Editor’s note: For more AAP News coverage of the measles outbreak, visit https://bit.ly/Measles2025.
Measles has spread to nearly half of U.S. states as the number of confirmed cases continues to grow. At the same time, pertussis cases and pediatric flu deaths continue to rise, according to the latest government reports.
As of April 10, the Centers for Disease Control and Prevention (CDC) has reported 712 confirmed cases of measles. The total likely is an undercount as it may represent only those ill enough to seek medical care.
The outbreak includes three deaths. Two of the deaths were unvaccinated school-age children in Texas who had no underlying conditions. They are the first measles-related deaths in the United States in a decade.
Seventy-nine people have been hospitalized with measles, including 45 children under age 5 and 20 children ages 5 to 19 years. Of the total number of cases, 97% include unvaccinated individuals or those having an unknown vaccination status.
Cases have been reported in Alaska, Arkansas, California, Colorado, Florida, Georgia, Hawaii, Indiana, Kansas, Kentucky, Maryland, Michigan, Minnesota, New Jersey, New Mexico, New York City, New York state, Ohio, Oklahoma, Pennsylvania, Rhode Island, Tennessee, Texas, Vermont and Washington.
There have been seven outbreaks (defined as three or more related cases) this year, and 93% of total cases are outbreak-associated.
The largest outbreak continues to be in Texas, where 541 cases have been reported as of April 11, according to the Texas Department of State Health Services. Fifty-eight cases have been reported in neighboring New Mexico, according to the New Mexico Department of Health. Kansas (32), Ohio (10) and Indiana (6) are among states that also have reported cases.
The AAP and CDC recommend health care professionals ensure all patients are up to date on measles-mumps-rubella (MMR) vaccination to prevent infection and spread. The first dose is given at 12-15 months of age, and the second is given at 4-6 years of age. One dose of MMR is 93% effective against measles, and two doses are 97% effective.
The measles virus is transmitted by contact with infectious droplets or by airborne spread when an infected person breathes, coughs or sneezes. Measles virus can remain infectious in the air up to two hours after an infected person leaves an area.
Illness onset (high fever, cough, runny nose and red, watery eyes) begins a week or two after someone is exposed. A few days later, a rash breaks out as flat, red spots on the face and then spreads down the neck and trunk to the rest of the body. A person is contagious about four days before the rash appears to four days after.
Other measles symptoms may include small spots in the cheek area inside the mouth, diarrhea and ear infection. Measles can lead to pneumonia, swelling of the brain, deafness, intellectual disability and death.
Measles was officially declared eliminated from the United States in 2000, however, declining vaccination rates have led to multiple outbreaks in recent years. The country will lose its measles elimination status if endemic measles virus transmission continues in a defined geographic area for 12 months or more.
Pertussis cases more than double
According to a provisional report published April 5, 4,125 more cases of pertussis, aka whooping cough, have been reported compared to this time last year.
The CDC counts 7,586 cases of whooping cough in Week 14 ending April 5 compared to 3,461 in Week 14 of 2024.
Last year saw a sharp spike in whooping cough cases nationwide, according to CDC data, with 35,435 cases reported. That’s over five times more than 2023’s total of 7,063, which was a significant increase itself – 3,044 and 2,116 pertussis cases were reported by the CDC in 2022 and 2021, respectively.
No new pediatric pertussis deaths were reported this week. The Louisiana Office of the Surgeon General confirmed on March 27 that two infants died of whooping cough within the previous six months. The state’s last infant death due to pertussis was in 2018.
Vaccination is the best prevention against whooping cough. The immunization schedule calls for the first dose of the diphtheria, tetanus and acellular pertussis (DTaP) vaccine to be given at 2 months of age. Subsequent doses are given at 4 months and 6 months, with boosters at 15-18 months and 4-6 years. A tetanus, diphtheria and pertussis (Tdap) booster is recommended at 11-12 years old.
To prevent adult transmission to babies, people in close contact with infants younger than 1 year should get a booster, and pregnant people should get the vaccine during the third trimester.
Pertussis is a highly contagious infection of the breathing passages. Symptoms vary by age, preexisting conditions and vaccination status, but the main sign is strong coughing. Deep, fast breaths taken between those coughs produce a “whooping” sound. Infants younger than 1 year who contract pertussis are at risk of developing pneumonia, seizures and other complications.
20 more pediatric flu deaths
The CDC on Friday reported 20 more pediatric flu deaths for the week ending April 5. That’s 11 more than the previous week, and brings the total for the 2024-’25 flu season to 188. No new human cases of avian influenza were reported.
All other flu activity continues to decline since February’s peak, including outpatient visits and hospital admissions for respiratory illness and positive lab tests for influenza.
The newly reported pediatric deaths occurred between Dec. 21, 2024, and March 29. Nineteen of those were associated with influenza A viruses; the remaining case was associated with influenza B.
National outpatient visits are below baseline. No jurisdictions on the CDC’s ILINet map, which depicts the severity of influenza-like illness across the nation, reported high or very high flu activity for the week ending April 5. Three regions within the Department of Health and Human Services are above their own baselines.
Flu activity is expected to continue for several more weeks, and the CDC recommends that everyone over 6 months old get a flu shot this season as long as that activity continues. Flu shots typically begin to protect against infection two weeks after administration.
The CDC estimates there have been at least 46 million illnesses, 590,000 hospitalizations and 26,000 deaths related to the flu this season.
