Duration of effectiveness of vaccines against SARS-CoV-2 infection and COVID-19 disease: results of a systematic review and meta-regression
Open accessAbstract
BACKGROUND: Knowing whether COVID-19 vaccine effectiveness wanes is crucial for informing vaccine policy, such as the need for and timing of booster doses. We aimed to systematically review the evidence for the duration of protection of COVID-19 vaccines against various clinical outcomes, and to assess changes in the rates of breakthrough infection caused by the delta variant with increasing time since vaccination. METHODS: This study was designed as a systematic review and meta-regression. We did a systematic review of preprint and peer-reviewed published article databases from June 17, 2021, to Dec 2, 2021. Randomised controlled trials of COVID-19 vaccine efficacy and observational studies of COVID-19 vaccine effectiveness were eligible. Studies with vaccine efficacy or effectiveness estimates at discrete time intervals of people who had received full vaccination and that met predefined screening criteria underwent full-text review. We used random-effects meta-regression to estimate the average change in vaccine efficacy or effectiveness 1-6 months after full vaccination. FINDINGS: Of 13 744 studies screened, 310 underwent full-text review, and 18 studies were included (all studies were carried out before the omicron variant began to circulate widely). Risk of bias, established using the risk of bias 2 tool for randomised controlled trials or the risk of bias in non-randomised studies of interventions tool was low for three studies, moderate for eight studies, and serious for seven studies. We included 78 vaccine-specific vaccine efficacy or effectiveness evaluations (Pfizer-BioNTech-Comirnaty, n=38; Moderna-mRNA-1273, n=23; Janssen-Ad26.COV2.S, n=9; and AstraZeneca-Vaxzevria, n=8). On average, vaccine efficacy or effectiveness against SARS-CoV-2 infection decreased from 1 month to 6 months after full vaccination by 21·0 percentage points (95% CI 13·9-29·8) among people of all ages and 20·7 percentage points (10·2-36·6) among older people (as defined by each study, who were at least 50 years old). For symptomatic COVID-19 disease, vaccine efficacy or effectiveness decreased by 24·9 percentage points (95% CI 13·4-41·6) in people of all ages and 32·0 percentage points (11·0-69·0) in older people. For severe COVID-19 disease, vaccine efficacy or effectiveness decreased by 10·0 percentage points (95% CI 6·1-15·4) in people of all ages and 9·5 percentage points (5·7-14·6) in older people. Most (81%) vaccine efficacy or effectiveness estimates against severe disease remained greater than 70% over time. INTERPRETATION: COVID-19 vaccine efficacy or effectiveness against severe disease remained high, although it did decrease somewhat by 6 months after full vaccination. By contrast, vaccine efficacy or effectiveness against infection and symptomatic disease decreased approximately 20-30 percentage points by 6 months. The decrease in vaccine efficacy or effectiveness is likely caused by, at least in part, waning immunity, although an effect of bias cannot be ruled out. Evaluating vaccine efficacy or effectiveness beyond 6 months will be crucial for updating COVID-19 vaccine policy. FUNDING: Coalition for Epidemic Preparedness Innovations.
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None of the published systematic reviews have assessed the magnitude and duration of protection conferred by booster doses of mRNA vaccines, particularly for the fourth dose, for a comprehensive range of COVID-19 outcomes caused by the Omicron subvariant and its sublineages.
“however, none have assessed the magnitude and duration of protection conferred by booster doses of mRNA vaccines, particularly for the fourth dose, for a comprehensive range of COVID-19 outcomes caused by the Omicron subvariant and its sublineages.”
From Protection of the third-dose and fourth-dose mRNA vaccines against SARS-CoV-2 Omicron subvariant: a systematic review and meta-analysis (2023) · cites this paper as [11]
Experimental — accuracy not yet measuredProtection against SARS-CoV-2 infection starts to wane within a few months of administration of the primary series of mRNA vaccines.
“protection against infection starts to wane within a few months of administration.8–11”
From Protection of the third-dose and fourth-dose mRNA vaccines against SARS-CoV-2 Omicron subvariant: a systematic review and meta-analysis (2023) · cites this paper as [11]
Several systematic reviews of COVID-19 vaccine efficacy and effectiveness, with or without meta-analyses, have been published.
“Several systematic reviews of COVID-19 vaccine efficacy and effectiveness, with or without meta-analyses, have been published11 17–22”
From Protection of the third-dose and fourth-dose mRNA vaccines against SARS-CoV-2 Omicron subvariant: a systematic review and meta-analysis (2023) · cites this paper as [11]
Vaccine protection against severe disease has been shown to wane much less rapidly than against symptomatic infection.
“vaccine protection against severe disease has been shown to wane much less rapidly than against symptomatic infection [7,34].”
From Assessing COVID-19 vaccine effectiveness against Omicron subvariants: Report from a meeting of the World Health Organization (2023) · cites this paper as [34]
Waning of vaccine-induced protection is greater against symptomatic infection than against severe COVID-19 disease.
“more so against symptomatic infection than against severe COVID-19 disease [14].”
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“1 is somewhat surprising given that vaccine protection against severe disease has been shown to wane much less rapidly than against symptomatic infection [7,34].”
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“However, as vaccination campaigns progressed, additional vaccine effectiveness (VE) studies revealed waning of the vaccine-induced protection over time [8–13], more so against symptomatic infection than against severe COVID-19 disease [14].”
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- Authors
- Feikin, D. R., Higdon, M. M., Abu-Raddad, L. J., Andrews, N., Araos, R., Goldberg, Y., Groome, M. J., Huppert, A., O'Brien, K. L., Smith, P. G., Wilder-Smith, A., Zeger, S., Deloria Knoll, M., & Patel, M. K.
- Affiliations
- World Health Organization (CH)
- Johns Hopkins University (US)
- Weill Cornell Medical College in Qatar (QA)
- UK Health Security Agency (GB)
- Technion – Israel Institute of Technology (IL)
- National Health Laboratory Service (ZA)
- Tel Aviv University (IL)
- London School of Hygiene & Tropical Medicine (GB)
- Corresponding author
- Feikin, Daniel R
- Venue
- The Lancet
- Publisher
- Elsevier BV
- Published
- 2022-03
- Volume
- 399
- Issue
- 10328
- Pages
- 924-944
- ISSN
- 0099-5355 (ISSN-L)
- 0140-6736
- PMC
- PMC8863502
- OpenAlex
- W4220739924
- Cited by
- 1,237
- References
- 37
- Citations by year
- 2026: 85 · 2025: 170 · 2024: 294 · 2023: 412 · 2022: 274 · 2021: 2
- FWCI
- 44.30
- Type
- journal article
- Language
- en
- Update notices
- Open access
- hybrid
- doi.org
- Licence
- Locations
- The Lancet (publishedVersion, cc-by)
- PubMed Central (publishedVersion, cc-by)
- PubMed (publishedVersion)
- LSHTM Research Online (London School of Hygiene and Tropical Medicine) (acceptedVersion)
- Funders
- Bill and Melinda Gates Foundation
- Coalition for Epidemic Preparedness Innovations
- Topics
- Health Sciences › Medicine › Infectious Diseases › SARS-CoV-2 and COVID-19 Research
- Physical Sciences › Mathematics › Modeling and Simulation › COVID-19 epidemiological studies
- Social Sciences › Health › Vaccine Coverage and Hesitancy
- Keywords
- COVID-19 vaccines, SARS-CoV-2, waning vaccine effectiveness, duration of protection, breakthrough infection, Delta variant, booster vaccination, vaccine efficacy, older adults, mRNA vaccines, adenovirus vector vaccine, Moderna mRNA-1273, risk of bias
- MeSH terms
- COVID-19, SARS-CoV-2, COVID-19 Vaccines, BNT162 Vaccine, Ad26COVS1, Humans, Immunization Schedule, Immunization, Secondary, Time Factors
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