Booster shots against the covid-19 coronavirus may become a regular necessity, according to recent comments from David Kessler, chief science officer for President Joe Biden’s covid-19 task force, as well as from Pfizer CEO Albert Bourla.
Kessler said during a House congressional committee meeting today that booster shots may be needed within a year and that “those who are more vulnerable will have to go first” in getting them. The reason, he said, is the vaccine-provided immunity could wane over time and may be “challenged” by new variants of the virus.
The head of Pfizer, the maker of one of the covid-19 vaccines authorised for emergency use in the U.S., said in a recent interview that it was “likely” that people would need a third booster shot of their vaccine within 12 months. Bourla also left open the possibility that annual shots against the coronavirus could be a reality.
Bourla’s statements were made during an interview with CNBC, as part of an event jointly held by CVS Health. The event aired Thursday but took place two weeks ago, on April 1. In discussing the potential long-term protection offered by Pfizer’s vaccine, Bourla brought up other vaccine-preventable viral diseases like polio and influenza, which require different vaccine schedules. And in the case of the coronavirus, it’s probably closer to the flu, which requires annual vaccination.
“A likely scenario is there will be likely a need for a third dose somewhere between six and 12 months and then from there there would be an annual revaccination,” Bourla said.
The similar mRNA-based vaccines made by Pfizer/BioNTech and Moderna have been highly effective (over 90%) at preventing illness from covid-19, especially serious illness and death. And more recent real-world evidence has suggested that they’re about as effective at preventing infection and greatly reducing the risk of transmission. Earlier today, the Wall Street Journal reported that the Centres for Disease Control and Prevention has so far only identified 5,800 “breakthrough” cases out of 66 million Americans given a covid-19 vaccine, an infection rate of less than 0.008%. Of these rare cases among fully vaccinated people, a third have been asymptomatic, 7% have needed hospitalisation, and about 1% have died — 74 deaths total. For comparison, around 1,000 people have been dying every day from covid-19 in the U.S. this spring, with over 3,000 people dying every day during the winter peak.
Other research has suggested that reinfection is rare in people naturally infected at least three months later, while recent data from Pfizer’s clinical trials has suggested that vaccine-provided immunity remains strong for at least six months. It’s certainly possible that these vaccines will provide durable protection for even longer than that.
Our current vaccines are still widely effective against different variants of the coronavirus that have emerged in recent months, but some (such as B.135, first found in South Africa) do seem slightly better at evading immunity than others. And even before these variants were widely spreading, scientists were warning that the coronavirus could meaningfully mutate down the road in ways that would allow it to evade the immunity provided by natural infection or vaccination.
Both Pfizer and Moderna are currently conducting trials of a booster strategy against B.135, and Moderna is also testing a modified dose of its vaccine meant to target the variant specifically. Ultimately, though, the best long-term solution to our covid woes will likely be a universal vaccine that can effectively target any and all future strains of the virus — a plan that scientists are already working on, according to Anthony Fauci, who also spoke in front of House members on Thursday.