US measles cases have climbed past 5,000 for the first time in more than three decades, reaching 5,182 so far in 2026, the Centers for Disease Control and Prevention (CDC) said on Friday. The total, counted through November 5, is up 330 cases from the CDC's previous update and comes in a week in which three Americans died of measles: a Wisconsin infant, a Pennsylvania resident and a child in Lewis County, New York. Four measles-associated deaths have now been reported this year, already more than the three recorded in all of 2025.

Key Points

• The CDC reported 5,182 measles cases in the US as of November 5, 2026, up 330 from the previous update — the highest annual total since 1991.
• Some 562 people, or 11 percent of all cases, have been hospitalised with measles this year.
• Four measles-associated deaths have been reported in 2026, above the three deaths recorded in all of 2025.
• 96 percent are in people unvaccinated or with unknown status; 96 percent are linked to 43 outbreaks this year.
• Three people died of measles this week: an infant in Wisconsin, a Pennsylvania resident and a child in Lewis County, New York.

What Happened

The CDC published its latest weekly measles update on Friday, November 6, putting the national case count at 5,182 as of November 5. The rise of 330 cases is one of the largest weekly jumps of the year, lifting the 2026 total well past the 4,852 cases reported as of October 29. For comparison, the United States recorded 2,289 measles cases in all of 2025.

Hospitalisations now stand at 562, or 11 percent of all reported cases. Measles can cause pneumonia, brain swelling and death, and it hits hardest in young children and people with weakened immune systems. Three of this year's four deaths came in a single week: the Wisconsin infant was the state's first measles death in more than 35 years; the Pennsylvania resident was the state's sixth death of the outbreak; and the Lewis County child was New York's first measles death in 30 years.

Background: How the Outbreak Grew

Measles was declared eliminated in the United States in 2000, meaning the virus no longer spread continuously within the country. What changed is coverage: the share of kindergarten children vaccinated against measles fell from 95.2 percent in the 2019-20 school year to 92.4 percent in 2025-26, below the roughly 95 percent threshold needed to stop the virus spreading in a community. Around 280,000 kindergarten children are now estimated to be at risk.

The 2026 surge has been driven by large state outbreaks. Pennsylvania has reported 1,467 cases across 44 counties, with community transmission in 16 of them. Kentucky has reported 204 cases in its largest surge since 1991.

US Measles Cases: Who Is Getting Sick

The age breakdown shows the virus reaching every age group. Adults aged 20 and older account for the largest share, with 2,132 cases. Children and teenagers aged 5 to 19 account for 2,104 cases, and children under 5 for 908. Infants too young to be vaccinated and adults who were never immunised are among the most vulnerable.

Vaccination status is the clearest dividing line: 96 percent of infections this year have been in people unvaccinated or with unknown vaccination status. The measles, mumps and rubella (MMR) vaccine is about 97 percent effective at preventing measles after two doses, according to the CDC, which recommends a first dose at 12 to 15 months and a second at 4 to 6 years.

Reactions and Official Guidance

The CDC continues to urge anyone unsure of their vaccination status to check their records and get vaccinated if needed, and it advises parents to make sure children receive both doses of the MMR vaccine on schedule. The agency has repeatedly said vaccination is the most effective protection against measles and that the vaccine has been used safely for decades.

State health departments in the hardest-hit states have run vaccination drives, opened pop-up clinics and alerted doctors and hospitals to watch for symptoms — high fever, cough, runny nose, red eyes and a rash that usually starts on the face.

Why It Matters

Measles is one of the most contagious diseases known to medicine. An infected person can spread it simply by breathing or coughing in a room, and the virus can linger in the air for up to two hours after the person leaves. Around nine in ten unvaccinated people exposed to measles will catch it, which is why even a small dip in vaccination coverage can produce a large outbreak.

The human cost is already visible: 562 hospitalisations and four deaths, including an infant and a child, from a disease preventable with a vaccine costing a few dollars a dose.

What Happens Next

The CDC will publish its next weekly update on Friday, and health officials will watch whether the weekly increase stays above 300 cases. If it does, the national total will pass 5,500 within two weeks and could approach 6,000 before the end of the year. State health departments in Pennsylvania, Kentucky, Wisconsin and New York are continuing contact tracing and vaccination campaigns.

Parents and adults unsure of their vaccination status can check records with their doctor or state immunisation registry. Health officials say the most important step now is the simplest: two doses of MMR, on schedule, for every child, and a catch-up dose for any adult who never received one.

Frequently Asked Questions

How many measles cases are there in the US in 2026?
The CDC reported 5,182 measles cases in the United States as of November 5, 2026, up 330 from the previous update — the highest annual total since 1991.

How many people have died of measles in the US this year?
Four in 2026, versus three in all of 2025 — three in one week: an infant in Wisconsin, a Pennsylvania resident and a child in Lewis County, New York.

Who is most at risk from measles?
Unvaccinated people, infants too young to be vaccinated, and people with weakened immune systems. Some 96 percent of 2026 cases were in people unvaccinated or with unknown vaccination status.

How effective is the MMR vaccine?
Two doses of MMR are about 97 percent effective at preventing measles, according to the CDC. A first dose is recommended at 12 to 15 months and a second at 4 to 6 years.

Is measles still eliminated in the United States?
Measles was declared eliminated in the US in 2000. Sustained outbreaks can threaten that status, so officials are working to raise vaccination coverage.

Read More on US News Pulse

• US measles cases hit 4,852 as CDC reports 264 new infections nationwide
• Wisconsin infant dies of measles in state's first measles death in over 35 years
• Pennsylvania measles outbreak hits 1,467 cases as sixth death reported

Image: a nurse gives an MMR vaccine to a young child at a US health clinic. Source: CDC / Reuters.