Coronavirus affected by warm temperatures, may follow a seasonal path - study

Countries across the world should experience a drop in positive coronavirus cases during the summer months, and a resurgence when the colder weather reemerges, the researchers claimed.

A woman photographs the setting sun on the Spanish island of Ibiza August 29, 2001. Ibiza, one of the most popular tourist attractions in Spain, was hosting the all-night MTV Ibiza 2001 party at Privilege disco which claims to be the largest in the world. (photo credit: REUTERS)
A woman photographs the setting sun on the Spanish island of Ibiza August 29, 2001. Ibiza, one of the most popular tourist attractions in Spain, was hosting the all-night MTV Ibiza 2001 party at Privilege disco which claims to be the largest in the world.
(photo credit: REUTERS)
Heat and sunlight reduce the spread of coronavirus and the pervasiveness of COVID-19, according to new research.
In the study, published in the journal Scientific Reports, the researchers found a statistical significance in the prevalence of COVID-19 in populations living in warmer climates versus those living in more hibernal sections of the world, uncovering a "significant positive association between latitude and the number of cases" in countries located in closer proximity to the equator.
"A one-degree increase in absolute latitude is associated with a 4.3% increase in cases per million inhabitants as of January 9, 2021," the study authors wrote. "Our results imply that a country, which is located 1000 km closer to the equator, could expect 33% fewer cases per million inhabitants."
The researchers claimed that this provides evidence that countries across the world should experience a drop in positive coronavirus cases during the summer months, and a resurgence when the colder weather reemerges, year in and out.
"However, our results do not imply that the disease will vanish during summer or will not affect countries close to the equator," the authors explained. "Rather, the higher temperatures and more intense UV radiation in summer are likely to support public health measures to contain SARS-CoV-2."
They added that the increase in temperatures and the longer exposure to sunlight during the summer months may even "boost the impact of public health policies and actions to control the spread" of coronavirus, and that public health officials should take into to consideration the possibility the "threat of epidemic resurgence may increase during winter," so as to adapt their policies to parallel such indicators throughout the year and
The study did note its limitations, however, stating that while the results remain consistent with the hypothesis, the precise reasoning for the positive association between higher temperatures and UV radiation with the prevalence of coronavirus in a population is still unclear, adding it could be up to "not only biological, but also behavioral factors" for that effect to take place.
Examples given for both sides of the argument could be biological processes such as the human's immune response to coronavirus in the winter as opposed to the summer, or behavioral examples like the tendency to gather less indoors when the weather is more favorable outdoors; and the benefits that come along with that, such as boosted vitamin D levels and less crowded indoor venues.
To arrive at their conclusions, the researchers used a data set consisting of 117 countries to mainly analyze the relationship between the latitude of a country and the transmission rate of coronavirus throughout its population.
Other factors taken into consideration to even out the results included the number of passengers entering the country by air, the number of registered vehicles per capita, the percentage of those living in urban areas, testing and reporting capabilities of the country under observation, among other factors measuring demographics, government spending, health infrastructure and socioeconomic positioning.
Taking all into account, the researchers stated that within the apex of the coronavirus spread, between the months of March and April 2020, that the estimated effects "stayed rather stable over time" noting the positive association between latitude and the number of cases a country reports.
And throughout the year, the numbers began to even off and shape more towards this association, possibly due to better data quality and larger numbers of observations in the updated data sets, the researchers stated.
All in all, the study points to signs of the coronavirus following a seasonal course. That like the flu, its prevalence diminishes amid the summer months and reemerges during the winter.
While biological processes such as longer exposure to sunlight and warmer temperatures invoking behavioral changes in populations can all be viewed determining factors in the spread of the novel disease, the researchers provided the evidence pointing to a positive association between latitude of a country - in relation to the equator - and the number of coronavirus cases within a country. What that exactly means is yet to be determined.