Seasonal variations impact on SARS-CoV-2 incidence and mortality in southern and northern hemispheres: Two years pandemic period based study

OBJECTIVES: The Severe Acute Respiratory Syndrome Coronavirus (SARS-CoV-2) infection is a highly challenging problem in the world. The impact of weather conditions on the spread of SARS-CoV-2 has been hypothesized, but the level of understanding remains lacking. This study investigates the impact of seasonal variations on SARS-CoV-2 incidence and mortality in the Southern and Northern hemispheres. METHODS: We enlisted all the countries from both hemispheres and then randomly selected 20 countries, 10 countries from each hemisphere. After that, we recorded the SARS-CoV-2 daily cases and deaths in these selected countries from the Worldometer for the period of two years from December 31, 2019, to December 31, 2021. RESULTS: During the study period, in 10 selected countries of the Northern hemisphere, the number of SARS-CoV-2 cases was 18381.6 ± 419.7 and deaths 300.4 ± 6.4. However, the number of cases in the southern hemisphere is 6282.9 ± 205.8, and mortality was 210.0 ± 7.7. In the Northern hemisphere, the number of SARS-CoV-2 cases (p = 0.001) and deaths (p = 0.001) significantly increased compared to the southern hemisphere. The maximum number of cases and deaths occurred during the winter (18806.4 ± 785.3) and autumn (17034.1 ± 538.4) periods in both the hemisphere compared to spring and summer. Similarly, the number of deaths increased in winter (391.0 ± 13.4, p = 0.001) and autumn (308.6 ± 11.6) compared to spring and summer in both hemispheres. CONCLUSIONS: The highest occurrence of SARS-CoV-2 cases and deaths was found during the winter and autumn seasons, while the lowest was found in the spring and summer during the study period of two years. The health officials inform the public about the seasonal occurrence of the SARS-CoV-2 outbreak and take priority preventive measures to minimize the disease burden.