The ongoing US measles outbreak underscores the importance of childhood vaccines-opponents of vaccination notwithstanding, say experts.
The ongoing US measles outbreak underscores the importance of childhood vaccines-opponents of vaccination notwithstanding, say experts.
Drawing heavy traffic from visitors around the world, Disneyland makes an ideal incubator for a major infectious outbreak, says Sheila Fallon Friedlander, MD. She is professor of clinical pediatrics and medicine (dermatology) at the University of California, San Diego.
“And that’s just what happened. It is believed that in December, unvaccinated individuals who had traveled to the Philippines and contracted measles there then visited Disneyland. That led to an outbreak of measles, which has now extended to more than 100 people” in 14 states including California and Arizona.
The park draws an estimated 16 million visitors annually. On any given day, Friedlander says, “People are standing in line, jammed together for an hour or more.” In such an environment, the index patient or patients could easily have spread the extremely infectious measles virus via sneezing and coughing. “The people around him then inhaled or touched a surface where the droplets landed.”
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Measles is the world’s most infectious agent, says Stephen K. Tyring, MD, PhD, clinical professor of dermatology, microbiology/molecular genetics, and internal medicine at the University of Texas Health Science Center, and medical director of the Center for Clinical Studies in Houston.
Not only can the measles virus survive up to 2 hours on a surface or in the air, he explains, but it also takes less of it to cause disease than any other infectious agent. “If you were in a room that a patient with Ebola was in 2 hours ago, you’d have to actually touch the patient’s bodily secretions to get infected-the Ebola virus is not airborne.” However, after a patient with measles coughs or sneezes, “The virus is still at high enough concentration 2 hours later that the next person who hasn’t had measles or been vaccinated has a 90% chance of catching it.”
At Disneyland, says Friedlander, at least half of the reported cases occurred in unvaccinated people. “How did this happen?”
Measles was eradicated in the United States in 2000, say Friedlander and Tyring. However, Friedlander points out, Americans don’t always choose to have their children vaccinated (19 states allow parents to opt out of vaccinations for personal beliefs). If these children travel abroad, she says, “They may become exposed to people who have measles.”
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The current measles outbreak is particularly alarming, says Tyring, because the purported link between vaccines and autism that initially caused parents to abandon vaccines has been discredited. It originated with a publication1 by Andrew Wakefield, who was paid by lawyers to advance the fraudulent claim so they could sue vaccine makers. Subsequently, “Investigators reexamined all these children that Wakefield said got autism after being vaccinated, and they found that it was all a lie,”2 for which he lost his British medical license. Several years later, “We still have people believing the big lie.”
More recently, some parents-and even the occasional physician-oppose vaccination out of concern for potential toxins including aluminum, mercury, antibiotics, and fetal proteins used in various vaccines.
Paradise Valley, Arizona-based cardiologist Jack Wolfson, DO, said on CNN in early 2015, “We cannot sterilize our society. Our children have the right to get infections. We have immune systems for that purpose.” Ultimately, he added, measles is “a benign childhood infection” that most victims survive.
Friedlander and Tyring counter that measles is anything but benign.
Before the measles vaccine became widely used in the United States in the 1960s, says Tyring, measles killed more than 1 million persons globally and permanently injured 4000 in the United States annually. Friedlander adds that the disease can cause pneumonia, encephalitis, and ocular complications, particularly in younger children. Other complications can include ear infections that may cause permanent hearing loss. Rarely, says the Centers for Disease Control and Prevention (CDC), patients who survive measles can develop subacute sclerosing panencephalitis, a fatal disease of the central nervous system, approximately 7 to 10 years later.
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“In 2014,” says Tyring, “there were 644 cases of measles in the United States. We’ve already had more than 100 this year” nationally.
Worldwide, he adds, measles killed more than 1 million children annually at the end of the 20th century. Even now, more than 150,000 children worldwide die annually of measles. Even in the healthiest nations, Tyring says, it’s impossible to predict which patients will develop encephalitis or die from measles.
Most fatalities occur in children too young to undergo vaccination, or living in areas where the vaccine is unavailable. Because of malnutrition, says Tyring, infected children in the Third World are likely to contract bacterial infections atop the measles, leading to viral or bacterial pneumonia and death.
Babies, toddlers, and pregnant women suffer the most serious infections, says Friedlander. “Mortality can be as high as 1 to 2 in 1000 cases, and severe morbidity including encephalitis can occur in 1 in 1000.”
“Since you don’t know who’s going to suffer serious consequences,” says Tyring, “why not vaccinate everybody?”
The vaccine is overwhelmingly safer than the virus, Tyring says. With a serious adverse event (AE) rate of less than 1 per billion recipients, “The vaccine was proven in study after study to be extremely safe.” Independent bodies including the CDC, the Institute of Medicine, and European experts using databases going back to the 1980s have analyzed tens of millions of vaccine records and found no hint of increased risks of serious AEs. Tyring adds, “In 30 years of practice, I’ve never seen or heard of anyone who ever developed serious complications from the vaccine. Those people that say they have are unable to prove the vaccine caused it.”
Even if serious post-measles sequelae were truly the exception, he says, “What parent would want their child sick, home from school, and miserable for 2 weeks?” Actually, public health officials advise parents to keep children with measles home for 3 weeks to reduce the risk of transmission. Meanwhile, says Tyring, the kids can’t do much because light hurts their eyes, and their parents miss work.
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Instructions for the measles vaccine recommend administering it at 1 year of age, followed by a booster at age 4 to 6 years. The first shot confers around 90% protection; the second raises it to 99%, says Tyring.
However, he says, the fact that the vaccine requires 2 shots for maximum protection has led to miscommunication in the media, with some outlets reporting that anyone who has had 1 measles shot doesn’t need a booster. Rather, “The second shot is imperative. The 100-plus cases at Disneyland included a handful of children who had gotten the first shot, but not the second.”
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These children didn’t get as sick as unvaccinated children, says Friedlander, but they can also serve as a source of infection for others. “Even fully vaccinated people can get disease, but it is uncommon. No vaccine is 100% effective, but the measles vaccine comes close.”
Patients can be contagious for 4 days before and 4 days after rash onset, says Friedlander. Often, she says, “People are out coughing and spewing before they even have a rash and know what’s happening.” Other early symptoms include lethargy and coryza.
A few days after the fever, which Tyring says he’s seen as high as 104°F, small white spots called Koplik’s spots, which are pathognomonic for measles, can develop within the mouth. They’re difficult to pick up, says Friedlander, and they don’t last long, fading right before the rash occurs, says Tyring.
With the nonspecific early symptoms of measles, Tyring notes, “Hardly anybody ever looks in the patient’s mouth. It’s only when the rash appears, starting behind the ears, and starts progressing down to the trunk and extremities that most people would recognize measles.” Younger doctors may not recognize measles, he adds, because those trained in the 21st century have never seen a case.
Among the lay public, he says, “The ignorance about vaccination may not stop with measles.” Any disease that vaccines have rendered rare in America could resurge because it’s still common elsewhere. Also, many parents are complacent because “they grew up without seeing anyone get very sick or die of these diseases.”
Skipping the measles vaccine instantly raises the risk of mumps and rubella, the 2 other vaccines that come with it, says Tyring. Chicken pox vaccination rates also may decline, he adds. Over the past 2 years, he says, “Thousands of West Coast children have contracted whooping cough [pertussis] because their parents refused the vaccine.” According to the California Department of Public Health, 3 infants died from pertussis contracted in 2014, and 1 infant has died from pertussis contracted in 2015.
Addressing such challenges will require physicians and media members to stick meticulously to the facts regarding vaccine-related matters in the future, says Tyring. “Vaccines have been the greatest breakthrough in the history of medicine. They have saved more lives than any other intervention. The ignorance about vaccination is a tragedy.”
To prevent many deaths and serious injuries from measles, Tyring tells parents, “Don’t just get vaccinated for yourself or your child. Do it to protect the millions of children under 12 months and immunocompromised people who can’t get vaccinated.”
To clinicians, Friedlander says that when one suspects measles, “Get a vaccination history and involve your state public health agency if you need further help in evaluating the patient.” Because there’s no antiviral medication for measles, adds Tyring, “Treat the fever, and the rash if it causes itching as it heals.”
Drs. Friedlander and Tyring report no relevant financial interests.
REFERENCES
1. Wakefield AJ, Murch SH, Anthony A, et al. RETRACTED: Ileal-lymphoid-nodular hyperplasia, non-specific colitis, and pervasive developmental disorder in children. Lancet. 1998;351(9103):637-641.
2. Godlee F, Smith J, Marcovitch H. Wakefield’s article linking MMR vaccine and autism was fraudulent. BMJ. 2011;342:c7452.
Mr Jesitus is a medical writer based in Colorado. He has nothing to disclose in regard to affiliations with or financial interests in any organizations that may have an interest in any part of this article.