Decreased Antibody Response After Severe Acute Respiratory Syndrome Coronavirus 2 Vaccination in Patients With Down Syndrome

The risk of a severe course of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in adults with Down syndrome is increased, resulting in an up to 10-fold increase in mortality, in particular in those >40 years of age. After primary SARS-CoV-2 vaccination, the higher risks remain. In this prospective observational cohort study, SARS-CoV-2 spike S1-specific antibody responses after routine SARS-CoV-2 vaccination (BNT162b2, messenger RNA [mRNA]-1273, or ChAdOx1) in adults with Down syndrome and healthy controls were compared. Adults with Down syndrome showed lower antibody concentrations after 2 mRNA vaccinations or after 2 ChAdOx1 vaccinations. After 2 mRNA vaccinations, lower antibody concentrations were seen with increasing age. In this prospective cohort study that included 222 adults with Down syndrome, a significantly lower antibody response was found after SARS-CoV-2 mRNA or vector vaccination compared to healthy controls. After mRNA vaccination, lower antibodies were found with increasing age.

Automated summary

Adults with Down syndrome have an increased risk of severe course and mortality from SARS-CoV-2 infection, and this risk persists after vaccination. This study compared the antibody responses to routine SARS-CoV-2 vaccination in adults with Down syndrome and healthy controls, finding lower antibody concentrations in adults with Down syndrome, especially with increasing age.