PurposeTo describe SARS-CoV-2 infection outcome in unvaccinated children and young adults with inborn errors of immunity (IEI) and to compare their specific acute and long-term immune responses with a sex-, age-, and severity-matched healthy population (HC).MethodsUnvaccinated IEI patients up to 22 years old infected with SARS-CoV-2 were recruited along with a cohort of HC. SARS-CoV-2 serology and ELISpot were performed in the acute phase of infection (up to 6 weeks) and at 3, 6, 9, and 12 months.ResultsTwenty-five IEI patients (median age 14.3 years, min.-max. range 4.5-22.8; 15/25 males; syndromic combined immunodeficiencies: 48.0%, antibody deficiencies: 16.0%) and 17 HC (median age 15.3 years, min.-max. range 5.4-20.0; 6/17 males, 35.3%) were included. Pneumonia occurred in 4/25 IEI patients. In the acute phase SARS-CoV-2 specific immunoglobulins were positive in all HC but in only half of IEI in whom it could be measured (n=17/25): IgG+ 58.8% (10/17) (p=0.009); IgM+ 41.2% (7/17)(p