Pennsylvania measles outbreak surpasses 1,000 cases

PHILADELPHIA - Pennsylvania reached a grim milestone on Tuesday, surpassing 1,000 measles cases this year as the state finds itself at the center of its worst years for measles in decades.

What we know:

Health officials say Pennsylvania’s current outbreak started in April, west of Philadelphia. There have been 1,004 cases, including 198 hospitalizations and five deaths, state officials said.

Health experts attribute such outbreaks to low vaccination rates.

Big picture view:

The U.S. is enduring its worst year for measles since 1991, with nearly 3,900 reported cases, according to the CDC. The nation has seen eight reported measles-associated deaths in the past two years — more than the combined total of reported deaths over the previous three decades.

Since the beginning of last year, large outbreaks have been reported in several states, including Texas and Utah, as well as South Carolina, which had the largest with 997 cases reported.

It’s been decades since a U.S. state has seen an outbreak surpass 1,000 cases, stretching back to a multiyear outbreak in New York City in the early 1990s that infected more than 4,500 people.

The nation eliminated the domestic spread of measles in 2000 by maintaining high vaccination rates, but those rates have fallen in recent years to below the 95% coverage needed to prevent outbreaks.

The backstory:

Measles is highly contagious. It spreads when people who have it breathe, cough or sneeze, and through contaminated surfaces. It also can linger in the air for two hours. Up to 9 out of 10 people who are susceptible will get the virus if exposed, according to the Centers for Disease Control and Prevention.