Non-mandatory immunization and its potential impact on pertussis epidemiology

Area of Science:

• Epidemiology
• Public Health Policy
• Mathematical Modeling

Background:

• Argentina proposed a 2017 bill for informed consent in immunization, making the schedule non-mandatory for minors.
• The introduction of such legislation may erode public confidence in vaccine efficacy and safety.
• Pertussis (whooping cough) remains a significant public health concern, particularly for infants.

Purpose of the Study:

• To quantitatively analyze the short-term impact of the proposed Argentine immunization bill on pertussis transmission.
• To estimate the potential increase in severe pertussis cases and deaths among infants under one year old.

Main Methods:

• Utilized a pre-existing mathematical model for pertussis transmission dynamics.
• Simulated scenarios with a 5% and 10% annual reduction in vaccination coverage over four years, starting in 2018.

Main Results:

• A 5% annual coverage reduction projected over 100% increase in severe infant pertussis cases and 101 estimated deaths in the next outbreak.
• A 10% annual coverage reduction projected over 200% increase in cases and 163 estimated deaths in the next outbreak.

Conclusions:

• The draft bill on non-mandatory immunization in Argentina poses a significant risk of increased pertussis outbreaks.
• Reduced vaccination coverage due to legislative uncertainty could lead to a substantial rise in infant mortality from pertussis.