Estimating the effectiveness of routine asymptomatic PCR testing at different frequencies for the detection of SARS-CoV-2 infections

BMC Medicine

Gavin Kelly¹  Catherine Houlihan²  Eleni Nastouli³  Rupert Beale⁴  Joel Hellewell⁵  Timothy W. Russell⁵  Adam J. Kucharski⁵ 

[1] Bioinformatics and Biostatistics, The Francis Crick Institute, 1 Midland Road, NW1 1AT, London, UK;Bioinformatics and Biostatistics, The Francis Crick Institute, 1 Midland Road, NW1 1AT, London, UK;Department of Infection and Immunity, University College London, London, UK;Department of Clinical Research, London School of Hygiene & Tropical Medicine, London, UK;Bioinformatics and Biostatistics, The Francis Crick Institute, 1 Midland Road, NW1 1AT, London, UK;Department of Population, Policy and Practice, UCL Great Ormond Street Institute of Child Health, WC1N 1EH, London, UK;Cell Biology of Infection Laboratory, The Francis Crick Institute; Division of Medicine, UCL, London, UK;Centre for Mathematical Modelling of Infectious Diseases, London School of Hygiene & Tropical Medicine, London, UK;

关键词: Test sensitivity;    PCR testing;    COVID-19;    SARS-CoV-2;    Healthcare workers;    Presymptomatic infections;   

DOI  :  10.1186/s12916-021-01982-x

来源: Springer

【 摘 要 】

BackgroundRoutine asymptomatic testing using RT-PCR of people who interact with vulnerable populations, such as medical staff in hospitals or care workers in care homes, has been employed to help prevent outbreaks among vulnerable populations. Although the peak sensitivity of RT-PCR can be high, the probability of detecting an infection will vary throughout the course of an infection. The effectiveness of routine asymptomatic testing will therefore depend on testing frequency and how PCR detection varies over time.MethodsWe fitted a Bayesian statistical model to a dataset of twice weekly PCR tests of UK healthcare workers performed by self-administered nasopharyngeal swab, regardless of symptoms. We jointly estimated times of infection and the probability of a positive PCR test over time following infection; we then compared asymptomatic testing strategies by calculating the probability that a symptomatic infection is detected before symptom onset and the probability that an asymptomatic infection is detected within 7 days of infection.ResultsWe estimated that the probability that the PCR test detected infection peaked at 77% (54–88%) 4 days after infection, decreasing to 50% (38–65%) by 10 days after infection. Our results suggest a substantially higher probability of detecting infections 1–3 days after infection than previously published estimates. We estimated that testing every other day would detect 57% (33–76%) of symptomatic cases prior to onset and 94% (75–99%) of asymptomatic cases within 7 days if test results were returned within a day.ConclusionsOur results suggest that routine asymptomatic testing can enable detection of a high proportion of infected individuals early in their infection, provided that the testing is frequent and the time from testing to notification of results is sufficiently fast.

【 授权许可】

CC BY