Vaccination against SARS-CoV-2, the virus that causes Covid-19, not only reduces the risk of severe acute disease in children and adolescents, but provides some protection against long Covid, i.e. the onset of persistent health problems over months after the disease.

The above results from a large retrospective study, the results of which were published in the journal Pediatrics. The study involved researchers from 17 health systems in the US, led by researchers at the Children’s Hospital of Philadelphia.

While the overall severity of Covid-19 is lower in children than in adults, the burden of long-term Covid symptoms is difficult to accurately describe as symptoms can vary. Some that have been reported are brain fog, shortness of breath, gastrointestinal upset, generalized pain and fatigue, and more acutely, inflammatory reaction or heart problems.

The evaluation of the effectiveness of the vaccine was done in two groups of patients, aged 5-11 years and 12-17 years. In total, data on over one million children were evaluated, of which 56% had been vaccinated. The study estimated that the effectiveness of the vaccine within 12 months of administration was 35.4% against probable long Covid and 41.7% against diagnosed long Covid. The efficacy estimate was higher in adolescents compared to younger children (50.3% vs. 23.8%) and higher at six months (61.4%), decreasing to 10.6% at 18 months.

Children vaccinated after recovery from Covid-19 also appeared to benefit with 46% vaccine effectiveness against possible long-term Covid after a subsequent episode of Covid-19.

“The study provides important evidence for the vaccine’s protective effects against long-term Covid and suggests that this protection comes mainly from the prevention of visible infections. We hope this means that as vaccines are improved to be more effective against current strains of SARS-CoV-2, their protection against long-term Covid will also become better,” notes lead study author Charles Bailey, associate professor of Pediatrics at the Children’s Hospital of Philadelphia.