As measles continues to spread nationwide, hospitals and health officials are pouring more money into efforts to increase vaccinations, testing and surveillance of the disease. The funds include a surprise $100 million infusion in recent weeks to states from the Centers for Disease Control and Prevention.

As of Oct. 2, the United States had recorded nearly 4,000 measles cases, the highest by far in decades. About one-quarter of those cases have occurred in Pennsylvania, where state officials say five people with the virus have died. But nearly every state has reported cases this year, including New York, where the governor on Monday declared measles a statewide health emergency.

Some state officials welcomed the funding from the C.D.C., released in two $50 million tranches in August and September, as a bulwark against future outbreaks.

“Our state has not yet seen a large outbreak as in some other states, like Pennsylvania or South Carolina, but we fully expect to see more cases here,” said Dr. Scott Harris, the state health officer at the Alabama Department of Public Health. Alabama received $300,000 for measles immunization programs and $600,000 for surveillance and diagnoses, he said.

The funding is intended for immunization programs and for efforts to improve measles surveillance, including diagnoses of severe infections and cases in pregnant women and infants. Measles infections at birth had been extremely rare in the United States, but two of the Pennsylvania deaths were thought to have resulted from such cases.

The infusion of funds “comes at a time when public health funding and staffing has been cut, so it is sorely needed,” said Claire Hannan, executive director of the Association of Immunization Managers, which represents state and local officials.