Measles cases are surging in Pennsylvania

The big picture: The U.S. has reported at least 2,318 measles cases as of late last week — a 35-year record. The majority of cases are among unvaccinated people.

• None of Pennsylvania's cases this year have involved people who were fully vaccinated.

By the numbers: Pennsylvania has reported 142 measles cases through yesterday — far surpassing last year's total (16).

• That's the state's highest annual total in at least 25 years. The previous high was 17 cases in 2019, the state health department tells Axios.
• Pennsylvania has recorded 26 hospitalizations and no deaths this year.

Zoom in: Lancaster County is the epicenter of Pennsylvania's outbreak, accounting for roughly 60% of cases.

• The county also has some of the state's lowest student vaccination rates.

Other measles hotspots include Lebanon County (20 cases) and Chester County (14 cases).

• Meanwhile, Philadelphia, Delaware and Bucks counties have no reported cases.

Between the lines: Pennsylvania's student vaccination rate was estimated at 92.4% last year, per the CDC — below the herd immunity threshold of 95% that public health authorities say is necessary to contain the virus' spread.

Zoom out: The U.S. has confirmed measles cases across 45 jurisdictions —South Carolina, Utah, Texas, Florida and Arizona have the most reported cases.

• The last time the U.S. recorded more measles cases was in 1991, with 9,643 cases, according to CDC data.

Threat level: Measles symptoms include a cough, high fever and conjunctivitis as well as a telltale rash.

• But symptoms can escalate into complications such as severe ear infections, pneumonia and encephalitis or inflammation of the brain that can lead to permanent brain damage and even death, per Johns Hopkins Medicine.

What we're watching: Amid the alarming spread, Pennsylvania's health department recently launched an online dashboard to track measles cases.