Nature reports on how researchers are trying to establish whether existing COVID-19 vaccines and treatments can prevent lasting symptoms.
Research into long COVID — which is also known as post-acute sequelae of COVID-19, and is usually defined as COVID-19 symptoms that last longer than three months – has lagged behind studies of the acute phase of infection. People who experience long COVID live with a wide array of symptoms, ranging from mild to severely debilitating. Researchers have proposed a variety of causes for the condition — from lingering viral reservoirs, to autoimmunity, to tiny blood clots. Many think that a mix of these factors is to blame. “It took a while to get going on any serious mechanistic long-COVID research,” says immunologist Danny Altmann at Imperial College London. “It’s hard to piece the big picture together.”
Beyond vaccination, it’s unclear whether any existing COVID-19 therapy has an effect on long-COVID risk. In theory, a drug that reduces disease severity might reduce the severity of long-term symptoms, says Altmann. But long COVID is not always associated with serious acute illness. “There are loads of people out there who are really destroyed by long COVID and had asymptomatic or near asymptomatic infections,” he says. “It’s really hard to grapple with.”
Researchers are hoping to find out whether more treatments can reduce the risk of long COVID. A large UK-based trial called HEAL-COVID is testing two drugs that target the cardiovascular system in people who have been hospitalized with COVID-19. One, called apixaban, is an anticoagulant. The other, atorvastatin, is a cholesterol-lowering medication thought to reduce inflammation in blood vessels.