What Experts Know About ‘Long Covid’ and Who Gets It: QuickTake

Most people who suffer from Covid-19 fully recover. Millions of others find complete healing to be frustratingly elusive, in what’s often referred to as long Covid. Symptoms range from pulmonary, cardiovascular, gastrointestinal or neurological problems to cognitive issues such as so-called brain fog. No single explanation, diagnosis or treatment can be applied to them. Colloquially known as long-haulers, these patients reflect the pandemic’s lasting burden on society and the economy.

There’s no universally accepted definition yet. According to the World Health Organization, people with what it calls “post Covid-19 condition” have symptoms usually three months after an initial bout of Covid that last for at least two months and can’t be explained by an alternative diagnosis. Symptoms may persist from the acute phase of the illness or appear after -- even in a person who displayed no symptoms initially. They may also fluctuate. Other groups have proposed alternative definitions. The UK’s National Health Service, for example, suggests referring to symptoms that last more than four weeks as “ongoing symptomatic Covid,” and “post-Covid syndrome” if they persist for longer than 12 weeks and can’t be otherwise explained. Another definition may be needed for children.