Department of Environmental and Preventive Sciences, University of Ferrara, Ferrara, Italy.
Department of Public Health and Infectious Diseases, Sapienza University, Rome, Italy.
Eur J Clin Invest. 2022 Oct;52(10):e13845. doi: 10.1111/eci.13845. Epub 2022 Aug 8.
A precise estimate of the frequency and severity of SARS-CoV-2 reinfections would be critical to optimize restriction and vaccination policies for the hundreds of millions previously infected subjects. We performed a meta-analysis to evaluate the risk of reinfection and COVID-19 following primary infection.
We searched MedLine, Scopus and preprint repositories for cohort studies evaluating the onset of new infections among baseline SARS-CoV-2-positive subjects. Random-effect meta-analyses of proportions were stratified by gender, exposure risk, vaccination status, viral strain, time between episodes, and reinfection definition.
Ninety-one studies, enrolling 15,034,624 subjects, were included. Overall, 158,478 reinfections were recorded, corresponding to a pooled rate of 0.97% (95% CI: 0.71%-1.27%), with no substantial differences by definition criteria, exposure risk or gender. Reinfection rates were still 0.66% after ≥12 months from first infection, and the risk was substantially lower among vaccinated subjects (0.32% vs. 0.74% for unvaccinated individuals). During the first 3 months of Omicron wave, the reinfection rates reached 3.31%. Overall rates of severe/lethal COVID-19 were very low (2-7 per 10,000 subjects according to definition criteria) and were not affected by strain predominance.
A strong natural immunity follows the primary infection and may last for more than one year, suggesting that the risk and health care needs of recovered subjects might be limited. Although the reinfection rates considerably increased during the Omicron wave, the risk of a secondary severe or lethal disease remained very low. The risk-benefit profile of multiple vaccine doses for this subset of population needs to be carefully evaluated.
准确估计 SARS-CoV-2 再感染的频率和严重程度对于优化数亿既往感染人群的限制和疫苗接种政策至关重要。我们进行了一项荟萃分析，以评估初次感染后再次感染 COVID-19 的风险。
我们在 MedLine、Scopus 和预印本存储库中搜索了评估基线 SARS-CoV-2 阳性受试者新发感染的队列研究。对比例的随机效应荟萃分析按性别、暴露风险、疫苗接种状态、病毒株、两次感染之间的时间和再感染定义进行分层。
共纳入 91 项研究，纳入 15034624 名受试者。总体而言，记录到 158478 例再感染，累计发生率为 0.97%（95%CI：0.71%-1.27%），不同定义标准、暴露风险或性别之间无显著差异。初次感染后≥12 个月再感染率仍为 0.66%，且疫苗接种者的风险显著降低（未接种者为 0.74%，接种者为 0.32%）。在奥密克戎波的前 3 个月，再感染率达到 3.31%。总体严重/致死 COVID-19 发生率非常低（根据定义标准，每 10000 名患者中有 2-7 例），且不受主要流行株的影响。
初次感染后会产生强烈的自然免疫，并且可能持续一年以上，这表明康复患者的风险和医疗保健需求可能有限。尽管在奥密克戎波期间再感染率显著增加，但二次严重或致命疾病的风险仍然很低。对于这部分人群，多次接种疫苗的风险效益需要仔细评估。
