The U.S. added another 194 measles cases last week, and the outbreak in Pennsylvania is showing no signs of slowing down. CIDRAP has the news.

The case number across the country stands at 4,080, which represents the highest number of measles cases in the U.S. since 1991. The nation is on track to double last year’s 2,289 cases before the end of the year. The CDC said there have been 42 outbreaks so far this year, and 96% of confirmed cases are outbreak-associated.

Of the cases this year, 17% are in children under the age of 5. Ten percent of case-patients have been hospitalized. However, the CDC only lists two deaths this year from measles, despite Pennsylvania alone identifying five measles-associated deaths. The vast majority of the cases (95%) are in people who are unvaccinated or whose vaccination status is unknown.

Pennsylvania’s outbreak shows no signs of slowing. The state has 1,136 confirmed cases; 99% of patients are unvaccinated, and the hospitalization rate is 19%. The five deaths might indicate that the outbreak is even larger than reported. 67% of the state’s cases have been in adults, which is unusual.

The CDC is sending $100 million to states to help with outbreak responses. CDC director Erica Schwartz reiterated that the MMR vaccine is “absolutely safe [and] absolutely effective.”