Although there have been suggestions that warmer weather might lead to the waning of the COVID-19 pandemic in the Northern Hemisphere, a new study published by the United States National Academy of Sciences has dashed some cold water on that hypothesis, saying that available data on diease spread has so far failed to show strong seasonality.

The preliminary analysis by the National Academies’ Standing Committee on Emerging Infectious Diseases and 21st Century Health Threats said that the number of well-controlled studies showing reduced survival of the coronavirus in elevated temperatures and humidity is small, and urged caution not to over-interpret results. While some data, particularly from laboratory studies, provide evidence supporting seasonality, the researchers note that these are not necessarily representative of the natural environment and that multiple countries currently in their summer season are experiencing significant volume of transmission,

Even if warmer temperatures are less favorable for COVID-19, “given the lack of host immunity globally, this reduction in transmission efficiency may not lead to a significant reduction in disease spread without the concomitant adoption of major public health interventions,” the experts wrote.  Some countries in warm climate are also experiencing rapid virus spread, the experts added, so that “a decrease in cases with increases in humidity and temperature elsewhere should not be assumed.”

The report also notes that neither of the other coronaviruses that have recently leaped from animals to humans, Severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS), nor the flu strains of previous pandemics, have shown a seasonal pattern.

The study evaluated available observational epidemiological data as well as laboratory experimental data, including studies both in China and other countries. Further study is required to better characterize the virus’ transmission patterns, reported the Univeristy of Minnesota Center for Infectious Disease Research and Policy. 

COVID-19 Cases in Spain Rise Once More

After a week of decreasing daily COVID-19 incidence, Spain once more reported elevated numbers on 3 consecutive days. Today, Spain reported 5,756 new cases, bringing the national total to 152,446 cases, including 15,238 deaths (683 new), reported the Johns Hopkins Center for Health Security. Italy reported more new cases than the previous day (3,836 compared to 3,039), but the daily incidence remains below 4,000 for the third consecutive day after exceeding that number for nearly 3 weeks. Italy is reporting a total of 139,442 confirmed cases, and 17,669 deaths.

Meanwhile, while US President Donald Trump expressed hopes that the US could “reopen again soon” experts were more reserved in light of the continued increase in US cases, with some 30,000 more infections reported in the US over the past 24 hours, 10,000 more than on the day before.

In South-East Asia, cases also continued to rise in India, in partvcular, which has reported more than 500 new cases a day, over the past 10 days, for a 300% increase, There are now 6,412 cases in the country, according to the official India Ministry of Health and Family Welfare data.

Meanwhile, WHO Director General Dr. Tedros Adhanom Ghebreyesus brushed off recent criticism of WHO’s response to the COVID-19 crisis, which US President Donald Trump on Tuesday tweeted was “very China centric.”  At a later White House briefing Trump repeated his charge that WHO had been too soft on China’s early management of the emergency, and suggested that US funding to the organization would be re-examined. Trump also criticized WHO’s strong opposition throughout January and February to the imposition of travel restrictions to stop the spread of the virus, saying that the Organization should have recommended restrictions much earlier, which the US later adopted on unilaterally followed by countries around the world.

At a WHO press briefing on Wednesday, the WHO Director General urged political leaders not to play politics with the coronavirus emergency, adding: “why do I care about being attacked when people are dying.”

Cumulative and active cases. Numbers change rapidly.

-Updated 4 April, 2020

Image Credits: D Sharon Pruitt.