Measles and Pertussis Are Making a Comeback
In 2000, the United States declared measles eradicated, meaning this infectious disease had been nearly eliminated in our country. Much of this success was due to comprehensive vaccination programs. Because measles is highly transmissible through casual contact, the threshold for “herd immunity” — the critical percentage of immune individuals required to slow the spread of a contagious disease — is quite high, around 93–95%.
That means approximately 95 out of every 100 people need to have antibodies against measles (best achieved through vaccination) in order to prevent its spread within a community.
Young children are particularly susceptible to measles complications, including pneumonia, encephalitis (swelling of the brain), and death. In children under five years old, more than half of measles cases require hospitalization.
In 2025, the Centers for Disease Control and Prevention reported over 2,000 measles cases associated with 49 separate outbreaks. Of those with confirmed measles, 89% were outbreak-associated. This is significant because it demonstrates that incidence increases where there are pockets of vulnerability — areas with low vaccination rates.
Two recent examples include an outbreak in South Carolina that has sickened nearly 800 individuals, and last summer’s Texas outbreak, which resulted in 762 measles cases and two pediatric deaths.
The two-dose MMR vaccine series provides approximately 97% protection against severe measles infection.
Pertussis Is Also on the Rise
Cases of Pertussis, also known as whooping cough, likewise surged following the COVID-19 pandemic. The CDC reported six times as many pertussis cases in 2024 compared to 2023.
As its name suggests, whooping cough is characterized by severe coughing fits that can knock the wind out of a patient and cause a gasping “whoop” sound upon inhalation. It may also cause fever, cough-induced vomiting, and even death.
For infants under one year of age, pertussis frequently requires hospitalization for respiratory support, including supplemental oxygen or mechanical ventilation. Symptoms can persist for weeks to months after the initial illness.
Protection against pertussis begins at two months of age with the DTaP vaccine.
Why Vaccination Still Matters
Measles and pertussis are dangerous, highly contagious, and vaccine-preventable illnesses. They disproportionately affect the youngest and most vulnerable children.
Serious illness is largely preventable by following the established childhood immunization schedule. Communities with pockets of unvaccinated individuals create high-risk environments where herd immunity is not achieved and cannot adequately protect those who rely on it most.
