Small world, giant petri dish

The ongoing U.S. 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, M.D. She is professor of clinical pediatrics and medicine (dermatology) at the University of California, San Diego.

"And that's just what happened," she says. "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.

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The park draws an estimated 16 million visitors annually. On any given day, Dr. 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."

Measles is the world's most infectious agent, says Stephen K. Tyring, M.D., Ph.D., 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 two 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.

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"If you were in a room that a patient with Ebola was in two hours ago, you'd have to actually touch the patient's bodily secretions to get infected – the Ebola virus is not airborne," Dr. Tyring explains. But after a patient with measles coughs or sneezes, "The virus is still at high enough concentration two hours later that the next person who hasn't had measles or been vaccinated has a 90% chance of catching it."

At Disneyland, Dr. Friedlander says, more than 80% of the reported cases occurred in unvaccinated people. "How did this happen?"

Measles was eradicated in the United States in 2000, Drs. Friedlander and Tyring say. However, Americans don't always choose to have their children vaccinated (19 states allow parents to opt out of vaccinations due to personal beliefs), Dr. Friedlander says. And if these children travel abroad, she adds, "They may become exposed to people who have measles."

NEXT: The "big lie"

The "big lie"

The current U.S. measles outbreak is particularly alarming, Dr. Tyring says, because the purported link between vaccines and autism that initially caused parents to abandon vaccines has been discredited. It originated with a publication¹ whose author was paid by lawyers to advance the fraudulent claim so they could sue vaccine makers. Subsequently, "Investigators re-examined all these children that Dr. 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.

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Paradise Valley, Arizona-based cardiologist Jack Wolfson, D.O., 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.

Drs. Friedlander and Tyring counter that measles is anything but benign.

Before the measles vaccine became widely used in the United States in the 1960s, Dr. Tyring says, measles killed more than one million people globally and permanently injured 4,000 in the United States annually. Dr. 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, adds the U.S. Centers for Disease Control & Prevention (CDC), patients who survive measles can develop subacute sclerosing panencephalitis, a fatal disease of the central nervous system, approximately seven to 10 years later.

"In 2014, there were 644 cases of measles in the United States," Dr. Tyring says. "We've already had more than 100 this year" nationally.

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Worldwide, he adds, measles killed more than one million children annually at the end of the 20th century. Even now, more than 150,000 children worldwide die annually of measles. And even in the healthiest nations it's impossible to predict which patients will develop encephalitis or die from measles, Dr. Tyring says.

Most fatalities occur in children too young to undergo vaccination, or who live in areas where the vaccine is unavailable. Due to malnutrition, Dr. Tyring adds, 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 Dr. Friedlander. "Mortality can be as high as one to two in 1000 cases, and severe morbidity including encephalitis can occur in one in 1000."

"Since you don't know who's going to suffer serious consequences," says Dr. Tyring, "why not vaccinate everybody?"

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The vaccine is overwhelmingly safer than the virus, he says. With a serious adverse event rate of less than one per billion recipients, "The vaccine was proven in study after study to be extremely safe." Independent bodies including the CDC and the Institute of Medicine have used databases going back to the 1980s. They have analyzed tens of millions of vaccine records and found no hint of increased risks of serious AEs, Dr. Tyring adds. Likewise, "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 two weeks?" Actually, public health officials advise parents to keep children with measles home for three weeks to reduce the risk of transmission. Meanwhile, says Dr. Tyring, the kids can't do much because light hurts their eyes, and their parents miss work.

NEXT: Media miscommunication

Media miscommunication

Instructions for the measles vaccine recommend administering it at one year of age, followed by a booster at age four to six years. The first shot confers approximately 90% protection; the second raises it to 99%, Dr. Tyring says.

However, he adds, the fact that the vaccine requires two shots for maximum protection has led to miscommunication in the media, with some outlets reporting that anyone who has had one 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."

These children didn't get as sick as unvaccinated children, Dr. Friedlander says, but they can serve as a source of infection for others.

"Even fully vaccinated people can get the disease, but it is uncommon," Dr. Friedlander says. "No vaccine is 100% effective, but the measles vaccine comes close."

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Dermatologists are less likely to encounter parents who refuse to vaccinate their children than are pediatricians, Dr. Tyring says. Nevertheless, Dr. Friedlander says that dermatologists must be aware of the appearance of the measles rash and the mode of measles transmission, as well as its highly infectious nature and incubation period - patients can be contagious for four days before and four days after rash onset. Often, she says, "People are out coughing and spewing before they even have a rash and know what's happening. The dermatologist can be a hero if he or she quickly identifies the possibility of measles in a febrile child with conjunctivitis, cough, and a morbilliform rash," Dr. Friedlander says. Other early symptoms include lethargy and coryza.

A few days after the fever, which Dr. 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 Dr. Friedlander, and they don't last long, fading right before the rash occurs, says Dr. Tyring.

With the nonspecific early symptoms of measles, he adds, "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 adds, "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. And many parents are complacent because "they grew up without seeing anyone get very sick or die of these diseases."

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Skipping the measles vaccine instantly raises the risk of mumps and rubella, the two other vaccines that come with it, says Dr. Tyring. Chickenpox vaccination rates also may decline, he says. Over the past two years, he adds, "Thousands of West Coast children have contracted whooping cough because their parents refused the vaccine." According to the California Department of Public Health, two infants have died from pertussis contracted in 2014.

Addressing such challenges will require physicians and media members to stick meticulously to the facts regarding vaccine-related matters in the future, says Dr. 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, Dr. 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, Dr. 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 Dr. Tyring, "Treat the fever, and the rash if it causes itching as it heals."

Next: REFERENCES

Drs. Friedlander and Tyring report no relevant financial interests.

For more info:

www.mauiderm.com 

References

1. Wakefield AJ, Murch SH, Anthony A, et al. Ileal-lymphoid-nodular hyperplasia, non-specific colitis, and pervasive developmental disorder in children. Lancet. 1998;351(9103):637-41.

2. Godlee F, Smith J, Marcovitch H. Wakefield's article linking MMR vaccine and autism was fraudulent. BMJ. 2011;342:c7452.