Background: The understanding of viral positivity and seroconversion during the course of coronavirus disease 2019 (COVID-19) is limited Objective: To describe patterns of viral polymerase chain reaction (PCR) positivity and evaluate their correlations with seroconversion and disease severity Design: Retrospective cohort study Setting: 3 designated specialty care centers for COVID-19 in Wuhan, China Participants: 3192 adult patients with COVID-19 Measurements: Demographic, clinical, and laboratory data Results: Among 12 780 reverse transcriptase PCR tests for severe acute respiratory syndrome coronavirus 2 that were done, 24 0% had positive results In 2142 patients with laboratory-confirmed COVID-19, the viral positivity rate peaked within the first 3 days The median duration of viral positivity was 24 0 days (95% CI, 18 9 to 29 1 days) in critically ill patients and 18 0 days (CI, 16 8 to 19 1 days) in noncritically ill patients Being critically ill was an independent risk factor for longer viral positivity (hazard ratio, 0 700 [CI, 0 595 to 0 824];P &lt; 0 001) In patients with laboratory-confirmed COVID-19, the IgM-positive rate was 19 3% in the first week, peaked in the fifth week (81 5%), and then decreased steadily to around 55% within 9 to 10 weeks The IgG-positive rate was 44 6% in the first week, reached 93 3% in the fourth week, and then remained high Similar antibody responses were seen in clinically diagnosed cases Serum inflammatory markers remained higher in critically ill patients Among noncritically ill patients, a higher proportion of those with persistent viral positivity had low IgM titers (&lt;100 AU/mL) during the entire course compared with those with short viral positivity Limitation: Retrospective study and irregular viral and serology testing Conclusion: The rate of viral PCR positivity peaked within the initial few days Seroconversion rates peaked within 4 to 5 weeks Dynamic laboratory index changes corresponded well to clinical signs, the recovery process, and disease severity Low IgM titers (&lt;100 AU/mL) are an independent risk factor for persistent viral positivity Primary Funding Source: None
Dynamics and Correlation Among Viral Positivity, Seroconversion, and Disease Severity in COVID-19: A Retrospective Study