Children and adolescents are two times more likely to develop long COVID after a second infection, a study found.
The study, published Sept. 30 in Lancet Infectious Diseases, used data from the electronic medical records of about 465,000 people younger than 21 at 40 children’s hospitals. Children in the study had either a first or second coronavirus infection between Jan. 1, 2022, and Oct. 13, 2023, and the study focused on the omicron wave.
Here are five things to know:
1. Over a six-month period, the incident rate of long COVID after two infections among young people was 1,884 per million. This was twice the rate of those who had only one infection.
2. Tens of thousands of people in the study who did not receive a long COVID diagnosis were treated for conditions that could be symptoms of long COVID, such as respiratory problems and abdominal pain.
3. After a second infection, young people were 3.6 times as likely as those infected once to develop myocarditis. They were also 2.8 times more likely to experience changes in taste and smell, 2.3 times more likely to develop blood clots and nearly twice as likely to develop heart disease and kidney damage.
4. About 75% of people in the study were unvaccinated. This is partly due to vaccines for their age groups not being widely available until mid-2021. The study did not evaluate the effect of vaccines on long COVID, but did find that regardless of vaccination status, a second infection raised the risk of long COVID. The most severe symptoms were more likely to be experienced by people who had not been vaccinated.
5. The CDC estimates that about 1.3% of people younger than 18 have long COVID.
