Risk of developing Long Covid falls, but remains substantial, shows study

By Jason Gale
 

The risk of getting long Covid has dropped steadily since the start of the pandemic, according to a study of US veterans. 

The probability of having long Covid a year after a SARS-CoV-2 infection fell to 3.5 per cent among vaccinated people during the period when the omicron variant swept through the country, scientists at the Washington University School of Medicine and the Veterans Affairs St. Louis Health Care System said.  

That was down from 10.4 per cent among unvaccinated people before the emergence of the delta strain, they said. 

Still, the risk isn’t entirely gone: The research suggested that despite the drop, hundreds of people are still developing the often-debilitating condition each week. 

 

“The decline in risk is certainly welcome news,” epidemiologist Ziyad Al-Aly, the study’s senior author, said in an email. “But the remaining risk is substantial and will lead to millions more with long Covid — adding to an already significant toll of disease and disability.”

The World Health Organization says tens of thousands of Covid cases are being reported globally. The actual number of infections is likely to be significantly higher because of home-testing and underreporting. A household survey by the US Centers for Disease Control and Prevention in late April found that about 4 per cent of all adult American males and 6.6 per cent of all adult females were experiencing long Covid, also known as post-acute sequelae of Covid-19, or PASC. 

Al-Aly’s research, published Wednesday in the New England Journal of Medicine, found the declining incidence of PASC was largely attributable to vaccination against Covid and, to a lesser extent, a reduction in the inherent disease-causing propensity of more recent variants.

“Vaccine uptake will be key to maintaining the lower cumulative incidence of PASC relative to earlier phases of the pandemic,” Al-Aly and colleagues said in the study.

The research was based on an analysis of the electronic health records of 441,583 veterans with a SARS-CoV-2 infection and 4.7 million who avoided it. Study participants were mostly older white men, which might limit how generalizable the findings are to other groups.