mRNA booster vaccines may be a good investment in developing countries

Vaccines based on inactivated SARS-CoV-2 virus are commonly used in developing countries due to their low cost. New research from Karolinska Institutet in Sweden shows that a booster shot of mRNA vaccine to individuals who have received two doses of inactivated vaccine offers the same level of protection against COVID-19 as three doses of mRNA vaccine. The findings are published in the journal Nature Communications. “Our results indicate that one booster shot of an mRNA vaccine, as a complement to the cheaper but less effective inactivated vaccines, is sufficient to achieve the ‘gold-standard’ immune response measured after three doses of mRNA vaccine,” says Qiang Pan Hammarström, professor at the Department of Biosciences and Nutrition, Karolinska Institutet, who led the study. “That would likely be a good investment even in resource-poor countries to protect against severe COVID-19.”