After a meeting in March 2023, WHO’s Strategic Advisory Group of Experts on Immunisation (SAGE) revised the roadmap for prioritising COVID-19 vaccines. This result is intended to “reflect the impact of Omicron and high population-level immunity” through infection and vaccination. WHO states that the roadmap “continues SAGE’s prioritisation of protecting populations at the greatest risk” from SARS-CoV-2 infection and its “focus on maintaining resilient health systems”.
Cost and context
The roadmap now considers “cost-effectiveness” of vaccination for lower-risk groups, such as healthy children and adolescents, in comparison with “other health interventions”. It also includes revised recommendations on boosters. SAGE Chair Dr Hanna Nohynek reflected that “much of the population” has either received vaccinations, been infected, or both. However, the roadmap “reemphasises the importance of vaccinating those still at-risk of severe disease”.
“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 roadmap presents a recommended prioritisation system for COVID-19 vaccination. The levels are high, medium, and low, and are “principally based on risk of severe disease and death”, consider “vaccine performance, cost-effectiveness, programmatic factors, and community acceptance”.
The high priority group includes older adults, younger adults with “significant comorbidities”, such as heart disease, people with immunocompromising conditions, such as people living with HIV or transplant recipients, children aged 6 months and older, pregnant people, and frontline health workers.
For this group, SAGE is recommending an “additional booster” of either 6 or 12 months after the last dose, with the timeframe “depending on factors such as age and immunocompromising conditions”. It emphasises this advice applies for the “current epidemiological scenario only” and should not be seen as for “continued annual” boosters.
“The aim is to serve countries planning for the near- to mid-term.”
The medium priority group covers healthy adults, usually younger than 50 or 60, without comorbidities, and children and adolescents with comorbidities. SAGE suggests that this group should be offered primary series and first booster doses but does not routinely recommend additional boosters “given the comparatively low public health returns”.
The low priority group includes health children and adolescents between the ages of 6 months and 17 years. Primary and booster doses are “safe and effective” in this group, but the consideration of the “low burden of disease” led SAGE to urge countries to “base their decisions on contextual factors”.
“The public health impact of vaccinating health 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”.
Other meeting considerations
During the meeting SAGE also considered other public health concerns, such as polio and measles. For polio, it evaluated the data on the novel oral polio vaccine type 2 and concluded that it should be the “preferred choice for response to circulating vaccine-derived poliovirus type 2” (cVDPV2) where possible. It also recommended that in “hard to reach or conflict-prone areas” the interval between vaccines could be reduced to 1 week, from the regular 4 weeks.
Regarding measles, SAGE described the “repercussions of the pandemic’s seismic impact on routine immunisation”. Measles cases have increased in all WHO regions in 2022, which prompts the need to review policies on vaccination, and accelerate the development and deployment of new technologies.
The meeting also covered TB concerns, identifying an urgent need for a more effective vaccine for adolescents and adults. SAGE recognised “substantial” efforts towards that end, with “several candidates” in trials.
Another concern during the meeting was the introduction of the RTS,S malaria vaccine, which has “resulted in a substantial reduction in severe malaria and all-cause mortality among age eligible children”. The high demand for the vaccine is at odds with the “highly constrained” supply, with SAGE recommending flexibility in the immunisation schedule.
WHO also stated that it is in the process of “defining regional priority targets” for new vaccine development for “non-epidemic pathogens”. Early research suggests that tuberculosis, HIV, and pathogens exhibiting “high levels on antimicrobial resistance” (AMR), are important across “all regions”.
Do you agree with SAGE’s recommendations, and do you think they will have an effect on vaccination efforts in your region? To participate in discussions about COVID-19 vaccination schedules and other pathogenic concerns, join us at the World Vaccine Congress in Washington next week.