The Georgia Department of Public Health said the cluster remains contained to known contacts, but the rising case count underscores the highly contagious nature of the virus and the importance of vaccination. Public health experts say measles can spread through the air when an infected person breathes, coughs or sneezes, and can linger in a room for up to two hours after they leave.

"Vaccination is the best protection against measles," the department said in a statement, urging residents to ensure they and their children are up to date on the measles-mumps-rubella (MMR) vaccine. Two doses of the vaccine are about 97% effective at preventing measles, according to the Centers for Disease Control and Prevention.

Officials also cautioned that anyone experiencing symptoms — including high fever, cough, runny nose, red eyes and a rash — should contact a healthcare provider before visiting a doctor's office, hospital or clinic. Because measles is so contagious, arriving without warning can expose other patients and staff in waiting rooms.

The Macon County cluster is part of a broader national uptick in measles cases, driven in part by declining vaccination rates in some communities. Georgia's 28 cases this year already far exceed the annual totals of recent years, and public health advocates are calling for renewed outreach to families who may have missed routine childhood immunizations during the pandemic or who face barriers to access.

Measles was declared eliminated in the United States in 2000, but outbreaks continue to occur when unvaccinated travelers bring the virus back from countries where it remains endemic, or when pockets of low vaccination allow it to spread locally. State health officials are continuing to monitor the Macon County cluster and will provide updates as new information becomes available.