Moderna has started testing an omicron-specific booster shot in adults, the company announced Wednesday.
The trial, which will include several hundred people at two dozen sites across the U.S., comes as companies and health officials grapple with a rise in cases linked to the omicron variant.
Omicron has become the dominant strain in the U.S. since it first appeared in the country late last year, with the highly transmissible virus driving up cases and hospitalizations, though early data suggests it causes less severe disease.
“Given the long-term threat demonstrated by Omicron’s immune escape, we are advancing our Omicron-specific variant vaccine booster candidate,” Stephane Bancel, the CEO of Moderna, said in a statement, adding he was “pleased” by the trial start.
“We are also evaluating whether to include this Omicron-specific candidate in our multivalent booster program. We will continue to share data with public health authorities to help them make evidence-based decisions on the best booster strategies against SARS-CoV-2.”
The news follows Pfizer’s announcement on Tuesday that it was starting a human trial for an omicron-targeted vaccine including about 1,400 participants. Pfizer expects that vaccine to be available in March.
Bancel previously hinted about starting a clinical trial for an omicron booster. The CEO said earlier this month he was discussing making such a booster available by the fall, citing the need to be “careful to try to stay ahead of a virus and not behind the virus.”
In Moderna’s phase two trial, candidates are grouped into two “cohorts” who will receive the omicron-specific booster shot.
The first cohort includes those who are fully vaccinated with the Moderna vaccine, with the last dose being six months ago. The second includes those who are fully vaccinated and boosted with the Moderna vaccine, and the last dose being three months ago.
Officials have been pushing booster shots to combat the spread of omicron. On Wednesday, Moderna said its booster remains durable against omicron, but six months after the third dose, protection had waned and was six times lower.