“Based on all the data we now have in hand, we have confidence in bivalent covid-19 vaccines and their ability to create better protection against covid-19, including these currently circulating variants, than the original vaccine wouldn’t have,” Peter Marks, director of the Food and Drug Administration’s Center for Biologics Evaluation and Research, said. He urged the public to consider getting the updated recall before Thanksgiving.
Pfizer presented the data in a press release, and it has not been peer reviewed or published.
The press release does not directly address a concern raised by small studies over the past week that immune evasion variants that have recently emerged and are rapidly taking over appear to be much better at evading anti-virus antibodies. generated by the recall.
One of the most threatening new variants gaining traction in the United States, BQ.1.1, is linked to BA.5, a component of the new recall, so Marks said he hoped the bivalent vaccine would hold up, in especially against serious illnesses and hospitalization.
What you need to know about covid boosters and the latest research
The new data also adds to, but does not resolve, an ongoing scientific debate about how much better new boosters are than old boosters. This remains a critical issue for scientists to address as they design a long-term vaccine strategy against the virus. But this technical debate is largely separated from the public health question of whether to get a recall. Old boosters have been replaced by bivalent vaccines, with the exception of the Novavax vaccine, and data from Pfizer shows that the new vaccines provide a significant boost to antibodies, a key line of immune defense.
The new vaccine boosted BA.4/BA.5 blocking antibody levels over pre-booster levels in adults of all ages – a 9.5-fold increase in adults under 55 and a 13.2 times in older adults.
Some scientists have argued that a 10-fold increase from baseline would likely be clinically significant, and the Pfizer vaccine has triggered a change of this magnitude in adults.
In adults over 55, the new booster elicited a stronger immune response against BA.4 and BA.5 than the original booster, although it is unclear whether the difference, measured in tests laboratory, would provide a significant difference in the way people were. protected.
It was unclear whether the new vaccine also caused a stronger response than the old booster in young adults, as there was no comparison group of young adults who received the original vaccine.
One month after vaccination, the new booster triggered a four-fold increase in omicron-blocking antibody levels against the BA.4/BA.5 version of omicron compared to the old booster in the elderly. That’s a benefit, but scientists have differing opinions on whether it will make a difference in how likely people are to get sick or how long they’ll be protected.
Marks said a fourfold increase in antibodies compared to the original vaccine could better protect people against symptomatic infection and increase the durability of protection, as the antibodies – which break down over time – would shrink by a higher initial level. Other scientists questioned whether this fourfold difference was large enough to provide a major benefit in terms of hospitalizations averted and lives saved over the old booster.
The debate is a moot point for this winter. Bivalent boosters clearly boost immunity and are an essential tool in the face of a possible winter flare. But they also raised questions about how to design the best vaccine strategy for a population that has a varied history of infection and vaccination.
“We must now seriously rethink the national policy of vaccination against covid. Chasing variants with booster redesigns is clearly not a sustainable solution,” said John P. Moore, professor of microbiology and immunology at Weill Cornell Medicine, who criticized the formulation chosen for the booster-specific booster. ‘omicron.
Adoption of updated boosters has been disappointing. According to the Centers for Disease Control and Prevention, only 10% of people 18 and older have received a new booster. The low booster coverage is particularly concerning among adults aged 65 and over, who are at increased risk of complications from the coronavirus due to their age. About 23% of people in this age group received the new reminders.