Warmer countries with more intense UV radiation experience fewer cases of Covid-19, according to a new study.

The research offered findings that are consistent with the idea that heat and sunlight reduce the spread of the virus.

Scientists looking at 117 countries found that the further a country was located from the equator, the more cases the country had, relative to the number of inhabitants.

An 1% increase in absolute latitude was associated with a 4.3% increase in Covid-19 cases per million inhabitants.


Many viral acute respiratory tract infections, such as flu and coronavirus, are climate dependent and share seasonal patterns.

Some viruses may have better stability in low-temperature, low-humidity, and low-UV radiation environments.

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Scientists from Vienna University of Economics and Business said this could indicate there is a direct link between climate conditions and the spread of Covid-19.

However, the report found there was 'scant evidence' this was true for the virus.

On March 9, 2020, the World Health Organization (WHO) stated that “from the evidence so far, the COVID-19 virus can be transmitted in all areas, including areas with hot and humid weather."

The researchers included data on air travel, urbanisation, testing intensity, cell phone usage, income, old-age dependency, and health expenditure.

According to the results of the research, countries are expected to see a decline in new COVID-19 cases during summer and a resurgence during winter.

However, scientists said the results do not imply that the disease will vanish during summer.

Rather, it found that that higher temperatures and more intense UV radiation in summer were more likely to support public health measures to contain the virus, such as physical distancing and more time spent outdoors.

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Klaus Prettner, Department of Economics, Vienna University of Economics and Business, said: "The closer a country is to the equator, the fewer cases of COVID-19 virus per million population occur.

"The closer to the equator, the higher the humidity and temperatures tend to be, as well as the UV radiation.

"Knowing this is important in order to set appropriate measures against the spread of the COVID-19 virus.

"Overall, however, our results do not mean that countries closer to the equator will not be affected by the pandemic at all or that the virus will disappear altogether in the summer.”

The study said future research should aim at uncovering how the transmission of SARS-CoV-2 is affected by changes in  climatic factors such as heat and humidity, geographic factors such as altitude and sunlight intensity, factors related to human behavior and different potential of the human immune system to cope with diseases in summer as opposed to winter.