Science & Technology

Strong evidence that COVID-19 is a seasonal infection – and we need “air hygiene”

New studies provide strong evidence that COVID-19 is a seasonal infection associated with low temperature and humidity, such as seasonal influenza.

A new study led by the Barcelona Global Health Institute (ISGlobal), an institution backed by the La Caixa Foundation, provides solid evidence that: COVID-19 (New Coronavirus Infection) It is a seasonal infection related to low temperature and humidity, such as seasonal influenza. Result is, Nature Computational ScienceAlso supports significant contributions in the air SARS-CoV-2 The need for a transition to means that promote communication and “air hygiene”.

An important question about SARS-CoV-2 is whether it behaves as a seasonal virus like influenza, or does it infect the same at any time of the year. The first theoretical modeling study suggested that climate is not a driving force for COVID-19 infection, given the large number of sensitive individuals who are not immune to the virus. However, some observations suggested that the first transmission of COVID-19 in China occurred at latitudes between 30 and 50.o o N, low humidity level, low temperature (5-5)o o And 11 o o NS).

“The question of whether COVID-19 is a true seasonal disease becomes increasingly central and influences the determination of effective interventions,” said IS Global’s director of climate and health programs and research. Coordinator Xavier Rodó explains. To answer this question, Rod and his team first spread the temperature in the early stages of SARS-CoV-2 to 162 countries on five continents before changes in human behavior and public health policy were implemented. And the relationship between humidity was analyzed. The results show that there is a negative relationship between global transmission (R0) and both temperature and humidity. The higher the transmittance, the lower the temperature and humidity.

The team then analyzed how this link between climate and illness evolved over time and whether it was consistent on different geographic scales. To this end, they used a specially developed statistical method (ie, a pattern recognition tool) to identify similar fluctuation patterns in different time frames. Again, they have a strong negative association in the short time frame between illness (number of cases) and climate (temperature and humidity), in the first, second and third waves of the pandemic. During that time, I discovered that there are consistent patterns on different spatial scales. , Individual regions within the high-impact countries (Lombardy, Thuringia, Catalonia), and even to the city level (Barcelona).

The first epidemic wave weakened as temperature and humidity increased, and the second wave increased as temperature and humidity decreased. However, this pattern was broken during the summer on all continents. “This can be explained by several factors, including youth mass gatherings, tourism, and air conditioning,” explains Alejandro Fontal, a researcher and lead author of the study at IS Global.

The same negative correlations were observed when the model was adapted to analyze transient correlations at all scales in the countries of the Southern Hemisphere where the virus arrived later.Climate effects were most pronounced at temperatures between 12o o And 18o oC and humidity levels are 4-12 g / m3Although the author warns that these ranges are still indicators, given the short records available.

Finally, using epidemiological models, the research team finds that incorporating temperature into transmission is suitable for predicting the rise and fall of various waves, especially the first and third waves in Europe. Was shown. “Overall, our findings support the view of COVID-19 as a true seasonal cold infection, similar to influenza and the benign circulating coronavirus,” says Rodó.

This seasonality makes an important contribution to the transmission of SARS-CoV-2, as low humidity conditions have been shown to reduce aerosol size and thereby increase airborne transmission of seasonal viruses such as influenza. There is a possibility. “This link ensures that the aerosol can remain floating for extended periods of time, thus ensuring an emphasis on’air hygiene’through improved indoor ventilation,” said Rod, who said weather parameters in the evaluation and planning of control measures. Emphasize the need to include.

See also: Fontal A, Bouma MJ, San José A, Lopez L, Pascual M, RodóX, October 21, 2021, “Climate Signatures of Different COVID-19 Pandemic Waves Across Both Hemispheres” Nature Computational Science..
DOI: 10.1038 / s43588-021-00136-6

Strong evidence that COVID-19 is a seasonal infection – and we need “air hygiene” Strong evidence that COVID-19 is a seasonal infection – and we need “air hygiene”

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