The Centers for Disease Control and Prevention says the number of measles cases in the US jumped again last week.
There are now 839 cases confirmed in 23 states, including 5 in Pennsylvania.
That's the highest number since 1994 and since measles was declared eliminated in the year 2000.
The outbreaks in New York state and southern California continue to grow.
Health officials say misinformation about vaccines is helping outbreaks spread.
Pennsylvania State Senator Daylin Leach (D-Montgomery/Delaware) introduced a bill Monday to get more children vaccinated by eliminating the religious and philosophical exemptions to vaccinations.
Children in Pennsylvania are required by law to receive immunization for diphtheria, tetanus, poliomyelitis, measles (rubeola), rubella, mumps, hepatitis B, chickenpox, whooping cough and meningococcal disease before attending school.
Leach's bill would not affect the medical exemption for children with a pre-existing health problem that conflicts with the immunization.
"The law requires us all to get vaccinated to attend school because that's the only way we can protect the health of students who are medically unable to get a vaccination," Leach said. "Vaccines are safe and they are essential to public health."
Leach introduced the policy's language as Senate Bill 653. Next, the president pro tempore will assign the bill to a senate committee for consideration, at which time the proposal will be numbered and available online. Pennsylvania has seen an increase in the number of exemptions in recent years.
If it drops below 95% (depending on the disease), there's a loss of 'herd immunity,' which protects those who cannot get vaccinated due to pre-existing medical conditions by having vaccinated people all around them.
Meanwhile, authorities in Curacao may allow 28 passengers and crew members off a ship today where a crew member was sick with measles. They were quarantined aboard the Freewinds because of uncertainty about their vaccination status.
The ship is reportedly owned by the Church of Scientology.
Number of measles cases spikes above 800, CDC says