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Question clinique
How protective are previous infection, vaccination, or both against symptomatic COVID-19 infection and against severe infection?
L’Essentiel
Three doses of vaccine with or without previous infection or 2 doses of vaccine plus previous infection both conferred excellent protection against serious disease in the first part of the omicron wave. A limitation of this study is that the authors did not report results for the BA.4 and BA.5 variants now sweeping the globe. So, stay tuned. 3b
Référence
Plan de l'etude: Case-control
Financement: Foundation
Cadre: Population-based
Sommaire
This study was done in Qatar, which has a diverse, young population that includes many guest workers from south and east Asia. Only 9% are older than 50 years. This study looked at symptomatic COVID-19 infections between December 23, 2021, and February 21, 2022. They used a case-control, test-negative design, matching each confirmed person with symptomatic COVID-19 with a control person who had not been infected. The researchers evaluated the following for protection during the initial omicron wave with the BA.1 and BA.2 variants: infection with a variant prior to the omicron wave, 2 doses of mRNA vaccine, 3 doses of mRNA vaccine, and hybrid immunity in patients with 2 or 3 doses of vaccine and a previous infection. For those who received 2 doses, the median interval from the second dose to PCR test was 268 days, while that interval was only 42 days for patients who received a third dose. Protection from symptomatic infection was 50.8% for previous infection without vaccine, 0% for 2 doses of vaccine (mostly given at least 6 months ago) and no previous infection, 55.5% for 2 doses of vaccine and previous infection, 54.0% for 3 doses of vaccine, and 76.3% for 3 doses of vaccine plus a previous infection. The authors did not evaluate 4 doses of vaccine. The good news is that protection against severe, critical, or fatal COVID-19 was much better: 71.6% for previous infection only, 73.5% for 2 doses and no previous infection, 94.3% for 2 doses and previous infection, 92.5% for 3 doses and no previous infection, and 100% for 3 doses and previous infection.
Reviewer
Mark H. Ebell, MD, MS
Professor
University of Georgia
Athens, GA
Commentaires
Good info
Will help me in future decision making
Is repeated support of vaccination for coronoviruses really
makes me wonder who the editors of POEM really are
severe covid infection and vaccination previous infection
vaccinate