The Protection of Naturally Acquired Antibodies Against Subsequent SARS-CoV-2 Infection: A Systematic Review and Meta-Analysis

Abstract

The specific antibodies induced by SARS-CoV-2 infection may provide protection against a subsequent infection. However, the efficacy and duration of protection provided by naturally acquired immunity against subsequent SARS-CoV-2 infection remain controversial. We systematically searched for the literature describing COVID-19 reinfection published before 07 February 2022. The outcomes were the pooled incidence rate ratio (IRR) for estimating the risk of subsequent infection. The Newcastle–Ottawa Scale (NOS) was used to assess the quality of the included studies. Statistical analyses were conducted using the R programming language 4.0.2. We identified 19 eligible studies including more than 3.5 million individuals without the history of COVID-19 vaccination. The efficacy of naturally acquired antibodies against reinfection was estimated at 84% (pooled IRR = 0.16, 95% CI: 0.14-0.18), with higher efficacy against symptomatic COVID-19 cases (pooled IRR = 0.09, 95% CI = 0.07-0.12) than asymptomatic infection (pooled IRR = 0.28, 95% CI = 0.14-0.54). In the subgroup analyses, the pooled IRRs of COVID-19 infection in health care workers (HCWs) and the general population were 0.22 (95% CI = 0.16-0.31) and 0.14 (95% CI = 0.12-0.17), respectively, with a significant difference ( P = 0.02), and those in older (over 60 years) and younger (under 60 years) populations were 0.26 (95% CI = 0.15–0.48) and 0.16 (95% CI = 0.14-0.19), respectively. The risk of subsequent infection in the seropositive population appeared to increase slowly over time. In conclusion, naturally acquired antibodies against SARS-CoV-2 can significantly reduce the risk of subsequent infection, with a protection efficacy of 84%. Registration number: CRD42021286222

Epidemiology and outcomes of SARS-CoV-2 infection associated with anti-nucleocapsid seropositivity in Cape Town, South Africa

“…This was the period where testing capacity was severely constrained and there was greater bias towards testing individuals with risk factors for severe disease. Overall, our finding is broadly in line with studies included in a systematic review examining the issue of relative anti-N seropositivity protection (21).…”

“…While the fourth wave saw a sharp increase in SARS-CoV-2 cases, this did not result in a concomitant increase in related mortality (see line graph in Figure 1). Analyses from our setting have found that the Omicron variant was associated with less severe disease when compared to the Delta variant (20,21), but the low case ascertainment rates in this study complicates this interpretation (22).…”

Association of Results of Four Lateral Flow Antibody Tests with Subsequent SARS-CoV-2 Infection

“…Antibodies to the SARS-CoV-2 spike and nucleocapsid proteins are generated in over 90% of individuals with symptomatic infection and persist for months (9)(10)(11)(12)(13)(14). Multiple studies following up individuals with SARS-CoV-2 infection have described protection from SARS-CoV-2 following natural infection in individuals with detectable antibody levels: protection from subsequent symptomatic infection with SARS-CoV-2 was estimated at about 85% protection in two overlapping meta-analyses of 19 studies performed in the general population, health care workers, college students, and residents in long-term care facilities (15,16). In some studies, quantitative antibody levels were recorded, and increased protection in individuals with higher antibody levels was observed (10,17).…”

Association of air pollution and fine particulate matter (PM2.5) exposure with gestational diabetes: a systematic review and meta-analysis

“…The NOS scale scores articles according to 8 questions in 3 domains, with a total score of 9. A study with a score of 0–3 was rated as low quality; a study with a 4–6 score was considered as moderate quality; and a study with a 7–9 score was graded as high quality ( 17 ). In contrast, the risk of bias in the included cross-sectional studies was assessed using the Joana Brigg’s Institute (JBI) critical appraisal checklist, with a total score of nine.…”