Health officials in the United States, Israel and other nations have for months been pushing for COVID-19 booster shots among older populations, and those calls are now growing worldwide. The issue was discussed at an extraordinary meeting at World Health Organization in Geneva convened by SAGE, the 15-member Strategic Advisory Group of Experts on vaccination.
Current data show that vaccines against COVID-19 provide a robust level of protection against severe forms of disease. However, emerging evidence indicates vaccines begin to lose their effectiveness about six months after they have been administered. This puts older adults and people with underlying conditions at particular risk.
Chair of SAGE, Alejandro Cravioto, says the group of experts agrees a booster shot would provide a greater level of protection for people at risk. However, he notes vaccines are in short supply in many parts of the world. He says the wide administration of booster doses risks exacerbating inequities in vaccine access.
He notes most current infections are among unvaccinated people, the majority of whom live in poor, developing countries. He says SAGE believes they should receive these life-saving vaccines instead of further doses being provided to people who already are fully inoculated against the coronavirus.
“For the time being, we continue to support — one, the need for equity in the distribution and allocation of vaccines and, two, the use of third doses only on those that we have previously recommended. Those that have received inactivated vaccines and those that are immuno-compromised, which are the two groups that we feel should be protected further by a third dose of the primary process,” he said.
Cravioto said meeting participants also discussed the feasibility of mixing and matching different vaccines, such as those developed by Pfizer and Moderna to achieve full immunity against COVID.
“WHO supports a flexible approach to homologous or a single platform versus a heterologous mix and match schedules. We still believe that the best approach is to use the same vaccine for the two primary doses,” Cravioto said.
For national immunization programs, however, he said a different vaccine can be used for an additional third dose. This, if the vaccine used for the two primary shots is in short supply and unavailable.