U.S. moves to approve booster shots despite minimal evidence

Timeline of the scientific results and policy moves leading up to Wednesday’s announcement. Chart via Your Local Epidemiologist.

This week, the federal government announced that the U.S. intends to provide third vaccine doses to all Americans who received the Pfizer or Moderna vaccines. This booster shot distribution will start in September, with adults becoming eligible once they hit eight months after their second shot.

While the booster shot regimen still must be approved by the FDA and CDC, federal officials are making it sound like a pretty sure thing—President Biden himself announced the decision at a press conference on Wednesday. However, many epidemiologists, vaccine experts, global health experts, and other scientists have criticized the decision.

Here are three main criticisms I’ve seen in the past few days.

First: Scientific evidence is lacking. As the booster shot decision was announced on Wednesday, the CDC published three new studies that appear to show a decline in the Pfizer and Moderna vaccines’ ability to stave off symptomatic COVID-19 infection after several months. One of these reports, from a network of U.S. nursing homes, suggests that efficacy among nursing home residents fell to just 53% by June and July 2021, many months after this vulnerable population was vaccinated. The other two reports show similar declines, though the CDC found that vaccination remains effective against severe disease, hospitalization, and death.

The federal government—and others arguing in favor of booster shots—have also pointed to data from Israel, which appear to similarly demonstrate that the vaccines lose their effectiveness after several months. In Israel, where almost 80% of residents over age 12 are vaccinated, the majority of those hospitalized with COVID-19 are now fully vaccinated individuals.

But the act of interpreting these data is more complicated than it first appears. In a blog post at COVID-19 Data Science, biostatistics professor Jeffrey Morris explains that, when the majority of a population is vaccinated, vaccination numbers will go up in this population simply because they are the majority. But the risk remains far higher for the unvaccinated. Plus, Morris explains, stratifying hospitalization numbers by age reveals that older adults are more likely to have a severe COVID-19 case regardless of vaccination status, while younger adults are less likely to be vaccinated (and thus have a non-breakthrough case).

Simply put, the vaccines do still work well against severe COVID-19—you just need to be precise in calculating effectiveness. And yet, the U.S. government is saying that vaccine efficacy wanes so much, everyone’s going to need a third shot in the fall or early next year. This suggests that the federal government has more data that it is not sharing publicly, which leads us to the second criticism.

Second: Transparency is also lacking. Typically, when the government makes a decision about approving a new medical product, this decision follows a series of prescribed steps: data submission from the company behind the product, review by FDA scientists, FDA approval, followed by more review by other agencies (such as the CDC or the Centers for Medicare & Medicaid Services) as needed. Review meetings are typically open to the public, with data shared in advance of a decision. In the case of these booster shots, however, the president has announced a specific rollout plan before full scientific review has taken place.

As STAT’s Helen Branswell explains:

To many experts, including Baylor, the sequencing of the decisions being made is also out of whack. While U.S. health officials said booster shots could start being offered the week of Sept. 20, the Food and Drug Administration has not even ruled yet on Pfizer’s application for approval of a third shot; it was filed only Monday. Moderna hasn’t yet asked the agency to authorize a third shot at all.

Plus, remember that the CDC has not publicly shared any comprehensive data on breakthrough cases since the spring, before Delta became dominant.

The FDA and CDC will certainly still be reviewing the need for booster shots, but the experts cited in Branswell’s piece are skeptical that any decision other than, “Yes, go ahead” will be considered. I, for one, will be very curious to see how the discussions proceed—and what data get cited—at the FDA and CDC committee meetings.  

Third: We need to vaccinate the world. As I’ve explained in the CDD before, getting vaccines to the low-income nations that have yet to start their rollouts is not just a humanitarian priority. It also protects us, here in the U.S., because the longer the coronavirus circulates, the more opportunities it has to mutate into increasingly-dangerous variants.

By moving to provide booster shots to everyone—not just the immunocompromised, the elderly, or the otherwise extra-vulnerable—the U.S. is likely delaying shots to other countries, prolonging the pandemic overall.

As Dr. Michael Ryan, emergencies chief at the World Health Organization, told reporters last week: “We’re planning to hand out extra life jackets to people who already have life jackets, while we’re leaving other people to drown without a single life jacket.”

More vaccine news

  • We need more data for fall booster decisions
    This week, the FDA’s vaccine advisory committee met to discuss fall booster shots, in anticipation of another COVID-19 surge next winter. The discussion demonstrated the U.S.’s continued failure to provide the data that are really needed to make these decisions.
  • Sources and updates, May 8
    Sources and updates for the week of May 8 include booster shots, vaccine attitudes, wastewater data, and source diversity.
  • The US still doesn’t have the data we need to make informed decisions on booster shots
    Last fall, I wrote that the U.S. did not have the data we needed to make informed decisions about booster shots. Several months later, we still don’t have the data we need, as questions about a potential BA.2 wave and other future variants abound. Discussions at a recent FDA advisory committee meeting made these data gaps clear.
  • Sources and updates, March 13
    Sources and updates for the week of March 13 include vaccine data annotations, free rapid tests, a combination of Delta and Omicron, and more.
  • Pandemic preparedness: Improving our data surveillance and communication
    What has the U.S. learned from the last two years, and what lessons can we take forward for future COVID-19 surges and other infectious disease outbreaks? The Biden administration has released a new pandemic preparedness plan that addresses these questions.

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