Will COVID-19 end as the weather warms?

So, is the "pandemic" COVID-19 really seasonal? A paper published in 2018 by Michaela Martinez of Columbia University shows that at least 68 infectious diseases are seasonal (see chart)With the arrival of summer, may the COVID-19 outbreak begin to weaken? However, experts who like to pour cold water warn against being too hopefulpicture source: Scienceexperts are right to be cautious that SARS-CoV-2, which caused the COVID-19 outbreak, is a new virus without any exact data on cases changing with the seasonsIn 2003, the virus that caused SARS (also known as SARS-CoV-1) was quickly brought under control after an outbreak, and little information was available about how it was affected by the seasonsCan some clues be found from other human-infected coronaviruses to determine whether SARS-CoV-2 will eventually become a seasonal virus?10 years ago, a study by Kate Templeton, the University of Edinburgh's Centre for Infectious Diseases, found that three coronaviruses (HCoV-HKU1, HCoV-NL63 and HCoV-OC43) showed "significant winter seasonality", all from patients with respiratory infections in Edinburgh hospitals and GPsThe viruses appear to cause infection mainly between December and April, similar to the pattern of influenzaThe fourth type of coronavirus (HCoV-229E) is found in patients with impaired immune systems and is more esotinousdoi: 10.1128/JCM.00636-10Other than that, some early studies suggest that COVID-19 may vary with the seasonan analysis published in the preprint platform medRxiv compared the weather in 500 regions around the world where COVID-19 cases occurred, indicating a link between the spread of the virus and temperature, wind speed and relative humidityAnother study, also published in medRxiv, also showed that higher temperatures were associated with lower incidence of COVID-19, but temperature alone could not explain the global change in morbiditydoi: https://doi.org/10.1101/2020.03.16.20037168doi: further research https://doi.org/10.1101/2020.03.18.20036731(still published on the preprint platform medRxiv) predicts that warm and cold temperate regions are most vulnerable to current COVID-19 eruptions, followed by arid areasThe researchers say the tropics may be the least affected doi: https://doi.org/10.1101/2020.03.12.20034728 "pandemic" is different
because there is no real data for multiple seasons, researchers can only rely on computer modeling to predict what might happen during the year It is challenging to infer seasonal data on COVID-19 from endemic coronaviruses, especially since endemic viruses are seasonal and may not currently apply to COVID-19 "Ultimately, we want COVID-19 to be endemic," says Jan Albert, a professor of infectious disease control at the Karolinska Institute in Stockholm who specializes in viruses The big question is whether the virus's seasonal sensitivity affects its ability to spread in pandemic situations We're not sure, but it's possible therefore, caution is needed when using an understanding of the seasonal behavior of other coronaviruses to predict the current COVID-19 pandemic But why is the associated coronavirus seasonal and what inspiration will this outbreak reveal? we know that coronaviruses are a class of single-stranded RNA viruses with encapsulation, which means that their genomes consist of a single strand of RNA (not DNA), and that each virus particle is encased in a protein "encapsulation." This means that they are coated with an "oily coat" called a lipid bimolecular layer, covered with a protrusion protein like a crown, which is known as Corona (the ancient Greek crown) Studies of other encapsulation viruses have shown that this oily coat makes the virus more susceptible to heat than viruses without the envelope In colder conditions, the oily coat hardens to rubber, just as the fat in cooked meat hardens when it cools down to protect the virus from the body for longer As a result, most endometheviruses tend to exhibit strong seasonality previous studies have shown that SARS-CoV-2 can survive for up to 72 hours on hard surfaces such as plastic and stainless steel at temperatures of 21-23 degrees C (70-73F) and 40 percent relative humidity The exact performance of SARS-CoV-2 viruses at other temperatures and humidity has yet to be tested, but studies of other coronaviruses have shown that they can survive for more than 28 days at 4 degrees C DOI: 10.1056/NEJMc2004973
The SARS virus is also best able to survive in colder, drier conditions The SARS virus remains contagious on a smooth surface for more than 5 days at relative humidity of 22-25 degrees C and 40-50% The higher the temperature and humidity, the shorter the virus's survival time the survivability of SARS-CoV-1 and SARS-CoV-2 on aerosols and various surfaces Photo Source: NEJM Miguel Araujo, of the National Museum of Natural Sciences in Madrid, who studies the effects of environmental change on biodiversity, said: "Climate works because when people cough or sneeze, it affects the stability of the virus outside the body The longer the virus remains stable in the environment, the greater the ability to infect others and become an epidemic Although SARS-CoV-2 has spread rapidly around the world, the main outbreaks occur in cool, dry places SARS-CoV-2 is less sensitive to the weather than expected
Ara?jo believes that if COVID-19 is similarly sensitive to temperature and humidity, it could mean that cases of coronavirus will occur at different times around the world His computer model appears to coincide with outbreak patterns around the world, with the highest number of cases outside the tropics a study by the University of Maryland found that the virus is most commonly transmitted in cities and regions with a world average temperature of 5-11 degrees Celsius (41-52F) and lower humidity However, there are also considerable cases in the tropics Researchers at Harvard Medical School recently analyzed the spread of the virus in Asia The results showed that the pandemic coronavirus was less sensitive to the weather than expected because the spread of the virus depends far more than on its ability to survive in the environment For diseases like COVID-19, the virus is now being transmitted The initial outbreak coincided with the Chinese New Year, which played a key role in the widespread spread of COVID-19 Therefore, seasonal changes in human behavior can also lead to changes in infection rates, which explains why understanding the seasonality of disease becomes more complex for example, the weather interferes with the immune system and makes the body more susceptible to infection There is evidence that vitamin D levels in the body can affect susceptibility to infectious diseases In winter, our bodies lose less vitamin D due to sunlight, mainly because we spend more time indoors, wrapping ourselves in clothes to ward off the cold air But some studies have found that this theory is unlikely to explain seasonal changes in diseases such as influenza more controversial is whether cold weather weakens our immune system Some studies have shown that this is true, but others have found that cold can actually increase the number of cells that protect our bodies from infection However, there is more evidence that humidity has a greater impact on our susceptibility to disease When the air is particularly dry, the amount of mucus stuck to our lungs and airways can be reduced This viscous secretion naturally protects against infection, and if the amount of mucus is low, we are more susceptible to the virus a study by Chinese scientists showed a link between the lethality of COVID-19 and the weather conditions They surveyed nearly 2,300 deaths in Wuhan, China, and compared them to humidity, temperature and pollution levels on the day of the incident doi: https://doi.org/10.1101/2020.03.15.20036426 their research shows that mortality rates are lower on days with higher humidity levels and temperatures Their analysis also showed higher mortality rates on days with highest and lowest temperature ranges But much of this work is also based on computer modeling, so the exact nature of the relationship and whether it applies to the rest of the world remains to be explored reduce unnecessary exposure because the virus that causes the COVID-19 pandemic is a new virus, so many people are not immune to it unless someone is infected Vittoria Colizza, research director at the French Institute of Health and Medical Research, says air travel has been the main route of the virus spreading so quickly around the world In addition, once the virus begins to spread in the community, close contact between people can also promote transmission Stopping human-to-human contact should also reduce infection rates "there is no evidence of seasonal behavior in COVID-19," Collizza said It is not yet clear whether these measures will be sufficient to stop the spread of the virus On its own, it may partially reduce the effectiveness of infectious diseases by reducing exposure to potentially transmitted diseases If COVID-19 cases do decrease in the coming months, there may be several reasons for the success of preventive measures such as isolation and blocking; even if COVID-19 does exhibit some seasonal variation, it is unlikely to disappear completely in the summer However, in some cases the decline in the number of cases may bring some benefits "Economically, the measures we take to smooth the curve are expensive, but they can help us push this pandemic into the summer," Albert said Time, it is what we urgently need now "
References: Why do dozens of diseases wax and wane with the seasons-and will COVID-19? original title: Will warmer weather end COVID-19?