As health experts around the world race to gather data on the omicron variant of COVID-19, top health officials in the United States say early studies underscore the importance of getting a third COVID booster shot to protect against the viral strain. 

What You Need To Know

  • Top health officials in the United States say early studies underscore the importance of getting a third COVID booster shot to protect against the omicron variant of COVID-19 

  • Pfizer-BioNTech released preliminary results from a study that showed a three-dose regimen of their COVID-19 vaccine increased antibody protections against omicron by 25-fold

  • A separate study of individuals two weeks after receiving a third dose of the Moderna vaccine showed a “substantial degree of elevation” of antibody protections against omicron

  • Dr. Anthony Fauci said the studies are evidence that “our booster vaccine regimens work against omicron," adding there is “no need” for a variant-specific vaccine"

Currently, the U.S. Centers for Disease Control and Protection (CDC) says all Americans aged 16 and up are eligible for a booster shot against COVID-19. Individuals aged 16 and 17 can get a Pfizer-BioNTech booster; individuals 18 years old and up can get a booster shot of any approved vaccine. 

A booster shot for the Pfizer and Moderna vaccines is recommended six months after the final dose of the original regimen, while those who received a Johnson & Johnson shot should get boostered two months after the single-dose regimen. 

The omicron variant has currently been detected in at least 36 states and around 75 countries, but still only makes up around 3% of total COVID-19 cases in the U.S., CDC director Dr. Rochelle Walensky said in a press briefing Wednesday.

The vast majority of cases – around 96% – are made up of the delta variant. 

The omicron caseload might be even higher in certain areas of the country, like New York and New Jersey, Walensky noted, adding that officials “expect to see the proportion of omicron cases here in the United States continue to grow in the coming weeks.” 

That’s due, in part, to early data showing while omicron might not cause more severe disease than other COVID-19 variants, it is likely more transmissible than delta, with a doubling time of about two days. 

“What does this mean for individuals and families as we head into the winter months, a time when families may be gathering with one another over the holidays?” Walensky said, adding: “It means that it is vital for everyone to get vaccinated and boosted if they are eligible.” 

A number of early studies have shown that a booster, or third dose, of both mRNA vaccines from Moderna and Pfizer-BioNTech offer increased protection against the omicron variant compared to individuals who only received a two-dose regimen of either shot. 

Last week, Pfizer-BioNTech released preliminary results from a laboratory study that showed a three-dose regimen of their COVID-19 vaccine effectively “neutralized” the omicron variant, and increased antibody protections for individuals by 25-fold. 

Essentially, a three-dose regimen of the Pfizer vaccine offers as much protection against the omicron variant as a two-dose regimen offers against previous variants of COVID-19. 

A separate study from the National Institute of Allergy and Infectious Diseases (NIAID), which will be published in a preprint survey next week, looked at the amount of neutralizing antibody titers in individuals two weeks after receiving a third dose of the Moderna vaccine. 

The initial data showed a “substantial degree of elevation” of antibody protections, which are “well within the range of neutralizing omicron,” according to NIAID director Dr. Anthony Fauci. 

Moderna called the study “encouraging initial data,” adding there will be more information on a booster that is double the micrograms of the booster included in the above study (100 µg compared to 50 µg).  

“The early in vitro and clinical studies that I mentioned indicate that boosters reconstitute the antibody titers and enhance the vaccine protection against omicron,” Fauci said of the studies. “Our booster vaccine regimens work against omicron.” 

“At this point, there is no need for a variant-specific booster,” he added. “And so the message remains clear: If you are unvaccinated, get vaccinated, and particularly in the arena of omicron, if you are fully vaccinated, get your booster shot.”

When asked if, given the current information about the effectiveness of vaccines against the omicron variant, officials would change the definition of “fully vaccinated” to include a booster dose of a COVID vaccine, Dr. Walensky said experts are continuing to monitor the science. 

“We are continuing to follow that science, and it is literally evolving daily,” she said, adding: “As data science evolves, we will continue to review the data and update our recommendations as necessary.”

The CDC currently defines fully vaccinated as two weeks after the final shot of a two-dose regimen, or two weeks after the single-dose Johnson & Johnson vaccine.