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As the pandemic wears on, some Americans could need booster shots

Some health officials now think a third shot could help older and immunocompromised people.

A man holding a yellow sign that says “vaccine” directs people towards a mobile Covid-19 vaccine clinic in Los Angeles, California.
Willie Golden directs people towards a mobile Covid-19 vaccine clinic, hosted by Mothers In Action in collaboration with LA County Department of Public Health, on Friday, July 16, 2021 in Los Angeles, California.
Irfan Khan / Los Angeles Times via Getty Images

The Biden administration now believes that fully vaccinated people who are older or immunocompromised may need a booster shot.

Though all three vaccines authorized for use in the United States — Pfizer/BioNTech, Moderna, and Johnson & Johnson — are highly effective in preventing Covid-19 infections, recent data suggests that the efficacy of Pfizer’s two-dose vaccine can wane slightly four to six months after vaccination, according to the New York Times.

However, a booster shot could lift antibody levels even more substantially than the current two-dose regimen for the Pfizer and Moderna vaccines, and could be especially beneficial for people 65 and older and those who are immunocompromised.

People who are immunocompromised may receive significantly less immune protection than the general population after two vaccine doses, increasing the upside of a potential third shot.

According to a Centers for Disease Control and Prevention advisory committee, which met earlier this week to discuss the potential need for booster shots, about 2.7 percent of the US population is currently immunocompromised in some way, whether due to ongoing medical treatment like chemotherapy, their status as organ transplant recipients, or another reason.

Immunocompromised people are also more likely to become severely ill from Covid-19, and they have a markedly higher chance of experiencing breakthrough infections despite being vaccinated — a concern magnified by a delta variant-fueled resurgence of Covid-19 cases in the US.

As things stand, data from Pfizer indicates that its vaccine — the first to be authorized in the US, and still the most common among US vaccine recipients — declines from 95 percent to 84 percent effectiveness against symptomatic infection after four to six months, according to the Times’ Sharon LaFraniere.

Data from Israel, where Covid cases are once again rising, suggest that an even sharper decline in effectiveness against symptomatic infections is possible — but even then, the vaccine remains “more than 90 percent effective in preventing severe disease,” and the small sample size means there is still uncertainty about Israel’s findings.

“The goal of this vaccine is not to prevent mild or low, moderate infectious disease,” Dr. Paul Offit, a member of the Food and Drug Administration’s outside advisory committee, told the Times. “The goal is to prevent hospitalization to death. Right now this vaccine has held up to that.”

A booster shot administered at the six-month mark could increase antibody levels as much as tenfold, according to data released earlier this year by both Pfizer and Moderna, underscoring its potential value to older and immunocompromised people.

Israel is already offering a third Pfizer shot for immunocompromised residents — though millions of Palestinians in the West Bank and the Gaza Strip have yet to be vaccinated — and Pfizer has previously suggested that a booster shot could be needed in the US.

Regulatory questions abound

Though the US currently has tens of millions of surplus Covid-19 vaccine doses on hand, making a third Pfizer or Moderna shot available to millions of immunocompromised or elderly Americans likely won’t be a quick process.

Currently, all three Covid-19 vaccines in use in the US are being administered under an emergency use authorization, or EUA, issued by the FDA, which sets specific regimens for each vaccine: two doses several weeks apart for both Pfizer and Moderna, and a single dose for Johnson & Johnson.

Changing that, according to the Washington Post, would require either full FDA approval for the vaccine or an amendment to the EUA. And until that happens, the CDC’s Advisory Committee on Immunization Practices can’t go forward with recommending a third shot for vulnerable populations in the US.

According to the New York Times, “doctors would have vastly more leeway to prescribe a booster for their patients” once the vaccine is fully approved by the FDA.

However, there are some potential workarounds to get third shots in arms more quickly. According to Dr. Amanda Cohn, chief medical officer for the CDC’s immunization and respiratory diseases center, the US is “actively looking into ways ... to potentially provide access earlier than any potential change in regulatory decisions” — including through “a study, or through an investigational new drug format.”

As the Washington Post reported after the advisory board meeting earlier this week, that strategy could open up access to a third shot under the FDA’s compassionate use program, which “would require enrolling individuals in a clinical study where additional doses can be given.”

President Joe Biden also struck an encouraging tone on the prospects for the FDA’s full vaccine approval in coming months, at a recent town hall in Cincinnati, Ohio.

“They’re [the FDA] not promising me any specific date, but my expectation, talking to the group of scientists we put together... plus others in the field, is that sometime, maybe in the beginning of the school year, at the end of August, beginning September, October, they’ll get a final approval,” Biden told CNN’s Don Lemon on Wednesday.

President Joe Biden gestures on stage at a town hall in Cincinnati, Ohio
President Joe Biden participates in a CNN town hall hosted by Don Lemon at Mount St. Joseph University in Cincinnati, Ohio on July 21, 2021.
SAUL LOEB/AFP via Getty Images

Full FDA approval requires a massive amount of data, including at least six months of vaccine efficacy data, and it usually takes about 10 months for the agency to review license applications and reach a decision.

“When we were reviewing applications back when they were on paper, there was so much, it would not fit on the freight elevator,” Norman Baylor, the former head of the FDA’s Office of Vaccines Research and Review, told CNN. “That’s how big the application is.”

However, the Pfizer/BioNTech vaccine has already been granted a priority review, which shortens the potential timeline to six months, and multiple officials have said approval will likely come even sooner, potentially clearing the way for booster shots for older and immunocompromised people.

Moderna is currently “in the process of completing our rolling submission” to the FDA, according to a Moderna spokesperson, and approval for the Moderna vaccine will almost certainly take longer. The company told CNN this week that it has no specific timeline in place yet.

Full FDA approval could also have a number of other benefits, in addition to opening up the possibility of booster shots for vulnerable groups. As NBC’s Shannon Pettypiece explained on Tuesday, “the official regulatory signoff would remove a significant legal and public relations barrier for businesses and government agencies that want to require vaccinations for their employees and customers,” and could also boost vaccine confidence.

Thus far, the US has largely held back from imposing vaccine mandates, though other countries, such as France, have embraced them to positive effect.

The delta variant is spreading fast

As the Biden administration consensus coalesces behind the need for a booster shot for vulnerable groups, the delta variant of Covid-19 is gaining ground quickly in the US, fueling a sharp rise in new cases.

On Saturday, the US reported a rolling seven-day average of nearly 50,000 cases per day — the highest level since early May, according to CNN’s Ryan Struyk, and almost 39,000 more cases than the same seven-day average in late June.

Additionally, at a Thursday White House briefing on the pandemic, CDC director Dr. Rochelle Walensky warned that the delta variant “now represents more than 83 percent of the virus circulating in the United States.”

“Compared to the virus we had circulating initially in the United States at the start of the pandemic, the delta variant is more aggressive and much more transmissible than previously circulating strains,” Walensky said. “It is one of the most infectious respiratory viruses we know of and that I have seen in my 20-year career.”

As Vox’s Umair Irfan explained in late June, when delta accounted for just 20 percent of new Covid cases in the US, the CDC has identified delta as one of five “variants of concern.” Not only does it spread far faster than the original strain of Covid, but it’s better at evading vaccine protections, and, as Irfan reports, there’s some evidence that it can cause “more severe outcomes from Covid-19 compared to the original versions of the virus.”

Despite those breakthrough cases, however, the delta surge is overwhelmingly proving to be “a pandemic of the unvaccinated,” as Walensky put it earlier this month. In the US, more than 99 percent of recent deaths and about 97 percent of recent hospitalizations from Covid-19 have been among unvaccinated individuals.

As a result, this latest virus outbreak has been especially bad in parts of the US with low vaccine uptake, such as rural Missouri.

As The Atlantic’s Ed Yong reported from Missouri earlier this month, “ICUs are also filling with younger patients, in their 20s, 30s, and 40s, including many with no underlying health problems.”

According to Yong,

Almost every COVID-19 patient in Springfield’s hospitals is unvaccinated, and the dozen or so exceptions are all either elderly or immunocompromised people. The vaccines are working as intended, but the number of people who have refused to get their shots is crushing morale. Vaccines were meant to be the end of the pandemic. If people don’t get them, the actual end will look more like Springfield’s present: a succession of COVID-19 waves that will break unevenly across the country until everyone has either been vaccinated or infected.

A swath of southern states, including Louisiana and Florida, are currently reporting more cases per 100,000 people than anywhere else in the US, with Florida alone contributing more than one-fifth of all new cases in the US.

“Folks [are] supposed to have common sense,” Alabama Gov. Kay Ivey, a Republican, said this week. “But it’s time to start blaming the unvaccinated folks, not the regular folks. It’s the unvaccinated folks that are letting us down.”

Currently, only 34 percent of Alabamans are fully vaccinated — the worst vaccination rate of the any state in the US, along with Mississippi.

Getting vaccinated protects individuals — and the whole community

As of Saturday, about 57 percent of the vaccine-eligible population in the US — more than 162 million people — have been fully vaccinated, according to data from the CDC. Another 15 million or so more have received at least one dose of the vaccine.

That level of widespread vaccination is unequivocally good news, but with US Covid cases on the rise and the delta variant running rampant, it invariably also means some of the new Covid cases in the US are “breakthrough infections” — fully vaccinated people nonetheless testing positive for Covid-19.

As Vox’s Umair Irfan explains,

The CDC definition of a breakthrough infection is a laboratory-confirmed infection more than 14 days after the final dose of a Covid-19 vaccine, as it can take a while for the full protection of a vaccine to spool up. This definition includes everything from infections that produce no symptoms at all to cases that result in death. “People often think about ‘infection’ and ‘disease’ as being the same thing, and that is not the case,” said Brianne Barker, a virologist at Drew University.

It’s only when a virus starts causing symptoms that an infected person is said to have disease, so not all SARS-CoV-2 infections cause Covid-19. But as we’ve seen throughout the pandemic, people can carry and transmit the virus without falling ill themselves, creating a major route for the spread of Covid-19. That’s why tracking breakthrough cases is so important.

The good news about breakthrough infections, though, is that if you’re vaccinated and get sick with Covid-19, you’re far less likely to get severely ill than you would without a vaccine. With a vaccine, the chance of hospitalization and death are both reduced compared to unvaccinated individuals, according to Dr. Anthony Fauci, the United States’ top infectious disease expert.

“If you look at the number of deaths, about 99.2 percent of them are unvaccinated. About 0.8 percent are vaccinated,” Fauci told NBC’s Chuck Todd on Meet the Press earlier this month. “No vaccine is perfect. But when you talk about the avoidability of hospitalization and death ... it’s really sad and tragic that most all of these are avoidable and preventable.”

Currently, the country is administering about 537,000 doses per day on average, down from more than a million per day on average at the start of July — and that dropoff could fuel a brutal, self-reinforcing cycle.

Specifically, according to Irfan, “with vaccination rates slowing, reports of people becoming infected after their immunizations could feed vaccine hesitancy, which in turn can fuel more breakthrough cases.”

In reality, however, getting vaccinated actually heads off the risk of further breakthrough infections by making it harder for the virus to spread. And by the same token, getting more people vaccinated will also go a long way toward protecting older and immunocompromised people who have already been vaccinated but may now need a booster shot.

“Each day, hundreds of thousands of Americans are choosing to protect themselves, their kids, and their neighbors by getting their first shot,” White House Covid czar Jeff Zients said this week. “These Americans are stepping up and doing their part. Each shot matters. Each additional person fully vaccinated is a step closer to putting this pandemic behind us.”