Moscow. 22 of October. INTERFAX.RU – Scientists at the Barcelona Institute of Global Health have come to the conclusion that COVID-19 is still a seasonal infection associated with low temperatures and humidity, the scientific organization said.
It is noted that the initial theoretical models did not consider the climate as the driving force behind the transmission of infection, but later it was found that COVID-19 in China began to spread in areas between 30 and 50 degrees north latitude with low humidity and low temperatures (from 5 to 11 ° C).
Scientists analyzed the relationship between temperature and humidity during the early spread of SARS-CoV-2 in 162 countries on five continents, before changes in human behavior and public health policies were adopted.
“The results show a negative relationship between the transfer rate (R0) and temperature and humidity globally: higher transfer rates were associated with lower temperatures and humidity,” it said.
It is noted that this pattern was triggered in the first two waves of the pandemic: the first weakened as the temperature and humidity increased, and the second wave grew as these indicators decreased.
However, this pattern was broken in the summer on all continents during the third wave. “This can be attributed to several factors, including mass youth gatherings, tourism and air conditioning, among others,” said study co-author Alejandro Fontal.
In the Southern Hemisphere, where the virus began to spread later, the pattern was the same.
Climatic effects were most evident at temperatures between 12 and 18 ° C and humidity levels between 4 and 12 g / m3. However, these ranges are still indicative, the scientists emphasize.
Using an epidemiological model, the research team showed that incorporating temperature into the transmission rate is better for predicting the rise and fall of infection waves.
This seasonality may make an important contribution to SARS-CoV-2 transmission as low humidity conditions have been found to reduce aerosol size and thereby increase airborne transmission of seasonal viruses such as influenza.
