For this group of people under 60 years of age called at medium risk - to which are added children and adolescents with comorbidities from 6 months to 17 years - there is no risk of receiving additional injections but "the returns in terms of health are low", said the WHO vaccine experts.

WHO's Strategic Advisory Group of Experts on Immunization (SAGE) issued updated recommendations after its meeting this week in Geneva.

The new SAGE recommendations reflect the impact of Omicron and the high level of immunity now achieved in the global population due to infections and vaccination, the WHO said.

SAGE has proposed three new priority categories for Covid vaccination based on the risk of developing severe disease or death: high, medium and low.

In contrast, older people, other adults with comorbidities, all immunocompromised people, pregnant women and frontline health workers are encouraged to increase vaccination with a booster dose after the initial vaccination regimen and a first booster. SAGE recommends an interval of 6 to 12 months between boosters depending on morbidities.

New vaccines

On the other hand, the evidence "lacks consistency" regarding the impact of anti-Covid vaccines on long Covid, which sees the initial illness develop into often very disabling symptoms such as extreme fatigue or inability to concentrate.

Nearly 13.3 billion doses of Covid vaccine have been administered worldwide.

Nearly 13.3 billion doses of Covid vaccine have been administered worldwide © Eugene Hoshiko / POOL / AFP / Archives

WHO is looking for new Covid vaccines that cover a wide range of variants, have a more drable effect and show better performance against infection and transmission.

The organization is also examining new methods of administering nasal, oral or dermal serums.

Referring to two nasal vaccines, including one used in China, SAGE Executive Secretary Joachim Hombach stressed: "We know they are immunogenic ... But what we really need is data that actually looks at the impact on transmission -- because that could indeed make a big difference."

© 2023 AFP