The World Health Organization's (WHO) expert group on immunization said yesterday that additional boosters of the Covid-19 vaccine are no longer recommended for the medium-risk group, such as healthy adults under the age of 60.

This recommendation was announced at a press conference by the chair of the WHO's Strategic Advisory Group of Experts on Immunization (SAGE), quoted by Lusa, following last week's meeting, at which it was decided to simplify the priority groups for vaccination against covid-19, which are now classified as high, medium and low risk.

Hanna Nohynek explained that the decision to simplify the risk groups for the first time took into account the fact that we are living in the "era of the Omicron, with a reduction in the severity of the disease and a high level of immunity in the population, which has been achieved through infection or vaccination" or even both.

To this end, experts from various areas of the WHO have come up with a "different approach to primary and booster vaccination for each of these groups", she added, noting that the update has also taken into account the fact that the SARS-CoV-2 virus will continue to evolve.

In this sense, the WHO consultants consider that the high-priority group includes the elderly, younger adults with comorbidities such as diabetes and heart disease, immunocompromised people (HIV and transplant patients), pregnant women and frontline health workers.

For this group, SAGE recommends administering an additional booster of the COVID-19 vaccine six or 12 months after the first booster dose.

According to the SAGE experts, the medium-risk priority group includes healthy adults, usually under 50 to 60 years of age, and children and adolescents with comorbidities, who are recommended primary vaccination and the first booster, but not subsequent additional boosters, even though they are safe.

The SAGE recommendation includes healthy children and adolescents aged between six months and 17 years in the low-priority group, and countries should evaluate vaccination of this age group based on various factors, such as their specific context, disease burden and health priorities.

Children with immunocompromising conditions and comorbidities face a higher risk of suffering from severe covid-19 and are therefore included in the high- and medium-risk priority groups, experts say.

SAGE also analyzed global vaccination programs against other diseases, such as tuberculosis, considering that "a vaccine to prevent the disease in adolescents and adults is urgently needed".

The experts said that a "substantial effort" is underway to develop vaccines, with several candidates in clinical trials and at an advanced stage, with the potential to receive regulatory authorization within three years.