study: "COVID-19" It will not end soon and will turn into an endemic disease within two years.

Many people are wondering when the Covid-19 pandemic will end, but a new study says the disease will not go away and could reach an endemic stage within two years.

Diseases such as the common cold and the flu have become endemic in humans and everyone gets sick from time to time, but for most people they are not particularly dangerous.

According to his research, COVID-19 will become endemic at some point, possibly within two years. Yale University researchersand published July 5 in PNAS Nexus magazine.

To better understand when and how COVID-19 might become endemic, Yale University researchers turned to mice, which, like us, are also susceptible to coronaviruses.

By collecting data on the rate of re-infection with coronavirus in mice, they were able to model the likely course of COVID-19.

Animals such as pigs and chickens also live with endemic coronaviruses. A major factor identified in the spread of both animal and human coronaviruses is their tendency to induce so-called non-sterile immunity.

“This means that immunity is pretty good initially, but it wanes relatively quickly,” said Caroline Zeiss, a professor of comparative medicine at the Yale School of Medicine and lead author of the study. Even if an animal or person is vaccinated or infected, they are likely to become susceptible to infection again.

Over the past two years, scientists have determined that SARS-CoV-2 produces non-sterile immunity.

Individuals who have been infected or have been vaccinated are still at risk of reinfection. Therefore, experts predict that the virus will not disappear anytime soon.

To better understand what SARS-CoV-2 can do over time, the scientists used mathematical models. Given the strong similarities between animal and human coronaviruses, collecting relevant animal data provides an opportunity to better understand SARS-CoV-2, Zeiss said.

In this study, Zeiss and her colleagues observed how the coronavirus is transmitted, like the virus that causes the common cold in humans, through populations of mice.

The team modeled an exposure scenario reminiscent of human exposure in the United States, where part of the population is vaccinated against “Covid-19” and where people continue to experience natural exposure to SARS-CoV-2.

The team also replicated different types of human exposure in the United States, with some animals exposed through close contact with an infected rat (risk of infection) and others through placing an infected rat in a cage (low risk of infection).

Infected animals developed an upper respiratory tract infection, after which they recovered. Three to four months later, the mice were re-infected with the virus.

Infection rates again showed that natural exposure resulted in a combination of levels of immunity: those who were exposed to more viruses through close contact had stronger immunity, while those who were placed in an infected cage (and thus were exposed to less exposure to the virus), had higher rates of re-infection. .

Zeiss notes that when naturally infected, some people develop better immunity than others. People also need vaccination, which is administered in a certain dose and creates a predictable immunity. The study found that both vaccination and natural exposure in the population develop broad immunity that pushes the virus towards endemic stability.

Seiss and her team then used this data to inform mathematical models and found that the average time it takes for the SARS-CoV-2 virus to become a pandemic in the United States is 1,437 days, or just under four years from the onset of a pandemic. pandemics in March 2020

In this scenario, the model predicts that 15.4% of the population will be susceptible to infection at any time after it reaches the endemic stage (when the disease spreads within a population, country or continent without any external influences).

“The virus is constantly spreading,” Zeiss said. “So it will be important to consider the most vulnerable. We cannot assume that once we reach endemicity, everyone will be safe.”

She explained that four years is the average time predicted by the model, so it may take longer to reach the endemic stage. This does not take into account mutations that can make SARS-CoV-2 more dangerous.

“Coronaviruses are very unpredictable, so a mutation can occur that makes them more pathogenic. However, the most likely scenario is that we see an increase in transmissibility and a potential decrease in pathogenicity. This means the virus will be easily transmitted, “Zeiss is found in humans, but is less likely to cause severe illness, such as the common cold.”

Source: Medical Express