Studies continue to show that mRNA vaccines and boosters for COVID-19 are very successful at preventing hospitalization and death, but there has been some data to suggest their overall effectiveness against coronavirus infections is waning — especially when confronted with the omicron variant.
Notably, one recent study published in the New England Journal of Medicine analyzed data from 2,239,193 people in Qatar who had received at least 2 doses of either the Pfizer-BioNTech or Moderna COVID-19 vaccines. Researchers found that for those who were fully vaccinated and boosted, protection against the delta variant was 86.1 percent; but against symptomatic illness from the omicron variant, protection was only 49.4 percent. A separate study from the United Kingdom determined the effectiveness of a third Pfizer dose declined from 67 to 46 percent within a few months after vaccination at preventing a symptomatic infection.
