CONICET | Buscador de Institutos y Recursos Humanos

Objective: Strategies such as changes in vaccination schedules, improvement in coverage, and avoiding delayed administration could be implemented to improve the control of pertussis in infants. To assess the potential impact of such strategies, we use mathematical modeling and epidemiological data.Material and Method: We used an age-structured deterministic mathematical model developed by us [1]. The population dynamics is described using transferring individuals among epidemiological classes that differ in immune and infectious status. Since the model incorporates the age specific coverage for each dose we could evaluate the changes in both coverage and age of administration. To analyze the timing of vaccination we considered the 4 schedules most widely used: 2-4-6 months (mo), 6-10-14 weeks (w), 2-3-4 mo and 3-4-5 mo. To evaluate the effect of delays on infant incidences, we included vaccination profiles from La Plata, Argentina. Results: We found that a change from 2-4-6mo schedule to 6-10-14w decreases the infant incidences by 40%. Furthermore, we observed that the change from 2-4-6 mo to 2-3-4 mo decreases the incidences by 30%, while changing from 2-4-6 mo to 3-4-5mo increases it by 5%.This new result is in agree with our previous findings: avoiding delays in primary vaccination cause a strong reduction in infant incidences [2]. In regions with high coverage, the adherence to recommended vaccination schedule without delay decreases the incidence by 20%. Similarly, evolving from a situation with 80% coverage with delay to a stage with 95% coverage without delay, decreases the incidence by 40%.Conclusion: Our results point out the magnitude of the reduction of incidence in infants that could be achieved by adopting an early schedule, with high vaccine coverage and shorter delays.[1] Fabricius G et al. Epidem. Inf. 141(2013)[2] Pesco P et al. Vaccine 33(2015)