Effectiveness of COVID-19 vaccines against post-COVID-19 condition/long COVID: systematic review and meta-analysis
Caroline Peine, Anna Stoliaroff-Pépin, Ulrich Reinacher, Katharina Heldt, Giselle Sarganas, Vanessa Piechotta, Agata Mikołajewska, Antonia Pilic, Nina Barkowski, Daniel Bleve, Marie H. Giebeler, Susanne Poser, Laura Searle, Elisabeth Kißner, Leonie Nitsche, Fatimanur Bayram, Waldemar Siemens, Annika Ziegler, Joerg J Meerpohl, Frank Sandmann, Ole Wichmann, Thomas Harder
Abstract
BACKGROUND: Persons infected with SARS-CoV-2 can develop long-term symptoms known as postCOVID-19 condition (PCC; symptoms ≥3 months after infection) or long COVID (LC; symptoms ≥1 month after infection). Vaccination against COVID-19 might prevent PCC/LC, but the extent of protection is unclear. OBJECTIVES: The aim of this systematic review was to evaluate the vaccine efficacy/effectiveness (VE) of COVID-19 vaccines given prior to SARS-CoV-2 infection in preventing PCC or LC. METHODS DATA SOURCES: Studies were identified in Embase, MEDLINE, PreView, COVID-19 L.OVE repository, and Cochrane Library up to August 1, 2024. STUDY ELIGIBILITY CRITERIA, PARTICIPANTS, AND INTERVENTIONS: Randomized controlled trials and nonrandomized studies of interventions (NRSI) that investigated immunization with a COVID-19 vaccine before SARS-CoV-2 infection were eligible, irrespective of participant age and sex. ASSESSMENT OF RISK OF BIAS: Risk of bias was assessed using the ''Risk Of Bias In Nonrandomized Studies-of Interventions'' tool. METHODS OF DATA SYNTHESIS: Primary outcome was PCC, secondary outcomes were LC, time until reconvalescence, limitations in everyday activity, and quality of life. Meta-analyses were primarily conducted using the random-effects model. RESULTS: A total of 6423 records were screened, and 65 NRSI reporting adjusted estimates were included, comprising >5.7 mio. PARTICIPANTS: VE for ≥1 vaccine dose against PCC was 41.0% (95% CI 27.8%; 51.7%; 22 NRSI, certainty of evidence: low). VE after 1, 2, or 3 doses versus unvaccinated was 19.1% (-119.4%; 70.2%, 3 NRSI), 43.2% (4.5%; 66.2%; 4 NRSI), and 70.0% (30.0%; 87.0%; 1 NRSI), respectively. In <18 years old, VE against PCC was 26% for ≥1 dose (-4%; 48%, 1 NRSI) and in >60 years old 41% (17%; 59%, 1 NRSI). VE after pre-Omicron-SARS-CoV-2 infection was 32.1% (-54.3%; 70.1%, 3 NRSI) and 20.9% (-10.1%; 43.3%, 2 NRSI) after Omicron infection. Sensitivity analyses indicated no influence of risk of bias and effect measure. CONCLUSIONS: COVID-19 vaccines may be moderately effective in preventing PCC/LC. VE may increase with the number of vaccine doses administered.