TUESDAY, July 16, 2024 (HealthDay News) -- People's odds for Long COVID appear to be declining with the advent of new variants of the virus, along with repeat infections and vaccinations, new research shows.
That suggests that the average person's chances of developing long-term symptoms is falling over time, concluded a team from Germany.
"Although the cause of post-COVID-19 condition is still not fully understood, the outlook for the future for all those who have not yet developed post-COVID-19 is positive," concluded study senior author Dr. André Karch, from the University of Münster.
His team based its findings on a survey of almost 110,000 Germans, conducted in the fall of 2022.
People were asked about whether (and when) they'd experienced Long COVID, including symptoms such as physical exhaustion, cardiovascular problems and cognitive impairment.
According to the World Health Organization, Long COVID involves new or persistent symptoms that occur within three months of a COVID infection that can't be explained by other causes.
At the time of the online survey, over 80% of respondents said they had already gotten three or more COVID vaccines and 60% said they'd already been infected with the illness.
About a third (35%) of those who said they'd had COVID-19 said they had also experienced at least one persistent symptom anywhere from four to 12 months after their infection, the researchers said.
Among this subgroup, a quarter said they had nine or more symptoms commonly linked to Long COVID.
However, there were some encouraging long-term trends.
First of all, rates of Long COVID were lowest among people who'd been infected with the latest COVID variant, Omicron, the team found.
Long COVID rates were higher among those infected with the earliest ("wild type") variant circulating in late 2020, the Alpha variant circulating in early 2021, or the Delta variant that dominated between July and December of 2021, the study found.
"As our analysis indicates, the virus variant has an impact on the risk of post-COVID-19 condition," said study lead author Dr. Rafael Mikolajczyk. He directs the Institute of Medical Epidemiology, Biometrics and Informatics at University Medicine Halle.
"The risk appears to decrease with the new virus variants," he explained in a news release from Halle and the German National Cohort. "An Omicron infection was substantially less frequently associated with post-COVID-19 condition than earlier virus variants."
Perhaps counterintuitively, a person's odds for Long COVID also appeared to decline the more times they had been infected.
"Those who did not develop post-COVID-19 condition after an infection and were infected again had a lower risk of post-COVID-19 condition than people who were infected for the first time," Mikolajczyk noted.
Getting a COVID vaccine for a fourth time also appeared to cut a person's odds for Long COVID.
That may be because repeat vaccination lowers the odds that a person's case of COVID-19 will be severe.
So, even if "previous vaccinations did not directly protect against post-COVID-19 condition, indirect protection can be assumed" over time, Mikolajczyk said. "This is because, according to the data currently available, those vaccinated had a lower probability of developing symptomatic coronavirus infections or suffering a severe infection."
It's been noted in prior research that a person's odds for Long COVID rises along with the severity of their initial infection.
Finally, the time elapsed between a COVID shot and the onset of a new case of COVID-19 appeared to matter, in terms of the likelihood of developing Long COVID.
Specifically, the German team found that "if a coronavirus infection occurred within three months of vaccination, participants were more likely to report post-COVID-19 condition than people who had the infection at a longer interval from vaccination," according to the news release.
The findings were reported recently in the Journal of Infection.
Overall, folks' odds for developing Long COVID may be declining over time, "given both the reduced risk resulting from Omicron infections and the massively reduced risk for those who already had a SARS-CoV-2 infection which was not followed by post-COVID-19 symptoms," Karch said.
"Our results are in line with the fact that the incidence of post-COVID-19 condition, as observed last winter, is decreasing substantially," he added.
More information
Find out more about Long COVID at the U.S. Centers for Disease Control and Prevention.
SOURCE: University Medicine Halle and the German National Cohort, joint news release, July 14, 2024
