Abstract
Coronavirus disease 2019 (COVID-19) is a severe acute respiratory syndrome caused by Coronavirus 2 (SARS-CoV-2). In the light of its rapid global spreading, on 11 March 2020, the World Health Organization has declared it a pandemic. Interestingly, the global spreading of the disease is not uniform, but has so far left some countries relatively less affected. The reason(s) for this anomalous behavior are not fully understood, but distinct hypotheses have been proposed. Here we discuss the plausibility of two of them: the universal vaccination with Bacillus Calmette–Guerin (BCG) and the widespread use of the antimalarial drug chloroquine (CQ). Both have been amply discussed in the recent literature with positive and negative conclusions: we felt that a comprehensive presentation of the data available on them would be useful. The analysis of data for countries with over 1000 reported COVID-19 cases has shown that the incidence and mortality were higher in countries in which BCG vaccination is either absent or has been discontinued, as compared with the countries with universal vaccination. We have performed a similar analysis of the data available for CQ, a widely used drug in the African continent and in other countries in which malaria is endemic; we discuss it here because CQ has been used as the drug to treat COVID-19 patients. Several African countries no longer recommend it officially for the fight against malaria, due to the development of resistance to Plasmodium, but its use across the continent is still diffuse. Taken together, the data in the literature have led to the suggestion of a possible inverse correlation between BCG immunization and COVID-19 disease incidence and severity.
Highlights
The coronavirus disease 2019 (COVID-19) was first reported in Wuhan, China, in December 20191–3
As five different strains of Bacillus Calmette–Guerin (BCG) were employed in different countries, we analyzed their correlative efficacy in protecting against COVID-19
Having found that countries with universal BCG vaccination policy perform better in limiting the spread of COVID-19 compared with countries without a universal BCG vaccination or with countries that discontinued it, we explored the association between BCG vaccination and COVID-19 mortality for different age groups
Summary
The coronavirus disease 2019 (COVID-19) was first reported in Wuhan, China, in December 20191–3. The available data on COVID-199 have revealed that the disease incidence and mortality vary, even dramatically, among countries. Our analysis of COVID-19 data from countries with universal BCG vaccination, discontinued vaccination, and countries that never adopted BCG vaccination suggests that disease incidence and morbidity are reduced in countries with universal BCG immunization compared with those that have not adopted the vaccine. Suggestive examples are Spain and Portugal: the incidence of COVID-19 and its fatalities are at the time of writing this manuscript 386 per million population in Spain, where BCG vaccination has never been adopted, whereas, in the neighboring Portugal, in which general BCG vaccination was adopted in 1965, the disease incidence and mortality are 56 per million, respectively[9]. Further analysis of age-related susceptibility towards COVID-19 disease has revealed that countries with universal vaccination exhibit reduced disease incidence in all age groups. There were significant differences in mortality in all age groups between the vaccinated and unvaccinated countries, there were no differences between the unvaccinated countries and those that have discontinued vaccination
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
