Moderna Inc.’s Omicron-targeting vaccine triggered the production of antibodies against the strain’s newest variants, though the immune response was less robust than seen with the original version that emerged late last year.
Everyone given Moderna’s lead Omicron immunization generated neutralizing antibodies against BA.4 and BA.5 in the latest trial involving about 800 people, the Cambridge, Massachusetts-based company said in a statement. However, the amount of antibodies induced against the newer strains was lower than the shot produced against the original version of Omicron.
As the coronavirus continues to mutate, medical experts are trying to decide when and how to modify vaccines to fight emerging and future variants. Moderna’s lead candidate to replace its existing COVID inoculation combines parts of its original shot with elements that specifically target Omicron. The results are encouraging, company officials said.
“The antibody levels are still extremely high,” and should be enough to provide good protection against newer variants, Paul Burton, Moderna’s chief medical officer, said in an interview. “It is really reassuring.”
Still, some analysts were dubious how long protection from the booster would last. The vaccine generated “nowhere near as much” of a response against the new variants compared to the first Omicron, Bloomberg Intelligence analyst Sam Fazeli wrote in a note Wednesday. “Durability is likely to be low.”
Moderna shares fell as much as 2.6% at the New York open.
The results will be submitted urgently to regulators, Chief Executive Officer Stephane Bancel said in the statement. The company is preparing to supply the next-generation bivalent booster shot starting in August, he said.
Rising cases
Earlier this month, Moderna reported data from the same trial showing the bivalent vaccine generated a superior immune response against the original Omicron strain. In the new data, the company evaluated how it stacked up against the the BA.4 and BA.5 variants that account for a rising share of U.S. cases.
In the new analysis, antibody levels against the newer variants were evaluated in the roughly half of participants who were given a booster shot of the new vaccine. It increased their antibodies against the newer variants by 5.4-fold compared to levels before getting it.
Neutralizing antibodies against BA.4 and BA.5 “were approximately 3-fold lower” than those against the original omicron strain, the company said.
Rival vaccine manufacturers Pfizer Inc. and BioNTech SE are expected to have data soon from the Omicron-specific booster shots they are developing together.
On June 28, advisers to the Food and Drug Administration will meet to discuss whether future COVID immunizations should be modified to account for changing variants, and if so, which strains should be included for the fall when cases may rise with cooler weather.
BA.4 and BA.5 accounted for about 35% of U.S. cases in mid-June, up from around 9% of cases at the end of May, according to U.S. government estimates.
