By Haruna Gimba
The World Health Organisation (WHO) Strategic Advisory Group of Experts on Immunization (SAGE) has revised the roadmap for prioritizing the use of COVID-19 vaccines, to reflect the impact of Omicron and high population-level immunity due to infection and vaccination.
The roadmap continues SAGE’s prioritization of protecting populations at the greatest risk of death and severe disease from SARS-CoV-2 infection and its focus on maintaining resilient health systems.
The roadmap newly considers the cost-effectiveness of COVID-19 vaccination for those at lower risk, namely healthy children and adolescents, compared to other health interventions.
The roadmap also includes revised recommendations on additional booster doses and the spacing of boosters. The current COVID-19 vaccines’ reduction of post-COVID conditions is also considered but the evidence on the extent of their impact is inconsistent.
“Updated to reflect that much of the population is either vaccinated or previously infected with COVID-19, or both, the revised roadmap reemphasizes the importance of vaccinating those still at-risk of severe disease, mostly older adults and those with underlying conditions, including with additional boosters,” stated SAGE Chair Dr Hanna Nohynek.
“Countries should consider their specific context in deciding whether to continue vaccinating low risk groups, like healthy children and adolescents, while not compromising the routine vaccines that are so crucial for the health and well-being of this age group.”
The revised roadmap outlines three priority-use groups for COVID-19 vaccination: high, medium, and low. These priority groups are principally based on risk of severe disease and death, and consider vaccine performance, cost-effectiveness, programmatic factors and community acceptance.
The high priority group includes older adults; younger adults with significant comorbidities (e.g. diabetes and heart disease); people with immunocompromising conditions (e.g. people living with HIV and transplant recipients), including children aged 6 months and older; pregnant persons; and frontline health workers.
For the high priority group, SAGE recommends an additional booster of either six or 12 months after the last dose, with the timeframe depending on factors such as age and immunocompromising conditions.
All the COVID-19 vaccine recommendations are time-limited, applying for the current epidemiological scenario only, and so the additional booster recommendations should not be seen as for continued annual COVID-19 vaccine boosters. The aim is to serve countries planning for the near- to mid-term.
The medium priority group includes healthy adults – usually under the age of 50-60 – without comorbidities and children and adolescents with comorbidities. SAGE recommends primary series and first booster doses for the medium priority group.
Although additional boosters are safe for this group, SAGE does not routinely recommend them, given the comparatively low public health returns.
The low priority group includes healthy children and adolescents aged 6 months to 17 years. Primary and booster doses are safe and effective in children and adolescents.
However, considering the low burden of disease, SAGE urges countries considering vaccination of this age group to base their decisions on contextual factors, such as the disease burden, cost effectiveness, and other health or programmatic priorities and opportunity costs.
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.
Children with immunocompromising conditions and comorbidities do face a higher risk of severe COVID-19, so are included in the high and medium priority groups respectively.
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.
Vaccinating pregnant persons – including with an additional dose if more than 6 months have passed since the last dose – protects both them and the fetus, while helping to reduce the likelihood of hospitalization of infants for COVID-19.
Countries that already have a policy in place for additional boosters should assess the evolving need based on national disease burden, cost effectiveness and opportunity costs.
Separate to the roadmap, SAGE also updated their recommendations on bivalent COVID-19 vaccines, now recommending that countries can consider using BA.5 bivalent mRNA vaccine for the primary series.
