Background Routine 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. Methods We 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. Results We 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. Conclusions Our 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. Supplementary Information The online version contains supplementary material available at 10.1186/s12916-021-01982-x.
【저자키워드】 COVID-19, SARS-CoV-2, Healthcare workers, PCR testing, Test sensitivity, Presymptomatic infections, 【초록키워드】 Bayesian, hospital, Infection, RT-PCR, Symptoms, healthcare worker, Probability, Nasopharyngeal swab, sensitivity, Vulnerable populations, PCR, Asymptomatic, outbreak, asymptomatic infection, Effectiveness, Asymptomatic case, Asymptomatic cases, statistical model, dataset, PCR test, estimates, Care, symptomatic infection, Frequency, test results, medical staff, symptom onset, notification, twice weekly, supplementary material, infected individual, infected individuals, positive PCR test, help, symptomatic cases, symptomatic case, routine, populations, Prevent, Course, Result, performed, detect, proportion, peaked, provided, returned, 【제목키워드】 SARS-COV-2 infection, Asymptomatic, Effectiveness, Frequency,