Using the original vaccines against Covid-19 as boosters against emerging variants is the wrong approach, said a WHO expert group, adding that the world needs new vaccines that protect against infection and transmission.

“A vaccination strategy based on repeated booster doses of the original vaccine composition is unlikely to be appropriate or sustainable,” the Technical Advisory Group on Covid-19 Vaccine Composition (TAG-Co-VAC) said on Tuesday.

While some countries may recommend boosters, “the immediate priority for the world is accelerating access to the primary vaccination, particularly for groups at greater risk of developing severe disease,” the group added, pointing out the “need for equity in access to vaccines across countries to achieve global public health goals.”

While the currently available vaccines focus on “reducing severe disease and death, as well as protecting health systems,” there is a need for vaccines “that have high impact on prevention of infection and transmission.” Until such jabs are developed, the existing vaccines may need to be updated to better target emerging virus variants such as Omicron, the group said.

Developers should work to create vaccines that “elicit immune responses that are broad, strong, and long-lasting in order to reduce the need for successive booster doses,” the TAG-Co-VAC urged.

On Tuesday, the EU drug regulator EMA’s head of Biological Health Threats and Vaccines Strategy said they don’t yet have enough data to recommend a second booster – the fourth jab so far – even as some countries urged such a move.

Marco Cavaleri said they were “rather concerned about a strategy that entangles repeat vaccination within a short term,” adding that “we cannot really continuously give a booster dose every three-four months.”

The WHO said that Omicron could infect more than half of the EU population over the next two months and urged the bloc’s authorities not to treat the virus as endemic.