Rationale for vaccinating adolescents and children
Vaccines which have received authorization by stringent regulatory authorities for the age indication of children and adolescents are safe and effective in reducing disease burden in these age groups.
Although benefit-risk assessments clearly underpin the benefit of vaccinating all age groups, including children and adolescents, the direct health benefit of vaccinating children and adolescents is lower compared with vaccinating older adults due to the lower incidence of severe COVID-19 and deaths in younger persons. Safety signals identified after widespread roll-out, such as myocarditis, albeit rare, are reported more frequently in young persons aged 16-24 years, particularly males; the risk of myocarditis in adolescents and/or children has not yet been determined.
Reducing intergenerational transmission is an important additional public health objective when vaccinating children and adolescents. Prior to the emergence of the delta variant, it was reported that the risk of symptomatic cases in household contacts of vaccinated cases was about 50% lower than that among household contacts of unvaccinated cases(22). However, the impact of vaccination on reducing transmission in the context of the more transmissible delta variant appears to be lower(23). Teachers, family members, and other adult contacts of children and adolescents should all be vaccinated.
Vaccinating children and adolescents may also help advance other highly valued societal goals. Maintaining education for all school-aged children should be an important priority during this pandemic. School attendance is critical to the well-being and life prospects of children and to parental participation in the economy. Vaccinating school-aged children may help minimize school disruptions by reducing the number of infections at school and the number of children required to miss school because of quarantine requirements.
The benefit of vaccinating children and adolescents may be lower in settings with high seropositivity rates in that age group, however, more evidence is needed on seroprevalence of school-aged children.
Conclusions
Countries should consider the individual and population benefits of immunising children and adolescents in their specific epidemiological and social context when developing their COVID-19 immunisation policies and programs. As children and adolescents tend to have milder disease compared to adults, unless they are in a group at higher risk of severe COVID-19, it is less urgent to vaccinate them than older people, those with chronic health conditions and health workers.
There are benefits of vaccinating children and adolescents that go beyond the direct health benefits. Vaccination that decreases COVID transmission in this age group may reduce transmission from children and adolescents to older adults, and may help reduce the need for mitigation measures in schools. Minimizing disruptions to education for children and maintenance of their overall well-being, health and safety are important considerations. Countries’ strategies related to COVID-19 control should facilitate children’s participation in education and other aspects of social life, and minimize school closures, even without vaccinating children and adolescents (24). UNICEF and WHO have developed guidance on how to minimize transmission in schools and keep schools open, regardless of vaccination of school-aged children(25).
Aligned and coordinated action is needed to achieve the global COVID-19 vaccination targets. Given current global inequity in vaccine access, the decision to vaccinate adolescents and children must account for prioritization to fully protect the highest risk subgroups through primary vaccination series, and as vaccine effectiveness declines with time since vaccination, through booster doses. As such, before considering implementing primary vaccination series in adolescents and children, attaining high coverage of primary series - and booster doses as needed based on evidence of waning and optimizing vaccination impact - in highest risk subgroups, such as older adults, must be considered(26).
As a matter of global equity, as long as many parts of the world are facing extreme vaccine shortages, countries that have achieved high vaccine coverage in their high-risk populations should prioritize global sharing of COVID-19 vaccines through the COVAX facility before proceeding to vaccination of children and adolescents who are at low risk for severe disease.
It is of utmost importance for children to continue to receive the recommended childhood vaccines for other infectious diseases.