The resurgence of measles in communities with overall high vaccination rates but pockets of vaccine refusal demonstrates the critical importance of achieving and maintaining immunization coverage above 95 percent in every community. Mathematical models show that even a small geographic cluster of unvaccinated individuals can sustain local transmission of measles, a pathogen so contagious that one infected person can transmit to 12 to 18 unvaccinated contacts.
Public health officials are using the outbreaks to communicate the herd immunity concept with unusual directness, emphasizing that vaccination decisions affect not just individual children but also the medically fragile neighbors, infants too young for vaccination, and immunocompromised individuals who cannot be vaccinated and depend on community immunity for protection. Social media health communication strategies that meet vaccine-hesitant communities where they are have shown the most consistent success in improving acceptance.
