According to a WHO vaccine expert, a third Covid-19 vaccine dose is currently only useful in a few exceptional cases. Instead, the available vaccine doses should be used for those who have not yet been vaccinated. Ana-Maria Henao-Restrepo, a vaccine expert at the World Health Organization (WHO), and an international working group have evaluated a Covid-19 third dose, also known as a booster, in a publication in The Lancet, stating that it is “mostly not useful.” According to the experts, the one or two doses of the vaccine, depending on the vaccine, already prevent severe illness, even with the Delta variant, so a booster is currently not appropriate given the current global vaccination status. The scientists explain that the benefits of a third vaccine dose do not outweigh the risk of potential side effects, especially for young people. Additionally, it is currently more sensible to vaccinate as many people as possible. Therefore, the available vaccines should be used for those who are currently unvaccinated instead of third doses.
However, the working group explains that this recommendation does not apply to all groups of people. In exceptional cases, such as those with weakened immune systems, a third vaccine dose may already be useful. This is confirmed by a study published in the Annals of Internal Medicine, which shows that a third vaccine dose leads to a significant improvement in the immune response in organ transplant recipients with artificially suppressed immune systems. Although the protection against symptomatic infections also decreases over time in people with intact immune systems, according to current observational studies, this does not affect severe cases. Therefore, according to the experts, a third vaccine dose for the general population would only be useful in the future if a mutation occurs that significantly weakens the protection provided by the vaccines or if the immune protection against the existing variants decreases significantly.
In conclusion, the WHO vaccine expert and the international working group have stated that a third Covid-19 vaccine dose is currently not necessary for the general population. Instead, the available vaccine doses should be used for those who have not yet been vaccinated. However, in exceptional cases, such as those with weakened immune systems, a third vaccine dose may already be useful. The experts emphasize that the benefits of a third vaccine dose do not outweigh the risk of potential side effects, especially for young people. Therefore, it is currently more sensible to vaccinate as many people as possible.
