PHILADELPHIA—The Philadelphia Department of Public Health is reporting that there is a cluster of measles among unvaccinated residents. In addition to an index case, three locally acquired cases have been confirmed, with two of those cases being hospitalized and released. In addition, there are at least two more possible cases that have been hospitalized after contact with one of the known cases; the Health Department is facilitating testing on those cases. The Health Department is strongly recommending that anyone who may have been exposed to measles should quarantine themselves by staying home and away from others. Additionally, people who have not received both doses of Measles, Mumps, and Rubella (MMR) vaccine should talk with their healthcare provider about getting caught up. These cases are connected with the situation mentioned in the City’s December 23, 2023 press release.

Measles is a very dangerous virus, however Philadelphia has high vaccination rates, with at least 93% of children fully vaccinated against measles by age 6. However, ninety percent of people with close contact with an infected person will get measles if they are not vaccinated. About 1 in 5 unvaccinated people in the U.S. who get measles is hospitalized. As many as 1 out of every 20 children with measles gets pneumonia, the most common cause of death from measles in young children. About 1 child out of every 1,000 who get measles will develop encephalitis (swelling of the brain) that can lead to convulsions and can leave the child deaf or with intellectual disability. Nearly 1 to 3 of every 1,000 children who become infected with measles will die from respiratory and neurologic complications.

In response to this cluster, the City is working through the Health Department to stop this cluster from spreading. The Health Department is working to identify everyone who may have been exposed, checking their vaccine status, warning them that they may have been exposed, and issuing quarantine and exclusion orders where necessary. The Health Department is also working to educate healthcare providers about measles symptoms and what they should do if they see a potential case. The Health Department is working to inform the public about the current threat and encourage them to get up to date on their MMR vaccine so they won’t have to worry about this in the future.

The two new possible cases under investigation were exposed as a result of one of the confirmed cases attending day care disregarding quarantine and exclusion instructions. The Health Department has been working with the following places to contact people who may have been exposed on the dates listed:

  • Jefferson Health building at 33 S 9th/833 Chestnut St
    • Exposures took place on December 19 between 2 p.m. and 5:30 p.m.
  • Multicultural Education Station Day Care at 6919 Castor Ave
    • Exposures took place on December 20 and 21
  • Children’s Hospital of Philadelphia Emergency Room at 3401 Civic Center Blvd
    • Exposures took place on December 28
  • Christopher’s Hospital for Children Emergency Department
    • Suspected exposures may have happened overnight December 30 – December 31 mid-afternoon
  • Christopher’s Hospital for Children inpatient unit 5 North
    • Suspected exposures may have happened between December 31 and January 3
  • Nazareth Hospital Emergency Room
    • Suspected exposures may have happened on December 31 and January 2

If you were at any of the above sites on the days listed, you may have been exposed to measles.

“Children under 12 months and adults and children who are immunocompromised remain vulnerable to measles but are generally protected because of the wall of immunity created by high community vaccination levels,” said Health Commissioner Dr. Cheryl Bettigole. “Unfortunately, we are seeing cases of measles that have spread to vulnerable individuals including young children due to people declining vaccination and also failing to adhere to quarantine recommendations. Philadelphia is a city where we believe in a duty to take care of each other. We are asking all city residents who may have been exposed to measles to do their part to ensure that no additional infants are harmed by this infection.”

She continued, “If you have not been vaccinated against measles or have not vaccinated your children who are 12 months of age or older, please reach out to your healthcare provider to do so immediately. If you or your child has been exposed to measles, please follow public health guidance to avoid exposing additional children.”

If you are immune to measles, you do not have to do anything even if you were in those buildings on the dates listed. People are immune if they:

  • Were born before 1957, or
  • Have already had measles, or
  • Have received two doses of measles-containing vaccine (usually given as measles, mumps, rubella (MMR) vaccine) and are not immune compromised.

If you were in one of those buildings on the dates listed and are not immune to measles (including infants under 12-15 months, who typically have not yet been vaccinated):

  • You should contact your healthcare provider or pediatrician right away, especially if you don’t feel well. Let your doctor know about your possible measles exposure.
  • If you must go out to seek healthcare, please alert the healthcare provider prior to going in that you have been exposed to measles and have them call the Health Department.
  • You could potentially give measles to vulnerable people and therefore must quarantine (stay home).


  • If you or your child was exposed at the Multicultural Education Station, you should quarantine until at least January 23.
  • If you or your child was exposed at CHOP on December 28, you should follow the instructions given to you by CHOP.
  • If you or your child was exposed at St. Christopher’s, you should quarantine until you receive instructions from St. Christopher’s or the Health Department.
  • If you or your child was exposed at Nazareth, you should quarantine until January 23, unless otherwise instructed by Nazareth or the Health Department.

If you were in one of those buildings on the dates listed and are not sure if you’re immune to measles:

  • You should contact your healthcare provider or pediatrician right away, especially if you don’t feel well. They can review your immunization records to make sure that you have received both doses of MMR vaccine.
  • You should wear a mask in indoor public spaces and around anyone who is unvaccinated until you learn your status. This will help keep other people from being exposed.

Measles is an extremely contagious virus and each person who has measles has the ability to infect dozens of other people. Measles symptoms usually appear about a week or two after being infected. The first symptoms are usually:

  • High fever,
  • Cough,
  • Runny nose,
  • Red, watery eyes or pinkeye.

A few days after the first symptoms, more symptoms appear. They include:

  • Koplik spots, which are tiny white spots that can appear in the mouth.
  • Measles rash, which usually begins as flat red spots that appear on the face at the hairline and spread downward to the neck, trunk, arms, legs, and feet.
  • An even higher fever, which can present when the rash appears.

MMR vaccine, which protects against measles, mumps, and rubella, is extremely safe and effective at preventing measles. MMR vaccine has been safely used for decades and protects millions of Americans. Two doses of vaccine are 97% effective at preventing measles. People who have received 2 doses of vaccine and are not severely immune compromised are very unlikely to get measles. Children should get their first dose of vaccine between 12 and 15 months of age and their second dose between 4 and 6 years of age. If you haven’t gotten both doses by age six, you should get your first or second dose as soon as possible. Infants 6-11 months who are travelling internationally should get an early dose of MMR. Talk to your healthcare provider to learn how you can get your MMR vaccine. The Health Department has additional resources on where to get vaccines, including information on how to get your child vaccinated for free at a City Health Center.