NEW YORK (Reuters Health) – Children between 12 and 18 years old who have received solid-organ transplants appear to mount a better immune response than their adult counterparts after a standard two-dose vaccination against COVID-19, clinicians in the U.S. report.
Nearly three-fourths of the pediatric transplant recipients they studied had a “positive and protective” antibody response after receiving two doses of the Pfizer-BioNTech mRNA vaccine, “in contrast with many adult transplant recipients evaluated in previous Johns Hopkins Medicine studies who needed a third dose,” Dr. Douglas Mogul of Johns Hopkins Hospital Children’s Center and Johns Hopkins University School of Medicine, in Baltimore, Maryland, said in a statement.
Solid-organ transplants often need immunosuppressive agents to prevent rejection, which may impair vaccine responses, Dr. Mogul and his colleagues note in the American Journal of Transplantation.
Many adult solid-organ transplant recipients have shown impaired antibody response to SARS-CoV-2 vaccination, but responses in pediatric solid-organ transplant recipients has not been assessed.
The researchers studied 57 pediatric solid-organ transplant recipients who had received the Pfizer-BioNTech vaccine. The median age was 14 (range 12 to 18 years), 40% were male, and 74% were white.
Patients had gone a median of 10 years (range, 5 to 13 years) since receiving their transplant, most commonly a liver transplant (44%). Most patients were taking more than one immunosuppressive medication.
Positive antibody levels against SARS-CoV-2 were observed in 33 of the 45 children (73%) with available samples after two vaccine doses.
In the 30 children who had antibody titers measured after both their first and second vaccinations, 17% had negative titers after both, 33% had a negative titer that became positive, and 47% had positive titers after both. One patient who had a positive titer after the first dose that became negative after the second.
Negative antibody levels after two vaccine doses were seen most often in patients who had received their transplanted organ within three years before vaccination, were taking multiple immunosuppressive drugs or used an antimetabolite immunosuppressant.
“Importantly, no organ rejection or other unanticipated adverse events were reported,” the authors report.
“Our preliminary findings suggest the possibility that the standard two-dose regimen for mRNA vaccines is safe in pediatric transplant recipients,” lead author and Johns Hopkins medical student Caroline Qin, said in the news release.
“Further research is needed to show if two doses provide clinical protection and if not, the role that a third dose may play in boosting the immune systems of those unable to respond after two,” she added.
The study had no commercial funding.
SOURCE: https://bit.ly/3oBMV2H American Journal of Transplantation, online September 30, 2021.
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