As an exception during this period of health crisis, some of the publications mentioned are at the time of writing still in pre-publication, undergoing peer review and subject to change. The results of this pre-print study should be interpreted with utmost caution.
- Interim SIREN (SARS-CoV-2 Immunity and Reinfection EvaluatioN) findings suggest that a history of SARS-CoV-2 infection confers significant protection against reinfection for at least 5 months.
Why this matters
- Carrying antibodies may not be 100% effective against reinfection.
- The authors say, however, that the substantial protective effect they identified is the "minimum likely effect."
- 20,787 enrolled (6614 in positive cohort, 14,173 in negative cohort).
- 84% were women, and 88% were White.
- Median age, 45.9 (interquartile range, 35.8-53.6) years.
- 409 new infections.
- 79% of PCR-positive cases were symptomatic, 12% were asymptomatic, and no data were available for 9%.
- Reinfection (44 total events):
- 3.3 reinfections/100,000 follow-up days in the positive cohort vs
- 17.0 new infections/100,000 follow-up days in the negative cohort.
- On multivariate analysis:
- Probable reinfections (2 cases): aOR, 0.01 (P<.01>
- Combined probable + symptomatic possible (15 cases): aOR, 0.06 (P<.01>
- Probable + all possible (44 cases): aOR, 0.17 (P<.01>
- Prospective UK multicenter cohort study, including health care workers in months following initial infection, June 18-November 9, 2020.
- Funding: Department of Health and Social Care and Public Health England; Scottish, Welsh, and Northern Irish governments.
- Limited data, samples.
- Measurement error (primary infection onset date).
- Recall bias.
- Short follow-up.