The Biden administration is "in discussions" to ensure that it can obtain booster COVID-19 shots if they become necessary, a top official told lawmakers on Thursday. The announcement comes as drugmakers are touting their progress in developing the additional shots, which are designed to increase the body's immune response months after the initial doses are administered.
"We are in discussions right now, making sure that we can secure those vaccines for a boost or variants. We are in that process right now," Dr. David Kessler, chief science officer for the administration's COVID-19 response, told the House Select Subcommittee on the Coronavirus Crisis.
Federal health officials and drugmakers have said for months that booster shots would likely be required at some point, though it's not yet clear when that will be. The shots will likely be very similar to the original version of the vaccines, but may be administered in different doses or be tweaked to protect against variants.
Kessler cautioned that "no decision" had been reached over the strategy of how the booster shots would be administered, citing ongoing research into how long the immunity created by the vaccines lasts. Recent studies from Pfizer and Moderna suggest their COVID-19 shots remain effective for at least 6 months.
"With many vaccines, we understand that at a certain point in time we need to boost, whether that's 9 months, 12 months. And we are preparing for that," Kessler said.
The companies behind all three of the COVID-19 vaccines currently allowed for use in the United States have said they are pursuing additional shots.
"There will be likely a need for a third dose, somewhere between 6 and 12 months. And then from there. There will be an annual revaccination. But all of that needs to be confirmed," Pfizer CEO Albert Bourla said Thursday at a virtual event hosted by CVS Health.
In February, Pfizer announced it was launching a study with their German partners BioNTech to examine a third dose of its vaccine, delivered 6 to 12 months after participants completed their first two doses. Moderna announced plans to test an additional booster shot of its own in late January.
"We believe especially people at high risk should get a boost in the fall, and we want to make sure we have the best possible boost," Moderna CEO Stéphane Bancel told Yahoo Finance on Wednesday, adding that he expects a "boost market" as governments work to secure booster doses.
The National Institutes of Health also announced in late March that it was launching early trials into a version of Moderna's vaccine tweaked to target the B.1.351 virus variant first spotted in South Africa. Pfizer is working on a potential version of its vaccine for B.1.351, though the drugmaker said earlier this month that its shots appeared highly effective against the mutant strain.
Johnson & Johnson had been actively recruiting for its "ENSEMBLE 2" study to evaluate a two-dose regimen instead of its current single-shot vaccine. But trials have been paused by the company over concerns of the rare clotting events currently being investigated by the CDC and FDA.
Data from all three trials will need to be scrutinized by the FDA, which laid out updated guidelines for authorizing additional doses of the vaccines earlier this year. Even small tweaks to the next generations of COVID-19 vaccines will need to be supported by some clinical research, though in smaller trials than the vast numbers of people that were needed to test the initial doses.
"Probably after we do that three or four times, we'll look at everything and if everything seems consistent, then we might move more towards the influenza-like model," Dr. Peter Marks, director of the FDA's Center for Biologics Evaluation and Research, said in February.
But finding space for the booster doses could prove tricky. The Government Accountability Office warned this week that use of the Defense Production Act to prioritize COVID-19 vaccine production has strained capacity for other critical drugs, including the seasonal flu vaccine.
Making the next round of doses for Americans could also further delay a global vaccination effort already facing what WHO Director-General Dr. Tedros Adhanom Ghebreyesus described as "severe supply constraints."
While the U.S. has already administered nearly 200 million doses, touting nearly 1 in 2 adults with at least one shot, the World Health Organization warned Wednesday that less than 0.2% of the global supply of vaccines had reached low income countries.
"Global manufacturing capacity and supply chains have not been sufficient to deliver vaccines quickly and equitably where they are needed most. More funding is needed, but that's only part of the solution. Money doesn't help if there are no vaccines to buy," Ghebreyesus said.