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WMO cautions against seasonal easing on virus

The U.N. weather agency advised governments against relaxing COVID-19 restrictions based on assumptions the coronavirus will decline with warm weather.

Patchwork farmland in Saxony, Germany
Patchwork farmland in Saxony, Germany (AN/Tobias Tullius)

GENEVA (AN) — The U.N. weather agency advised governments against relaxing COVID-19 restrictions on Thursday based on false assumptions that the coronavirus will decline with the spread of warm weather in the Northern Hemisphere.

The World Meteorological Organization's first report on how weather and air quality affect the pandemic downplayed those factors in curbing the spread of the virus. Instead, its task force emphasized the importance of face mask mandates, travel restrictions, social distancing and other socially imposed measures.

The report by a WMO task team of experts is important because it comes just as richer nations push vaccination programs to increasingly focus on reopening economies and schools.

"At this stage, evidence does not support the use of meteorological and air quality factors as a basis for governments to relax their interventions aimed at reducing transmission,” task force co-chair Ben Zaitchik, an associate professor of Earth and planetary sciences at Johns Hopkins University, said. “We saw waves of infection rise in warm seasons and warm regions in the first year of the pandemic, and there is no evidence that this couldn’t happen again in the coming year.”

WMO's chief scientist, Jürg Luterbacher, cautioned against jumping to conclusions by noting that "the rapid pace of COVID-19 research has meant that studies with limited data appeared faster than the information could be cross-checked and peer-reviewed" in a thorough manner.

"It soon became clear that reported evidence was often contradictory or selective due to methodological and data-related shortcomings," said Luterbacher, adding that the WMO task force also is trying to "encourage good practice in research and communications" through its report.

Potential role of air pollutants

There is some evidence COVID-19 survives longer in "cold, dry and low ultraviolet radiation conditions," said the 42-page report, but seasonal fluctuations on coronavirus are not yet clearly understood the way that temperatures and times of year affect respiratory viral infections such as colds and influenza.

"These studies have not yet indicated if direct meteorological influences on the virus have a meaningful influence on transmission rates under real world conditions," the report found.

Similarly, it pointed to preliminary evidence that poor air quality increases COVID-19 mortality rates, but said it was too early to conclude just how air quality influences the coronavirus. It also noted there is still no peer-reviewed evidence of how pollution might affect the way the virus goes airborne.

"Air pollutants might also play a role in airborne transmission of viruses. It has been demonstrated that particulate matter can be a carrier of airborne pathogens, and that aerosols can enhance the stability of some viruses," the report said. "The importance of these pathways to infection risk relative to the influence that air pollution has on host resistance to infection is not well characterized."

Next up for the task force will be to set research priorities for the nexus between pandemics, weather, climate and air quality, and to offer best practices and standards for integrating infectious disease modeling with environmental factors.