An Omicron-targeted vaccine

Moderna says trial shows COVID combo shot boosts protection against the variant.

Moderna’s experimental COVID-19 vaccine that combines its original shot with protection specifically targeted against the Omicron variant appears to work, the company said Wednesday.

COVID-19 vaccine makers are studying updated boosters that might be offered in the fall to better protect people against future coronavirus surges.

Moderna’s preliminary study results show that people given the combination shot experienced an eightfold increase in virus-fighting antibodies capable of targeting the Omicron mutant, the company said.

Today’s COVID-19 vaccines all are based on the original version of the coronavirus. They’re still providing strong protection against severe disease, hospitalization and death even after the appearance of the super-contagious Omicron strain — especially if people have had a booster or two.

But the virus continues to mutate rapidly in ways that let it evade some of the vaccines’ protections and cause milder infections.

U.S. regulators and the World Health Organization are considering whether to order a change in the vaccine recipe for a new round of booster shots in the fall, when cold weather and kids returning to school are likely to drive another surge.

Key questions: How will that change be made without losing the continued strong protection against COVID-19’s worst outcomes? And what’s the right variant to target? After the huge winter surge fueled by Omicron, its genetically distinct siblings now are the main threats, including one that’s driving the current U.S. wave of infections.

The Food and Drug Administration has set a meeting in late June for its scientific advisors to debate those questions and evaluate data from vaccine makers’ tests of potential new formulas. Pfizer also is studying a combination shot, which scientists call a bivalent vaccine.

Moderna said its new study found that a month after the combo shot, recipients harbored higher Omicron-fighting antibody levels — and cross-protection against other prior variants — than those triggered by the original vaccine. However, antibodies naturally wane, so it’s not clear how long the protection against infection will last.

The study was performed in 437 people, and the results haven’t yet undergone scientific review.