This story is part of a partnership between MedPage Today and VICE News.
The first death of an American measles patient in more than a decade has rekindled discussions about vaccination coverage that were sparked earlier this year after an outbreak linked to Disneyland in California drew attention to the vulnerability of children who had not been vaccinated against the disease.
Health officials told VICE News that though the woman who died earlier this year in Washington State was likely vaccinated, her immune system was compromised due to other health problems and medications.
The woman, who remains unnamed, became the first person to die of the measles since 2003, according to the Washington State Department of Health. She likely caught the virus while visiting a medical clinic in Clallam County, where another woman later developed a rash and was diagnosed with measles.
Although the deceased woman's mother recalled that she had been immunized against the virus, she couldn't find a medical record or remember when the woman was vaccinated, Washington State Department of Health spokesman Donn Moyer told VICE News.
The woman was given an antibody test after she learned that she had possibly been exposed to the measles virus, and doctors determined she had "adequate antibodies for a person with a fully functioning immune system to be protected against measles," Moyer said.
"Regrettably, she did not have a fully functional immune system, as her immune system was suppressed by medications for other health conditions," he said. "This made her particularly vulnerable."
The woman's official cause of death was pneumonia due to measles, according to the state health department. She did not have the telltale measles rash, and she was diagnosed with the illness after her death.
The department has stressed that this case demonstrates the importance of "herd immunity," in which the chances of an outbreak of a contagious disease are limited because a critical proportion of a population has been immunized against it.
"This tragic situation illustrates the importance of immunizing as many people as possible to provide a high level of community protection against measles," state health officials said in a statement announcing the death. "People with compromised immune systems often cannot be vaccinated against measles. Even when vaccinated, they may not have a good immune response when exposed to disease; they may be especially vulnerable to disease outbreaks."
Clallam County had been experiencing an outbreak at the time the deceased woman is believed to have been exposed to the virus there, state officials noted.
According to state immunization recordsfor the 2014-15 school year, between 3 and 4 percent of Clallam County kindergartners were exempt from immunizations, which is lower than many other counties in the state. But data suggests that only between 68 percent and 77 percent of them had complete vaccinations, which also pegged Clallam as among the most non-compliant.
Iva Burks, an administrator at the Clallam County Department of Health and Human Services, said the state data was not reliable, however, because many of the county's schools had difficulty submitting data to the state department of health and were not reflected in its immunization rates.
Including the deceased woman, there have been six measles cases in the county from late January through April 19, Burks told VICE News. She said that her department has administered hundreds of no-cost vaccinations, and noted that there has been an increased effort by local healthcare providers and school nurses to get students up-to-date on their vaccinations as a result of the outbreak.
Measles have been front and center in the news this year thanks to the largest multi-state outbreak in recent memory started at Disneyland last winter. The outbreak prompted the California legislature to pass a bill that eliminated the state's "personal belief exemptions" for vaccinating children, allowing only medical exemptions. The bill was signed into law last week.
There have been 178 measles cases in 24 states as part of five separate outbreaks from January 1 through June 26, according to the Centers for Disease Control and Prevention (CDC). At least 125 of these cases were linked to the outbreak that began at Disneyland.
"The measles virus is thought to be the most transmissible virus we know," Dr. William Schaffner, chief of preventive medicine at Vanderbilt University in Nashville, Tennessee, told VICE News.
For every single case, the airborne virus can typically infect 12 to 18 other people.Schaffner said that the virus can linger in a room for up to two hours after a contagious person has vacated.
"That's an extraordinarily infectious virus, much more infectious than the flu," he remarked.
Schaffner added that people on certain medications, like steroids or chemotherapy; people with certain types of cancer, like leukemia; and people with immune deficiencies are most likely to benefit from herd immunity because their immune systems aren't working properly.
"These patients — the ones who are immunocompromised — essentially depend on others around them to receive vaccines to maintain what is referred to as herd immunity," said Dr. Robert Glatter, an emergency physician at Lenox Hill Hospital in New York City. This also helps protect babies under a year old, who are too young to be vaccinated. "The bottom line is that we have a responsibility for the health of others in our community, and the most effective way we can help to safeguard their health is by getting vaccinated."
In the 10 years before the measles vaccine became available in 1963, between 400 and 500 children died of the measles each year, according to the CDC. The vaccine, which is given in two doses, is 97 percent effective after the second dose.
Measles had been eliminated from the US in 2000, with sporadic cases occurring as the result of travel to and from countries where it was still endemic or where outbreaks were occurring.
But thanks to a combination of foreign measles outbreaks, such as the ongoing outbreak in the Philippines and increasing numbers of parents who chose not to vaccinate their children over the last decade, measles cases have again been on the rise, according to the CDC. The US had 668 reported cases in 2014, including 383 as part of a large outbreak linked to unvaccinated Amish populations in Ohio.
The country's last spate of measles deaths occurred in 2003, when two people died from the virus. One victim was a 13-year-old girl who had recently undergone a bone marrow transplant, requiring her to be immunosuppressed to prevent rejection. The other was a 75-year-old international traveler who was infected in Israel. The girl died of measles encephalitis and the other victim had measles pneumonitis and encephalopathy. Encephalitis, or swelling of the brain, is a rare but life-threatening complication of measles.
Follow Sydney Lupkin on Twitter: @slupkin