New research offers substantial evidence that COVID-19 is a periodic disease

Nov, 2021 - By WMR

Recent research performed by the Barcelona Institute for Global Health shows evidence that COVID-19 is a seasonal virus associated with low temperature and relative humidity like influenza. The findings further suggest the significant role of airborne SARS-CoV-2 spread and the necessity to move toward strategies that enhance air quality.

A crucial question about SARS-CoV-2 is whether this is or it will be a seasonal virus the same as influenza, or if it will be similarly spread throughout the year. Given the vast number of vulnerable individuals with no antibodies to the virus, a preliminary conceptual modeling study concluded that temperature was not a cause of COVID-19 spread. Some data, however, indicated that the earliest spread of COVID-19 in, with low temperatures and humidity levels.

Before improvements in human behavior and public health measures were implemented, researchers first examined the relationship between temperature and relative humidity during the initial stage of SARS-CoV-2 transmission in 162 countries on five continents. At the global level, the data demonstrate a negative association between transmission rate and both humidity and temperature: greater transmission levels were linked with lower temperature and relative humidity.

The researchers then looked at how this link between climate and disease changed over time and if it held true in different geographical regions. They employed a mathematical model built expressly to find similar patterns of change (namely a pattern-recognition technique) at distinct periods to do this. Then, they discovered a strong negative relation between disease (number of cases) and climate (temperature and humidity) for short time windows, with predictable patterns during the first, second, and third waves of the pandemic at various spatial scales: globally, nations, extremely affected regions, and even at the city scale.

The first pandemic waves faded as heat and humidity increased, while the second wave increased when heat and humidity decreased. This trend, however, was interrupted throughout the summer across all continents. Furthermore, using an epidemiological system, the researchers demonstrated that including temperature in the rate of transmission works much better for forecasting the fall and rise of the several waves, especially the first and third in Europe. Since low humidity circumstances have been found to alter the size of aerosols and hence increase airborne transmission of seasonal viruses such as influenza, this seasonality could play an essential role in SARS-CoV-2 spread.