January 28 Winter has arrived, and the number of confirmed cases of COVID-19 around the world has soared, and has now exceeded the 100 million mark.
Is seasonal factors one of the “behind-the-scenes”? According to a report on the website of Physicists on the 27th, American scientists analyzed the relevant data of 221 countries and gave the affirmative answer: COVID-19 is a seasonal disease.
Illinois researchers published a paper in Evolutionary Bioinformatics that confirmed cases of COVID-19, mortality rates and other epidemiological indicators are significantly related to temperatures and latitudes in 221 countries.
“One of the conclusions we have come to is that COVID-19 may be a seasonal disease similar to influenza,” said Gustavo Caetano Arnoldes, a senior author of the paper.
The seasonality of viral diseases is very common. For example, influenza has a higher incidence in cold winters.
In the early days of the COVID-19 pandemic, researchers and public health officials believe that the novel coronavirus may be ravaged in autumn and winter like other coronaviruses, but there is a lack of data, especially at the global level, and the latest research fills this knowledge gap.
In the latest study, the researchers downloaded relevant epidemiological data from 221 countries, including morbidity, mortality, rehabilitation cases, detection and hospitalization rates, as well as longitude, latitude and average temperatures in these countries.
They began collecting data on April 15, 2020, because it was the day with the largest change in the global temperature season, and the number of COVID-19 infections peaked around the world.
Subsequently, the research team used statistical methods to test whether epidemiological variables were related to temperature and longitude and latitude.
They said: “Our global epidemiological analysis shows that there is a significant statistical correlation between temperature and morbidity, mortality, recovery cases, etc.
The same trend has been found in latitude, but not in longitude, which is similar to what we expected.”
While temperature and latitude are clearly correlated with the number of confirmed cases of COVID-19, researchers note that climate is only one of the factors contributing to seasonal COVID-19, and our own immune system may also be one of the reasons for this seasonal pattern.
For example, our immune response to influenza can be affected by temperature and nutritional status, including whether to take vitamin D or not.
In winter, there is less sunshine and insufficient vitamin D intake.
Researchers stressed that more research is needed to explain the role of climate and seasonality in the COVID-19 pandemic, but the impact of policies, such as whether to wear masks, is also key factors.