WASHINGTON (SBG) — As COVID-19 cases surge and the highly infectious delta variant spreads across the United States, drugmakers and federal health officials remain divided over when and if people who have been vaccinated might need booster shots to bolster their immunity.
With the federal government focused on convincing hesitant Americans to line up for initial doses, officials have downplayed concerns that the efficacy of the vaccines will wane over time. They have emphasized that two doses of the Pfizer or Moderna vaccines or a single dose of the Johnson & Johnson vaccine appear to work against all known variants.
“These vaccines are some of the most effective that we have in modern medicine,” Dr. Rochelle Walensky, director of the Centers for Disease Control and Prevention, said at a White House briefing Thursday. “And the good news is that, current scientific evidence shows that our current vaccines are working as they did in clinical trials, even against the delta variant.”
However, Dr. Anthony Fauci, the federal government’s top infectious disease expert, acknowledged in an interview with CNN Sunday there appears to be “some diminution in protection” from the Pfizer vaccine over time. He suggested those who have suppressed immune systems due to conditions like organ transplants, cancer treatment, or autoimmune diseases might soon need another shot.
“Those are the kind of individuals that, if there's going to be a third boost, which might likely happen, will be among the vulnerable,” Fauci said.
Ugur Sahin, CEO of BioNTech—the German company that teamed with Pfizer to develop the first COVID-19 vaccine to receive emergency use authorization—told The Wall Street Journal evidence is growing that the effectiveness of the initial two-dose regimen of their drug had begun to fade amid the spread of the delta variant. He stopped short of explicitly recommending booster shots, saying governments would need to decide for themselves based on the data the companies provide.
“The vaccine protection against the new variant is considerably lower,” Sahin said.
Sahin cited research from Israel, where people who were vaccinated in January were three times more likely to get infected recently than those where were vaccinated in May. However, even those who were inoculated earlier typically did not experience severe symptoms if they caught the virus.
Preliminary data from a relatively small study published by Israel’s Health Ministry indicated the Pfizer vaccine was 39% effective at reducing the risk of infection between June 20 and July 17, when the delta variant was dominant in the country. It was still 91% effective at preventing serious illness, though.
A separate study in the United Kingdom released last week concluded Pfizer and AstraZeneca’s vaccines were both highly effective against the delta variant in those who received two doses, with the Pfizer vaccine preventing symptomatic infection in 88% of people who were fully vaccinated. A single dose of either vaccine was found to offer far less protection.
While breakthrough infections among the vaccinated are a concern in the U.S., recent data similarly suggests the Pfizer, Moderna, and Johnson & Johnson vaccines can defend against the worst consequences. An internal CDC document obtained by ABC News estimated there had been approximately 153,000 symptomatic breakthrough cases reported so far, which accounts for less than 0.1% of the vaccinated.
“It is very much about making sure people don’t get sick and die,” said Dr. Joanna Drowos, an associate professor of integrated medical science at Florida Atlantic University.
Given that the vaccines still seem to prevent serious symptoms, Dr. Eleanor Wilson, an infectious disease expert at the University of Maryland School of Medicine, cautioned against interpreting the Israeli study as proof that protection is weakening. If the problem is that the delta variant is simply different from the strain of COVID-19 the vaccines were designed to fight, administering more of the original antibodies might not make much difference.
“It’s sort of conflating two things,” Wilson said.
A recent study published in Nature found the immune response produced by Pfizer and Moderna’s mRNA-based vaccines has characteristics that should lead to long-lasting protection. As the delta variant has demonstrated, the emergence of new variants can undermine that protection, potentially requiring either an additional dose of the original vaccine or an augmented version engineered to counter the variant.
BioNTech’s partners at Pfizer have been more aggressive than Sahin in pushing for boosters, and Pfizer CEO Albert Bourla has been saying for months he expects a third shot will likely be necessary within a year. The companies announced earlier this month they plan to seek Food and Drug Administration emergency authorization for a booster shot in the near future.
In trials, the companies have found a third dose administered six months after the second dose produces levels of antibodies five to 10 times higher. Still, the CDC and FDA issued a joint statement on July 8 rejecting calls for booster shots, saying the decision on whether to recommend an additional shot would be dictated by “a science-based, rigorous process.”
At a meeting in mid-July, federal scientists and regulators pressed Pfizer representatives to provide more evidence in support of booster shots. According to The New York Times, officials indicated several months of additional data might be required before a decision can be made.
Officials in Israel already began offering a third dose of the Pfizer vaccine to immunocompromised individuals in early July. With over 65% of their country at least partially vaccinated, they are still debating whether to recommend another dose for the wider population.
The CDC's Advisory Committee on Immunization Practices discussed issuing similar guidance to those with weakened immune systems in the U.S. last week. After reviewing findings from several small studies of transplant and dialysis patients, members of the committee concluded an additional dose for the immunocompromised would be helpful and would not be likely to cause harm.
The panel cannot formally recommend booster shots unless the FDA updates its emergency use authorization or grants full approval of a vaccine first. Pfizer applied for full approval in May and Moderna submitted its application in June, but it is unclear how long the “priority review” process for either will take at this point.
Federal officials might not be convinced booster shots are justified, but they are taking steps to ensure there are doses available if their position changes. On Friday, Pfizer announced the U.S. government purchased 200 million additional doses of its vaccine to be delivered between October 2021 and April 2022, with an eye toward immunizing children and administering boosters.
In the meantime, new infections are rising steadily, up 10% over the last week nationwide with several states seeing new cases increase by 50% or more, and hospitals in some communities are filling up with mostly unvaccinated patients. Federal officials said last week 97% of those being hospitalized are unvaccinated, and 99.5% of deaths are among the unvaccinated.
“This pandemic is spiraling out of control yet again,” former Surgeon General Dr. Jerome Adams said on CBS’ “Face the Nation” Sunday. “And it’s spiraling out of control because we don’t have enough people vaccinated.”
As of Sunday morning, 49.1% of the U.S. population was fully vaccinated, and 69% of all adults had received at least one dose. Federal officials have cited promising signs that the pace of vaccination has accelerated in recent days, but they are still confronting persistent opposition from a large segment of the population.
“I think we’re in a position where we need more Americans to get the vaccine, period,” Drowos said. “What’s happening with the delta variant is frightening Messaging that we want everyone vaccinated is truly the priority.”
Although there has been no indication that another dose of any of the vaccines being administered in the U.S. would be harmful, Wilson said offering boosters prematurely might be a waste of a shot that could have been used to inoculate someone else. The immunocompromised have had a weaker response to the vaccines, but increasing community protection and preventing the spread of the virus around them would also keep them safe.
“That population might be better served by more people getting the vaccine themselves,” she said.
The initial rollout of COVID-19 vaccines in the U.S. has involved an unprecedented mobilization of federal and state resources to administer more than 340 million doses of vaccines in eight months. A booster shot campaign could look much different, both because there is no longer a shortage of supplies and because recommendations for an additional dose could be targeted to specific vulnerable populations.
“If the recommendation were to come, the implementation would not be challenging,” Drowos said.
As wealthy countries weigh the costs and benefits of administering extra doses to their citizens, the World Health Organization has criticized them for hogging the global vaccine supply while only a small fraction of residents of less developed countries have been immunized. WHO Director-General Tedros Adhanom Ghebreyesus recently accused countries approving booster shots of making “conscious choices not to protect those in most need.”
"Instead of Moderna and Pfizer prioritizing the supply of vaccines as boosters to countries whose populations have relatively high coverage, we need them to go all-out to channel supply to COVAX, the Africa Vaccine Acquisition Task Team and low and low-middle income countries, which have very low vaccine coverage,” Tedros said.
Experts have long warned allowing the virus to spread unchecked in other parts of the globe could lead to new variants developing and reaching more developed countries, including some that are resistant to vaccines. The U.S. has committed to donating tens of millions of doses to other countries, but the need still far outstrips the supply.
Wilson agreed administering first doses to parts of the U.S. and the world with lower vaccination rates delivers the most “bang for your buck,” but she added that does not have to come at the expense of booster shots for the immunocompromised if that is deemed effective. Pfizer, Moderna, and other manufacturers are stepping up production, and there should be enough vaccines to go around.
“It’s not necessarily one thing or another,” she said. “I think we can do all of the above.”