Long Covid appears to be driven by ‘long infection’. Here’s what the science says (28 November 2024)

Summary

Around 5–10% of people with Covid infections go on to experience Long Covid, with symptoms lasting three months or more.

Researchers have proposed several biological mechanisms to explain Long Covid. However, in a perspective article published in the latest Medical Journal of Australia, the authors argue that much, if not all, Long Covid appears to be driven by the virus itself persisting in the body.

Since relatively early in the pandemic, there has been a recognition that in some people, SARS-CoV-2 – or at least remnants of the virus – could stay in various tissues and organs for extended periods. This theory is known as “viral persistence”.

While the long-term presence of residual viral fragments in some people’s bodies is now well established, what remains less certain is whether live virus itself, not just old bits of virus, is lingering – and if so, whether this is what causes long COVID. This distinction is crucial because live virus can be targeted by specific antiviral approaches in ways that “dead” viral fragments cannot.

Viral persistence has two significant implications:

1. when it occurs in some highly immunocompromised people, it is thought to be the source of new and substantially different-looking variants, such as JN.1
2. it has the potential to continue to cause symptoms in many people in the wider population long beyond the acute illness. In other words, long COVID could be caused by a long infection.