The protection provided by COVID-19 vaccines generally lasts about 5 to 6 months after the primary vaccination series, during which antibody levels decline significantly. Protection against infection starts to wane after this period, although it may last longer against severe disease. Booster doses can restore antibody levels and extend protection for an additional 5 to 6 months. Different vaccine types show some variation in duration, with viral vector vaccines like AstraZeneca showing protection up to about 9 months, and mRNA vaccines providing high protection for about 5 months. Additionally, hybrid immunity from prior infection plus vaccination may result in longer-lasting protection. Antibodies decline over time, but cellular immunity may also contribute to longer protection.
Key Points:
- Antibody levels drop by about 50% by 4-6 months post-vaccination.
- Protection from reinfection wanes, but vaccines still protect well against severe illness for longer.
- Booster doses help restore and prolong immunity by raising antibody levels.
- Duration varies by vaccine type and individual factors including prior infection.
- Immune memory beyond antibodies contributes to ongoing protection though exact duration is uncertain.
This is the current understanding as of mid-2025 from multiple recent studies and health agency data.
