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Insights into the practical effectiveness of RT-PCR testing for SARS-CoV-2 from serologic data, a cohort study

Insights into the practical effectiveness of RT-PCR testing for SARS-CoV-2 from serologic data, a cohort study

Authors :
Lan Wei
Andrew S. Azman
Zhen Zhang
Shisong Fang
Yongsheng Wu
Justin Lessler
Wenfeng Gong
Xin Wang
Wei Gao
Renli Zhang
Qiru Su
Jianfan He
Xiaojian Liu
Qifang Bi
Xuan Zou
Publication Year :
2020
Publisher :
Cold Spring Harbor Laboratory, 2020.

Abstract

BackgroundVirologic detection of SARS-CoV-2 through Reverse Transcriptase Polymerase Chain Reaction (RT-PCR) has limitations for surveillance. Serologic tests can be an important complementary approach.ObjectiveAssess the practical performance of RT-PCR based surveillance protocols, and the extent of undetected SARS-CoV-2 transmission in Shenzhen, China.DesignCohort study nested in a public health response.SettingShenzhen, China; January-May 2020.Participants880 PCR-negative close-contacts of confirmed COVID-19 cases and 400 residents without known exposure (main analysis). Fifty-seven PCR-positive case contacts (timing analysis).MeasurementsVirological testing by RT-PCR. Measurement of anti-SARS-CoV-2 antibodies in PCR-negative contacts 2-15 weeks after initial testing using total Ab ELISA. Rates of undetected infection, performance of RT-PCR over the course of infection, and characteristics of seropositive but PCR-negative individuals were assessed.ResultsThe adjusted seropositivity rate for total Ab among 880 PCR-negative close-contacts was 4.1% (95%CI, 2.9% to 5.7%), significantly higher than among residents without known exposure to cases (0.0%, 95%CI, 0.0% to 1.0%). PCR-positive cases were 8.0 times (RR; 95% CI, 5.3 to 12.7) more likely to report symptoms than the PCR-negative individuals who were seropositive, but otherwise similar. RT-PCR missed 36% (95%CI, 28% to 44%) of infected close-contacts, and false negative rates appear to be highly dependent on stage of infection.LimitationsNo serological data were available on PCR-positive cases. Sample size was limited, and only 20% of PCR-negative contacts met inclusion criteria.ConclusionEven rigorous RT-PCR testing protocols may miss a significant proportion of infections, perhaps in part due to difficulties timing testing of asymptomatics for optimal sensitivity. Surveillance and control protocols relying on RT-PCR were, nevertheless, able to contain community spread in Shenzhen.Funding sourceBill & Melinda Gates Foundation, Special Foundation of Science and Technology Innovation Strategy of Guangdong Province of China, and Key Project of Shenzhen Science and Technology Innovation Commission, Shenzhen, China

Details

Database :
OpenAIRE
Accession number :
edsair.doi...........6939f4f0f2d4c6c962c1f32fb6689d5b
Full Text :
https://doi.org/10.1101/2020.09.01.20182469