Adolescents with type 1 diabetes may be at increased risk for severe coronavirus disease-2019 (COVID-19) and are therefore prioritized for access to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccination. The pivotal trial that assessed the efficacy of the BNT162b2 vaccine among adolescents demonstrated 100% protection against SARS-CoV-2 infection after a two-dose regimen. However, the research did not include adolescents with type 1 diabetes. In this study, the investigators aimed to assess the humoral immune response of infection-naive adolescents with type 1 diabetes following vaccination with the BNT162b2 vaccine in comparison to that of infection-naive healthy controls and the factors associated with that response.

Having either form of diabetes as a comorbidity has been implicated as a risk factor for severe COVID-19. Therefore, vaccination against COVID-19 has been highly recommended for people with diabetes. However, since diabetes is associated with persistent and profound impairments in both innate and acquired immunity, whether the immune system of people with diabetes will be able to mount an adequate antibody (ab) response following COVID-19 vaccination has remained in question. Some studies have reported that adults with diabetes develop an inadequate immune response to hepatitis B vaccines, whereas less consistent results have been reported for varicella-zoster and influenza vaccines. Likewise, certain pediatric studies have found that serum ab titers against hepatitis B surface antigen and pneumococcal antigens were lower in children with type 1 diabetes than in controls following hepatitis B vaccine and unconjugated pneumococcal polysaccharide vaccine administration. In this context, concerns about the effectiveness of COVID-19 vaccines in people with diabetes have led to the investigation of their immunogenicity after vaccination against COVID-19.

Thus far, few studies have explored the ab response of people with diabetes following COVID-19 vaccination. In the majority of studies conducted, the seroconversion rates of people with diabetes were found to be lower than those of age-matched healthy controls. Nonetheless, the majority of the diabetic people included in these studies were still able to elicit a strong ab response. However, most of these studies only enrolled adults with type 2 diabetes. The ab response to COVID-19 vaccination in a pediatric cohort with type 1 diabetes has not been investigated. Thus, in this single-centered prospective observational study, the investigators aimed to analyze the ab response to a widely used and effective mRNA (messenger ribonucleic acid)-based SARS-CoV-2 vaccine, BNT162b2, in adolescents with type 1 diabetes compared to that of healthy controls and the factors associated with that response.

Inclusion Criteria for adolescents with type 1 diabetes:

• aged between 12-18 years
• history of diabetes
• willingness to provide informed consent

Exclusion Criteria for adolescents with type 1 diabetes:

• age < 12 years and age > 18 years
• history of chronic disease
• previous episode of COVID-19
• respiratory symptoms up to 14 days before the study
• history of systematic treatment with corticosteroids and/or immunosuppressant medications

Inclusion Criteria for controls:

• aged between 12-18 years
• good health
• no previous history of diabetes
• willingness to provide informed consent

Exclusion Criteria for controls:

• age < 12 years and age > 18 years
• history of chronic disease
• previous episode of COVID-19
• respiratory symptoms up to 14 days before the study
• history of systematic treatment with corticosteroids and/or immunosuppressant medications

SARSCoV2-naive adolescents with type 1 diabetes and SARSCoV2-naive healthy control adolescents who will undergo blood sampling for testing levels of antibodies against SARSCoV2 after SARSCoV2 vaccination will be consecutively included in this prospective study.