The case in Illinois is not considered an outbreak and the risk of measles transmission for the general public in the state remains low, according to IDPH.

States with active outbreaks include Indiana, Kansas, Michigan, Oklahoma, Ohio, Texas, Pennsylvania and New Mexico. The U.S. has more than double the number of measles cases it saw in all of 2024.

Health secretary Robert F. Kennedy Jr.’s efforts to contain an epidemic in a tight-knit, religious community in West Texas have run counter to established public health strategies deployed to end past epidemics.

Indiana health officials announced a measles outbreak Wednesday, with six cases that have no known links to the outbreaks in several other states.

The U.S. has more than double the number of measles cases it saw in all of 2024, with Texas reporting the majority of them: nearly 500.

Measles is caused by a highly contagious virus that’s airborne and spreads easily when an infected person breathes, sneezes or coughs. It is preventable through vaccines, and had been considered eliminated from the U.S. since 2000.

The measles outbreak is surging in West Texas, especially in under-vaccinated communities, but it’s not just coverage with the measles vaccine that is lagging behind. The use of other key vaccines in the childhood immunization schedule has decreased too.

A record share of U.S. kindergartners had an exemption for required vaccinations last school year, leaving more than 125,000 new schoolchildren without coverage for at least one state-mandated vaccine.

The acknowledgement that approximately 500 people returned to city shelters after living there for at least two months raises new questions about plans by officials to start evicting families with school-age children from city shelters on Monday.

The end of the outbreak comes after nearly six weeks, or two incubation periods, without any new measles cases, according to a news release. The last measles case was reported April 20.

Measles cases in Chicago account for more than half of reported cases in the U.S. so far this year. More than half of the measles cases in the city were in children ages 4 or younger.

The Chicago Department of Public Health says they are fighting the spread through testing and vaccinations — particularly in the Pilsen migrant shelter where the majority of cases are emerging.

The measure set for a final vote by the full City Council on April 17 would require officials to detail how many people are evicted from city shelters every week. In addition, officials must report on the type and number of complaints filed by shelter residents twice per month, according to the proposal.

In all, 31 Chicagoans have been diagnosed with measles since March 4.

The U.S. Centers for Disease Control and Prevention issued a health alert to doctors on Monday to increase awareness of the international spread of measles, and urged them to vaccinate infants a few months ahead of the typical schedule if families are planning to go abroad.

City health officials did not immediately identify whether the latest people to contract measles are children or adults, nor did they disclose their condition, as they have with all other cases of measles.