The World Health Organization on Tuesday offered more full approval for booster shots of coronavirus vaccines than before, though it continued to emphasize the importance of increasing access to initial doses in parts of the world lagging behind vaccination efforts.
The widespread adoption comes as the WHO’s stance on boosters continues to evolve. Last year it opposed booster shots to the general public, arguing that giving extra doses to already vaccinated people in rich countries was morally indefensible when billions of people in poorer countries had yet to receive their first dose. It also only supported supplemental doses for immunocompromised people, for whom the first vaccine series may be less effective.
Tuesday’s approval is an extension of the organization’s previous guidelines on booster shots. It was released as part of a larger WHO review of vaccination efforts amid the wave caused by the Omicron variant, which may evade some of the protection offered by vaccines and previous coronavirus infections.
The agency strongly supports urgent and broad access to current Covid-19 vaccines for primary series and booster doses, especially for groups at risk of developing serious disease,” the organization said in a statement.
On Dec. 9, the WHO recommended that people who received the Johnson & Johnson vaccine in one dose receive a second dose if possible, based on growing evidence that the vaccine performed better when given as two injections. On Jan. 11, it said countries could recommend boosters, but primary vaccinations were the top priority. On Jan. 21, it recommended boosters from Pfizer’s mRNA vaccine, starting with high-risk groups.
In August it called for a moratorium on booster shots and in September urged leaders to extend that moratorium at least until the end of the year.
Geographical and economic differences in vaccination coverage remain striking: Only 14 percent of people in low-income countries have received a dose, according to the Our World in Data project at the University of Oxford. Worldwide this is about 65 percent and in some countries even more than 90 percent.
But the science surrounding boosters has changed along with the virus, and the WHO’s increasingly pro-booster position reflects that. Initial vaccine regimens are much less effective at preventing infection with the Omicron variant than with previous variants, and while they remain very good at preventing serious disease, their efficacy on that front has also declined to a lesser extent.
As a result, boosters have become an increasingly important means against the virus.
Rebecca Robbins reporting contributed.