Measles outbreaks across the US continue to add to record case count

There have been an average of 27 new measles cases reported each week since the end of August, according to data from the US Centers for Disease Control and Prevention.

(CNN) — A deadly measles outbreak in Texas ended in August, but outbreaks in other parts of the United States continue to add hundreds of new measles cases to this year’s record national total.

There have been an average of 27 new measles cases reported each week since the end of August, according to data from the US Centers for Disease Control and Prevention. The annual total – now up to 1,563 cases since January – is the highest by a significant margin since measles was declared eliminated in the US a quarter-century ago.

There’s a new outbreak in Ohio, a recent surge in cases in Minnesota and more than 150 unvaccinated schoolchildren in South Carolina are in quarantine because of an ongoing outbreak there.

Before this year, the US had recorded only 10 large measles outbreaks – defined by the CDC as more than 50 related cases – since reaching elimination status in 2000. But an ongoing outbreak along the border between Arizona and Utah is already the third large outbreak this year.

There have been more than 90 confirmed cases related to the outbreak – at least 59 in Arizona and 36 in Utah, according to state health departments – and case counts continue to grow.

Dr. Leisha Nolen, state epidemiologist in Utah, said there is still a lot of opportunity for measles to continue to spread in the area.

“Unfortunately, I think we still have quite a while to go with infections. We know that most of our infections have been localized down towards the southern end of our state, but I think we are starting to see now people get infected even at the very north end of our state,” she said. “So I do think that this is going to continue to bop around and spread in different communities. I suspect we’re in the middle of it.”

Experts say that any amount of measles spread is cause for concern, and large outbreaks highlight the dangers of declining vaccination rates.

“When you have multiple cases happening, particularly with those numbers, it’s only possible because you have susceptible individuals,” said Dr. Scott Harris, president of the Association of State and Territorial Health Officials.

There are measles cases in the US every year, often introduced via international travel, Harris said. But those cases can really multiply only if they’re happening among other people who are unvaccinated – and can multiply at large scale only if large parts of a community are unvaccinated. The Texas outbreak is evidence of this, he said, with state health department data showing that 97% of its cases were among people who had not gotten one or both of the recommended two vaccine doses.

“The story here is: Parents of young children are skeptical about vaccination,” Harris said. “There are lots of reasons why, but if that weren’t the case, this wouldn’t be a story, because we wouldn’t have these outbreaks.”

A record share of US kindergartners had an exemption for a required vaccination in the last school year, and coverage for all reported vaccines – including the measles vaccine – continued on a downward trend, according to the CDC.

Coverage with the measles-mumps-rubella (MMR) vaccine dropped to 92.5%, the latest data shows. Because measles is such a highly contagious disease, public health experts say that at least 95% MMR coverage is needed to prevent spread. Last year marks the fifth year in a row that coverage has been below that target.

In Utah, Nolen says that public health officials have a good grasp on where measles is spreading thanks to wastewater monitoring that can capture virus levels beyond official case counts, and where the risk is elevated due to low vaccination rates.

“In those areas, we try to work with the local health department and the community to get the word out that we know that there is measles in their area and that we really encourage families to consider getting vaccines,” she said. Misinformation has created some vaccine hesitancy, she said, but vaccination rates have ticked up as awareness about the current outbreak has grown.

A separate ongoing outbreak in South Carolina also threatens to grow quickly.

More than 150 unvaccinated children are in quarantine after measles exposures at two schools in the northern part of the state, one public elementary school and one public charter school in Spartanburg County.

“Those schools are following the protocols to exclude these students until the period of potential disease transmission has safely ended,” Dr. Linda Bell, South Carolina’s state epidemiologist, said Thursday. “Those students are identified as having been exposed and not having been vaccinated, and that’s the reason for the exclusion.”

About 90% of people who have been exposed to measles and do not have immune protection from vaccination could get infected, Bell said, and “worst-case scenario” would be that rate of infection among the at-risk students who are being closely monitored for symptoms while in quarantine.

There have been 11 confirmed measles cases in South Carolina this year, including seven associated with the Spartanburg County outbreak since September 25, according to the state health department.

Spartanburg County has one of the lowest school vaccination rates in the state, according to data from the state health department. Last school year, less than 90% of school students there received their required immunizations, which includes two doses of the MMR vaccine. School vaccination coverage has been falling in Spartanburg County for years, as it has across the state and nationwide.

A measles case reported Thursday in Greenville County, South Carolina’s most populous county, is being investigated for a possible link to the Spartanburg outbreak. But the state health department is not aware of any other potentially related cases in other states or jurisdictions, Bell said Thursday.

It’s “incredibly expensive and demanding” for local health departments to respond to measles threats, said Dr. Caitlin Rivers, an epidemiologist and director of the Center for Outbreak Response Innovation at the Johns Hopkins Bloomberg School of Public Health. The organization has worked with health departments from across the country to help them learn from their experiences responding to measles.

“Health departments are already stretched thin by budget constraints and staff attrition. Adding measles outbreaks to their workload is draining the reserves of even the best-resourced departments,” Rivers said. “It’s been hard to understand from the outside what supports the federal government is offering to local responders.”

The CDC has continued to update its measles tracker during the federal government shutdown, even as other surveillance data systems have come to a halt. And local health leaders say they have continued to stay in contact with CDC experts, although they have been warned that response times may be a bit slower.

“Due to a lapse in federal funding, CDC has developed an orderly shutdown plan, ensuring critical public health and safety functions continue without interruption. As found in the plan, CDC and [the Agency for Toxic Substances and Disease Registry] would collect data being reported by states, hospitals, and others, and report out critical information needed for state and local health authorities and providers to track, prevent and treat diseases,” according to a statement from the CDC.

But federal surveillance systems are far from perfect, and experts say that formally reported measles cases in the US are probably a significant undercount, with some estimating that this year’s total could be closer to 5,000 cases.

Current measles outbreak trends are “consistent with an undervaccinated population,” said Dr. Paul Offit, director of the Vaccine Education Center and an attending physician in the Division of Infectious Diseases at Children’s Hospital of Philadelphia. US Department of Health and Human Services Secretary Robert F. Kennedy Jr. has exacerbated problems with both disease surveillance and vaccination rates, he said, by cutting federal health agency workers and failing to fully endorse the MMR vaccine. Instead, as the measles outbreak in Texas spread earlier this year, Kennedy touted unconventional therapies for treatment and said that getting vaccinated is a personal choice.

“We’re in the midst of a measles epidemic,” Offit said. “We should have an administration that stands up clearly and definitively and holds press conferences saying, ‘Vaccinate your children. These are preventable illnesses.’ ”

In a statement to CNN, HHS said that “Secretary Kennedy has been outspoken in his support for the measles vaccine and has encouraged both national and state-level action to address and prevent outbreaks.”

Trust in federal health leadership has suffered under Kennedy, a new poll shows, with most US adults saying they disapprove of the way he’s handled vaccine policy and his role as health secretary overall.

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