New research has found that young people who contract COVID-19 more than once face a significantly greater risk of developing Long COVID, raising concerns about the long-term impact of repeated infections even as vaccines and prior exposure have reduced the severity of the virus for most.
In what is described as the largest study of Long COVID in young people to date, researchers at the University of Pennsylvania reported that children and young adults aged 21 and under who were infected twice were twice as likely to develop Long COVID symptoms compared with those infected only once. The findings come from the ongoing RECOVER project, a National Institutes of Health-funded initiative examining the long-term health consequences of COVID-19.
Long COVID can involve a wide range of symptoms affecting vital organs, including the heart, lungs and kidneys, as well as neurological issues such as loss of taste and smell. The study found that young people with two infections were nearly three times as likely to report changes in taste and smell than those with just one infection.
“People think that reinfections don’t matter as much and don’t take them seriously,” said Yong Chen, professor of biostatistics and director of the Center for Health AI and Synthesis of Evidence at the University of Pennsylvania, who led the study. “Our primary message is that reinfections still matter, and you should do what you can to avoid reinfection by taking a vaccine or wearing a mask.”
Importantly, the elevated risk persisted regardless of vaccination status or the severity of illness during initial or subsequent infections. However, researchers stressed that the findings should not be interpreted as evidence that vaccines are ineffective against Long COVID. Instead, they noted that vaccinated children were far less likely to be infected at all, and therefore less likely to experience multiple infections.
The study also clarified that vaccination data reflected whether participants had received their shots before the study period, not how recently. The research began before the rollout of updated vaccines targeting the Omicron variant.
While the acute dangers of COVID-19 have lessened, experts say the findings underline the importance of continued caution. Reinfections remain a concern, particularly for young people whose risk of developing persistent health problems could increase with each exposure.
The authors of the study say their work highlights the need for parents and policymakers to encourage vaccination and other protective measures. As Chen emphasized, “The fact that reinfections can double the risk of Long COVID in young people is something families and communities should take seriously.”