Effects of Previous Infection and Vaccination on Symptomatic Omicron Infections

Heba N. Altarawneh et al.

No notable differences were observed in the effectiveness against BA.1 and BA.2 of previous
infection, vaccination, and hybrid immunity. Protection from previous infection with variants other than omicron against reinfection was moderate and durable, but protection of primary-series vaccination against infection was negligible by 6 months after the second dose. Recent booster vaccination had moderate effectiveness, whereas hybrid immunity from previous infection and recent booster vaccination conferred the strongest protection against infection, at approximately 80%. All five forms of immunity were associated with strong and durable protection against Covid-19–related hospitalization and death.

Latest articles

Swiss Policy Research … data from both Germany and Switzerland does show...
Kenji Yamamoto Recently, The Lancet published a study on the effectiveness of...
Kit Knightly Polio is on the front pages of British newspapers again...
Carey Gillam Glyphosate, a synthetic herbicide patented in 1974 by the Monsanto...
Suzanne Burdick A study published last week in Environment International showed 29...

Your donation helps us
stand up for health freedom!

Canada Health Alliance is volunteer run and 100% supported by the generous donations of those who share our concerns and value our work.

Stay up to date

Sign up to our newsletter to get the latest health-related news and events delivered straight to your inbox.

Become a CHA member

Become an active value-added member and trusted provider of medical and healthcare information and education by joining the CHA Membership Program.

Your donation helps us stand up for health freedom!

Canada Health Alliance is volunteer run and 100% supported by the generous donations of those who share our concerns and value our work.