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Together Summer Waves As COVID-19 infections spread across the country, a timely new study looked at the risk of contracting COVID-19 and whether that probability has changed over time.
The odds of long-COVID have fallen since the pandemic began, but they remain high, especially for people who have not been vaccinated against the coronavirus, the study found.
About 7% of American adults, or roughly 18 million people, have had long-Covid, according to an analysis by the federal Agency for Healthcare Research and Quality. Now published June 1999. Harvard economist David Cutler Estimation In 2022, the total cost to the nation of Long Covid is expected to be $3.7 trillion, or 17% of pre-Covid gross domestic product.
The new study, published Wednesday in the New England Journal of Medicine, uses computers and advanced machine learning to comb through data from millions of medical records held by the Department of Veterans Affairs, suggesting the human and economic toll is only going to get worse.
Researchers from Washington University in St. Louis and the VA Healthcare System sought to find people who had COVID-19 at different times during the pandemic — before vaccines were available, when the delta variants dominated infections, and after the emergence of Omicron family variants — to see whether their risk of lingering symptoms associated with long COVID-19 changed.
Vaccination status was also taken into account: people who had received at least the first series of doses were considered vaccinated, and those who had not were considered unvaccinated.
The study included more than 441,000 people who were infected with COVID-19 between March 2020 and the end of January 2022 and survived more than 30 days after infection. Their records were compared with those of more than 4.7 million people who did not contract COVID-19 but visited the VA for other reasons during the same period.
The researchers found that one in 10 people who contracted Covid-19 in the first year, when ancestral coronavirus strains were circulating and people had little immunity to the virus, subsequently developed symptoms consistent with long Covid. Symptoms were counted as part of long Covid across 10 disease categories if they newly appeared between 30 days and one year after the initial Covid-19 infection.
Vaccines have been a game changer, halving the risk of long Covid during the delta wave in summer 2021.
But the risk remained high for unvaccinated people during the Delta period: About 10% of people had lingering symptoms after their initial infection.
During the Omicron period that began after Thanksgiving 2021, 3.5% of vaccinated people developed long Covid after the acute phase of infection, compared with 7.7% of unvaccinated people.
The study has some limitations: Because most people treated at the VA are white men, the study population is not as diverse as the general population, and the findings may not generalize to everyone.
for example, Recent Research It has been found that nearly one in 10 people who have their first COVID-19 infection while pregnant develop long COVID-19, a rate that may be higher than in the general population.
The new study did not take into account differences between people who stop receiving a COVID-19 vaccine after their first dose and those who continued with the recommended booster shot to keep their immunity up to date as the virus mutates over time.
It also doesn’t take into account any immunity people may develop after infection or reinfection, a question that Dr. Ziyad Al Ali, director of research and development at the VA St. Louis Healthcare System and the study’s lead author, said he is investigating as a follow-up.
Al Ali estimates that vaccines are responsible for nearly three-quarters of the decline in long-COVID risk since the early days of the pandemic.
Although the causes of long COVID symptoms are not fully understood, there is some evidence that people with long COVID continue to harbor active virus in their bodies long after the initial infection.
“The vaccine actually helps the immune system to clear the virus,” Al Ali said. “It helps the immune system to suppress the viral load and clear the virus faster.”
Dr. Hector Bonilla, co-director of Stanford University’s Post-COVID Acute Syndrome Clinic, said the importance of vaccination is a key finding from the study.
Bonilla said when COVID-19 vaccines first became available, most people were eager to get vaccinated, and the number of new patients visiting doctors with lingering symptoms dropped significantly.
Now, rather than a flood of patients, his clinic is seeing a steady influx of new patients, some of whom are developing long-covid after getting infected a second or third time.
“Long Covid is a very nasty disease,” Bonilla said. And many people are caught off guard when they experience it. But at this point, most people have made up their minds about whether to continue with the vaccination. He says more people need to understand that vaccination is an important way to lower the risk of long Covid.
“Vaccination remains a critical component of preventing long-term COVID-19,” Bonilla said.
The remaining 30% of risk decline over time after vaccination is probably due to changes in the virus itself, according to the study.
“The virus is mutating and evolving, and the risk of long COVID-19 is decreasing over time, even among unvaccinated people, compared to the initial pandemic and the very early days of the pandemic,” Al Ali said.
As such, the latest data suggests that around three in 100 people who have received at least the first dose of the vaccine and who currently contract COVID-19 will go on to develop long-COVID-19, Al Ali said.
While this is an important step forward, many people still live with disabilities and poor health.
Experts not involved in the study agree that 3.5% means the risk of long-Covid remains large and serious.
“We are seeing a high number of new cases and reinfections, and we are still seeing a huge increase in long-covid cases,” Dr. Daniel Griffin, an infectious disease specialist at Columbia University who treats long-covid patients, said in an email.
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“Although the numbers are lower than at the beginning of the pandemic, we are still seeing cases of long COVID-19 who developed symptoms after recent infection,” he added.
Al Ali said this study and others underscore the need for increased funding for coordinated and continuing care for long COVID-19 patients, as well as greater urgency in the search for a cure.
“I don’t think the U.S. is doing enough to address this issue,” Al Ali said. “I understand the desire to move on and put everything behind us, but the reality is that there are literally millions of people suffering from long-covid, and even if those numbers go down, there will continue to be millions more.”
“There really is no plan to address this issue and there can’t be.”
