The booster shot conversation: What you should know

Pfizer vaccine, in use at Walter Reed National Military Medical Center. DoD photo by Lisa Ferdinando.

Recently, a lot of U.S. COVID-19 news has centered around booster shots—additional vaccine doses to boost patients’ immunity against the coronavirus. Questions abound: do we need these shots, when might we need them, how do they impact vaccination campaigns?

In other countries, booster shots are being deployed as a measure of extra protection for people with weaker immune systems as Delta spreads. In France, extra vaccine doses are available for organ transplant recipients, those on dialysis, and others. Israel is similarly offering third Pfizer doses to Israelis with medical conditions that cause immunodeficiency. And in Thailand, healthcare workers are getting booster shots of the AstraZeneca vaccine after two doses of Sinovac, which has demonstrated lower efficacy than other vaccines.

Even in the U.S., a small number of immunocompromised patients have received third doses—many of them in clinical trials analyzing how well boosters work. Medical experts tend not to question why boosters may be needed for immunocompromised patients, as their weakened immune systems also make the patients more vulnerable to severe cases of COVID-19.

The real questions come when we start to consider booster shots for everyone. Pfizer, which has developed a third dose for the general population, recently announced that the company applied for Emergency Use Authorization from the FDA. The company says its currently approved two-shot regimen will cause patients to lose some protection six months after they’ve been vaccinated—and become more vulnerable to Delta—with continued lower immunity over time.

Officials at the FDA and CDC, however, have said that boosters aren’t yet necessary. The agencies released a joint statement to that effect, and U.S. health officials say they want to see more data—especially from Israel, where Pfizer has been in heavy use. Pfizer’s data on waning efficacy aren’t yet public (released by press release, not scientific paper), which complicates the conversation. Still, some health officials say we will eventually need booster shots, just not right now, according to POLITICO.

While U.S. public health experts seek more data, our booster shot conversation appears selfish in other parts of the world. While over 3.6 billion doses have been administered globally across 180 countries, high-income countries are getting vaccinated 30 times faster than lower-income countries, according to Bloomberg. More than half of Americans have received at least one shot, compared to under 1% in many African countries.

Dr. Tedros Adhanom Ghebreyesus, Director-General of the WHO, slammed the U.S. and other wealthy nations at a press briefing last week for even considering booster shots. “The priority now must be to vaccinate those who have received no doses and protection,” he said. “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.”

For more details and expert takes on the situation, I recommend this article from several ace STAT News reporters.

More vaccine reporting

  • Booster shots exacerbate global vaccine inequity
    At the end of last week’s post on booster shots, I wrote that these additional doses take up airtime in expert discussions and in the media, distracting from discussions of what it will take to vaccinate the world. But these shots do more harm than just taking over the media cycle. When the U.S. and other wealthy nations decide to give many residents third doses, they jump the vaccine supply line again—leaving low-income nations to wait even longer for first doses.
  • Another COVID-19 endgame take
    Trevor Bedford, computational virologist at the Fred Hutchinson Cancer Research Center—and widely regarded expert on coronavirus variants—wrote a useful Twitter thread this week. In the thread, Bedford provides his take on the “COVID-19 endgame.” In other words, what will happen once the virus reaches endemic levels?
  • Unreliable population numbers hinder vaccination rate analysis
    An excellent article in the Financial Times, published this past Monday, illuminates one major challenge of estimating a vaccine campaign’s success: population data are not always reliable. Health reporter Oliver Barnes and data reporter John Burn-Murdoch explain that, in several countries and smaller regions, inaccurate counts of how many people live in the region have led to vaccination rate estimates that make the area’s vaccine campaign look more successful—or less successful—than it really is.
  • Booster shots: What we’ve learned—and what we still don’t know
    This week, the FDA’s vaccine advisory committee had a two-day meeting to discuss booster shots for Moderna’s and Johnson & Johnson’s COVID-19 vaccines. From the outside, these meetings may have appeared fairly straightforward: the committee voted unanimously to recommend booster shots for both vaccines. But in fact, the discussions on both days were wide-reaching and full of questions, touching on the many continued gaps in our knowledge about the need for additional vaccine doses.
  • COVID source callout: Booster shot trends
    Since August 13, the CDC’s dashboard says, about 7.3 million Americans have received a third dose. These booster shots are obfuscating the country’s vaccination trends. Over one million people have been vaccinated every day for the past week, but roughly half of those people were getting their booster shots.

Leave a Reply