Influence of the COVID-19 pandemic on the incidence of tuberculosis and influenza

We examined whether the COVID-19 pandemic has affected the incidence of tuberculosis (TB) and influenza in Serbia, a Southeast European country with a low TB incidence rate and a mandatory BCG vaccination at birth. The first case of COVID-19 was registered on March 6, 2020. Despite the need for a sudden adaptation of the health care system, routines of mycobacterial laboratories have never stopped. In 2020, the number of newly diagnosed TB patients was significantly lower than expected (p = 0.04), but the number of patients with influenza increased when compared to 2019. Although many patients with influenza A H1N1 were observed before the beginning of the COVID-19 pandemic, the increment of cases could also be a consequence of cases of influenza with COVID-like symptoms detected thereafter. It may also be attributed to misclassification of clinical cases that were negative for SARS-CoV-2 and reported as influenza. Difficulties to seek medical attention because of the COVID-19 pandemic and possible underreporting are considered as reasons for the decline in the incidence rate of TB. On the other hand, individual and social measures to prevent the spread of SARS-CoV-2 such as wearing face masks, social distancing, lockdown, which were strictly applied to COVID-19 patients, health care staffs and most of the population, could have hindered TB infections more than the two viral diseases, which appear to be more contagious. The increased motivation of the population to protect their health during the COVID-19 pandemic provided an opportunity for their effective education. This is crucial in further combating TB as a preventable disease.