Qatar Omicron-wave study shows slow decline of natural immunity, rapid decline of vaccine immunity

A recent Pfizer or Moderna mRNA-vaccine booster provided good but temporary protection against infection by the SARS-CoV-2 Omicron variant, according to a study from researchers at Weill Cornell Medicine — Qatar.

In the study, published June 15 in the New England Journal of Medicine, the researchers analyzed the Omicron wave in Qatar last winter, comparing prior infections, vaccine immunity and combinations thereof among more than 100,000 Omicron-infected and non-infected individuals.

The analysis showed, as expected, that full mRNA vaccination plus a booster dose, atop natural immunity due to infection by an earlier variant, was associated with the strongest protection from Omicron infection. However, vaccine immunity against new infection appeared to wane rapidly, whereas people with a prior-variant infection were moderately protected from Omicron with little decline in protection even a year after their prior infection.

The study, the most comprehensive of its kind in investigating different combinations of immunity for Omicron-variant SARS-CoV-2 infections, also found evidence that both vaccination and prior infection provided strong and durable protection from severe, critical, or fatal COVID-19 during the Omicron wave.

“We found that the rates of severe COVID-19 during Qatar’s Omicron wave were very low even among those who had only two doses of vaccine or only a prior infection,” said study first author Dr. Heba Altarawneh, a postdoctoral research associate who conducted this study working with study senior author Dr. Laith Abu-Raddad, a professor of population health sciences at Weill Cornell Medicine — Qatar and at Weill Cornell Medicine in New York.

Qatar’s highly centralized and comprehensive electronic health records database, which includes all RT-PCR tests for SARS-CoV-2 performed in the country, permits unusually rapid and large-scale epidemiological studies. Dr. Abu-Raddad and colleagues have already published prominent papers on infection and illness rates for prior SARS-CoV-2 variants and waves.

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