Results of a study were inconclusive as to whether the risk for atopic diseases is decreased among children who receive the first dose of whole-cell pertussis vaccine before 6 months of age, according to a review published in the Cochrane Database of Systematic Reviews.
In this review, researchers analyzed 26 studies to compare the efficacy and safety of whole-cell pertussis vs acellular pertussis vaccines for the prevention of atopic diseases in children. The studies comprised randomized controlled trials (RCT) and nonrandomized studies of interventions published through September 7, 2020. The 2 primary outcomes were diagnosis of immunoglobulin (Ig)E-mediated food allergy and all-cause serious adverse events. Diagnosis of encephalopathy was a key secondary outcome, which further measured the safety and efficacy of the whole-cell pertussis vaccine.
Because there was limited data concerning outcomes of food allergies, the researchers assessed the associated risk of developing any atopic disease with either vaccine. Of the 26 studies included in the analysis, 4 reported atopic disease and comprised 7333 children from 3 high-income countries (Australia, Sweden, and the United Kingdom). Of these 4 studies, 3 were found to have an increased risk of bias, and 1 (n=497) showed uncertain evidence regarding whether there is an increased risk for atopic diseases among children who received the whole-cell pertussis vaccine before 6 months of age (risk ratio [RR], 0.85; 95% CI, 0.62-1.17).
Among 15 studies comprising 38,072 children, the researchers noted that the risk for serious adverse events was decreased following the administration of either the whole-cell or acellular pertussis vaccines before 6 months of age (RR, 0.94; 95% CI, 0.78-1.15; I2 = 0%). For every 1000 infants vaccinated with a first dose of either whole-cell or acellular pertussis vaccines, 11 and 12 children experienced at least 1 serious adverse event, respectively.
Among 7 studies comprising 115,271 children, there were no cases of encephalopathy identified in either vaccine group.
This study was limited by the inability to conduct subgroup analyses due to the paucity of studies included in the analysis.
“Large, well-conducted RCTs are needed to investigate the possible allergy protective benefits of a first dose of [whole-cell pertussis vaccine] given [to children] before 6 months [of age], ideally in populations with [an increased] prevalence of IgE-mediated food allergy,” the researchers concluded.
Perez Chacon G, Ramsay J, Brennan-Jones CG, et al. Whole-cell pertussis vaccine in early infancy for the prevention of allergy in children. Cochrane Database of Syst Rev. 2021;9(9):CD013682. doi:10.1002/14651858.CD013682.pub2