Effectiveness of successive booster vaccine doses against SARS-CoV-2 related mortality in residents of Long-Term Care Facilities in the VIVALDI study

This research has not been peer-reviewed. It is a preliminary report that should not be regarded as conclusive, guide clinical practice or health-related behaviour, or be reported in news media as established information.

We evaluated the effectiveness of 1-3 booster vaccinations against SARS-CoV-2 related mortality among a cohort of 13407 older residents of long-term care facilities (LTCFs) participating in the VIVALDI study in England in 2022. Cox regression was used to estimate relative hazards of SARS-CoV-2 related death following booster vaccination relative to 2 doses (after 84+ days), stratified by previous SARS-CoV-2 infection and adjusting for age, sex and LTCF capacity. Each booster provided additional short-term protection relative to primary vaccination, with consistent pattern of waning to 45-75% reduction in risk beyond 112 days.

Author list



  1. University College London
  2. UK Health Security Agency
  3. University of Birmingham


Oliver Stirrup1, Madhumita Shrotri1, Natalie L. Adams1, Maria Krutikov1, Borscha Azmi1, Igor Monakhov2, Gokhan Tut3, Paul Moss3, Andrew Hayward1, Andrew Copas1 and Laura Shallcross1


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