Geographic Differences in the Spread, Morbidity and Mortality of COVID -19:Important Contributing Factors

The COVID-19 pandemic is creating a panic all over the world. By this time it has reached almost all countries causing variable morbidity and mortality in different countries. The mapping of COVID-19 pandemic shows a great difference in the spread of virus, morbidity and mortality. Several studies have shown that in middle high and high-income countries, its spread is very rapid and very high, and is associated with higher rates of morbidity and mortality. However, in developing countries and in most of the lower income countries, the spread of infection is comparatively very slow and is associated with comparatively lower morbidity and mortality. BCG vaccination policy, presence of more natural killer (NK) cells, killer immunoglobulin receptor (KIR) genes, repeated microbial infections, environmental factors, and malaria endemicity appear to be important contributing factors. Looking at these contributing factors, which are in favor of developing and lower income countries, the COVID-19 pandemic may not be very dreadful like affluent countries.