Warmer countries less vulnerable to COVID-19, study finds

By Angela Betsaida B. Laguipo, BSNNov 29 2020

The northern hemisphere winter season is fast approaching, and, in some countries, the temperature has declined substantially over the past weeks. Based on previous flu seasons, health experts are worried that the coronavirus disease (COVID-19) pandemic will worsen due to lower temperatures.

In fact, a new study by a researcher at the University College London (UCL) suggests that global temperature plays an essential role in the spread of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent of COVID-19.

The COVID-19 pandemic

The coronavirus pandemic first emerged in late December 2019 in Wuhan City, China. It has rapidly spread to most countries worldwide. Many studies have shown that some countries and cities with moderately cold winter temperatures exhibited a rapid virus spread. These include the United Kingdom, Spain, Italy, and the northern parts of the United States, compared to other countries in the African continent and Australia.

Further, frigid countries like Russia, Canada, and Scandinavian only showed moderate severity. Consequently, some countries that had moderate severity had worsened status from the end of April.

Colder regions were more affected compared to warmer places. During the peak of the winter season in China in January, Wuhan City experienced the maximum severity of the death toll and the surge of new cases. In February, other cold countries such as Italy, Iran, and South Korea reported outbreaks.

Rolling 7-day average of daily confirmed COVID-19 deaths per million up to 6 May 2020 (Ourworldinddata 2020). India, Asia, Africa and Australia all are very low compared to the rest throughout and practically merges with X axis (hence not visible). The bottom three curves are for Russia, Brazil and Canada, respectively. All three are showing a rising trend. Top four high peak curves are for UK, USA, Spain and Italy. All four are currently in a declining state. Plot generated using: https://ourworldindata.org/grapher/daily-covid-deaths-per-million-7-day-average. Accessed 10 May 2020

Temperature and COVID-19

In the study published in the International Journal of Environmental Science and Technology, the researchers wanted to determine the role of variable global temperatures in the transmission of the virus globally.

The team analyzed global air temperature data collected by the NCEP/NCAR Reanalysis product, which was freely available online.

The team has found that based on March and April temperatures, they identified many degrees of vulnerability. The highest reported case and death were noted when the temperature ranged between 2 °C and 17 °C. Many countries experience this range of temperature, including the United Kingdom, the United States, Italy, and Spain.

Meanwhile, countries from Southeast Asia, Africa, and Australia, which have temperatures above 27 °C, have a lesser vulnerability.

The main point of the study is that the virus is susceptible to temperature. Viruses can spread in favorable situations, including in moderately cold places. On the other hand, warm countries were likely to be less vulnerable.

The researchers also pointed out that some countries can change their vulnerability state, depending on their climate. For instance, parts of Russia and Canada started from severe cold to moderate cold at the end of April, while Brazil and other warm countries in South America moved from warm to less warm states. These countries reported a sudden surge of cases and deaths by May 2020.

“As regional temperature plays a significant role in the transmission and spread, these results and future predictive maps have a major implication for future planning,” the researchers wrote in the paper.

Regulating temperatures

The team noted that the influence of temperature on the virus and the results of previous trials with similar viruses could provide a valuable insight that regulating the temperature can help stem the pandemic.

The study provides valuable insight into regulating the temperature level to provide a crucial strategy to stop the outbreak. The researchers noted that this method is cost-effective, practical, and safe.

“To adopt these solutions, no vast amount of funding is required. Another novelty of such an approach is that it can be implemented immediately across the globe,” the team concluded.

To date, the SARS-CoV-2 virus has infected more than 62.62 million individuals and claimed over 1.45 million lives globally. The United States reports the highest number of cases, reaching 13.36 million cases.