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Impact of Vaccination, Prior Infection, and Therapy on Omicron Infection and Mortality
Xiaofeng Wang1, Joe Zein1,2, Xinge Ji1
1Lerner Research Institute, Cleveland, Ohio, USA.
Background:
Understanding immunity against Omicron infection and severe outcomes conferred by coronavirus disease 2019 (Covid-19) vaccination, prior severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, and monoclonal antibody therapy will inform intervention strategies.
Methods:
We considered 295 691 patients tested for SARS-CoV-2 at Cleveland Clinic between 1 October 2021 and 31 January 2022. We used logistic regression to investigate the association of vaccination and prior infection with the risk of SARS-CoV-2 infection and used Cox regression to investigate the association of vaccination, prior infection, and monoclonal antibody therapy with the risks of intensive care unit (ICU) stay and death.
Results:
Vaccination and prior infection were less effective against Omicron than Delta infection but provided strong protection against ICU admission and death. Boosting greatly increased vaccine effectiveness against Omicron infection and severe outcomes, although effectiveness waned rapidly over time. Monoclonal antibody therapy considerably reduced risks of ICU admission and death. The relatively low mortality of the Omicron variant was due to both reduced lethality of this variant and increased population immunity acquired from booster vaccination and previous infection.
Conclusions:
Booster vaccination and prior SARS-CoV-2 infection provide strong protection against ICU admission and death from Omicron infection. Monoclonal antibody therapy is also beneficial.
Insights
Booster vaccination and prior SARS-CoV-2 infection offer strong protection against severe outcomes from Omicron variants. Monoclonal antibody therapy also reduces risks of intensive care unit admission and death.
Area of Science:
- Immunology
- Infectious Diseases
- Public Health
Background:
- Understanding immunity to Omicron infection is crucial for effective intervention strategies.
- Investigating immunity from COVID-19 vaccination, prior SARS-CoV-2 infection, and monoclonal antibody therapy is essential.
Purpose of the Study:
- To assess the effectiveness of COVID-19 vaccination, prior SARS-CoV-2 infection, and monoclonal antibody therapy against Omicron infection and severe outcomes.
- To inform public health strategies for managing the Omicron variant.
Main Methods:
- A retrospective study of 295,691 patients tested for SARS-CoV-2.
- Logistic and Cox regression analyses were used to investigate associations between immunity factors and infection/severe outcomes.
Main Results:
- Vaccination and prior infection were less effective against Omicron than Delta but provided strong protection against ICU admission and death.
- Booster vaccination significantly increased effectiveness against Omicron, though it waned over time.
- Monoclonal antibody therapy substantially reduced the risks of ICU admission and death.
Conclusions:
- Booster vaccination and prior SARS-CoV-2 infection provide robust protection against severe outcomes from Omicron.
- Monoclonal antibody therapy is a beneficial treatment option for severe Omicron infections.
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