Some people hope that the emerging coronavirus will fade with increasing temperatures, but the pandemic will not behave in the same way as seasonal epidemics. Many infectious diseases pass in various phases with seasons. The flu usually comes in the coldest winter months, such as the "vomiting bacterium", and other diseases, such as typhoid, reach its peak during the summer, and measles cases decrease during the summer in moderate climates. , While in the tropics and the tropics, the peak is in the dry season.
It is not surprising, perhaps, that many people ask, now, whether we can expect a similar season with "Coffed 19". Since it first appeared in China in about mid-December, the virus has spread rapidly, with the number of cases now increasing sharply in Europe and the United States.
Many of the largest outbreaks were in areas where the weather was colder, leading to speculation that the disease might begin to fade with the arrival of summer, but many experts cautioned against excessive betting that the virus will fade during the summer.
They are right to be careful: the virus that causes "Covid 19" is so new that there is no hard data available on how cases change with seasons. The SARS virus, which spread rapidly in 2003, has been contained, which means there is little information available on how it was affected by the seasons. But there are some clues from other coronaviruses that infect humans about whether corona may eventually become seasonal.
Seasonal viruses
A study conducted by the researcher, Kate Templeton, from the Center for Infectious Diseases at the University of Edinburgh in the United Kingdom, 10 years ago, showed that three coronaviruses, all of which were obtained from patients with respiratory infections, in hospitals and surgery rooms, in Edinburgh, showed that they are «seasonal Winter »significantly. These viruses appeared to cause infection mainly, between December and April, a pattern similar to that seen with influenza. The fourth coronavirus, which was found mainly in patients with weakened immune systems, was more irregular than others.
There are some early hints that "Covid 19" may also differ with the seasons, and the outbreak of the new disease around the world seems to indicate its preference for cold and dry conditions, although it should be noted that the virus appeared in countries with a wide range of climates. , Including warm wet.
The unpublished analysis, which compares the weather in 500 locations around the world where there have been "corona" cases, appears to indicate a link between virus spread, temperature, wind speed, and relative humidity. As another unpublished study showed, high temperatures are associated with a lower occurrence of "Covid 19", but they indicate that temperature alone cannot explain the global difference in terms of outbreaks.
The researchers say the tropical and tropical regions of the world are likely to be the least affected. But without real data over a number of chapters, researchers rely on computer models to predict what might happen throughout the year.
A real surprise
Extrapolating data about the seasonality of "Covid 19", which is based on endemic coronaviruses (which have been circulating among humans for some time), is difficult, and endemic viruses are seasonal for a number of reasons that may not currently apply to the "Covid 19" pandemic.
Epidemics often do not follow the same seasonal patterns that occur in regular outbreaks. The Spanish flu, for example, peaked during the summer months, while most flu outbreaks occur during the winter.
"Ultimately, we expect to see an epidemic (Covid 19) settlers," said Professor Albert Infectious Jean-Albert, a specialist in virology at the Karolinska Institute in Stockholm. "It will be surprising, really, that it does not appear seasonally at the time, and the big question is what If the sensitivity of this virus to (seasons) will affect its ability to spread in a pandemic? We don't know for sure, but it should be in the back of our heads that it is possible. ”
Therefore, we must be careful when using what we know about the seasonal behavior of other coronaviruses, to form forecasts for the current Covid 19 pandemic. Why are coronary related viruses considered seasonal? And why does that give hope to be in this outbreak?
Coronaviruses are a family called "coated viruses", meaning that they are covered with a fat layer, known as a "two-layer lipid", which is studded with proteins that protrude like nails from the crown.
Greasy paint
A study of other encapsulated viruses indicated that the lipid coating makes viruses more vulnerable to heat than those that do not have this coating. And in colder conditions, the grease coats to become like rubber - much like the cooked meat fat that becomes solid as it cools - to protect the virus for a longer period when it is outside the body. Most encapsulated viruses tend to show strong seasonal outbreaks, as a result.
Research has already shown that the emerging virus can survive up to 72 hours, on solid surfaces, such as plastics and steel, at temperatures between 21 and 23 ° C, and in humidity of 40%.
How exactly does the "Covid 19" virus behave in other temperatures and humidity? To find out, tests are required, but research on other coronaviruses suggests that they can survive more than 28 days at four degrees Celsius.
It turned out that the coronavirus, closely related to the present one, that caused the SARS outbreak in 2003, managed to survive better in cooler, drier conditions. After it was dried, the SARS virus remained contagious on smooth surfaces, for more than five days, between 22 and 25 degrees Celsius, and relative humidity between 40 and 50%. The higher the temperature and humidity, the more virus is alive.
"The climate is taken into consideration because it affects the stability of the virus outside the human body, when it is coughed or sneezed," says Miguel Araijo, who studies the effects of environmental change on biological diversity at the National Museum of Natural Sciences in the Spanish capital, Madrid. The more time the virus remains stable in the environment, the greater its ability to infect other people and become a pandemic. And while "Covid 19" has spread rapidly around the world, the main outbreaks have occurred mainly in places with cold and dry weather.
There are early hints that "Covid 19" may vary with seasonal variability, and the outbreak of the new disease globally seems to indicate its preference for cold and dry conditions, given that the virus has appeared in countries with a wide range of climates, including hot and humid.
The researchers say it is likely that the tropical and tropical regions of the world are the least affected by the Corona virus. But without real data over a number of chapters, researchers rely on computer models to predict what might happen throughout the year.
72
An hour the emerging virus can survive on hard surfaces such as plastics and steel, at temperatures between 21 and 23 ° C, and in humidity up to 40%.
Research on other coronaviruses suggests that it can survive more than 28 days at 4 ° C.