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Observational Study
. 2024 Oct:269:106903.
doi: 10.1016/j.imlet.2024.106903. Epub 2024 Jul 26.

Real-world effectiveness of original BNT162b2 mRNA COVID-19 against symptomatic Omicron infection among children 5-11 years of age in Brazil: A prospective test-negative design study

Cristina de Oliveira Rodrigues  1 , Julia Spinardi  2 , Regis Goulart Rosa  3 , Maicon Falavigna  4 , Emanuel Maltempi de Souza  5 , Josélia Larger Manfio  6 , Ana Paula de Souza  6 , Cintia Laura Pereira de Araujo  6 , Mírian Cohen  7 , Gynara Rezende Gonzalez do Valle Barbosa  6 , Fernanda Kelly Romeiro Silva  6 , Daniel Sganzerla  6 , Mariana Motta Dias da Silva  6 , Diogo Ferreira  8 , Nicolas Taciano Kunkel  6 , Nathan Iori Camargo  6 , Jean Carlos Sarturi  6 , Márcia Cristina Guilhem  6 , Jaqueline Carvalho de Oliveira  5 , Caroline Cardoso Lopes  6 , Fernanda Widmar  6 , Letícia Killes Barufi  6 , Gabrielle Nunes da Silva  6 , Daniela Fiori Gradia  5 , Ana Paula Carneiro Brandalize  1 , Carla Adriane Royer  5 , Rafael Messias Luiz  1 , Valter Antonio Baura  5 , Hellen Abreu  5 , Carolina Gracia Poitevin  5 , Gabriela Almeida Kucharski  9 , Fernando Pedrotti  9 , Srinivas Rao Valluri  2 , Amit Srivastava  10 , Viviane Wal Julião  2 , Olga Chameh Melone  2 , Kristen E Allen  2 , Moe H Kyaw  2 , Graciela Del Carmen Morales Castillo  2 , John M McLaughlin  2 ; Toledo BNT162b2 Study Group Investigators
Affiliations
Observational Study

Real-world effectiveness of original BNT162b2 mRNA COVID-19 against symptomatic Omicron infection among children 5-11 years of age in Brazil: A prospective test-negative design study

Cristina de Oliveira Rodrigues et al. Immunol Lett. 2024 Oct.

Abstract

Objective: To estimate original wild-type BNT162b2 effectiveness against symptomatic Omicron infection among children 5-11 years of age.

Methods: This prospective test-negative, case-control study was conducted in Toledo, southern Brazil, from June 2022 to July 2023. Patients were included if they were aged 5-11 years, sought care for acute respiratory symptoms in the public health system, and were tested for SARS-CoV-2 using reverse transcription polymerase chain reaction. In the primary analysis, we determined the effectiveness of two doses of original wild-type BNT162b2 against symptomatic COVID-19. The reference exposure group was the unvaccinated.

Results: A total of 757 children were enrolled; of these, 461 (25 cases; 436 controls) were included in the primary analysis. Mean age was 7.4 years, 49.7 % were female, 34.6 % were obese, and 14.1 % had chronic pulmonary disease. Omicron accounted for 100 % of all identified SARS-CoV-2 variants with BA.5, BQ.1, and XBB.1 accounting for 35.7 %, 21.4 % and 21.4 %, respectively. The adjusted estimate of two-dose vaccine effectiveness against symptomatic Omicron was 3.1 % (95 % CI, -133.7 % to 61.8 %) after a median time between the second dose and the beginning of COVID-19 symptoms of 192.5 days (interquartile range, 99 to 242 days).

Conclusion: In this study with children 5-11 years of age, a two dose-schedule of original wild-type BNT162b2 was not associated with a significant protection against symptomatic Omicron infection after a median time between the second dose and the beginning of COVID-19 symptoms of 192 days, although the study may have been underpowered to detect a clinically important difference.

Trial registration number: ClinicalTrials.gov number, NCT05403307 (https://classic.

Clinicaltrials: gov/ct2/show/NCT05403307).

Keywords: BNT162b2 vaccine; COVID-19 Vaccines; Child; SARS-CoV-2 variants; Treatment outcome.

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Conflict of interest statement

Declaration of competing interest Rodrigues, Maltempi de Souza, Manfio, de Souza, Araujo, Cohen, Barbosa, Romeiro Silva, Sganzerla, Dias da Silva, Ferreira, Kunkel, Camargo, Sarturi, Guilhem, Oliveira, Lopes, Widmar, Barufi, Nunes da Silva, Gradia, Brandalize, Royer, Luiz, Baura, Abreu, and Poitevin report honoraria fee for working in this study from Hospital Moinhos de Vento. Rosa reports honoraria fee related to investigator activities from Pfizer, and research grants from Pfizer, MSD and Brazilian Ministry of Health. Falavigna reports honoraria fee related to investigator activities from Pfizer and MSD, consulting fees from Sanofi, Ultragenyx, Novartis, Alnylam, PTC and JCR, and honoraria for lectures from Janssen, Abbvie, Sanofi, Roche, Pfizer and Novartis.Valluri, Srivastava, Julião, Melone, Allen, Kyaw, Spinardi, Castillo, and McLaughlin are Pfizer empolyees. Kucharski, and Pedrotti have nothing to disclose.

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