One day the pandemic will end. Scientists do not know how that finale will play out, but a new model offers a preview: the deadly SARS-CoV-2 may not disappear completely, but rather becomes a cold virus that spreads regularly, just a little sniff cause.
This model, published on January 12 in the magazine Science, is based on analyzes of other coronavirusmost of which cause only mild symptoms in humans. There are six coronaviruses that infect humans; four are coronaviruses that are ‘endemic’ or frequently spread among human populations and cause colds.
The other two coronaviruses – those that cause Severe Acute Respiratory Syndrome (SARS) and MERS (Middle East Respiratory Syndrome) – are more lethal, although the first years were eliminated and the latter are largely limited.
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To create their model, a group of researchers analyzed previously published data on the four milder coronaviruses and found that ‘immunity that blocks the infection decreases rapidly, but the disease-reducing immunity lasts a long time’, the authors write in the study. In other words, people can get infected again and again, but rarely get serious illnesses, said lead author Jennie Lavine, a postdoctoral fellow at Emory University in Atlanta, said in a statement.
Almost everyone catches one of these endemic coronaviruses during childhood; and these early infections confer partial immunity to adults who become infected again. “Re-infection is possible within one year, but even if it does occur, the symptoms are mild and the virus is removed from the body more quickly,” Lavine said.
However, there are no similar long-term data on the duration of immunity for the new coronavirus SARS-CoV-2 that causes COVID-19. It is not clear how long immunity, whether against vaccines or natural infection, to SARS-CoV-2 will last in humans; It is also unknown to what extent vaccines and natural infections will inhibit transmission or reduce the severity of the disease.
Some people have already been re-infected with SARS-CoV-2, Live Science reported earlier. But these cases were rare and most of these people had a mild illness for the second time, according to the study.
The model assumes that immunity to SARS-CoV-2 will work similarly to these other endemic coronaviruses, Lavine said. And one of the main conclusions of the model is that, for existing coronaviruses, the severity of infection during the endemic phase is directly linked to how serious the disease is when it infects children. Unlike the new coronavirus, almost none of these adults appear first as an adult. But “we do not really know what it would be like if someone as an adult got one of the other coronaviruses for the first time, rather than as a child,” she said. It is possible that if they did, they would experience worse illnesses.
Their model predicts that if SARS-CoV-2 becomes endemic and future generations are exposed primarily during childhood, the virus ‘may not be more virulent than colds’, the authors wrote. Once it is endemic, the mortality rate of the virus’ infection, or the number of people who die compared to those infected, will be below that of the seasonal flu, the authors wrote.
This is because children are generally less severely affected by COVID-19 infections and that mortality is usually low in children, so the severity of the baseline should predict the severity of SARS-CoV-2 in its endemic phase. But if SARS-CoV-2 seriously affected children, as is the case with the virus that causes MERS, a relatively high number of people could die even during the endemic phase, the authors predicted.
If this model holds true, exactly how the world will reach the endemic phase is still passed on to us: faster spread of viruses will lead to a faster transition as humans get herd immunity, but it will result in more deaths. Vaccinations are a safer way to establish such immunity, and once they are widely available, they will also accelerate the transition to a possible endemic phase – a phase in which the coronavirus can be tackled with a box of Kleenex, rather than ventilators. and locks.
Originally published on Live Science.