July 16, 2012

Measles Cases on the Rise
By Carolyn Gutierrez
For The Record
Vol. 24 No. 13 P. 22

A disturbing trend, perhaps spurred by the antivaccination movement, has infectious disease specialists concerned about what may lie ahead.

According to the Centers for Disease Control and Prevention’s (CDC) Morbidity and Mortality Weekly Report, there were 222 confirmed cases of measles in the United States in 2011, the highest number in 15 years, as well as 17 measles outbreaks. The increased number of cases is troubling considering that from 2001 through 2010, there was an annual average of 60 cases and four outbreaks.

The new report states that of the 222 confirmed cases, 200 were linked with importations, including 72 that were linked with importations from other countries. Of those 72 cases,,52 involved US residents who had traveled abroad, and 20 involved foreign visitors. Almost one-half of the 72 importation cases were acquired in the World Health Organization’s European regions. Of the 196 US residents with measles, 85% were either unvaccinated or their vaccination status was unknown.

For infectious disease specialists, the CDC report is worrisome, yet not surprising given the controversy over the past 13 years surrounding the measles, mumps, and rubella (MMR) vaccine that has lead to a small but disconcerting decline in vaccinations in the United States. The antivaccination movement’s influence by means of celebrity culture and social media, combined with more accessible international travel, has created a perfect storm for the measles microbe. If left unchecked, it may have devastating consequences.

An Efficient Virus
“Measles is the most transmissible, contagious, human disease known,” says Gregory A. Poland, MD, a professor of medicine, infectious diseases, molecular pharmacology, and experimental therapeutics and founder and director of the Vaccine Research Group at the Mayo Clinic.

The name measles stems from the 14th-century Arabic word for miser that meant “the unhappiness of lepers.” (Perhaps due to the patient’s bloodshot eyes and crimson rash, the disease is sometimes referred to as the “red measles” to distinguish it from German measles, or rubella).

In the 16th century, after spreading through North Africa and Europe, the ancient microbe made its way to the Americas via explorers such as Christopher Columbus, who brought measles and smallpox to Native Americans, decimating entire populations that had no exposure and thus no immunity to the disease. Native civilizations in Cuba and Central America also suffered devastating losses to measles in the 16th century.

In 1912, the United States began compiling nationwide statistical information on measles. In that year, 12,000 patients were reported to have died from the disease. As childhood measles was so prevalent in the era before vaccination, most people became ill with the disease before their 20th birthday.

When a patient is first exposed to measles, the microbe (from the paramyxoviridae family) sets up shop in the mucous membranes for two or three days. Several theories suggest measles is contagious because the virus multiplies to very high levels in the lungs and the throat, generating a cough that throws off massive amounts of viral material, allowing the organism to be expelled into the environment.

“The virus is fairly resistant to environmental degradation, and it’s extremely tiny,” Poland says. “It’s tiny enough that it fits a peculiar physical characteristic: It will not fall out of air down onto a surface. It will stay suspended in air, which is a little unusual for most viruses and bacteria.”

It is during the first three to four days of the disease, when there are no major symptoms other than a cough, that patients are thought to be most contagious.

“It’s a very efficient virus in that sense,” says Clyde Martin, PhD, Horn Professor of mathematics at Texas Tech University. “It keeps its host alive long enough to spread. Chickenpox does somewhat the same thing. Mumps, it’s a little different—it’s mostly a hand-to-mouth spread. Different diseases have different modes of spreading, but measles and chickenpox are pretty efficient. But the difference is that chickenpox seldom causes any serious problems.”

Conjunctivitis, a runny nose, and white spots on the throat known as Koplik’s spots appear eight to 12 days after exposure. A telltale rash forms on the torso and generally spreads to the face and the rest of the body, typically lasting between five to six days.

About 10 to 12 days after exposure, measles patients develop a high fever that can last from four to seven days. Extremely high fever can bring on grave complications, including blindness, ear infections that can lead to deafness, pneumonia, severe diarrhea, encephalitis, and brain damage. The febrile complications are responsible for most measles-related deaths.

Although traditionally a childhood disease, measles can present risks to adults as well, according to Poland. As a population ages, people are more likely to be compromised or immunocompromised by diseases and comorbidities.

“If you look at 10,000 adults,” Poland says, “and you look at 10,000 children, logically that collection of adults has more people with lung disease, with diabetes, with HIV as opposed to a collection of young children. That increases the risk of complications from the viral infection for adults.”

In pregnant women, measles may cause miscarriage, premature birth, or low birth weight.

As there is no treatment for measles itself, the virus is treated symptomatically. Extensive studies have shown that prevention through the MMR vaccination is the safest and most effective defense against measles.

Importance of Vaccination
In 1954, the measles virus was isolated in a laboratory at Harvard University. The first vaccine for measles was licensed in 1963, followed by the combined MMR vaccine in 1971.

According to the CDC, one dose of MMR vaccine is routinely recommended for children aged 12 to 15 months, with a second dose given between the ages of 4 and 6. Two doses are recommended for unvaccinated healthcare workers, international travelers, and college students, while adults without evidence of measles immunity are advised to receive one dose.

Before widespread vaccination in 1980, measles caused approximately 2.6 million deaths worldwide per year, according to the World Health Organization. Worldwide vaccination between 2000 and 2010 resulted in a 74% decrease in measles mortality.

“I’ve studied measles for two and a half decades,” Poland says, “and it’s kind of an interesting thing that over the years it’s been harder and harder to get grant funding for measles because people kind of assume we’re almost on the verge of eradicating it. It was eliminated in the US, and now here we are. It’s almost like going back to the ‘60s and ‘70s.” Through April, there have been 27 cases of measles reported in the United States this year.

A 1987 measles epidemic in Lubbock, Texas, home to Texas Tech, gave rise to a mathematical modeling research program, led by Martin, demonstrating that higher immunity was needed to offset major measles epidemics in large populations.

“What we found when we did the analysis of the measles epidemic was that the immunity rate had to be a lot higher than it was previously thought,” Martin says. “It had always been thought that if you had 90% of the population immune that a disease couldn’t spread. At that time, we had about 94%—that was more or less the national average—and then what we discovered in doing the analysis of the data and then through some computer simulations was that you had to have it in excess of 98% to prevent explosive epidemics in crowded conditions such as a university.”

Martin’s conclusions led to the state of Texas’ decision to require multiple vaccinations for all school-aged children.

Large population settings, such as universities, military bases, sporting events, and music festivals, are typically hotbeds for the contagion. For example, 13 confirmed cases of measles originated from two individuals visiting the Super Bowl Village in Indiana this February. According to a PBS NewsHour report, the infected people had declined MMR vaccinations.

Antivaccination Movement
According to the CDC, the increase in measles cases can be attributed to a decline in vaccinations in Europe and the United States. While there are various reasons people refuse immunization, Poland says fear of the MMR vaccine is cited most often.

Andrew Wakefield’s now-discredited 1998 article alleging that the MMR vaccine was associated with the development of autism spectrum disorders created a panic among parents. Although the article has been scientifically debunked, with Wakefield censured and stripped of his medical license, and despite prodigious data indicating the vaccines are safe and effective in the vast majority of patients, there remain parents who refuse to vaccinate their children.

The result is that measles will inevitably resurface in the United States in high numbers due to importations of the microbe during travel. As less people are vaccinated, the population’s herd immunity (the high immunization levels in a population that protects the small number of those not immune) decreases. When this occurs, outbreaks such as the one in the Super Bowl Village could become mammoth public health emergencies.

Because there are low vaccination rates and large numbers of measles cases in Europe, unvaccinated American visitors are at risk of carrying the virus home. According to the CDC’s report, the World Heath Organization’s European region reported more than 30,000 cases of measles in 2011, including 27 cases of encephalitis as a complication, and eight measles-related deaths.

If US vaccination rates were at 100%, the situation would not be so dire. If a case of measles occurs in a population with high vaccination rates, it would typically result in no more than one or two cases every few years, according to Martin. But now that there are children who are not being vaccinated or not being vaccinated at the proper times, the potential exists for a dangerous outbreak.

Fear, Ignorance, Misinformation
In addition to measles, “The most contagious disease in humans is fear,” says Poland. “And that’s something fanned by the Internet and for which anything can be posted without regard to competence or to truth. And I’ve said this over and over again: Science is not a democracy. There are scientific facts and a scientific method, and it doesn’t really matter whether any of us believe it or not or choose to believe it—usually for emotional or anecdotal reasons. They are the facts. The virus couldn’t care less what you emotionally believe.”

In the article “The Clinician’s Guide to the Anti-Vaccinationists’ Galaxy,” Poland and Robert M. Jacobson, MD, address common myths and misconceptions regarding vaccination.

Many antivaccination groups maintain that infants are in danger of “antigenic overload” when receiving an abundance of vaccinations, and that a baby’s immune system is too immature to process the number of antigens. The scientists point out that children actually receive far less antigenic exposure with today’s vaccine schedule than they did in the past, and that the number of active molecules in infant vaccines is extremely low. In fact, as soon as they are born, infants encounter far more antigens from a myriad of microorganisms in their environment than from any vaccine they subsequently receive.

Another common misconception is that vaccines can cause autoimmune diseases such as type 1 diabetes mellitus, multiple sclerosis, and Guillain-Barré syndrome. Poland and Jacobson counter this in their article by noting that “a recent Institute of Medicine review, by a panel of experts reviewing more than 12,000 published reports, failed to find evidence for the development of any of these three autoimmune diseases as a result of vaccines.”

A third belief held by many antivaccination groups is that natural immunity is safer and better than vaccines. In response to this claim, the scientists point out that although “natural” measles infection brings about lifelong immunity to an individual, the possibility of disabling complications or death do not make natural infection a safer route to immunity. Extensive data show that the measles vaccine has been proven to be safe and effective, and booster shots can address cases of shorter-lived immunity. In addition, Poland and Jacobson underscore the need for high levels of immunity in the general population to protect those immunocompromised children and adults who are unable to receive live viral vaccines.

In the conclusion of the article, the scientists stress the fact “that no man-made product, including vaccines, is absolutely and completely safe, or perfectly effective, but at both the individual level and population levels, vaccines that are licensed for use in the United States and elsewhere demonstrate extraordinarily high levels of safety and extremely rare rates of serious life-threatening side effects, with correspondingly great individual and population-level benefits.”

Thirteen years after the pandemonium created by the Wakefield article, the medical community is still battling the rampant misinformation and fear concerning vaccinations. In a survey published in the May 2011 issue of the American Journal of Preventive Medicine, approximately 80% of primary care physicians in the United States reported at least one vaccine refusal from parents per month.

“And I think, in part, the reason relates to measles as sort of an abstract concept to modern-day parents,” Poland says. “I was born in the middle of the last century. We all had measles; we knew what it was like; we saw complications. Certainly our parents saw complications. These parents are ignorant of it. They have no idea of the morbidity and mortality that this virus causes until it’s too late. The result of this is a growing population of un- or under-vaccinated children and adults, where now we have importations because of the global movement in travel.”

Once a measles patient himself, Martin adds, “It’s hard to convince people that kids can get horribly sick [from measles]. I can remember my mother sitting beside the bed, putting wet rags on my head, trying to keep my fever down.”

While the human costs of an epidemic can be devastating, the economic impact is considerable as well. The 1987 Lubbock measles epidemic was estimated to have cost about $10 million, according to Martin. Paying for medical personnel, the allocation of time and materials needed for the collection of data, tracing all contacts of the disease, containing the disease, the absenteeism from schools and the workplace due to sickness, and quarantines for the unvaccinated—all these factors snowball into a daunting economic loss.

Future Concerns
It’s too early to know whether measles cases will jump in 2012, but large public events such as the Summer Olympics in London have infectious disease specialists on edge. “We’ll have people from all over the world gathering in crowded venues,” Poland says. “It’s a microbe’s dream.”

In the United States, measles elimination was declared in 2000 but in retrospect, the declaration could be viewed as a double-edged sword. The so-called elimination of the insidious disease has perhaps created a culture of complacency. Younger generations that have not witnessed firsthand the harrowing complications of measles seem to casually write them off. As with fighting any disease, public education is key. The funding of high-quality studies and vaccine monitoring programs can help families make sound, scientifically based decisions about vaccination.

When discussing the antivaccination movement’s rhetoric, Poland is flummoxed. “It makes you realize that we live in an era now in which we think we’re so smart,” he says. “But as a society I think we are relatively scientifically illiterate. And so, I think what has happened is, rather than being evidence based, as I’ve said in my lectures, we have become eminence based. We pay more attention to what Oprah Winfrey says than to what scientists and the data say. It’s harming us, and it’s killing our children.”

— Carolyn Gutierrez is a freelance writer based in New York City.