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Meta-Analysis
. 2022 Jan 20;135(2):145-152.
doi: 10.1097/CM9.0000000000001892.

Reinfection rates among patients previously infected by SARS-CoV-2: systematic review and meta-analysis

Yinjun Mao  1 , Weiwei Wang  2 , Jun Ma  3 , Shanshan Wu  4 , Feng Sun  5
Affiliations
Meta-Analysis

Reinfection rates among patients previously infected by SARS-CoV-2: systematic review and meta-analysis

Yinjun Mao et al. Chin Med J (Engl). .

Abstract

Background: Asymptomatic or symptomatic infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can be followed by reinfection. The protection conferred by prior infection among coronavirus disease 2019 (COVID-19) patients is unclear. We assessed the incidence of SARS-CoV-2 reinfection and the protection effect of previous infection against reinfection.

Methods: We searched PubMed, EMBASE, Cochrane, Scopus, Web of Science, and ClinicalTrials.gov for publications up until the end date of May 1, 2021. The reinfection rate of recovered patients and the protection against reinfection were analyzed using meta-analysis.

Results: Overall, 19 studies of 1096 reinfection patients were included. The pooled reinfection rate was 0.65% (95% confidence interval [CI] 0.39-0.98%). The symptomatic reinfection rate was a bit lower (0.37% [95% CI 0.11-0.78%], I2 = 99%). The reinfection rate was much higher in high-risk populations (1.59% [95% CI 0.30-3.88%], I2 = 90%). The protection against reinfection and symptomatic reinfection was similar (87.02% [95% CI 83.22-89.96%] and 87.17% [95% CI 83.09-90.26%], respectively).

Conclusions: The rate of reinfection with SARS-CoV-2 is relatively low. The protection against SARS-CoV-2 after natural infection is comparable to that estimated for vaccine efficacy. These data may help guide public health measures and vaccination strategies in response to the COVID-19 pandemic. High-quality clinical studies are needed to establish the relevant risk factors in recovered patients.

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Conflict of interest statement

None.

Figures

Figure 1
Figure 1
PRISMA flow chart illustrating study selection process. PRISMA: Preferred Reporting Items for Systematic Reviews and Meta-analyses.
Figure 2
Figure 2
Forest plot illustrating the single study and summary incidence of SARS-CoV-2 reinfection. CI: Confidence interval; SARS-CoV-2: Severe acute respiratory syndrome Coronavirus 2.
Figure 3
Figure 3
Forest plot illustrating the protection afforded from initial SARS-CoV-2 infection (1-RR). (A) Protection against reinfection, (B) Protection against symptomatic reinfection. CI: Confidence interval; RR: Risk ratio; SARS-CoV-2: Severe acute respiratory syndrome Coronavirus 2.
See this image and copyright information in PMC

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