The astounding impact and reach of long Covid, in numbers and charts

Earlier this year, CDC researchers pored through millions of American health records looking for patients who might have long Covid. But figuring out who has the condition isn’t easy.

That’s because there is no test for long Covid.

In fact, scientists still don’t know what exactly causes it.

Long Covid is a catchall term to describe an array of symptoms people experience weeks or months after they recover from Covid-19, usually when they are no longer infectious. Some people have reported experiencing several of them; others report just one or two.

That’s why the CDC researchers looked at how many people experienced at least one of the symptoms of long Covid.

But they had to figure out which of these were caused by Covid, and which were caused by something else – because many of these symptoms, like being excessively fatigued, can be caused by long Covid or a host of other unrelated conditions.

So the researchers sorted through nearly 2m electronic health records and separated people who have had a positive Covid-19 diagnosis and people who haven’t. Then they looked for symptoms.

Long Covid studies all have slightly differing results, depending on how the data is collected and what’s being measured. For example, a separate study of nearly 3,800 people who probably have long Covid found that the probability of having at least one symptom after 35 weeks was greater than 90%.

But they all point in the same direction: something about Covid-19 causes a significant portion of people to experience symptoms long after the initial sickness, even if the initial sickness was mild – and no one is fully safe.

Older people appear to be at slightly higher risk of developing long Covid symptoms, notably kidney problems and mental health conditions, according to the CDC research. But the risk isn’t much lower for younger people.

People who were hospitalized with Covid-19 are probably at higher risk of developing long Covid symptoms compared with those who were not, according to a meta analysis of dozens of studies. But even people who had a mild case of Covid have a pretty good chance of experiencing long Covid symptoms.

Women are more likely to develop long Covid symptoms, according to the meta-analysis. This is in line with previous studies showing women have a higher risk level.

Being vaccinated may reduce your chances of developing long Covid symptoms, according to several studies. One study of nearly 26m electronic medical records found that people who received the first dose of a Covid vaccine before their diagnosis were significantly less likely to experience at least one long Covid symptom between 12 and 20 weeks after being diagnosed.

But it’s not so clearcut. A more recent study of US Veterans Affairs data found that being fully vaccinated before infection may only minimally reduce the risk of long Covid symptoms.

One area where data is lacking is race. Experts argue Black Americans haven’t been sufficiently included in long Covid trials and treatment programs, potentially because many of these studies only look at people enrolled in healthcare systems. So good data on racial disparities is hard to come by.

But it’s likely that long Covid affects Black, Latino and Indigenous Americans at higher rates because those communities had higher infection rates and higher rates of hospitalization. Some studies hint at this emerging racial disparity.

Socioeconomic factors also play a role: poor Americans consistently have worse outcomes.

Arguably the best hint for what causes long Covid comes from a study by dozens of researchers published in January 2022, in which they followed Covid patients for two to three months after their infection. They found that long Covid symptoms have a high correlation with four factors:

• A high levels of the virus RNA in blood.

• Pre-existing type 2 diabetes.

• High levels of Epstein-Barr virus DNA in blood.

• The presence of “autoantibodies” that attack the person’s own body.

Long Covid will cost the world a lot of money. Not only are long Covid symptoms being experienced by a huge number of people, but the condition also affects younger people who will suffer from the condition through several decades of life – including later years when other illnesses could compound the illness. It’s tough to estimate the worldwide cost long Covid will have. But in the US alone, the condition will cost the economy about $2.6tn, according to Harvard researchers – about a tenth of the annual US GDP.

Long Covid has caused a huge impact spike in medical spending. An analysis in the Journal of the American Medical Association estimated that if long Covid treatment is similar to that of chronic fatigue syndrome, it would cost about $9,000 each year per patient. A 2022 study estimates will cost the US between $149bn and $362bn in medical expenses and lost income. This doesn’t account for disability benefits, social services and other costs.

Long Covid drastically reduces people’s ability to work. A survey of people who probably have long Covid symptoms found that about two in three people had their work schedule affected by the disease.

Long Covid contributes to the American labor shortage, according to a Brookings Institution analysis. Long Covid shrunk the workforce by about 1.6 million full-time equivalent workers at any given time in the first 20 months of the pandemic.

These numbers don’t capture the frustration and helplessness long Covid has caused millions of people around the world.

The disease remains shrouded in uncertainty, but all new findings are small steps toward the answers millions of people around the world are seeking.