Is a fourth Covid-19 vaccine dose needed? US health officials say not yet

As Covid-19 cases continue to rise and the Omicron variant sweeps the world, some nations are rolling out fourth doses of coronavirus vaccine for the most vulnerable people.

A paramedic with Israel's Magen David Adom medical service gets a vial of the Pfizer-BioNTech Covid-19 vaccine on August 24, 2021 at a vaccination centre in Holon. - Israel lowered the age threshold to receive a third coronavirus booster dose to anyone aged 30 and above, as it continues to battle surging infections. (Photo by Ahmad GHARABLI / AFP) (Photo by AHMAD GHARABLI/AFP via Getty Images)

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Israeli Prime Minister Naftali Bennett’s office announced this week that adults 60 and older, medical workers and people with suppressed immune systems could receive a fourth dose if at least four months have passed since their third dose.

On Thursday, Germany’s health minister Karl Lauterbach said that a fourth dose will be needed to maintain protection against the Omicron variant, though the country has not yet initiated a rollout of fourth doses.

Meanwhile in the United States, it’s too early to be discussing a potential fourth dose of coronavirus vaccine for most people, Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, said Wednesday.

“I think it’s too premature to be talking about a fourth dose,” Fauci told Michael Wallace and Steve Scott of WCBS Newsradio 880.

A woman waits for injection of COVID-19 booster vaccine in Burlingame, California, on Dec. 4, 2021. The new Omicron variant of COVID-19 was identified in more than a dozen Americans in at least 10 U.S. states as of this weekend, early evidence of its presence across the country, as the federal government fights the pandemic with a consistent vaccination campaign, including broader use of vaccines. (Photo by Wu Xiaoling/Xinhua/Getty Images)

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“One of the things that we’re going to be following very carefully is what the durability of the protection is following the third dose of an mRNA vaccine,” Fauci said. Moderna and Pfizer/BioNTech are mRNA vaccines.

“If the protection is much more durable than the two-dose, non-boosted group, then we may go a significant period of time without requiring a fourth dose,” Fauci said. “So, I do think it’s premature – at least on the part of the United States – to be talking about a fourth dose.”

Once data are available on fourth doses, the US Centers for Disease Control and Prevention will examine and consider whether there might be a need for them nationally – but for now, third doses appear to be providing “durable protection,” CDC Director Dr. Rochelle Walensky told CNN’s John Berman on Tuesday.

“If there’s science and when there’s science that demonstrates that that is necessary, we will certainly be reviewing that,” Walensky said.

“Right now, we’re working to make sure that our vaccinated people get a booster,” she said. “We have many vaccines where two shots – primary series – and a booster gives some durable protection. So, while I think it’s an important question to evaluate, it may very well be that we have some added protection by this booster shot right now.”

A medical technician fills a syringe from a vial of the Moderna COVID-19 vaccine in Bates Memorial Baptist Church February 12, 2021 in Louisville, Kentucky.

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Even some vaccine makers have acknowledged that more time is needed to determine if or when a fourth dose could be necessary in the United States, and how quickly protection might wane following a third dose.

“We’re going to have to wait for a couple of months yet until we can see how those data develop and mature to understand when will that additional booster dose – if needed – have to be given,” Paul Burton, Moderna’s chief medical officer, told CNN’s Wolf Blitzer on Thursday.

However, Burton said he did not want to downplay the importance of boosters right now, and that people can be confident in that “getting a booster shot will provide protection throughout the holiday season and throughout these winter months.”

Moderna announced on Monday that preliminary data suggests its half-dose booster shot increased antibody levels against the Omicron variant compared with the levels seen when a fully vaccinated person has not received a booster.

Immunocompromised may need fourth dose, CDC says

While the CDC has not recommended fourth doses of coronavirus vaccine for the general public, the agency updated its guidelines in October to note that certain people who are moderately or severely immunocompromised may receive a fourth dose of the Moderna or Pfizer/BioNTech vaccines.

SAN RAFAEL, CALIFORNIA - OCTOBER 01: Safeway pharmacist Shahrzad Khoobyari (L) administers a Pfizer COVID-19 booster vaccination into the arm of Norman Solomon (R) at a vaccination booster shot clinic on October 01, 2021 in San Rafael, California. Marin County opened its first COVID-19 booster shot clinic inside a former Victoria's Secret store at Northgate Mall. The clinic is giving priority to residents over 75 years old but is open to all ages that are eligible to receive the Pfizer booster. (Photo by Justin Sullivan/Getty Images)

Related article Immunocompromised may need a fourth Covid-19 shot, CDC says

For moderately or severely immunocompromised people who received a two-dose Moderna or Pfizer/BioNTech vaccine series, the CDC recommends a third primary dose to increase protection against Covid-19, and notes that a subsequent dose may be administered.

In the future, some doctors anticipate that the United States could roll out fourth doses of coronavirus vaccine to more people, similar to Israel’s approach.

“What the Israelis understand – and I think a lot of people understand – is that the longevity of the booster is probably somewhat limited, and that after three or four months, we may start to see a lack of durability of the booster shot,” Dr. Jonathan Reiner, a CNN medical analyst and professor of medicine and surgery at George Washington University, told CNN’s Ana Cabrera on Wednesday.

Reiner added that Israel has taken the approach to “boost people that are most in harm’s way now,” such as health care workers, older adults, and people with preexisting illnesses or who are immunocompromised from medical treatments.

“So with more cases mounting around the world, it makes sense to take care of the health care system,” Reiner told Cabrera.

“That’s what the Israelis are going to do, and it’s clear to me that’s what we’re going to do. We’re just going to take it at an unnecessary, unacceptably long period of time to get to the point where we get a fourth dose. And I want to see a sense of urgency. Even more than urgency, I want to see a sense of nimbleness,” Reiner said. “It’s clear that we’re going to boost. We’re going to give a fourth dose to at least a big portion of this population.”

CNN’s Virginia Langmaid and Amanda Sealy contributed to this report.