Evidence map›Paper›PMID 35149106›Full record

ReviewEnvironmental research2022

SARS-CoV-2 reinfections: Overview of efficacy and duration of natural and hybrid immunity.

Stefan Pilz, Verena Theiler-Schwetz, Christian Trummer, Robert Krause, John P A Ioannidis

Open access · hybridAbstract readReview
PubMed Full text at PMC Publisher
In one paragraph

Review in Environmental research, 2022. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 171 papers, 5 of them syntheses that pooled it.

0numbers the graph read from it
0cells of the map it votes in
171citing papers in PubMed, 5 pooled it
29.8field-weighted citation impact, top 1% of its field
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

171 citing papers in PubMed, 5 syntheses or guidelines pooled it, 295 citations in OpenAlex.

  1. Pooled it
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  6. Trial
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  16. Annual Variant-Targeted Vaccination to Prevent Severe COVID-19 in Cohorts With Vaccine-Derived and Hybrid Immunity.Clinical infectious diseases : an official publication of the Infectious Diseases Society of America · 2025
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  17. Observational
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111 more citing papers are in PubMed but not listed here.

4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

5 authors at 2 institutions in 2 countries.

Stefan PilzDepartment of Internal Medicine, Division of Endocrinology and Diabetology, Medical University of Graz, 8036, Graz, Austria. Electronic address: stefan.pilz@medunigraz.at.
Verena Theiler-SchwetzDepartment of Internal Medicine, Division of Endocrinology and Diabetology, Medical University of Graz, 8036, Graz, Austria.
Christian TrummerDepartment of Internal Medicine, Division of Endocrinology and Diabetology, Medical University of Graz, 8036, Graz, Austria.
Robert KrauseDepartment of Internal Medicine, Division of Infectious Diseases, Medical University of Graz, 8036, Graz, Austria.
John P A IoannidisDepartments of Medicine, Epidemiology and Population Health, Biomedical Data Science, and Statistics, Stanford University, Stanford, CA, 94305, USA. Electronic address: jioannid@stanford.edu.
Medical University of Graz · ATStanford Health Care · US

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

Seroprevalence surveys suggest that more than a third and possibly more than half of the global population has been infected with SARS-CoV-2 by early 2022. As large numbers of people continue to be infected, the efficacy and duration of natural immunity in terms of protection against SARS-CoV-2 reinfections and severe disease is of crucial significance for the future. This narrative review provides an overview on epidemiological studies addressing this issue. National surveys covering 2020-2021 documented that a previous SARS-CoV-2 infection is associated with a significantly reduced risk of reinfections with efficacy lasting for at least one year and only relatively moderate waning immunity. Importantly, natural immunity showed roughly similar effect sizes regarding protection against reinfection across different SARS-CoV-2 variants, with the exception of the Omicron variant for which data are just emerging before final conclusions can be drawn. Risk of hospitalizations and deaths was also reduced in SARS-CoV-2 reinfections versus primary infections. Observational studies indicate that natural immunity may offer equal or greater protection against SARS-CoV-2 infections compared to individuals receiving two doses of an mRNA vaccine, but data are not fully consistent. The combination of a previous SARS-CoV-2 infection and a respective vaccination, termed hybrid immunity, seems to confer the greatest protection against SARS-CoV-2 infections, but several knowledge gaps remain regarding this issue. Natural immunity should be considered for public health policy regarding SARS-CoV-2.

Indexed as

COVID-19SARS-CoV-2HumansmRNA VaccinesReinfectionSeroepidemiologic StudiesVaccines, SyntheticmRNA VaccinesVaccines, SyntheticHybrid immunityNatural immunityReinfectionsSARS-CoV-2VaccinationVaccines

Identifiers

PMID35149106
PMCPMC8824301
OpenAlexW4225574157

What OpenQuestion holds

Textmetadata
Read underepoch 390

Registered trials

None linked

Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.