A recent study published in Medical Hypotheses of Elsevier observes that that older adults who have received diphtheria or tetanus vaccine booster within the past 10 years may have a lower risk of severe COVID-19. The researchers said that the vaccines could achieve this by priming the innate immune response to fight.
The study found that those who had received a tetanus booster were half as likely to develop severe COVID-19, and those who had received a diphtheria booster were 54% less likely. “No significant differences in the likelihood to test positive or [have] a severe case” with the pertussis vaccine, and the researchers noted the small sample size.
The researchers said that they chose the 10-year time frame to account for the waning of vaccine-induced antibodies over time as it is also the interval during which experts recommend booster shots.
The researchers said: “One possible mechanism for this would be that these vaccines instil cross-reactive immunity, i.e., that they ready the immune response for a SARS-CoV-2 infection, perhaps through protein sequence similarities between the pathogens. However, the possibility that these vaccinations may influence the severity of COVID-19 warrants follow-up investigations.”
The results of the study also showed that participants who had received any of the DTP vaccinations during the past 10 years were, on average, younger and had a higher socioeconomic status than those who had not been vaccinated against these diseases within the same timeframe.
The researchers pointed out that this connection to lower socioeconomic status, along with a wide range of social determinants of health that contribute to health inequity, has been examined by previous researchers as well.
The study was titled “Vaccination history for diphtheria and tetanus is associated with less severe COVID-19” and is available on medRxiv ahead of peer review.