By Stan Deresinski, MD, FACP, FIDSA
Clinical Professor of Medicine, Stanford University
SYNOPSIS: The estimated effectiveness of two doses of Pfizer-BioNTech vaccine in the prevention of multisystem inflammatory syndrome in children was 91%.
SOURCE: Zambrano LD, Newhams MM, Olson SM, et al. Effectiveness of BNT162b2 (Pfizer-BioNTech) mRNA vaccination against multisystem inflammatory syndrome in children among persons aged 12-18 years — United States, July–December 2021. MMWR Morb Mortal Wkly Rep 2022;71:52-58.
The BNT162b2 (Pfizer-BioNTech) COVID-19 vaccine has received emergency use authorization in the United States for children as young as 5 years of age, among whom its efficacy has been demonstrated to be excellent. Children and adolescents are at risk of multisystem inflammatory syndrome in children (MIS-C), which occurs two to six weeks after COVID-19 infection. An important question is whether vaccination prevents MIS-C.
Zambrano and colleagues used a test-negative case-control design to examine the effectiveness of primary vaccination with BNT162b2 to prevent MIS-C in children 12-18 years of age at 24 pediatric hospitals in 20 states. The children were hospitalized during July 1 to Dec. 9, 2021 — a time when the Delta variant of SARS-CoV-2 was prevalent. One hundred two children and adolescents hospitalized with MIS-C (cases) were matched to 181 hospitalized controls — 90 of whom were COVID-19 test-negative but had at least one COVID-19-like symptom, and 91 of whom were test-negative without such symptoms. The median age of the total of 283 patients was 14.5 years; 58% had one or more underlying condition, including obesity. Approximately 36% of controls had been vaccinated, but this was true of only approximately 5% of case patients.
Of the 102 case patients, 91 (89%), 84 (82%), and 68 (67%) had cardiovascular, gastrointestinal, and hematologic involvement, respectively. Thirty-eight (37%) case patients required life support, including invasive mechanical ventilation, vasoactive agent infusion, or extracorporeal membrane oxygenation. All 38 MIS-C patients requiring life support were unvaccinated.
The estimated effectiveness of two doses of the Pfizer-BioNTech vaccine in the prevention of MIS-C was 91% (95% confidence interval [CI] = 78% to 97%), and no child with MIS-C who was vaccinated required life support.
COMMENTARY
These dramatic results demonstrate the unequivocal protection against the development of MIS-C by vaccination. The calculated vaccine efficacy was 91% and, among those who developed MIS-C, there appeared to be absolute protection against disease severe enough to dictate the need for life support. It should be noted that this study covered a time prior to the emergence of the Omicron variant of SARS-CoV-2.
These data, along with recent evidence indicating an increased risk of newly diagnosed diabetes mellitus after COVID-19 in this same age group, provide further impetus to the need for universal vaccination, including children and adolescents.1
REFERENCE
- Barrett CE, Koyama AK, Alvarez P, et al. Risk for newly diagnosed diabetes > 30 days after SARS-CoV-2 infection among persons aged < 18 years — United States, March 1, 2020–June 28, 2021. MMWR Morb Mortal Wkly Rep 2022;71:59-65.