Most immunocompromised children mount response to two doses of COVID-19 vaccine
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DENVER — A study of immunocompromised children found that most mounted an immune response after two doses of COVID-19 vaccine, which increased modestly after a third dose, researchers reported at the Pediatric Academic Societies Meeting.
The CDC has recommended a third primary series dose for immunocompromised people for months, but Heather Morgans, DOMA, a pediatric nephrologist at Children's Mercy Hospitals and Clinics in Kansas City, Missouri, said her team aimed to determine the vaccine-induced cellular and humoral immune response to a third dose.
Their study included 37 patients aged between 12 and 21 years who were immunocompromised, had received two doses of a messenger RNA COVID-19 vaccine, and anticipated receiving a third dose. They measured the cellular response via SARS-CoV-2 antigen-specific T-cell (CD4/CD8) assays and the humoral response by quantitative SARS-CoV-2 IgG antibody levels to four viral proteins, with a neutralizing antibody level more than or equal to 30% indicating a positive response.
They assessed each patient in the cohort five times — once prior to receiving the third dose, again at 3 weeks, 4 weeks, 6 weeks and finally at 12 months after receiving the vaccine. Patients were also surveyed at each point.
According to the preliminary findings, 78% of participants had detectable humoral responses after two vaccine doses, with a modest increase occurring after the third dose, including a significant increase in neutralizing antibodies, Morgans and colleagues reported. Positive cellular immunogenicity increased from 82.6% after the second vaccine dose to 100% after the third vaccine dose, with a more prominent CD4 response compared with the CD8 response.
“Even with the two-dose vaccine series, a majority have a detectable response,” Morgans said. “But this was augmented further after receiving the third vaccine dose.”
In total, 86.5% of the cohort mounted a greater humoral and cellular response following the third dose. Morgans said more analyses were needed regarding the duration of immunogenicity and breakthrough infections.
“This supports the need for ongoing study of vaccination against COVID-19 in immunocompromised children,” Morgans said.
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Morgans H, et al. Cellular and humoral response to the 3rd COVID-19 vaccine dose in immunocompromised children; a multi-division prospective cohort. Presented at: Pediatric Academic Societies Meeting; April 21-25, 2022; Denver.
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