Listen Live

Dr. Anthony Fauci said Wednesday that those who have received the COVID-19 vaccine will likely need a booster shot within eight to 12 months.

>> Read more trending news

“I think we will almost certainly require a booster sometime within a year or so after getting the primary because the durability protection against coronavirus is generally not lifelong, similar to measles,” Fauci said.

“We know that the vaccine durability of the efficacy lasts at least six months, and likely considerably more,” Fauci said.

Albert Bourla, chief executive officer of the pharmaceutical company Pfizer, agreed with Fauci that a booster shot will likely be needed. Pfizer is one of three companies that has gained emergency use approval by the U.S. Food and Drug Administration for a COVID-19 vaccine.

“I believe in one, two months we will have enough data to speak about it with much higher scientific certainty,” Bourla said.

Bourla, during an Axios COVID-19 livestream this week, said that Pfizer is still conducting trials on the booster shot and the results should show whether additional shots will be needed.

According to Pfizer, the COVID-19 vaccine probably acts more like measles vaccines than flu vaccines. The flu vaccine is a yearly vaccine that is tweaked to fight the flu variant researchers believe will be prevalent in the world during flu season. The measles vaccine is given to youngsters who then require booster shots about four years later.

Bourla said if the trials prove they are needed, the booster shots could begin to be given in September or October. The FDA will have to approve the use of the booster shot before they can be given.

Moderna, whose vaccine was approved for emergency use a week after Pfizer’s was in December, is working on a booster shot said to be a half-dose of the vaccine it is giving now.

According to the vaccine maker, trials have shown the booster shot sparked an immune response against the virus and two variants of the virus currently active around the world. Moderna’s booster shot trials are showing an increase in protection against the virus two weeks after the shot was given, the company reported. The booster shot fights off not only the virus, but its variants, the company said.

“We are encouraged by these new data, which reinforce our confidence that our booster strategy should be protective against these newly detected variants,” Moderna CEO Stéphane Bancel said in the statement.

Johnson & Johnson, the third company whose vaccine has been approved for emergency use in the U.S., says it, too, is conducting trials to determine if a booster shot is needed for its vaccine.

The question of whether people will need a booster is receiving some pushback from researchers who say not enough information is available to make the decision.

The U.S. and other governments have begun to increase orders for vaccines even though it is not yet clear they will be needed, a story in The Wall Street Journal reported.

According to the story, the case for a booster shot would depend on two things — whether vaccine-induced immunity fades with time and whether the vaccine is effective against variants of the virus.

Researchers are still studying those issues.

“We don’t have a full picture of what the pathway is to protection,” Gigi Gronvall, an immunologist and associate professor at the Johns Hopkins Bloomberg School of Public Health, told the Journal.

CDC Director Dr. Rochelle Walensky said the agency is also following research to determine if a booster shot will be needed.

“Right now, if you have two doses of the mRNA vaccines, you are protected,” Walensky said in comments that aired last week during CNBC’s Healthy Returns Summit.

“What we’re talking about is thinking ahead. What happens if in a year from now or 18 months from now your immunity wanes? That’s really our job is to hope for the best and plan for what might happen if we need further boosters in the future, the way we get flu vaccine boosters every year.”

More coronavirus pandemic coverage:

>> Coronavirus: How long between exposure to the virus and the start of symptoms?

>> What are your chances of coming into contact with someone who has COVID-19? This tool will tell you

>> How to not let coronavirus pandemic fatigue set in, battle back if it does