by Measles, a highly contagious but preventable disease, is resurfacing in pockets of the United States, warning of the dangers of strengthening the anti-vaccination movement.
The Centers for Disease Control and Prevention has recorded more cases this year than the 58 high in all of 2023, though the agency is not expected to release exact numbers until Friday. On Monday, the agency advised health care providers to ensure that unvaccinated patients, especially those traveling internationally, stay current on their immunizations.
The number of cases is likely to continue to rise due to a sharp spike in measles worldwide, as well as spring travel to certain regions with outbreaks, including Britain, said Dr. Manisha Patel, chief medical officer at the CDC’s division of respiratory diseases.
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Almost all cases in the United States so far involve unvaccinated travelers. “We will not see widespread cases of measles going around the country,” Patel said. “But we expect additional cases and outbreaks to occur.”
Measles is one of the most contagious diseases; each infected person can spread the virus to as many as 18 other people. The virus is airborne and can remain airborne for up to two hours after an infected person leaves the room, spreading rapidly through homes, schools and childcare facilities.
In Chicago, one case of measles at a migrant shelter increased to 13, prompting the CDC to send staff to help contain the outbreak. (Two additional cases in the city appear to be unrelated.)
In Florida, seven elementary school students contracted measles even as the state’s surgeon general, Dr. Joseph Ladapo, left it up to parents to decide whether unvaccinated children should attend school.
In southwest Washington, officials identified measles in six unvaccinated adults of a family living in two counties. And in Arizona, an international traveler with measles ate at a restaurant and transmitted the virus to at least two others.
Measles was eliminated in the United States in 2000, and American children generally must be immunized to attend school. But sporadic cases lead to larger outbreaks every few years. But now due to a decline in vaccination rates, exacerbated by the coronavirus pandemic, experts are worried about a resurgence.
When the vaccines are running out, “the first disease to appear is measles, because it is very contagious,” said Dr. Saad Omer, dean of the O’Donnell School of Public Health at UT Southwestern in Dallas.
According to the CDC, nine out of 10 unvaccinated people will come into close contact with an infected measles patient.
Measles is much less deadly in countries with high immunization rates and good medical care. Fewer than 3 in 1,000 American children with measles will die as a result of serious complications such as pneumonia or encephalitis, swelling of the brain.
Still, about 1 in 5 people with measles may end up in hospital.
Because widespread outbreaks of measles are rare, most Americans, including doctors, may not recognize the bright red rash that accompanies respiratory symptoms in a measles infection. They may have forgotten the impact of the disease on individuals and communities.
“Most of our people in the local health department have never seen a measles outbreak,” said Dr. Christine Hahn, Idaho’s state public health researcher, who had a small cluster of cases last year.
“It’s going to be a big challenge for us to respond if and when we get our next outbreak,” she said.
Before the introduction of the first measles vaccine in the 1960s, the disease killed an estimated 2.6 million people worldwide each year. But perhaps his overall impact was greater.
Measles suppresses the immune system, allowing other pathogens to enter the body more easily. A 2015 study estimated that measles may account for up to half of all deaths in children from infectious diseases.
For about a month after the acute illness, measles can stun the body’s first response to bacteria and other viruses, said Dr. Michael Mina, chief science officer of digital health company eMed and a former public health researcher at Harvard School TH Chan. Public Health.
That leaves patients “very vulnerable to bacterial pneumonia and other things,” said Mina, who was the lead author of the 2015 study.
“It’s very risky for people in those first few weeks after measles,” he said.
The virus also induces amnesia of the immune system. The body usually “remembers” the bacteria and viruses it has fought before. Mina and her colleagues showed in 2019 that people with measles lose between 11% and 73% of their hard-won immune stores, a loss that can last for years.
That does not mean that the body no longer recognizes those pathogens at all, but it reduces the arsenal of weapons available to fight them.
“People should know that if they choose not to vaccinate, that’s the situation they and their family are in,” Mina said.
The CDC recommends that you get the first dose of the measles vaccine after 12 months of age, and the second dose between 4 and 6 years of age. Even a single dose of the vaccine is 93% effective. According to the World Health Organization, measles vaccination has prevented 56 million deaths between 2000 and 2021.
Vaccination rates in the United States have shown a significant, if small, decline to 93% in the 2022-23 school year from 95% in 2019-20 – the level needed to protect everyone in the community. Vaccination exemption rates increased in 40 states and the District of Columbia.
In a survey last year, just over half of Republicans said public schools should require measles vaccinations, compared to about 80% before the pandemic. (Support for vaccines among Democrats was steady.)
While vaccination rates at the national or state level may be high, there may be pockets of low immunity that provide tinder for the measles virus, Omer said.
If there are enough unvaccinated cases to fuel an outbreak, even those who are vaccinated but may have weakened immunity are vulnerable, he said.
In Idaho, 12% of kindergarten age children do not have a vaccination record. Part of the gap is a result of parents being unable or unwilling to share records with schools, not because their children are not immunized, Hahn said.
Still, online schools, which have grown through the pandemic and remain popular in the state, have some of the highest rates of vaccine exemptions, she said.
In September, a young Idaho man brought back measles after international travel and became ill enough to be hospitalized. Along the way, he exposed fellow passengers on two flights, dozens of healthcare workers and patients, and nine unvaccinated family members. All nine developed measles.
Idaho got “lucky” with the outbreak because the family lived in a remote area, Hahn said. But there are probably many other areas in the state where it would be difficult to contain an outbreak.
“We’ve got plenty of tinder, if you like,” she said.
Several large outbreaks have erupted in recent years among large clusters of unvaccinated people, including the Amish in Ohio and the Orthodox Jewish community in New York City.
In September 2018, one unvaccinated child returned from Israel to New York, carrying measles virus picked up during an outbreak in that country.
Although the city has high vaccination rates, that single case sparked an outbreak that lasted nearly 10 months, the largest in the country in decades. The city has declared a public health emergency for the first time in over 100 years.
“We had more than 100 transmission chains,” said Dr. Oxiris Barbot, then the city’s health commissioner, and who is now president and CEO of United Hospital Fund.
“It was a challenge to keep that straight,” she said. “And that we had to investigate over 20,000 exposures like that, that was huge.”
Working with community leaders, city officials urgently administered about 200,000 doses of vaccine. More than 550 city staff members were involved in the response, and the final cost to the city’s health department was $8 million.
The CDC is working with state and local health departments to identify pockets of low vaccination and prepare them for outbreaks, Patel said. The agency is also training health care providers to recognize the symptoms of measles, especially in patients with a history of international travel.
Measles is a slippery enemy, but public health is very familiar with the tools needed to contain it: screening, contact tracing and vaccinating the susceptible.
“We are not helpless spectators,” Omer said. “The focus needs to be public health meat and potatoes.”
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