Does climate play a major role in SARS-CoV-2 infection?

The emergence of Coronavirus Disease (COVID-19) was first reported in Wuhan, China in December 2019, and due to its rapid spread, the World Health Organization (WHO) has become a Public Health Emergency of International Concern (PHEIC). Was announced. ). Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), the causative agent of COVID-19, is highly contagious and spreads rapidly through respiratory droplets from infected individuals. Most people infected with COVID-19 develop mild symptoms or are asymptomatic. For others, it can cause acute respiratory problems, serious health problems, and in some cases can turn out to be fatal.

Scientists around the world have fought to control the spread of the disease by devising a variety of approaches, including the development of vaccines, nasal drops, sophisticated masks, oral medications, and more. They are also working to establish a valid link between environmental conditions and coronavirus infection rates in order to gain a better understanding of the nature of the virus and how it spreads.

In a new treatise released in medRxiv* A preprint server, a team of researchers at the Federal University of Itajuba in Brazil, reports that weather plays an important role in determining the transmission rate of SARS-CoV-2 infection. They further state that after controlling parameters such as age, population, and urbanization, meteorological variables are very important for predicting regional mortality. In the early days of the global outbreak of COVID-19 in early 2020, the virus was mistakenly assumed to propagate only in cold conditions. However, the subsequent violent spread of the coronavirus in many tropical countries such as Brazil and India has challenged this misconception.

Recently, the correlation between SARS-CoV-2 spread and meteorological variables such as temperature, wind speed, relative humidity, and precipitation in cities located in southeastern Brazil and less populated rural cities has been analyzed. In this study, researchers collected meteorological data from six research sites from the Federal University of Itajuba (UNIFEI, 2020) and the National Meteorological Research Institute (INMET, 2020) between April and December 2020. Daily COVID Data-19 cases were raised from the database of the Secretary of Health of the State of Minas Gerais (SHGMG, 2020). Correlation studies were performed using Spearman’s correlation coefficient.

In the first year of the pandemic, the study revealed a low incidence of COVID-19 in less densely populated areas (ie, study areas for experiments). This is in contrast to the high prevalence in other populated areas of Brazil. Scientists initially hypothesized that the low number of cases was probably due to the good air quality of the small cities.

Many previous studies suggest that relative humidity plays an important role in the persistence and transmission of the virus in closed environments or indoors. Low relative humidity increases viral infections. Similar studies conducted in different parts of the world, such as New York City, the state of China, and the region of South America, found a significant correlation between the daily incidence of COVID-19 cases and absolute humidity. Was shown. The current study under consideration further confirmed that the lower the relative humidity, the higher the virus infection rate, regardless of the level of contamination.

Many scientists also report that high and low temperatures are positively correlated with viral infections. Current studies support these findings and show that elevated temperatures and reduced relative humidity aid infection with the SARS-CoV-2 virus.

In many cities, wind speed was positively correlated with the incidence of COVID-19. However, researchers argue that this result may not be conclusive for a variety of reasons. For example, wind speed disperses pollutants present in the atmosphere. In areas with high wind speeds, the amount of pollutants is low. In addition, wind speeds vary from region to region. For example, coastal areas have faster wind speeds than inland areas. Therefore, further research is needed to determine the correlation between the incidence of COVID-19 and wind speed.

Researchers further report that daily cumulative rainfall is not correlated with COVID-19 infection. However, in another study conducted in Oslo, Norway, scientists found a significant correlation between lack of precipitation and an increase in COVID-19 cases.

Current research helps the scientific community understand the relationship between climatic conditions and the spread of SARS-CoV-2 in less densely populated areas. Such assessments help scientists design precautions to prevent the spread of the disease and thereby contain the pandemic. The results of this study are also expected to support an appropriate and more efficient mitigation policy framework for the SARS-CoV-2 epidemic, based on the regional climate profile.

*Important Notices

medRxiv publishes unpeer-reviewed preliminary scientific reports and should not be considered definitive, guide clinical / health-related behaviors, or be treated as established information.