COVID-19: WHO says no extra booster needed for medium-risk adults

WHO recommends primary doses and a first booster in healthy adults, children and adolescents with comorbidities.

covid vaccine
A pharmacist injects a patient with a booster dosage of the Moderna COVID-19 vaccine at a vaccination clinic in Lawrence, Massachusetts, the United States [File: Charles Krupa/AP]

The World Health Organization (WHO) says it no longer recommends additional COVID-19 vaccine booster doses for regular, medium-risk adults, as the benefit is marginal.

For people who have received their primary vaccination course and one booster dose, there is no risk in having further jabs, but the returns are slight, the WHO’s vaccine experts said on Tuesday.

The UN health agency’s Strategic Advisory Group of Experts on Immunization (SAGE) issued updated recommendations after its regular biannual meeting. Its new advice reflects the impact of the dominant Omicron variant of the virus and high-level immunity now achieved in the population through infection and vaccination, the WHO said.

SAGE came up with three new, simplified priority categories for COVID-19 vaccination: high, medium and low, based on the risk of severe disease or death.

It also recommended additional booster shots after the first one only for people at the highest risk of developing severe COVID-19 disease. They include older adults; younger adults with comorbidities such as diabetes; people with immunocompromising conditions like HIV; pregnant women; and front-line healthcare workers.

The medium-risk group includes healthy adults, usually under 60, and children and adolescents with comorbidities. SAGE recommends a primary series and a first booster dose.

“When it comes to the medium-risk group, additional booster doses … are no longer recommended,” said SAGE chair Hanna Nohynek.

“The vaccine is safe and it’s efficient against serious disease and death,” she said, noting that for the medium-risk group, while there was no harm in having another shot, “the benefit of these additional boosters is actually quite marginal”.

Burden higher in infants

The low-risk group includes healthy children and adolescents aged six months to 17 years.

While primary and booster doses are safe and effective for this group, considering the low burden of COVID-19 disease, SAGE said countries’ vaccination decisions should be based “on contextual factors” such as health programme priorities and cost-effectiveness.

“Though low overall, the burden of severe COVID-19 in infants under 6 months is still higher than in children aged 6 months to 5 years,” it said.

Vaccinating pregnant people – including with an additional dose if more than six months have passed since the last dose – protects both them and the fetus, while helping to reduce the likelihood of hospitalisation of infants for COVID-19.

As for the impact of COVID-19 vaccines on long COVID, or post-infection conditions, “the evidence on the extent of their impact is inconsistent”, said SAGE.

Nearly 13.3 billion COVID-19 vaccine doses have been administered around the world.

WHO seeking new vaccines

WHO vaccines chief Kate O’Brien said that with the Omicron variant, the existing vaccines provide very good immunity against severe disease, but “frankly they don’t last very long for the performance that they do have against mild disease or infection”.

The WHO is looking for new COVID-19 vaccines that cover a broad spectrum of variants, have longer durability and better performance against infection and transmission.

It is also seeking vaccines that move on from injection methods and ultra cold chain storage, O’Brien said, citing nasal, oral and skin patch vaccine methods.

Speaking of two nasally-administered vaccines, particularly one being used in China, SAGE executive secretary Joachim Hombach said: “We know that they are immunogenic … but what we really need is data that actually studies the impact on transmission – because that could indeed make a major difference.”

Source: Al Jazeera and news agencies