Measles is a highly contagious viral disease that spreads through respiratory droplets when an infected person coughs or sneezes. It can lead to severe health complications, including pneumonia, encephalitis (brain swelling), and even death. Children younger than five years old, unvaccinated individuals, pregnant women, and those with compromised immune systems are at higher risk of severe illness.
The United States is currently grappling with a significant measles outbreak, with nearly 300 cases reported nationwide. The epicenter of this surge is in Texas, which has documented 259 cases, and New Mexico, with 35 cases. This resurgence is particularly alarming, as measles had been declared eliminated in the U.S. in 2000.
In Illinois, there have been no confirmed measles cases reported so far in 2025. This is a notable improvement from the previous year, when the state experienced its largest outbreak since 1990. Between March 7 and June 3, 2024, Illinois reported 67 measles cases, primarily linked to a Chicago shelter for new arrivals. The outbreak was successfully contained, and no new cases have been reported since then.
The current outbreak has raised concerns about a potential increase in cases of Subacute Sclerosing Panencephalitis (SSPE), a rare and fatal neurological disorder that can develop years after a measles infection. SSPE is particularly prevalent in children infected with measles before the age of two. Additionally, measles can cause “immune amnesia,” weakening the immune system’s memory and leaving individuals susceptible to other infections they had previously overcome.
The resurgence of measles in the U.S. is largely attributed to declining vaccination rates. National vaccination coverage has fallen below the 95% threshold necessary to maintain herd immunity, allowing the virus to spread more easily.
The Centers for Disease Control and Prevention recommends vaccination as the best protection against measles.
Health officials nationwide are urging individuals to ensure they are up-to-date with the Measles, Mumps, and Rubella (MMR) vaccine, which is 93% effective after one dose and 97% effective after two doses. In Illinois, the Department of Public Health continues to monitor the situation closely and emphasizes the importance of vaccination to prevent potential outbreaks. Residents planning international travel are especially encouraged to verify their vaccination status, as measles remains prevalent in other parts of the world and can be imported into the U.S.
While Illinois has not reported any measles cases in 2025, the ongoing national outbreak underscores the critical need for maintaining high vaccination rates. Public health officials stress that vaccination is the most effective measure to prevent measles and protect communities from this potentially deadly disease. Schedule an appointment with your provider to discuss prevention options.