This article appeared on USA Today. Read more here.
Cases of measles have continued to crop up in states across the U.S. since a handful of infections were reported at the beginning of the year.
The Centers for Disease Control and Prevention first issued an emergency warning on Jan. 25, saying 23 cases were confirmed in several states between December 1, 2023, and January 23, 2024.
Since then, seven more states have been added to the list with at least 18 more infections.
The total case count remains relatively low at under 50, but health officials have advised increased vigilance, as the virus is highly contagious; so contagious, in fact, that 90% of unvaccinated people who are exposed end up contracting it. Additionally, 1 in 5 of those people end up hospitalized, according to the CDC.
See the map below for more information on where measles cases have been confirmed.
Measles cases by state
CDC data on current measles cases is updated monthly. The latest update from Feb. 29 reported 41 confirmed cases spread across 16 states. However, several state health departments have also shared information about cases, some of which are reported between CDC tracking updates.
Here’s what those states are reporting:
- Arizona – Two cases in Maricopa County
- California – One case in Los Angeles County
- Florida – Ten cases Broward and Polk counties
- Georgia – One case in the Atlanta Metro area
- Indiana – One case in Lake County
- Louisiana – Two cases in the Greater New Orleans area
- Maryland – One case in Montgomery County
- Michigan – Three cases in Washtenaw and Oakland counties
- Minnesota -Three cases in Dakota County
- Missouri – One case in Clay County
- New Jersey – One case in Camden County
- New York -Two cases in NYC
- Ohio – One case in Montgomery County
- Pennsylvania – Nine confirmed cases–eight in Philadelphia and one outside of that area
- Virginia – One case in Loudoun County
- Washington – Six cases in Clark and Wahkiakum counties
Measles cases reported by year
SOURCE Centers for Disease Control and Prevention, USA TODAY
The last major outbreak of measles in the U.S. occurred in 2019, when a total of 1,249 measles cases and 22 measles outbreaks were reported in the United States between Jan. 1 and Oct. 1. According to the CDC, this was the second-highest number of reported outbreaks since measles was declared eliminated in the United States in 2000 and the highest in a single year since 1992.
Many of these cases came from an outbreak in New York City. Of the cases, 1,107, or 89%, were in patients who were unvaccinated or had an unknown vaccination status.
Children receive MMR vaccines as part of the regular course between the ages of 12 and 15 months for the first dose and ages 4 to 6 for the second. The vaccine protects against measles, mumps, and rubella and is 97% effective at preventing measles when both doses are given.
The CDC also says that 3 of 100 people that receive two doses of MMR can still get measles if exposed to the virus; however, this usually leads to “milder illness.” This group of vaccinated people are also less likely to spread the disease to others, the CDC added.
Measles Symptoms
According to the CDC, measles symptoms appear 7 to 14 days after contact with the virus and typically include high fever, cough, runny nose and watery eyes. Measles rash appears 3 to 5 days after the onset of the first symptoms.
Other signs and symptoms of measles include:
- High fever
- Cough
- Runny nose and sneezing
- Red, watery eyes
- Loss of appetite, diarrhea
- Reddish-brown rash that can spread across the entire body
- Koplik spots, tiny white spots that may appear inside the mouth two to three days after symptoms begin
- Small raised bumps may also appear on top of the flat red spots (the spots may become joined together as they spread from the head to the rest of the body)
- When the rash appears, a person’s fever may spike to more than 104 degrees Fahrenheit