A recent study asks which factors impact the progression of the COVID-19 pandemic. The authors investigate meteorological factors and public health measures across multiple geographical locations.

As the COVID-19 pandemic rumbles on, scientists are observing its features from every possible angle. Some scientists are trying to identify factors that reduce the speed of its spread.

The authors of a recent study, published in the Canadian Medical Association Journal, asked whether school closures and other public health interventions result in a slowdown of the COVID-19 pandemic.

They also assessed whether geographical and meteorological factors play a part in curtailing the pandemic, including latitude, temperature, and humidity.

As expected, the authors found that “public health interventions were strongly associated with reduced epidemic growth.” However, more surprisingly, they concluded that the spread of SARS-CoV-2 was not associated with temperature.

Viruses and temperature

Scientists have established that influenza outbreaks — the most well-studied respiratory viral outbreaks — are associated with changes in climate; they tend to occur during colder months. However, questions remain as to why these viruses display such seasonality.

Although scientists are still investigating the matter, reduced case numbers in hotter months are likely to be due to higher temperatures, higher humidity, or higher solar radiation.

As the authors explain, “These three characteristics are all associated with geographic latitude, a measure that can be determined effortlessly and with precision.”

The fact that schools tend to close over the summer months could also play a part in reducing the risk of influenza outbreaks.

For the recent study, the researchers focused on data taken from ‘geopolitical areas with documented outbreaks of COVID-19’ during 2 separate weeks.

They classed the first week — March 7–13, 2020 — as the exposure period. The authors took note of latitude, temperature, humidity, school closures, restrictions of mass gatherings, and physical distancing measures.

Then, they measured the increase in the number of COVID-19 cases 14 days later to allow for the incubation period. They took their measurements for the week, March 21–March 27, 2020. In other words, they looked at the relevant variables during week one and measured how much these variables influenced COVID-19 rates 2 weeks later.

According to the authors, the chosen interval of 14 days reflects “the assumed time between transmission of SARS-CoV-2 and reporting of confirmed COVID-19 cases.”

Overall, though, the scientists conclude that seasonality is unlikely to play a significant role in the epidemiology of COVID-19.

Their take-home message is that “[o]nly area-wide public health interventions were consistently associated with reduced epidemic growth, and the greater the number of co-occurring public health interventions, the larger the reduction in growth.“

Medical reference: medicalnewstoday