Timo Vesikari, MD, PhD
Former Professor of Pediatrics and Virology, Nordic Research Network Oy
During the coronavirus pandemic, people have experienced a unique sense of helplessness in the absence of a quick fix. At the same time, vaccines have been developed at warp speed and the wait has felt like an eternity.
No wonder there has been renewed interest in the indirect benefits of vaccinations. The indirect effects have been known for decades, thanks to the pioneering observations of Peter Aaby in Guinea-Bissau, where BCG and measles vaccines reduced mortality and morbidity beyond their target diseases. That was in Africa, and the findings did not become mainstream until now, when COVID-19 poses a real threat for lives in developed countries.
The importance of repurposed vaccines
BCG and MMR are now called “repurposed” vaccines as it is believed that they may reduce the severity of COVID-19 disease. It is an enigma why children and adolescents mostly experience only mild or no symptoms at all with COVID-19. A simplified explanation is that live vaccines like BCG and MMR stimulate and “train” innate immunity. In Europe and America, the two doses of MMR given to children may play a key role.
Vaccinations through life are important for all.
Understanding efficacy of rotavirus vaccines
My lifetime work is with rotavirus vaccine. In the 1980’s and 1990’s others were often wondering why rotavirus vaccines worked better in Finland than elsewhere. BCG vaccination was still being administered in Finland but not in most European countries or the US. It is now plausible that BCG vaccine enhances the efficacy of rotavirus vaccine, through innate immunity.
The list of beneficial vaccines for COVID-19 may grow. A surprising piece of news is (unpublished) data from the Dutch University Hospital in Radboud, where it was reported that the incidence of COVID-19 in hospital workers was lower if they had received inactivated seasonal influenza vaccination.
The implications of this growing evidence may be reduced to a maxim: vaccinations through life are important for all.