COVID-19: the unvaccinated are at risk of reinfection at three months

More than 236 million people affected by COVID-19 have already been recorded worldwide, and there have been more than 4.8 million deaths, according to the World Health Organization. During this time, vaccination is helpful in reducing the risk of complications and death in those infected. However, 53.7% of humanity does not yet have a dose of the inoculant.

Now, Scientific research has more evidence on how long a person can contract the virus, recover and become infected again. Getting vaccinated is essential both to avoid infection and to stop suffering from the disease.

A team of scientists led by professors from the Yale School of Public Health and the University of North Carolina in Charlotte, USA, has an answer: the strong protection that is generated after natural infection with the coronavirus is short-lived.

Throughout the pandemic, there was a lot of uncertainty about how long immunity will last after someone has contracted COVID-19 and has not yet been vaccinated. “Reinfection can reasonably occur in three months or less,” said Jeffrey Townsend, professor of biostatistics at the Yale School of Public Health and lead author of the study published in the journal. The Lancet Microbe.

After spreading the word about the research, Dr Townsend made a great recommendation to the community: “Those who have been infected naturally should be vaccinated. A previous infection alone may offer very little long-term protection against later infections.”.

The study published in the journal The Lancet Microbe he is the first to determine the probability of re-infection after natural infection and without vaccination. It consisted of the analysis of known immunological and reinfection data from viral close relatives of the coronavirus that causes the common cold, as well as immunological data from SARS-CoV-1 (which was previously known as SARS and was detected in China in 2002) and Middle East Respiratory Syndrome (MERS).

Using evolutionary principles, the team was able to model the risk of re-infection with COVID-19 over time. According to the researchers, re-infections can and did occur even shortly after recovery. And they warned that re-infections will become more frequent as immunity wanes and new variants of the coronavirus emerge.

“We tend to think of immunity as whether or not we are immune. Our study warns that, on the contrary, we should focus more on the risk of reinfection over time ”, said Alex Dornburg, associate professor of bioinformatics and genomics at the University of North Carolina at Charlotte, who co-led the study.

“As new variants emerge, older immune responses become less effective at fighting the virus. Those who were naturally infected at the start of the pandemic are increasingly likely to be re-infected in the near future“Dornburg added.

The team’s data-driven model revealed striking similarities with the risks of reinfection over time between SARS-CoV-2 and endemic coronaviruses. “As with the common cold, year after year you may experience reinfection with the same virus.Townsend said. “The difference is that when it appeared in this pandemic, COVID-19 turned out to be much more deadly,” he said.

A hallmark of the modern world will be the evolution of new threats to human health, Townsend added. Evolutionary biology – which provided the theoretical foundations for these analyzes – is traditionally regarded as a historical discipline. “However, our results underscore its important role in decision making and are a crucial step towards a solid understanding of our prospects for resistance to reinfection with SARS-CoV-2,” he said. The co-authors include researchers from Temple University. The United States National Science Foundation funded the research.

The U.S. Centers for Disease Control and Prevention (CDC) has also warned the public about the possibility of reinfection. “This means that a person was infected (got sick) once, recovered and then got infected again”, clarified, and indicated that it continues to conduct studies to have more details on the complexity of the development of COVID-19.

From this public body, the need for access to vaccines was stressed due to the current situation of the pandemic. “Delta variant of coronavirus causes more infections and spreads faster than early forms of COVID-19 virus. It could cause more serious illnesses than the previous variants in unvaccinated people ”. To reduce the risk of becoming infected or re-infected, the CDC has advised getting vaccinated and wearing the mask or chin strap properly in closed public spaces to reduce the spread of Delta.

In the Americas, the trajectory of COVID-19 varies by region. As the Pan American Health Organization reported on Wednesday, cases have declined in the United States and Canada, but they have increased in Mexico. As cases decline in the Caribbean, Cuba and Bermuda continue to report high rates of new infections, with Barbados rising nearly 75% last week.

In Central America, and although cases are generally declining, Costa Rica continues to experience high rates of hospitalization and use of intensive care beds. Hospitalizations have also increased by two-thirds in Belize.

In South America, cases are decreasing in many countries, but they are increasing in Chile, where the increase is mainly due to epidemics in urban centers with the increasing predominance of the Delta variant.

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