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On October 5, 2020, this report was posted as an MMWR Early Release on the MMWR website (https://www.cdc.gov/mmwr). There is increasing evidence that children and adolescents can efficiently transmit SARS-CoV-2, the virus that causes coronavirus disease 2019 (COVID-19) (1-3). During July-August 2020, four state health departments and CDC investigated a COVID-19 outbreak that occurred during a 3-week family gathering of five households in which an adolescent aged 13 years was the index and suspected primary patient; 11 subsequent cases occurred. Both heads of each household were interviewed to assess demographic characteristics, exposures, symptoms, close contacts, and outcomes. Parents provided data for all children, adolescents, and young adults. Thirteen of the index patient's relatives sought viral testing; test results were reported by respondents, and all test results that were reported to be positive were verified in state reporting systems. For three children and adolescents who were not tested while symptomatic, a chemiluminescent immunoassay* detecting total antibody to SARS-CoV-2 was performed 28-46 days after symptom onset; results were positive for all three children and adolescents, including the index patient and her two brothers, indicating earlier infection. Likely exposure periods † and infectious periods § were estimated from symptom onset dates. This activity was reviewed by CDC and was conducted consistent with applicable federal law and CDC policy. ¶ While away from home, the index patient was exposed during a large COVID-19 outbreak in June 2020. Because of her exposure, she sought testing for SARS-CoV-2 after returning home. A rapid antigen test performed 4 days after exposure, when she was asymptomatic, was negative (Table) (Figure). She experienced nasal congestion 2 days later, her only symptom. That same day, she, her parents, and two brothers traveled to * https://www.fda.gov/media/136967/download. † The likely exposure period was estimated to begin 14 days before symptom onset and end 2 days before symptom onset, which corresponds to the longest potential incubation period. https://www.cdc.gov/coronavirus/2019-ncov/hcp/ clinical-guidance-management-patients.html. § The infectious period was estimated to begin 2 days before symptom onset and end 10 days after symptom onset, according to CDC guidance. https://www. cdc.gov/coronavirus/2019-ncov/php/contact-tracing/contact-tracing-plan/ investigating-covid-19-case.html.

BackgroundCost still limits HIV-1 viral load (VL) routine monitoring in resource limited settings (RLS), preventing early detection of virologic failure (VF). Pooled VL testing reduces cost over individual testing (IND). We previously showed in simulation, that additional cost benefits over previously-used pooling deconvolution algorithms can be achieved by using low-cost, routinely-collected clinical markers to determine the order for VL testing in deconvolution (termed marker-assisted minipool plus algorithm; mMPA). This algorithm has not been assessed in-vitro.Methods150 samples from 99 Ghanaian adults with HIV on first-line therapy (VF 17%; CD4-VL correlation −0.35) were used to construct 30, 5-sample pools: n = 10 with 0, n = 5 with 1, and n = 15 with 2 individuals with VF. VL testing was with Abbott M2000. Accuracy, number of tests and rounds of testing to deconvolute pools were estimated using four strategies: (1) IND; (2) Minipooling (MP); (3) Minipooling with algorithm (MPA); and (4) mMPA.ResultsCompared with IND, MP and MPA, mMPA reduced total number of tests per pool needed to ascertain VF: MP average 4.3 (95% confidence interval (CI) 3.5–5.2, p> 0.05), MPA 3.0 (95% CI 2.4–3.5, P < 0.001), and mMPA 2.5 (CI 2.0–3.0, P < 0.001). Compared with MP and MPA, mMPA further reduced VL tests by 42% (1.9 tests/pool, CI 1.3–2.4, P < 0.001) and 17% (0.5, CI 0.2–0.8, p = 0.004); and required fewer testing rounds than MPA by 17% (P < 0.01), thus producing results quicker. IND and MP had 100% sensitivity and specificity. MPA and mMPA had similar sensitivity of 96.1% (MPA CI 90.7–100%; mMPA CI 88.0–100.0%) and specificity of 99.5% and 99.2% (98.5–100.0% for MPA and 97.5–100.0% for mMPA). Specifically, 3/150 samples were misclassified with MPA and mMPA: one suppression as VF, and two VF as suppressed.ConclusionLaboratory evaluation confirms that deconvolution using mMPA with CD4 or other routinely-collected clinical information as low-cost biomarkers reduces the number of VL assays required to identify VF in a setting with a low prevalence of VF. Implementation of pooled VL testing using mMPA for deconvolution may increase the availability of VL monitoring in RLS. Work is ongoing to reduce complexity and misclassification, required prior to widespread implementation.Disclosures All authors: No reported disclosures.