Immunity from COVID-19 vaccines wanes quickly against Omicron

Embargoed until: Publicly released: 2023-05-04 01:00

International

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The effectiveness of COVID-19 vaccines against Omicron wanes rapidly over time, according to a review of 40 studies. The estimated vaccine effectiveness against both laboratory-confirmed Omicron infection and symptomatic disease was less than 20% six months after the primary vaccination cycle. Boosters restored vaccine effectiveness to levels similar to after the primary doses, but nine months later, booster effectiveness had reduced to less than 30%. The team also found protection vaccines provide against Omicron lasts less long than against Delta. They say these results could be used to inform the design and timing of future vaccination programmes.

Media release

From: JAMA

Evaluation ofWaning of SARS-CoV-2 Vaccine–Induced Immunity: A Systematic Review and Meta-analysis

The findings of this systematic review and meta-analysis of secondary data from 40 studies suggest that the effectiveness of COVID-19 vaccines against laboratory-confirmed Omicron or Delta infection and symptomatic disease rapidly wanes over time after the primary vaccination cycle and booster dose. These results can inform the design of appropriate targets and timing for future vaccination programs.

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Journal/
conference: JAMA Network Open

Research:Paper

Organisation/s: Bruno Kessler Foundation, Italy; University of Trento, Italy

Funder: This research was supported by EU funding within the NextGenerationEU-MUR PNRR Extended Partnership Initiative on Emerging Infectious Diseases (project no. PE00000007, INF-ACT; Drs Zardini, Guzzetta, and d’Andrea); funding from EU grant 101045989 VERDI (Drs Poletti and Marziano); funding from EU grant 874850 MOOD (Mr Merler and Dr Manica); and support from Cooperative Agreement no. NU38OT000297 of the Council of State and Territorial Epidemiologists (Dr Ajelli).

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