Three studies in the United States offer more evidence that the third dose of COVID vaccine is very effective against Omicron.
Pfizer-BioNTech and Moderna booster vaccines have been shown to be very effective in preventing Omicron-related hospitalizations, according to three new studies by the US Centers for Disease Control and Prevention.
Booster doses were 90 percent effective in keeping people out of the hospital after they became infected with the Omicron variant.
Doses were also 82 percent effective in preventing emergency room visits and emergency care, the data showed.
“This really shows the importance of getting a booster dose,” said Emma Acorcy of the CDC, one of the study’s authors, on Friday.
“Americans should get boosters if it’s been at least five months since they finished their Pfizer or Moderna series, but millions of eligible people haven’t received them.
The study includes the first major studies in the United States to look at protecting Omicron vaccines, health officials said.
The documents reflect previous studies – including studies in Germany, South Africa and the United Kingdom – showing that available vaccines are less effective against Omicron than earlier versions of the coronavirus, but also that booster doses boost antibodies to fight with the virus to increase the chance of avoiding a symptomatic infection.
The first study looked at hospitalizations and visits to emergency departments and emergency centers in 10 states from August to this month.
The vaccine was found to be most effective after three doses of Pfizer or Moderna vaccines to prevent COVID-19-related emergency department and emergency care visits.
Protection fell from 94 percent during the Delta wave to 82 percent during the Omicron wave.
Protection from just two doses is lower, especially if six months have passed since the second dose.
Authorities stressed the goal of preventing not only infection but also serious illnesses.
The second study focused on cases of COVID-19 and mortality in 25 states from early April to late December.
People who were boosted had the highest protection against coronavirus infection, both when Delta was dominant and when Omicron was taking over.
These two articles were published online by the Centers for Disease Control and Prevention.
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. 1 at more than 4,600 test sites in the United States.
Three injections of Pfizer and Moderna vaccines were about 67 percent effective against Omicron-related symptomatic disease compared to unvaccinated people.
However, two doses did not offer significant protection against Omicron when measured several months after the completion of the original series, the researchers found.
“If you’re eligible for a booster and you haven’t received it, you’re out of date and you need to get your booster,” CDC Director Dr. Rochelle Valensky told a White House briefing on Friday.