The prevalence of adaptive immunity to COVID-19 and reinfection after recovery – a comprehensive systematic review and meta-analysis

Chivese, Tawanda; Matizanadzo, Joshua T.; Musa, Omran A. H.; Hindy, George; Furuya‐Kanamori, Luis; Islam, Nazmul; Al-Shebly, Rafal; Shalaby, Rana; Habibullah, Mohammad; Al-Marwani, Talal; Hourani, Rizeq F; Nawaz, Ahmed; Haider, Mohammad Z.; Emara, Mohamed M.; Cyprian, Farhan S.; Doi, Suhail A.R.

doi:10.1101/2021.09.03.21263103

Cited by 8 publications

(9 citation statements)

References 127 publications

(222 reference statements)

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“…A low risk of reinfection and a very low risk of severe or lethal COVID‐19 for those who recovered from a primary infection were reported in the vast majority of the published studies, as well in the available systematic reviews 108–111 . Most of the available information, however, included data preceding the emergence of the Omicron wave, 110 or relied upon very preliminary data 108 .…”

Section: Discussionmentioning

confidence: 99%

Risk of reinfection and disease after SARS‐CoV‐2 primary infection: Meta‐analysis

Flacco

Martellucci

Baccolini³

et al. 2022

Eur J Clin Investigation

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Introduction 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. Methods 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. Results 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. Conclusions 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.

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Section: Discussionmentioning

confidence: 99%

Risk of reinfection and disease after SARS‐CoV‐2 primary infection: Meta‐analysis

Flacco

Martellucci

Baccolini³

et al. 2022

Eur J Clin Investigation

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“…This infection-blocking value was subjected to a sensitivity analysis. Vaccine protection is modelled in the context of naturally acquired immunity following SARS-CoV-2 infection, whereby natural immunity is assumed to reach peak immunity of 95% aligned with findings from Chivese and colleagues, 11 before waning exponentially to 20% in 600 days. 12…”

Section: Methodsmentioning

confidence: 99%

COVID-19 vaccine booster strategies in light of emerging viral variants: Frequency, timing, and target groups

Kelly

Rutte

Richter

et al. 2022

Preprint

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Background: Vaccinations have reduced severe burden of COVID-19 and allowed for lifting of non-pharmaceutical interventions. However, with immunity waning alongside emergence of more transmissible variants of concern, vaccination strategies must be examined. Methods: Here we apply a SARS-CoV-2 transmission model to identify preferred frequency, timing, and target groups for vaccine boosters to minimise public health burden and health systems risk. We estimated new infections and hospital admissions averted over two-years through annual or biannual boosting of those eligible (those who received doses one and two) who are 1) most vulnerable (60+ or persons with comorbidities) or 2) those 5+, at universal (98% of eligible) or lower coverage (85% of those 50+ or with comorbidities and 50% of 5-49-year-olds who are eligible) representing moderate vaccine fatigue and/or hesitancy. We simulated three emerging variant scenarios: 1) no new variants; 2) 25% more infectious and immune-evading, Omicron-level severity, variants emerge annually and become dominant; and 3) emerge biannually. We further explored the impact of varying seasonality, variant severity, timing, immune evasion, and infectivity, and vaccine infection blocking assumptions. Results: To minimise COVID-19-related hospitalisations over the next two years, boosters should be provided for all those eligible annually three-four months ahead of peak winter whether or not new variants of concern emerge. Only boosting those most vulnerable is unlikely to ensure reduced stress on health systems. Moreover, boosting all eligible protects those most vulnerable more than only boosting the vulnerable group. Conversely, more hospitalisations could be averted per booster dose through annual boosting of those most vulnerable versus all eligible, an indication of cost-effectiveness. Whereas increasing to biannual boosting showed diminishing returns. Results were robust when key model parameters were varied. However, we found that the more frequently variants emerge, the less the effect boosters will have, regardless of whether administered annually or biannually. Conclusions: Well-timed and targeted vaccine boosters preferencing vulnerable, and if possible, all those eligible to receive boosters, can minimise infections and hospital admissions. Findings provide model-based evidence for decision-makers to plan for administering COVID-19 boosters ahead of winter 2022-2023 to help mitigate the health burden and health system stress.

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“…Other studies, albeit on smaller samples [27,28], have shown the presence of anti-SARS-CoV-2 S-RBD IgG at 14 months in recovered patients. More recently, an interesting meta-analysis included 54 studies from 18 countries for a total of 12,011,447 individuals with 8-month (average) post-infection follow-up [29]. Overall, the authors demonstrated in these subjects the presence of IgG, CD4+ T lymphocytes and B memory cells in 90.4%, and 80.6% of the cases respectively; moreover the prevalence of a reinfection was 0.2%.…”

Section: Duration and Type Of Immunity From Previous Sars-cov-2 Infec...mentioning

confidence: 99%

SARS-CoV-2 - The Role of Natural Immunity: A Narrative Review

Diani¹,

Leonardi²,

Cavezzi³

et al. 2022

Preprint

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Background: Both natural immunity and vaccine-induced immunity to COVID-19 may be useful to reduce the mortality/morbidity of this disease, but still a lot of controversy exists. Aims: This narrative review analyzes the literature about: a) the duration of natural immunity; b) cellular immunity; c) cross-reactivity; d) the duration of post-vaccination immune protection; e) the probability of reinfection and its clinical manifestations in the recovered patients; f) comparisons between vaccinated and unvaccinated in the possible reinfections; g) the role of hybrid immunity; h) the effectiveness of natural and vaccine-induced immunity against Omicron variant; i) comparative incidence of adverse effects after vaccination in recovered individuals vs. COVID-19-naïve subjects. Material and Methods: through multiple search engines we investigated COVID-19 literature related to the aims of the review, published since April 2020 through July 2022, including also the previous articles pertinent to the investigated topics. Results: nearly 900 studies were collected and 238 pertinent articles were included. It was highlighted that the vast majority of individuals after COVID-19 develop a natural immunity both of cell-mediated and humoral type, which is effective over time and provides protection against both reinfection and serious illness. Vaccine-induced immunity was shown to decay faster than natural immunity. In general, the severity of the symptoms of reinfection is significantly lower than in the primary infection, with a lower degree of hospitalizations (0.06%) and an extremely low mortality. Conclusions: this narrative review regarding a vast number of articles highlighted the valuable protection induced by the natural immunity after COVID-19, which seems comparable or superior to the one induced by anti-SARS-CoV-2 vaccination. Vaccination of the unvaccinated COVID-19-recovered subjects may not be indicated. Further research is needed in order to: a) measure the durability of immunity over time; b) evaluate both the impacts of Omicron-5 on vaccinated and healed subjects and of hybrid immunity.

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The prevalence of adaptive immunity to COVID-19 and reinfection after recovery – a comprehensive systematic review and meta-analysis

Cited by 8 publications

References 127 publications

Risk of reinfection and disease after SARS‐CoV‐2 primary infection: Meta‐analysis

Risk of reinfection and disease after SARS‐CoV‐2 primary infection: Meta‐analysis

COVID-19 vaccine booster strategies in light of emerging viral variants: Frequency, timing, and target groups

SARS-CoV-2 - The Role of Natural Immunity: A Narrative Review

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