Focus Covid booster campaigns on high-risk people, WHO’s vaccine experts recommend

A panel of experts that advises the World Health Organization on vaccine use suggested Tuesday that countries no longer need to consider offering additional Covid-19 boosters to people at medium or low risk of becoming seriously ill if they contract the SARS-CoV-2 virus.

The Strategic Advisory Group of Experts on Immunization — which is known as the SAGE — said some countries may continue to offer boosters to people at medium and low risk, but those decisions should be made based on national conditions and health spending priorities.

“The rationale there is that the benefit of these additional boosters is actually quite marginal, based on what we know of the immune status of these people,” committee chair Hanna Nohynek said during a news conference outlining the SAGE’s new recommendations.

The group went so far as to suggest countries could also choose to forgo offering a primary vaccination series to healthy children and adolescents, if they haven’t had it already. Those decisions should be based on country-specific conditions, including the disease burden in these age groups, other health or programmatic priorities, and opportunity costs, an overview of the meeting that is posted online states.

WHO staff at the press conference were quick to stress that the SAGE is not telling countries they should not offer boosters to medium- or low-risk individuals, but rather that governments should make choices based on their own budgets and priorities.

“SAGE is in the business of having to give global recommendations. And we’re really at a point in the pandemic now where the country context and the country’s programmatic prioritization are starting to play a bigger and bigger role,” said Kate O’Brien, director of WHO’s department of immunization, vaccines, and biologicals.

The advisory group, which met last week, concluded that with growing global levels of hybrid immunity — immunity that is based both in vaccination and infection — the added protection offered by additional boosters is small and may not make sense from a cost-effectiveness point of view.

In fact, the group suggested that some countries might be better off focusing their vaccination budgets and efforts on catch-up campaigns for other vaccine-preventable diseases that suffered badly during the earlier stages of the Covid pandemic. Millions of children around the world are known to have missed important childhood vaccinations; O’Brien called this “a casualty of the pandemic.” The WHO and UNICEF, the U.N. Children’s Fund, have urged governments to intensify their efforts this year to get vaccine coverage levels back up to at least 2019 levels.

The advisory group said prioritizing other vaccines would make particular sense when it comes to people considered at low risk from Covid infection: healthy children and adolescents.

“The public health impact of vaccinating healthy children and adolescents is comparatively much lower than the established benefits of traditional essential vaccines for children — such as the rotavirus, measles, and pneumococcal conjugate vaccines — and of COVID-19 vaccines for high and medium priority groups,” the SAGE said in a statement.

For people at high risk of severe disease, though, the advisory group still recommends boosters, at a six-month or 12-month interval, depending on the health of the recipient.

In general, the recommendation is that people at high risk should have a booster 12 months after their previous booster, Nohynek said. That group includes older adults with preexisting health conditions, frontline health workers, people (including children) who are immunocompromised, as well as pregnant people who are six months or more out from their previous booster.

For some of those — those at highest risk and pregnant people — a booster at six months could be considered, Nohynek said.

Canada and the United Kingdom have already taken this step, offering spring boosters to those at highest risk from Covid. There is no word yet on whether the United States will also take this step.

“But the kind of overall recommendation is that the most efficient use of the Covid vaccines in these older adults and young adults with significant comorbidities or severe obesity would be the 12 months [interval],” Nohynek said.

The SAGE noted that the new recommendations should be considered “time limited” — meaning they address current needs, based on the epidemiological scenario as it exists now. They should not be interpreted as an endorsement from the SAGE of a need for annual Covid vaccine boosters, the group said.

Correction: A previous version of this article incorrectly stated that the SAGE’s recommendation should be interpreted as an endorsement of a need for annual Covid vaccine boosters.