Millions of people are dealing with Covid–19 symptoms long after their first infections. Two new studies – one looking at pregnant people and the other at children – provide a better understanding of the burden of this health problem that doctors say often goes under the radar.
The first research shows that 1 in 10 people who had Covid during their pregnancy will develop complaints in the long term. The results were shared Monday at the annual meeting of the Society for Maternal-Fetal Medicine in National Harbor, Maryland.
The researchers used data from the National Institutes of Health’s Recover Initiative, a project designed to determine the long-term effects of Covid in adults and children. Of the 1,503 people who were pregnant in the data set, 9.3% reported having symptoms six months or more after infection. The most common symptom was a feeling of fatigue after light physical or mental activity. Some also reported dizziness.
According to some studies, the proportion of pregnant people with long Covid-19 is on the low side compared to the proportion of the general US population. Estimates of adults developing long Covid-19 range from 2.5% to 25%, although different studies have different definitions of how ‘long’ Covid is defined. This study doesn’t address why the numbers might be different, but co-author Dr. Torri Metz, associate professor of obstetrics and gynecology and vice chair of obstetrics and gynecology research at University of Utah Health, has a few ideas.
“That could be because they generally have fewer medical complications. They are younger. It could also be that they have a different immune response,” said Metz.
A pregnant person’s immune system is generally more tolerant of “things that shouldn’t be there,” she said, so the mother’s body can accommodate and care for a fetus with different genetics.
Often, pregnant people tend to get sicker when exposed to a virus because their immune system doesn’t have the robust response it normally would. This could mean that the pregnant body develops less inflammation, the immune system’s natural response to an infection. Other studies have linked long-term inflammation after Covid for effects on the brain and damage to the lungs and kidneys.
“So maybe they don’t have as much of the surrounding organ damage and the downstream complex consequences,” Metz said.
Pregnant people who developed Covid for a long time also shared some common factors. Those who were obese, diagnosed with chronic anxiety or depression, or who required supplemental oxygen when ill had a higher risk of long Covid-19.
It didn’t seem to matter in which trimester someone got sick with Covid, and vaccination status was not a statistically significant factor. More than half of those with long Covid-19 had been fully vaccinated. But many studies have shown that vaccination reduces the risk serious illness, making a long Covid-19 period more likely.
Metz said the study found that socio-economic factors influenced long Covid numbers.
“It’s concerning that we had a very high proportion of patients reporting difficulty paying their bills,” she said. “That raises red flags about what kind of access people are getting to the care they need.”
The study paints a clearer picture of who is likely to have a long Covid-19 crisis, says Dr. Amy Edwards, associate medical director of pediatric infection control at UH Rainbow Babies & Children’s Hospital, who manages the hospital’s long Covid clinic.
“Chronic stress is known to mess up your immune system. Stress tends to stimulate a particularly maladaptive inflammatory response, and there is a known association with chronic stress,” says Edwards, who was not involved in the new research.
It will be useful for doctors to know that if someone who has had Covid during pregnancy is still tired eight weeks after birth, it may be due to Covid rather than the usual fatigue that comes with a newborn, she said .
An important next step – and one already underway, researchers say – is to look at the outcomes of the babies of pregnant people who developed Covid for a long time.
The other new Research published last week in the journal Pediatrics looked at several studies in children and concluded that this was the case 6 million have developed long Covid.
Most young people who had had Covid for a long time eventually recovered, the studies show, but a third had symptoms even a year after their first infection.
The long Covid symptoms in children include breathing problems such as coughing, shortness of breath and chest tightness, along with fatigue.
Edwards said it is important not to minimize the impact of long Covid-19 on children just because symptoms often go away.
“Imagine that as a teenager you miss two years of formative experience due to the long Covid-19 crisis. “I don’t even want to think about the long-term consequences of that,” she said.
The study also found that children had a higher risk of certain autoimmune diseases, such as type 1 diabetes, after Covid infection, even if the disease had been mild or asymptomatic. A US study the authors reviewed found that the risk of developing diabetes increases by 72% within six months of an initial infection.
Studies have not fully explained what factors children with long Covid-19 have in common. Those who experience housing and food insecurity and who have had access to health care disrupted in general have “exacerbation of the disease due to impaired immunological functioning,” according to the new research.
Edwards said she and some other doctors who run long Covid clinics for children around the country have recently noticed that the high flow of patients they saw earlier in the pandemic is slowing, “which is fantastic.”
But there are still so many young people with long Covid-19 epidemics that fewer patients just means a shorter waiting list, she said: Instead of waiting eight months to get into her clinic, patients now wait about five months.