UC San Diego

Background

In the general population, mRNA SARS-CoV-2 vaccines are highly efficacious. Early reports suggest a diminished antibody response in immunosuppressed adult solid organ transplant (SOT) patients, but this has not been reported in pediatrics.

Methods

Adolescent kidney transplant recipients (KTR) at our center who received both doses of an mRNA SARS-CoV-2 vaccine had SARS-CoV-2 spike (S) protein antibody presence evaluated 4-8 weeks after their second dose of the vaccine as part of routine clinical care.

Results

Thirteen of 25 fully vaccinated patients (52%) had a positive spike antibody. Median age of participants was 19 years old (IQR 18-20) and the median time from transplant was 5 years (IQR 4-9 years). KTR were treated with an immunosuppression regimen including a calcineurin inhibitor, corticosteroid, and antimetabolite (9 with mycophenolate, 3 with azathioprine, and 1 without an antimetabolite due to viremia). Of those who had an antibody response, fewer had a mycophenolate-containing immunosuppressant regimen than non-responders. There was a trend toward better vaccine response and higher anti-S antibody titers at lower doses of mycophenolate. Three patients with prior COVID-19 infection all had a positive antibody response.

Conclusion

Our results suggest vaccine response in adolescent KRT is lower than that of the general population, but similar to that previously described in adult SOT patients and slightly better than that seen in adult KTR. This data demonstrates vaccination is safe and supports immunizing KTR who remain hesitant. Future studies should focus on better understanding of the cellular immune response to vaccination and strategies to enhance vaccine immunogenicity in pediatric SOT patients.