Risk Factors Associated With Bordetella pertussis Among Infants ≤4 Months of Age in the Pre-Tdap Era: United States, 2002-2005

Universal Tetanus-Diphtheria-Pertussis Vaccination During Pregnancy: A Cost-Effectiveness Analysis

OBJECTIVE

To assess the cost effectiveness of tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis (Tdap) vaccination in pregnant patients in the United States.

METHODS

A decision-analytic model in TreeAge was developed to compare universal Tdap vaccination in pregnancy with no Tdap vaccination in pregnancy using a theoretical cohort of 3.66 million pregnant individuals, the approximate number of deliveries per year in the United States. Outcomes included infant pertussis infections, infant hospitalizations, infant encephalopathy cases, infant deaths, and maternal pertussis infections. All probabilities and costs were derived from the literature. Utilities were applied to discounted life expectancies at a rate of 3% to generate quality-adjusted life-years (QALYs). A strategy was considered cost effective if it had an incremental cost-effectiveness ratio of less than $100,000 per QALY. Univariable and multivariable sensitivity analyses were performed to assess the robustness of the model to changes in the baseline assumptions.

RESULTS

With a baseline assumption of vaccine cost at $47.75, Tdap vaccination was cost effective at $7,601 per QALY. The vaccination strategy was associated with a decrease of 22 infant deaths, 11 infant encephalopathy cases, 2,018 infant hospitalizations, 6,164 infant pertussis infections, and 8,585 maternal pertussis infections, with an increase of 19,489 QALYs. In sensitivity analyses, the strategy was cost effective until the incidence of maternal pertussis became lower than 1.6 cases per 10,000 individuals, the cost of the Tdap vaccine was greater than $540, or previous pertussis immunity was present in more than 92.1% of pregnant individuals.

CONCLUSION

In a theoretical U.S. cohort of 3.66 million pregnant individuals, Tdap vaccination during pregnancy is cost effective and reduces infant morbidity and mortality compared with no vaccination during pregnancy. These findings are especially relevant given that approximately half of individuals are not vaccinated during pregnancy and recent data have shown that postpartum maternal vaccination and cocooning strategies are ineffective. Public health strategies to encourage greater uptake of Tdap vaccination should be used to reduce the morbidity and mortality of pertussis infection.

Effects of Vaccination Against Influenza, Pertussis, and COVID-19 on Human Milk Antibodies: Current Evidence and Implications for Health Equity

Human milk contains three antibody classes that confer mucosal immunity to the breastfed infant: secretory IgA (SIgA), secretory IgM (SIgM), and IgG. Influenza and pertussis vaccines administered during pregnancy induce pathogen specific SIgA and IgG responses in human milk that have been shown to protect the breastfed infant from these respiratory illnesses. In addition, mRNA vaccines against the SARS-CoV-2 virus administered during pregnancy and lactation induce anti-SARS-CoV-2 IgG and IgA responses in human milk. This review summarizes the immunologic benefits of influenza, pertussis, and COVID-19 vaccines conferred by human milk. Additionally, future research direction in human milk immunity and public health needs to improve lactational support are discussed.