The risk of developing long Covid has decreased

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The risk of developing persistent Covid-19 disease has dropped significantly throughout the Covid-19 pandemic, according to an analysis of data from Washington University School of Medicine in St. Louis, US. The study was published in The New England Journal of Medicine.

Researchers attribute about 70% risk reduction from Covid-19 vaccination and 30% from changes over time, including evolutionary characteristics of the SARS-CoV-2 virus. and improving the detection and control of Covid-19. “The study of declining rates of persistent Covid infection marks a rare occasion when I have good news to report about this virus,” says lead study author Dr. Ziyad Al-Ali, a clinical epidemiologist at the University of Washington and a world leader in Covid-19 research. “The results also show a positive effect of vaccination”.

While his latest findings sound more encouraging than previous studies, Al-Ali tempers the good news: “Stubborn Covid is not over yet.”

IN more than 30 high-profile studiesAl-Ali detailed the virus’s indiscriminate and long-term impact on the health of nearly every organ system, including the heart, brain, kidneys and gastrointestinal tract.

While his latest results sound more encouraging than previous studies, Al-Ali tempers the good news. “Stubborn Covid is not over yet”– says a nephrologist who treats patients at the John J. Cochran Veterans Administration Hospital (USA), a branch of Washington University, in St. Louis. «We cannot let our guard down. This includes getting the Covid vaccine every year, as it is key to reducing the risk of persistent Covid infection. “If we stop getting vaccines, the risk is likely to increase.”

The study included 441,583 veterans with SARS-CoV-2 infection and more than 4.7 million uninfected veterans from March 1, 2020, to January 31, 2022.

Since the start of the pandemic, Al-Ali has dedicated herself analyze persistent Covid to help the public make informed health decisions; support scientists in developing research-based recommendations for prevention and treatment; and enable policymakers to make informed decisions on funding and public policy. Al-Ali’s latest study builds on this work by examining variants of the virus and their overall evolution.

To do this, Al-Ali and his team analyzed millions of anonymized medical records from the U.S. Department of Veterans Affairs, the largest integrated health care system in the country. The study included 441,583 veterans with SARS-CoV-2 infection and more than 4.7 million uninfected veterans from March 1, 2020, to January 31, 2022. The patients varied in age, race, and gender, and the statistical model ensured parity of representation.

The rate of persistent Covid was highest among those with the original strain, with 10.4% of those whose infection developed into persistent Covid, Al-Ali said.

The researchers divided the veterans into five groups: unvaccinated long-Covid patients infected with the original strain in 2020; the delta variant in 2021; and the omicron variant in 2022. The other two groups included people vaccinated with the delta variant and people vaccinated with the omicron variant. There were no vaccines available while the original strain was circulating. The team assessed the rate of persistent Covid infection one year after infection for each of the five groups.

As expected, The rate of persistent Covid was highest among those with the original strain, with 10.4% of those whose infection developed into persistent Covid, Al-Ali said. This number has decreased up to 9.5% among unvaccinated groups in the Delta era and up to 7.7% in the Omicron era. Among those vaccinated, the rate of persistent Covid infection with the delta variant was 5.3% and 3.5% with the omicron variant.

Al-Ali also stresses that even with the overall decline, the lowest rate (3.5%) remains a significant risk.

“A clear and significant difference in risk can be seen in the delta and omicron era between vaccinated and unvaccinated”– Al-Ali clarifies. “So if people think Covid is no big deal and decide to forego vaccines, they are essentially doubling their risk of developing persistent Covid.”

Al-Ali also emphasizes that even with the general decline The lower rate (3.5%) remains a significant risk. “This means that out of every 100 people vaccinated, three to four will develop persistent Covid.”– he notes. “If you multiply that by the large number of people who continue to become infected and re-infected, that’s a lot of people. That remaining risk is not trivial. “It will continue to exacerbate what is already a worrying health problem that people around the world are facing.”

Another notable finding provides insight into the evolution of the virus, Al-Ali adds. When analyzing the risk among all people infected with Covid in the omicron era of 2022, the likelihood of developing problems with the heart, brain, kidneys, and lungs has decreased. In contrast, the incidence of diseases and illnesses related to metabolic function and the gastrointestinal system has increased.

“We know that millions of people are already suffering from persistent Covid and that millions more will continue to suffer from it. “We must redouble our efforts to understand this so that we can prevent suffering and treat those affected.”

“People tend to think of SARS-CoV-2 as a homogeneous virus.”Al-Ali insists. “But each variant has its own consequences. The original virus hits the respiratory system hard. Omicron targets metabolic and gastrointestinal problems. “This is important because, although the risk of long-term Covid is quantitatively lower, a person may be at higher risk of developing the disease depending on which part of the body the Covid variant affects.”

“It’s very good news that the risk has gone down,” It is said. “But we know that millions of people are already suffering from persistent Covid and that millions more will continue to suffer from it. We must redouble our efforts to understand this so that we can prevent suffering and treat those affected.”