Effectiveness of Pfizer mRNA Vaccine Against MIS-C

Effectiveness of BNT162b2 (Pfizer-BioNTech) mRNA Vaccination Against Multisystem Inflammatory Syndrome in Children Among Persons Aged 12–18 Years

United States, July-December 2021

Laura D. Zambrano, PhD; Margaret M. Newhams, MPH; Samantha M. Olson, MPH; Natasha B. Halasa, MD; Ashley M. Price, MPH; Julie A. Boom, MD; Leila C. Sahni, PhD; Satoshi Kamidani, MD; Keiko M. Tarquinio, MD; Aline B. Maddux, MD; Sabrina M. Heidemann, MD; Samina S. Bhumbra, MD; Katherine E. Bline, MD; Ryan A. Nofziger, MD; Charlotte V. Hobbs, MD; Tamara T. Bradford, MD; Natalie Z. Cvijanovich, MD; Katherine Irby, MD; Elizabeth H. Mack, MD; Melissa L. Cullimore, MD; Pia S. Pannaraj, MD; Michele Kong, MD; Tracie C. Walker, MD; Shira J. Gertz, MD; Kelly N. Michelson, MD; Melissa A. Cameron, MD; Kathleen Chiotos, MD; Mia Maamari, MD; Jennifer E. Schuster, MD; Amber O. Orzel, MPH; Manish M. Patel, MD; Angela P. Campbell, MD; Adrienne G. Randolph, MD

Disclosures

Morbidity and Mortality Weekly Report. 2022;71(2):52-58. 

In This Article

Abstract and Introduction

Introduction

Multisystem inflammatory syndrome in children (MIS-C) is a severe postinfectious hyperinflammatory condition, which generally occurs 2–6 weeks after a typically mild or asymptomatic infection with SARS-CoV-2, the virus that causes COVID-19.[1–3] In the United States, the BNT162b2 (Pfizer-BioNTech) COVID-19 vaccine is currently authorized for use in children and adolescents aged 5–15 years under an Emergency Use Authorization and is fully licensed by the Food and Drug Administration for persons aged ≥16 years.[4] Prelicensure randomized trials in persons aged ≥5 years documented high vaccine efficacy and immunogenicity§,[5] and real-world studies in persons aged 12–18 years demonstrated high vaccine effectiveness (VE) against severe COVID-19.[6] Recent evidence suggests that COVID-19 vaccination is associated with lower MIS-C incidence among adolescents;[7] however, VE of the 2-dose Pfizer-BioNTech regimen against MIS-C has not been evaluated. The effectiveness of 2 doses of Pfizer-BioNTech vaccine received ≥28 days before hospital admission in preventing MIS-C was assessed using a test-negative case-control designamong hospitalized patients aged 12–18 years at 24 pediatric hospitals in 20 states** during July 1–December 9, 2021, the period when most MIS-C patients could be temporally linked to SARS-CoV-2 B.1.617.2 (Delta) variant predominance. Patients with MIS-C (case-patients) and two groups of hospitalized controls matched to case-patients were evaluated: test-negative controls had at least one COVID-19–like symptom and negative SARS-CoV-2 reverse transcription–polymerase chain reaction (RT-PCR) or antigen-based assay results, and syndrome-negative controls were hospitalized patients without COVID-19–like illness. Among 102 MIS-C case-patients and 181 hospitalized controls, estimated effectiveness of 2 doses of Pfizer-BioNTech vaccine against MIS-C was 91% (95% CI = 78%–97%). All 38 MIS-C patients requiring life support were unvaccinated. Receipt of 2 doses of the Pfizer-BioNTech vaccine is associated with a high level of protection against MIS-C in persons aged 12–18 years, highlighting the importance of vaccination among all eligible children.

*These authors contributed equally to this report.
These senior authors contributed equally to this report.
§ https://www.fda.gov/emergency-preparedness-and-response/coronavirus-disease-2019-covid-19/comirnaty-and-pfizer-biontech-covid-19-vaccine
In this context, the test-negative case-control design was used to compare the odds of previous Pfizer-BioNTech vaccine receipt among inpatients without evidence of SARS-CoV-2 infection with case-patients hospitalized for MIS-C. These control patients included those with respiratory virus infection who received a negative test result for SARS-CoV-2 infection (test-negative) or patients without symptoms compatible with COVID-19 (syndrome-negative), including fever, cough, shortness of breath, loss of taste, loss of smell, gastrointestinal symptoms, use of respiratory support for the acute illness, or new pulmonary findings on chest imaging consistent with pneumonia.
**This investigation included patients enrolled from 24 pediatric hospitals in 20 states: Alabama, Arkansas, California, Colorado, Georgia, Illinois, Indiana, Louisiana, Massachusetts, Michigan, Mississippi, Missouri, Nebraska, New Jersey, North Carolina, Ohio, Pennsylvania, South Carolina, Tennessee, and Texas.
†† https://overcomecovid.org/
§§CDC recommendation for pediatric COVID-19 vaccine for children aged 5–11 years: https://www.cdc.gov/media/releases/2021/s1102-PediatricCOVID-19Vaccine.html
¶¶The lower age bound for the study population was set at 12 years and 49 days to allow for the first vaccine dose on the patient's 12th birthday, a second dose 21 days thereafter, and a 28-day window between the patient's second dose and hospitalization for MIS-C.
***CDC case definition criteria for MIS-C are available at https://www.cdc.gov/mis/mis-c/hcp/index.html. For the purposes of this analysis, all MIS-C case-patients were required to have laboratory evidence of current or recent infection (RT-PCR, antigen-, or antibody-based testing).
†††Vaccine effectiveness studies in the context of respiratory viruses most commonly include test-negative controls. Because of potential biases related to the selection of controls, including the potential for misclassification of test-negative patients due to false-negative tests, syndrome-negative controls were also included as a separate control group. Among the 91 syndrome-negative controls, 18 (20%) had no record of SARS-CoV-2 testing. The remaining syndrome-negative controls had a record of SARS-CoV-2 testing by RT-PCR or antigen and received negative test results.
§§§Among the 102 MIS-C case-patients and 181 controls enrolled, 50 (49%) and 113 (62%), respectively, had information obtained through a combination of parent interview and medical records abstraction, while 52 (51%) case-patients and 68 (38%) control patients had information obtained solely through medical records abstraction.
¶¶¶45 C.F.R. part 46.102(l)(2), 21 C.F.R. part 56; 42 U.S.C. Sect. 241(d); 5 U.S.C. Sect. 552a; 44 U.S.C. Sect. 3501 et seq.
****VE against MIS-C was also assessed comparing the odds of antecedent vaccination with the second dose of the Pfizer-BioNTech vaccine ≥14 days before hospital admission. Point estimates did not significantly differ from the primary analysis presented in this report. (VE after 14 days: 86%; 95% CI = 70%–93%.)

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