How coronavirus spreads outdoors vs. indoors ?

Some months ago, when the novel coronavirus epidemic was still emerging in India, it was hoped that rising temperatures in the summer months would weaken the potency of the virus and slow down its spread. That did not happen. Now that the monsoon season is here, the likely impact of rain on the virus, and its transmission, is the subject of discussion.

Since it is a new virus, scientists are not yet sure how the rain might affect its behavior. So the effort is to look for clues in the way other similar viruses behave during the rainy season.

The problem, as Dr. Marc-Alain Widdowson, an infectious disease epidemiologist who worked with US Centers for Disease Prevention and Control and is now Director of the Institute of Tropical Medicine, Antwerp, Belgium, points out, is that even in the case of influenza, and several other viral respiratory diseases, the drivers for their seasonal behavior are not fully understood.

Dr. M S Chadha, former Deputy Director of National Institute of Virology who has worked on the seasonality of the respiratory syncytial virus (RSV), said it could take several years to determine how novel coronavirus is affected by different seasons. “Since RSV infection and other respiratory diseases usually do follow seasonal patterns, carrying out year-round Covid-19 surveillance for several years would be the key to determining its seasonality,” he said.