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Video: Everything We Know About The Seasonality Of COVID-19 Today
Everything we know about the seasonality of COVID-19 today
Symptoms of the COVID-19 coronavirus infection are similar to those of the flu and the common cold. Not surprisingly, many expected and still hope that with warm weather the virus will reduce activity. Understanding what we know about the seasonality of the new coronavirus today.
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The symptoms of COVID-19 coronavirus infection are similar to those of the flu and the common cold. Not surprisingly, many expected and still hope that with warm weather the virus will reduce activity. Understanding what we know about the seasonality of the new coronavirus today.
Not every cold goes away in summer
In February, the statement by US President Donald Trump about the hope for a spring retreat of the virus received a great response. Then in the media there were statements by many experts that there were no real reasons for such rosy expectations. For example, William Schaffner, an infectious disease specialist at Vanderbilt University Medical Center, said:
“His hope is our hope. But we have no knowledge that it will be so. It is a respiratory virus and we know they are often seasonal, but not every one of them.”
In the month and a half that have passed since Trump's announcement, several scientific publications have appeared, which, although they do not give unambiguous answers, shed light on this question.
Higher temperatures mean fewer infections
A new small study by scientists from the Massachusetts Institute of Technology suggests that in warmer places, the new coronavirus is more slowly transmitted from one person to another than in relatively cool places.
According to scientists' calculations, most of the infections with the new coronavirus occurred in areas where the temperature was from 3 to 17 degrees Celsius. In the countries of the Southern Hemisphere, in which it is now summer with temperatures above 18 degrees on average, the disease is also spreading. But at the time of completion of the study, which was published on March 19, these countries accounted for less than 6% of the global incidence of COVID-19.
Scientists have found a similar pattern in the United States. In the southern states (Arizona, Texas, Florida), the infection spread more slowly than in the northern states (Washington, New York, Colorado).
Qasim Bukhari, co-author of the study, told the New York Times in a commentary:
“Where the weather was colder, the number of cases grew faster. You see this in Europe, even though the region has some of the best health systems.”
An important limitation of this study is the lack of reliable data on the number of cases. The identification of infected people in different countries was organized according to different principles. For example, in South Korea, mass testing was extended to the general public, and in the United States and Great Britain - only to those who were sick and in contact with them. The morbidity could be affected by the willingness of hospitals and the rigidity of compliance with quarantine measures.
The conclusions of scientists from Spain and Finland are consistent with the data of their American colleagues. They write that the "comfort zone" for the virus is a temperature of 2 to 10 degrees Celsius.
Not only temperature, but also humidity
A little earlier, a group of Chinese scientists, using data from 14 countries as an example, showed that not only temperature, but also humidity affects the transmission efficiency of the new coronavirus. According to their data, an increase in temperature by only 1 degree Celsius and an increase in relative humidity by 1% is reflected in the ability of people to infect each other with a new coronavirus.
"In the early days of the outbreak, countries with relatively low temperature and humidity (Korea, Japan, Iran) experienced more severe epidemics than more humid countries (Singapore, Malaysia, Thailand)," the scientists write.
We still don't know for sure
All three studies cited have yet to be published in peer-reviewed medical journals. The correlation of air temperature with the slowing down of the spread of infection, which is shown in these scientific works, should not be a reason for relaxation.
“We still have to apply strict measures. If warm temperatures make transmission of the virus less efficient, that does not mean that transmission is disappearing,”Bukhari told the New York Times.
The opinion of Maria Van Kerkhove, an expert on infectious diseases at WHO, which she said at a press conference back on May 5, is probably still relevant now:
“We only know about this virus for eight weeks or so - from the end of December to the start of March. So, we don't know much about how he will behave during the change of seasons, if we know at least something."