Researchers: Dan Yamin¹, Erez Shmueli¹

Background: pertussis is a highly contagious disease, and is considered by the WHO as one of the ten deadliest disease in children. In Israel, despite vaccination coverage exceeding 90% in both infant immunizations and booster doses, a sharp increase in pertussis infection and hospitalization has been observed since 1998.

Objectives: determine a vaccination schedule against pertussis 1) that minimizes overall costs and keep the current number of doses for pertussis, 2) by conducting a cost-effectiveness analysis to offer booster doses in specific age groups.

Method: we developed a contact network based on aggregated and anonymized mobility data from the cell-phone devices of >1.8 million Israeli users. We used this network as a lattice to a transmission model for pertussis. We also developed a differential equation- type model to validate the necessity of the network model. We integrated an economic layer into the transmission model to evaluate the effectiveness and cost-effectiveness for policy recommendations.

Findings: 1) Tdap vaccination during pregnancy led to a sharp decline in reported cases and hospitalizations in Israel, 2) Using the same amount of vaccines administered today, the targeting of children at the age of six instead of seven is predicted to be the optimal schedule to decrease both outpatient visits and hospitalizations. 3) any increase in maternal vaccination coverage is likely to be cost-effective, with an incremental cost-effectiveness ratio of $77,000-$97,000 per QALY. 4) the contribution of the second booster dose is limited, with a probability of only 0.6 to be cost-effective at $110,000/QALY saved.

Recommendations: Additional effort should be invested to encourage maternal vaccination against pertussis. We recommend moving the first booster to age six and prudently considering the necessity of the second booster dose. Furthermore, due to the stable periodicity of pertussis, public health decision-makers should invest continuous efforts in the implementation of this strategy with additional reinforcement in expected peak years.

Research end date: 08/2020