Enlarge / A US child infected with measles during a 2024 outbreak. The child’s cheek shows the characteristic rash associated with this viral infection. (credit: CDC)

With one of the highest vaccine exemption rates in the country, Oregon is experiencing its largest measles outbreak in decades. This year's count is now higher than anything seen since 2000, when the Centers for Disease Control and Prevention declared the highly contagious virus eliminated from the US.

Since the start of the year, Oregon has tallied 31 cases of measles, all in unvaccinated people. The cases have been accumulating in sustained waves of transmission since mid-June.

Last month, when the outbreak tally was still in the 20s, health officials noted that it was nearing a state record set in 2019. There were 28 cases that year, which were linked to a large outbreak across the border in Washington state. But, with that record now surpassed, the state is in pre-elimination territory.

Enlarge / An MMR and VAR vaccine ready for a pediatric vaccination at Kaiser Permanente East Medical offices in Denver in 2015. (credit: Getty | Joe Amon)

For years, the US Centers for Disease Control and Prevention has bluntly stated the truth: "Vaccines do not cause autism," the agency affirms on its website. Yet, nearly a quarter of Americans still don't believe it.

In an April 2024 survey by the Annenberg Public Policy Center (APPC) of the University of Pennsylvania, 24 percent of US adults denied or disputed that the CDC ever said that. Specifically, the survey asked them to assess the accuracy of the statement that the CDC has said there is no evidence linking vaccines to autism. Six percent called the statement "very inaccurate," and 18 percent said it was "somewhat inaccurate." An additional 3 percent responded that they were "not sure." Of the remaining 73 percent, only 41 percent considered it "very accurate," and 32 percent said it was "somewhat accurate."

The results are largely unchanged from responses in 2018 when survey respondents were asked the same question. In that year, 26 percent of adults reported that the statement was "very inaccurate" or "somewhat inaccurate."