WHO: Coronavirus unaffected by seasonal changes

The novel coronavirus does not appear to wax and wane with the passing of the seasons, experts at the World Health Organization said Monday.

“In the absence of control measures, very often, viruses can show seasonal patterns. We’ve certainly seen that with influenza. This virus has demonstrated no seasonal pattern as such, so far,” said Mike Ryan, who heads the WHO’s emergencies program. “What it has clearly demonstrated is, you take the pressure off the virus, the virus bounces back.”

Some had hoped that heat and humidity would stifle transmission of the coronavirus. From the earliest days of the outbreak during the winter months, President Trump claimed the pandemic would end in warmer weather.

But studies — and the ebb and flow of the virus in the United States itself — have shown that is not the case.

Coronavirus cases rose quickly in cities such as Houston, Austin, Dallas and Phoenix in the summer months, even as the mercury rose into the triple digits. The two countries hit hardest by the virus outside North America — Brazil and India — are both hot weather climates. In Russia, where the climate is much cooler, more than 890,000 people have tested positive for the virus.

“This virus is proving exceptionally difficult to stop,” Ryan said.

In comments to reporters Monday, WHO Director-General Tedros Adhanom Ghebreyesus said there are at least some reasons for optimism. He pointed to New Zealand, a nation that has gone 100 days without community transmission; Rwanda, where testing is provided to anyone free of charge; and nations along the Mekong River and island states in the Caribbean and the Pacific where viral transmission has been low.

“There are green shoots of hope, and no matter where a country, a region, a city or a town is, it’s never too late to turn the outbreak around,” Tedros said.

In the United States, still the world’s worst-hit nation, the number of new cases reported every day has dropped slightly in some of the epicenters of the outbreak. Weekly case counts have declined for two straight weeks in 22 states and the District of Columbia.

But cases are still rising in 12 states, from tiny Hawaii and Vermont to Virginia, Illinois and Indiana.

Even some of the states that have seen declines are reporting substantially high numbers of cases. Texas reported more than 55,000 new cases last week. California and Florida both reported more than 45,000 new cases, figures that potentially undercount the actual number. California officials discovered two computer errors that may have delayed test results, while Florida locked down testing sites as Hurricane Isaias bore down on the state.

Georgia reported 22,000 new cases, and Illinois, Louisiana, North Carolina and Tennessee all topped 10,000.

WHO officials said the pandemic will continue for months but that emerging science shows that only a small fraction of those who contract the virus are responsible for the bulk of the spread. Maria Van Kerkhove, the American leading the technical team investigating the virus, said between 10 and 20 percent of cases are responsible for up to 80 percent of transmission.

“We know that if the virus has an opportunity to spread, it will,” Van Kerkhove said. “We know that the majority of the population still remains susceptible to infection.”