Three studies released Friday offered more evidence that COVID-19 vaccines are standing up to the omicron variant, at least among people who received booster shots. They are the first large U.S. studies to look at vaccine protection against omicron.
The papers echo previous research — including studies in Germany, South Africa and the U.K. — indicating available vaccines are less effective against omicron than earlier versions of the coronavirus, but also that boosters doses rev up virus-fighting antibodies to increase the chance of avoiding symptomatic infection.
It found vaccine effectiveness was best after three doses of the Pfizer or Moderna vaccines in preventing COVID-19-associated emergency department and urgent care visits. Protection dropped from 94% during the delta wave to 82% during the omicron wave. Protection from just two doses was lower, especially if six months had passed since the second dose.
The second study focused on COVID-19 case and death rates in 25 states from the beginning of April through Christmas. People who were boosted had the highest protection against coronavirus infection, both during the time delta was dominant and also when omicron was taking over.The Journal of the American Medical Association published the third study, also led by CDC researchers. It looked at people who tested positive for COVID-19 from Dec. 10 to Jan.
“It really shows the importance of getting a booster dose,” said the CDC’s Emma Accorsi, one of the study’s authors.