Hurt et al. referenced,10 tests were described in terms of the analytes they can detect and the types of technology (instrumented, laboratory-based, vs. single-use, rapid) that they use to do so. These changes have been implemented in CDC Web pages and documents contained therein.11 In particular, the advantages/disadvantages of Food and Drug Administration–approved HIV tests guide12 may be particularly useful for clinicians and others who need to understand differences in characteristics of the tests available in the United States.

Identifying patients at-risk for HIV infection, such as men who have sex with men (MSM), is an important step in providing HIV testing and prevention interventions. It is unknown how primary care providers (PCPs) assess MSM status and related HIV-risk factors. We analyzed data from a panel-derived web-based survey for healthcare providers conducted in 2014 to describe how PCPs in the U.S. determined their patients' MSM status. We calculated adjusted prevalence ratios (aPR) and 95% confidence intervals (CI) to describe PCP characteristics associated with systematically determining MSM status (i.e., PCP used "a patient-completed questionnaire" or "routine verbal review of sex history"). Among the 1008 PCPs, 56% determined MSM status by routine verbal review of sexual history; 41% by patient disclosure; 39% by questions driven by symptoms/history; 23% by using a patient-completed questionnaire, and 9% didn't determine MSM status. PCPs who systematically determined MSM status (n=665; 66%) were more likely to be female (aPR=1.16, CI=1.06-1.26), to be affiliated with a teaching hospital (aPR=1.15, CI=1.06-1.25), to routinely screen all patients aged 13-64 for HIV (aPR=1.29, CI=1.18-1.41), and to estimate that 6% or more of their male patients are MSM (aPR=1.14, CI=1.01-1.30). The majority of PCPs assessed MSM status and HIV risk factors through routine verbal reviews of sexual history. Implementing a systematic approach to identify MSM status and assess risk may allow PCPs to identify more patients needing frequent HIV testing and other preventive services, while mitigating socio-cultural barriers to obtaining such information.

In the United States, an estimated 67% of new HIV diagnoses are among men who have sex with men (MSM), however 25% of HIV-positive MSM in the 2014 National HIV Behavioral Surveillance Survey were unaware of their infection. HIV self-testing (HIVST) with rapid diagnostic tests (RDTs) may facilitate access to HIV testing. We evaluated the ability of 22 MSM to conduct two HIV RDTs (OraQuick (R) In-Home HIV Test and a home-use prototype of Sure Check (R) HIV 1/2 Assay), interpret sample images of test results, and collect a dried blood spot (DBS) specimen. While some participants did not follow every direction, most participants were able to conduct HIVST and correctly interpret their results. Interpretation of panels of RDT images was especially difficult when the "control" line was missing, and 27% of DBS cards produced were rated as of bad quality. Modifications to the DBS instructions were necessary prior to evaluating the performance of these tests in real-world settings.

OBJECTIVE: FDA-approved antigen/antibody combo and HIV-1/2 differentiation supplemental tests do not have claims for dried blood spot (DBS) use. We compared two DBS-modified protocols, the Bio-Rad GS HIV Combo Ag/Ab (BRC) EIA and Geenius HIV-1/2 (Geenius) Supplemental Assay, to plasma protocols and evaluated them in the CDC/APHL HIV diagnostic algorithm. METHODS: BRC-DBS p24 analytical sensitivity was calculated from serial dilutions of p24. DBS specimens included 11 HIV-1 seroconverters, 151 HIV-1-positive individuals, including 20 on antiretroviral therapy, 31 HIV-2-positive and one HIV-1/HIV-2-positive individuals. BRC-reactive specimens were tested with Geenius using the same DBS eluate. Matched plasma specimens were tested with BRC, an IgG/IgM immunoassay and Geenius. DBS and plasma results were compared using the McNemar's test. A DBS-algorithm applied to 348 DBS from high-risk individuals who participated in surveillance was compared to HIV status based on local testing algorithms. RESULTS: BRC-DBS detects p24 at a concentration 18 times higher than in plasma. In seroconverters, BRC-DBS detected more infections than the IgG/IgM immunoassay in plasma (p=0.0133), but fewer infections than BRC-plasma (p=0.0133). In addition, the BRC/Geenius-plasma algorithm identified more HIV-1 infections than the BRC/Geenius-DBS algorithm (p=0.0455). The DBS protocols correctly identified HIV status for established HIV-1 infections, including those on therapy, HIV-2 infections, and surveillance specimens. CONCLUSIONS: The DBS protocols exhibited promising performance and allowed rapid supplemental testing. Although the DBS algorithm missed some early infections, it showed similar results when applied to specimens from a high-risk population. Implementation of a DBS algorithm would benefit testing programs without capacity for venipuncture.

BACKGROUND: The flow-through INSTI HIV-1/HIV-2 Rapid Antibody (INSTI) test is a 60s FDA-approved test for HIV-1 and HIV-2 antibody testing using whole blood and plasma. OBJECTIVE: We evaluated the performance of INSTI using plasma and simulated whole blood specimens. STUDY DESIGN: INSTI's performance in plasma specimens from commercial seroconversion panels was assessed by estimating the relative sensitivity using a 50% cumulative frequency analysis and by comparing its performance with other FDA-approved rapid tests (RTs). INSTI was further evaluated using 320 HIV-1 plasma specimens collected during a cross-sectional study and with 107 HIV-1 and 24 HIV-2 simulated whole blood specimens. Sensitivity and specificity were calculated using 615 known HIV-1 group M/O and 80 HIV-2 (Western blot (WB)-positive), and 497 HIV-negative plasma specimens, respectively. RESULTS: In HIV-1 seroconversion panels, INSTI became reactive 9days before a positive WB. When compared to FDA-approved antibody-based lateral flow RTs, INSTI detected significantly more early infections. Among HIV-1-infected cross-sectional plasma samples, INSTI detected 23 (27%) of 85 Architect-positive/Multispot-negative or indeterminate specimens. For plasma specimens, the sensitivity was 99.84% for HIV-1 and 100% for HIV-2, and the specificity was 99.80%. Using simulated whole blood from seroconverters, INSTI performed similarly to plasma. CONCLUSIONS: INSTI performed significantly better than antibody-based lateral flow RTs during early stages of seroconversion. Sensitivity and specificity were within the manufacturer's reported ranges. Considering the observed test performance and the almost immediate results, INSTI is an accurate option to detect HIV-1/HIV-2 antibodies in point-of-care settings where lab testing is not feasible.

The 2016 HIV Diagnostics Conference, held in Atlanta, Georgia, was attended by public health officials, laboratorians, HIV testing program managers, surveillance coordinators and industry representatives. The conference addressed test performance data, the implementation of new testing algorithms, quality assurance, and the application of new tests in a variety of settings. With regard to the recommended Centers for Disease Control and Prevention/Association of Public Health Laboratories HIV laboratory testing algorithm, the conference featured performance data, implementation challenges such as a lack of test options for the second and third steps, as well as data needs for new tests that may be used as part of the algorithm. There are delays when nucleic acid testing is needed with the algorithm. Novel tests such as point of care nucleic acid tests are needed on the U.S. market to readily identify acute infection. Multiplex tests are being developed which allow for the simultaneous detection of multiple pathogens. CDC staff highlighted new guidance for testing in non-clinical settings. Innovative approaches to linking testing and care in some settings have led to identification of early infections, improved receipt of test results and expedited initiation of therapy. Work continues to optimize testing so that infections are accurately identified as early as possible and time to treatment is minimized to improve health outcomes and prevent transmission.

BACKGROUND: Understanding the period of time between an exposure resulting in infection with HIV and when a test can reliably detect the presence of that infection, i.e. the test window period, may benefit testing programs and clinicians in counseling patients about when the clinician and the patient can be confident a suspected exposure did not result in HIV infection. METHODS: We evaluated the intervals between reactivity of the Aptima HIV-1 RNA nucleic acid test (Aptima) and 20 FDA-approved HIV immunoassays using 222 longitudinally collected plasma specimens from HIV-1 seroconverters from the United States. A multi-model framework based upon two general approaches, interval-censored survival and binomial regression, was implemented to estimate the relative emergence of test reactivity, referred to in this report as an inter-test reactivity interval (ITRI). We then combined ITRI results with simulated data for the eclipse period, the time between exposure and detection of HIV virus by Aptima, to develop estimates of the window period for each test. RESULTS: The estimated ITRIs were shorter with each new class of HIV tests, ranging from 5.9 to 24.8 days. The 99th percentiles of the window period probability distribution ranged from 44 days for laboratory screening tests that detect both antigen and antibody to 65 days for the Western blot test. CONCLUSIONS: Our directly comparable estimates of the emergence of reactivity for 20 immunoassays are valuable to testing providers for interpreting negative HIV test results obtained shortly after exposure, and for counseling individuals on when to retest after an exposure.

OBJECTIVE: In three U.S. State Public Health Laboratories (PHLs) using a fourth-generation immunoassay (IA), an HIV-1/HIV-2 differentiation antibody IA and a nucleic acid test (NAT), we characterized the yield and time to reporting of acute infections, and cost per positive specimen. METHODS: Routine HIV testing data were collected from July 1, 2012-June 30, 2013 for Massachusetts and Maryland PHLs, and from November 27, 2012-June 30, 2013 for Michigan PHL. Massachusetts and Michigan used fourth-generation and differentiation IAs with NAT conducted by a referral laboratory. In Maryland, fourth-generation IA repeatedly reactive specimens were followed by a Western blot (WB), and those with negative or indeterminate results were tested with a differentiation IA and HIV-1 NAT, and if positive by NAT, confirmed by a different HIV-1 NAT. Specimens from WB-positive persons at risk for HIV-2 were tested with a differentiation IA and, if positive, with an HIV-2 WB and/or differential HIV-1/HIV-2 proviral DNA polymerase chain reaction. RESULTS: Among 7914 specimens from Massachusetts PHL, 6069 from Michigan PHL, and 36,266 from Maryland PHL, 0.10%, 0.02% and 0.05% acute infections were identified, respectively. Massachusetts and Maryland PHLs each had 1 HIV-2 positive specimen. The median time from specimen receipt to laboratory reporting of results for acute infections at Massachusetts, Michigan and Maryland PHLs was 8, 11, and 7 days respectively. The laboratory cost per HIV positive specimen was $336 (Massachusetts), $263 (Michigan) and $210 (Maryland). CONCLUSIONS: Acute and established infections were found by PHLs using fourth-generation IA in conjunction with antibody tests and NAT. Time to reporting of acute HIV test results to clients was suboptimal, and needs to be streamlined to expedite treatment and interrupt transmission.

Novel data streams (NDS), such as web search data or social media updates, hold promise for enhancing the capabilities of public health surveillance. In this paper, we outline a conceptual framework for integrating NDS into current public health surveillance. Our approach focuses on two key questions: What are the opportunities for using NDS and what are the minimal tests of validity and utility that must be applied when using NDS? Identifying these opportunities will necessitate the involvement of public health authorities and an appreciation of the diversity of objectives and scales across agencies at different levels (local, state, national, international). We present the case that clearly articulating surveillance objectives and systematically evaluating NDS and comparing the performance of NDS to existing surveillance data and alternative NDS data is critical and has not sufficiently been addressed in many applications of NDS currently in the literature.

BACKGROUND: To improve clinical and public health outcomes through early human immunodeficiency virus (HIV) detection, fourth-generation antigen/antibody immunoassay (4IA) and supplemental testing results must be returned rapidly. METHODS: We examined HIV testing data at Harborview Medical Center (HMC), Massachusetts General Hospital (MGH), and the Medical University of South Carolina (MUSC), which used 4IA and supplemental antibody and nucleic acid tests (NATs). At MGH and MUSC, HIV-1 Western blot (WB) and HIV-2 testing were conducted at a reference laboratory. We compared time from specimen collection to laboratory result for established (positive WB) and acute infections (reactive 4IA, negative/indeterminate WB, detectable NAT), and we calculated testing cost per positive-test result. RESULTS: From 3731 (MUSC) to 19 774 (MGH) tests were conducted; 0.01% (MGH) to 0.05% (HMC) were acute infections. Each laboratory had reactive 4IA, WB-negative, or indeterminate specimens without NAT (ie, potential acute infections). Time to result was 1.5 (HMC) to 5.2 days (MGH) for acute and 1.0 (HMC) to 5.2 days (MGH) for established infections. Costs were $1054 (MGH) to $1521 (MUSC). CONCLUSIONS: Conducting supplemental testing in-house lowered turnaround times, which may be further reduced with rapid HIV-1/HIV-2 differentiation tests. Hospitals may benefit from quantitative NATs not requiring physician orders, so all potential acute infections receive NAT.