Malaria can elicit a non-specific immune response against viral, bacterial and other malarial and non-malarial infections. Early in this pandemic suggestions were raised for possible role of cross immunity induced by malaria or other agents against SARS-CoV-2 severity. A possible role of heterogeneous immunity generated by previous malaria infection was suggested to explain part of diversity in COVID-19 mortality among various countries. This study was designed to examine this hypothesis by looking for possible statistical relation between malaria elimination date and COVID-19 mortality. Sixty -nine malaria-free countries with a total population of 1 million or more were enrolled in this study using robust statistical tests which include: Mann-Whitney Test, Kendall's-τ coefficient test and receiver operation characteristic - (ROC) curve analyses. Results showed that there was a significant negative association among studied marker (COVID -19 deaths/million inhabitant , and date of elimination of malaria (using Kendall's-τ Correlation Coefficient test). There was a significant positive association between COVID-19 mortality and duration of time since the time of malaria elimination. With a cutoff point of 15, countries that eliminate malaria during the last 15 years had reduced median COVID-19 mortality, while countries that eliminate malaria more than 15 years ago there is high COVID-19 median mortality p value <0.05) . Receiver operation characteristic - (ROC) curve, was used to support these findings ( P value <0.05). The author of this article suggests that a correlation exists between malaria elimination duration and mortality due to COVID-19.
Keywords: COVID-19, Cross immunity, Malaria, Non malarious countries, SARS-COV2