Measles Update: 3,471 U.S. Cases in 2026
⚠ Measles Update: National, Pennsylvania, and New Jersey
Updated September 25, 2026. CDC reports 3,471 confirmed measles cases in the United States so far in 2026 (data as of September 17), already more than the 2,289 cases reported in all of 2025. In neighboring Pennsylvania, 835 cases have been confirmed across 39 counties (state health department, September 23). New Jersey has reported 1 confirmed case this year and lists no active exposure locations (New Jersey Department of Health, September 21).
If you have a baby or young child, measles headlines can be unsettling. This guide gathers the most recent official numbers in one place, explains what they mean for families in Mercer County and nearby towns, and walks through the practical steps: when the MMR vaccine is given, what to do if your baby is too young, which symptoms to watch for, and how to reach us. Our goal is to give you clear information so you can make the best decisions for your family.
The Latest Numbers
Across the United States (CDC, as of September 17, 2026)
- 3,471 confirmed cases in total: 3,454 reported by 47 jurisdictions, including New Jersey, and 17 among international visitors
- 39 new outbreaks (3 or more related cases) reported in 2026; 95% of cases are linked to an outbreak
- Children and teens make up most cases: 629 cases (18%) are in children under 5, and 1,519 (44%) are in children and teens ages 5 to 19
- 301 people (9%) have been hospitalized, including 13% of children under 5 who had measles (83 of 629)
- 95% of cases were in people who were unvaccinated or whose vaccination status was unknown; 3% had one MMR dose and 3% had two
- 1 death is listed on CDC's national dashboard for 2026, a number CDC notes may change as reviews are completed (3 deaths were reported in 2025)
For context, the 2,289 cases reported in 2025 were the most in more than three decades, and 2026 passed that total in late July. Weekly case counts rose again through August. CDC updates its national numbers weekly, and state health departments often have more current local information.
Close to home: Pennsylvania and Philadelphia
Pennsylvania currently has the largest measles outbreak in the country. As of September 23, the Pennsylvania Department of Health reports:
- 835 confirmed cases in 39 counties, including 43 new cases since its September 21 update
- 164 hospitalizations
- 4 confirmed measles-associated deaths, counted under Pennsylvania's own definition. This is why the state's figure is higher than the single death on CDC's national dashboard, which is still being updated
- 4 cases (less than 1%) among people who had been vaccinated
Lancaster County has reported more than 300 of those cases. In Philadelphia, the Department of Public Health has warned of possible exposures at Children's Hospital of Philadelphia (CHOP) on September 11 and at Philadelphia International Airport (Terminals B and F and connecting areas) on September 13 and 14. If your family was in those places at those times, check the Philadelphia Department of Public Health for exact times and call us.
New Jersey
As of its September 21 update, the New Jersey Department of Health reports 1 confirmed measles case in 2026 and no known active exposure locations. Earlier this year, the state also issued advisories about exposures linked to out-of-state visitors and a measles detection in wastewater. Risk in New Jersey remains low right now, but many local families travel to Pennsylvania or fly out of Philadelphia, so it is a good time to confirm your child's MMR status.
Where Vaccination Rates Stand
Measles is one of the most contagious diseases known. Public health experts set a goal of 95% MMR coverage among kindergartners because that level helps keep the virus from spreading through a community, protecting babies and others who cannot be vaccinated. CDC's most recent kindergarten data, for the 2025-2026 school year (published August 2026), show:
- National MMR coverage: 92.4%, down slightly from 92.5% the year before. About 280,000 kindergartners did not have documentation of completing both MMR doses
- National exemptions: 4.2%, up from 3.6%, with exemptions rising in 41 states and D.C.
- New Jersey MMR coverage: 92.5%, down from 92.8% the year before
- New Jersey exemptions: 5.7% of kindergartners, up from 4.7%
Behind every number is a family with its own questions and circumstances. If you have concerns about vaccines, or if your child fell behind for any reason, we welcome that conversation. We are happy to walk through the research, the schedule, and your child's specific situation without pressure.
Why Babies and Young Children Need Extra Attention
Young children, especially those under 5, are more likely to have serious complications from measles. Babies younger than 12 months are usually too young for the routine MMR dose, so they depend on the people around them being protected. Complications can include:
- Ear infections and diarrhea, which are the most common
- Pneumonia, the most common cause of measles-related death in young children
- Encephalitis (brain swelling), in about 1 in 1,000 children with measles
- Death in about 1 to 3 of every 1,000 children who get measles, even with the best care
The MMR Vaccine: Timing for Your Child
CDC recommends two doses of the measles, mumps, and rubella (MMR) vaccine for every child:
- First dose: 12 to 15 months
- Second dose: 4 to 6 years
One dose is about 93% effective at preventing measles, and two doses are about 97% effective. Protection is usually lifelong. Children may get the combined MMRV vaccine (which also covers chickenpox) instead.
If your baby is 6 to 11 months old
CDC recommends an early MMR dose for infants 6 to 11 months old before international travel. During outbreaks, public health authorities may also recommend an early dose for infants at risk of exposure. An early dose gives short-term protection but does not count toward the routine series, so your baby will still get two more doses after the first birthday. If you are planning a trip, including to an area with active spread, call us a few weeks ahead so we can talk through timing.
If your child is behind or you are not sure
It is never too late to catch up. Doses can be given at any age once your child is at least 12 months old, as long as they are 28 days apart. If you cannot find your child's records, call us and we can check what we have on file or look up New Jersey immunization registry records. Parents and caregivers should also check their own records, since adults around a baby help protect them too.
Signs and Symptoms of Measles
Symptoms usually start 7 to 14 days after exposure (and can take up to 21 days). Measles often begins like a bad cold:
- High fever, which may go above 104°F
- Cough
- Runny nose
- Red, watery eyes
- Tiny white spots inside the mouth (Koplik spots) 2 to 3 days after symptoms begin
- A red, blotchy rash 3 to 5 days after symptoms begin, usually starting at the hairline and face and spreading down the body
A person with measles can spread it from 4 days before through 4 days after the rash appears. The virus spreads through the air and can linger in a room for up to 2 hours after an infected person leaves. Up to 9 out of 10 people who are not protected will catch it after close contact.
Please call before you come in.
If you think your child has measles or was exposed, and it is not an emergency, call us at (609) 808-3123 before visiting our office or an urgent care. That lets us arrange a way to see your child without exposing babies and other patients in the waiting room. In an emergency, never delay care: call 911 or go to the ER, and tell them measles is possible.
When to Call Us
Please call our office if your child:
- Has a fever and a rash, especially after travel or a known exposure
- Was exposed to someone with measles and is not fully vaccinated or is under 12 months old
- Has cold-like symptoms with red, watery eyes and a high fever that is not improving
- Has been diagnosed with measles and seems to be getting worse, is drinking less, or has ear pain
Timing matters after an exposure. For someone who is not fully protected, an MMR dose within 72 hours, or immune globulin within 6 days for infants and certain high-risk people, can prevent measles or make it milder.
If it's an emergency, call 911 or go to your nearest ER.
Seek emergency care for trouble breathing, a seizure, unusual sleepiness or difficulty waking, confusion, or signs of dehydration such as no wet diaper in 8 hours. If you can, tell the 911 dispatcher or ER staff that measles is possible so they can prepare.
Treatment and Care at Home
There is no specific antiviral medicine for measles. Care focuses on rest, fluids, fever control, and watching for complications. Please do not give high-dose vitamin A on your own; doctors use it only in specific situations and at carefully measured doses. Children with measles need to stay home from school, daycare, and activities until at least 4 days after the rash appears, and we will guide you on when it is safe to return.
Common Questions from Parents
How many measles cases are there in New Jersey right now?
As of the New Jersey Department of Health's September 21, 2026 update, New Jersey has reported 1 confirmed measles case in 2026 and lists no active exposure locations. Neighboring Pennsylvania has reported 835 cases as of September 23, so families who travel to Pennsylvania or through Philadelphia should know the symptoms and check their MMR records.
When does my child get the MMR vaccine?
CDC recommends two doses of MMR for all children: the first at 12 to 15 months and the second at 4 to 6 years. Children may get MMRV (which also covers chickenpox) instead. If your child is behind, doses can be caught up at any age as long as they are at least 28 days apart.
Can my baby get the MMR vaccine before 12 months?
Yes, in certain situations. CDC recommends one early MMR dose for infants 6 to 11 months old before international travel, and public health authorities may recommend an early dose for infants at risk of exposure during an outbreak. An early dose does not replace the routine schedule, so your baby still needs two more doses after the first birthday. Call us before any trip so we can plan the timing together.
What should I do if I think my child was exposed to measles?
Call our office before coming in so we can protect other patients, especially babies too young to be vaccinated. For someone who is not fully protected, an MMR dose within 72 hours of exposure, or immune globulin within 6 days for infants and certain high-risk people, can prevent measles or make it milder. We will check your child's records and guide you on next steps and on which symptoms to watch for over the next 21 days.
My child has had both MMR doses. Are they protected?
Two MMR doses are about 97% effective at preventing measles, and protection is usually lifelong. No vaccine is perfect, so a small number of fully vaccinated people can still get measles, but their illness tends to be milder and they are less likely to spread it. Children with two documented doses do not need an extra dose unless public health officials recommend one.
Questions About Your Child's MMR Status?
Whether you want to confirm your child is up to date, plan an early dose before travel, catch up on a missed dose, or simply talk through your questions, we are here to help.
Call us at (609) 808-3123 during office hours:
- Monday – Friday: 9:30 AM – 5:30 PM
- Saturday: 9:30 AM – 12:30 PM
Sources
Numbers change quickly during an outbreak. Each figure above is labeled with its date; for the most current information, check these official sources:
- CDC: Measles Cases and Outbreaks (national data as of September 17, 2026)
- Pennsylvania Department of Health: Measles (statewide update of September 23, 2026)
- New Jersey Department of Health: Measles (update of September 21, 2026)
- CDC SchoolVaxView: Kindergarten Vaccination Coverage and Exemptions (2025-2026 school year)
- CDC: Measles Vaccination
This article is for general education and is not a substitute for medical advice for your child. Please call our office with questions about your child's health.