Moderna said its new two-strain Covid-19 booster increases people’s immunity against the dominant Omicron variant, bolstering the company’s hopes to roll it out as a fourth dose in the late summer.
The US biotech company is the first to report preliminary results from a clinical trial of a vaccine targeted to Omicron. It said on Wednesday that the trial showed the “bivalent booster” — which contains the genetic code of the Omicron variant and the original strain of the virus — was safe and well tolerated.
The vaccine elicited eight times more antibodies to tackle the Omicron variant than a fourth dose of the original formulation when measured one month after it was administered, the company said. It tackled the original strain just as well, but it could not prove it was superior.
The booster candidate should provide more durable protection against variants of concern, added Moderna.
Darius Hughes, Moderna’s UK general manager, said the company was “very, very pleased” with the results, which showed the new vaccine would offer “much better protection for the autumn and winter booster campaign”.
Many governments have not yet decided who should receive a fourth dose in the autumn, and whether to provide a booster targeted at Omicron. The US and the UK have already offered fourth doses to some of the most vulnerable groups, including the elderly. In April, regulators in the EU said it was too early to recommend fourth doses for the general population.
Hughes said there was “some appetite” in the UK for switching to the vaccine that was better at targeting Omicron, which the country could do within the terms of its existing contract with Moderna.
If the bivalent vaccine is approved, Moderna will need to scale up manufacturing, switching from producing the original vaccine. Hughes said making the switch was an “interesting challenge” but that the company had already spread its manufacturing around the world so it could move “pretty quickly”.
Experts remain divided over whether annual boosters targeting variants will be required to combat Covid, with some noting that existing vaccines continue to offer strong protection against severe disease and hospitalisation.
However, others say a new booster could potentially boost immunity against the Omicron variant which continues to spread rapidly in waves around the world.
“I would be cautiously optimistic that this bivalent vaccine will be at least a little more effective against Omicron than the original vaccine, but it’s far too early to talk about it being any sort of game-changer,” said David Dowdy, an epidemiologist at Johns Hopkins School of Public Health.
Pfizer is also pushing ahead with plans to develop an Omicron-specific booster shot that can provide better protection against new variants, but it has acknowledged growing vaccine fatigue among the public.