A team of experts from the US Centers for Disease Control and Prevention arrived in Chicago on Tuesday to help local public health officials manage a measles outbreak there.
The Chicago Department of Public Health said last week that the city had its first measles case since 2019. The person is recovering well at home, the department said.
The department announced Sunday that there were two unrelated measles cases among children at a migrant shelter in a large warehouse in the city’s Pilsen neighborhood. One child has recovered and is no longer infectious, the health department said. The second child is hospitalized but is in good condition.
The department also announced two cases among adults in the shelter on Monday and three further cases Tuesday, bringing the total count citywide to eight. stable condition.
The CDC, which sends its experts when requested by local authorities, says it has not sent personnel to other recent measles outbreaks.
The CDC team will work closely with the city and state health departments to help identify people who may be at risk for getting sick. The team will provide clinical guidance, help coordinate testing and work with those on the ground to educate influential community leaders and clinicians who can emphasize how important it is to get vaccinated. The CDC will also provide guidance on a vaccination campaign covering certain schools, shelters and other congregate settings, as well as provide extra vaccines to ensure that there is an adequate supply for both adults and kids.
“The majority of Chicagoans are vaccinated against measles and therefore are not at high risk but we are strongly urging those who aren’t vaccinated to do so as soon as possible, new arrivals and all Chicagoans. It is by far the best protection against measles, which for the first time in years is in our city,” Chicago Department of Public Health Commissioner Dr. Olusimbo “Simbo” Ige said in Sunday’s statement.
“Because of how contagious measles is, I anticipate seeing more cases. Should you be exposed to someone who has measles, if you are not vaccinated you need to immediately quarantine and call a health provider. If you are not sure of your vaccination status, stay home and call your health provider as soon as possible.”
Health care system Cook County Health said Monday that it was coordinating with other local departments to get in touch with patients and staff that were known to be in the vicinity of some of the patients with measles. The patients with measles had sought medical help from Stroger Hospital’s emergency department, Arlington Heights Health Center and the CCH’s Professional Building. In responding to the measles cases, Cook County Health said it followed all reporting protocols with local and state public health authorities.
“We believe the risk to our staff is low, as vaccination is a requirement of employment at Cook County Health,” the health care system said. “We cannot emphasize enough how important vaccination is to preventing the spread of measles.”
Measles is highly contagious and can cause serious symptoms that can lead to pneumonia and other potentially life-threatening complications, but it is preventable with vaccination.
People who aren’t vaccinated against the virus can get sick if they breathe in contaminated air or touch a surface that someone infected with the measles has touched. It can linger in the area where someone has sneezed or coughed for about an hour or two, research shows.
People who are infected can spread measles about four days before and four days after developing a rash that is a trademark of the virus, the CDC says.
Measles typically starts with a mild to moderate fever, along with a runny nose, a cough, and red and watery eyes. Some people also have stomach problems.
The illness can be particularly difficult for babies and young children.
Most people in the US get a series of two measles, mumps and rubella (MMR) shots in childhood. When it comes to preventing illness after exposure, the vaccine is considered more than 95% effective with a single dose and 97% effective after a second dose.
“CDC continues to recommend the safe and effective MMR vaccination as part of the routine immunizations schedule for all children and adults, with special guidance for international travel,” the agency said in a statement Monday. “We will continue to provide updates as more information becomes available.”
The Chicago health department said it has also teamed up with public health managers from Cook County Health, Rush University Medical Center and the University of Illinois-Chicago.
Health workers assessed nearly all of the shelter’s residents over the weekend and vaccinated more than 900 of them, the Chicago health department says.
More than 700 residents were found to have immunity from vaccination or infection, and they are allowed to come and go, the health department says. Those who have not been vaccinated or who were recently vaccinated by the city must quarantine for 21 days and monitor for symptoms.
Cook County Health offers medical assessments to all new arrivals who go through the city intake process. The health care system said it has cared for 27,057 patients to date and have offered all essential vaccines including the MMR shot. The department said Monday that it has administered more than 73,400 vaccinations to new arriving patients to protect against measles, flu, Covid, varicella and other diseases.
In May, officials said they expected an influx of migrants to follow the expiration of Title 42, a Trump-era pandemic public health order aimed at stopping the spread of Covid-19. The policy became a key tool officials used to turn back migrants at the US-Mexico border. Then-CDC Director Dr. Rochelle Walensky said at the time that communities may need to watch for possible cases of infectious disease.
As in past situations, health care providers need to recognize that “we may have under-vaccinated people who are settling in communities, and we need to watch out for infectious threats,” she said.
Measles is considered a disease that was eliminated from the US in 2000, but cases have been popping up across the country. An outbreak in Florida last month included several cases linked to children at an elementary school.
Get CNN Health's weekly newsletter
- Sign up here to get The Results Are In with Dr. Sanjay Gupta every Friday from the CNN Health team.
As of March 7, the CDC said, 45 cases have been reported in 17 jurisdictions across the country this year. For all of last year, there were 58 cases in the US.
About 92% of US children have been vaccinated against MMR by age 2, according to a 2023 report from the CDC – below the federal target of 95%.
The percentage of kindergartners who got their state-required vaccines for measles also remained below the federal target for the 2022-23 school year, according to CDC data. And the rate of vaccine exemptions for children has reached the highest level ever reported in the US.
Children should get two doses of the MMR vaccine, according to the CDC: the first dose at 12 to 15 months of age and the second at 4 to 6 years of age.
Before the nation’s measles vaccination program, about 3 million to 4 million people got the virus every year, and about 400 to 500 died.
CNN’s Amanda Musa, Jennifer Feldman and Carma Hassan contributed to this report.