Despite Effective Vaccine, Measles Still Threaten Worldwide
Nineteen days ago, several hundred people could have been exposed by a traveler with measles in Nova Scotia, Canada. The next day, someone flying from Minnesota to Nebraska may have spread the measles to other passengers. A couple weeks ago, it's possible that a man and his six-month old child spread the measles in several Seattle-based locations. Authorities are trying to locate persons who may have been in contact with these people. None of the persons with measles were vaccinated. Why?
Caused by the measles virus, measles, also called rubeola, is a highly contagious infection that attacks the respiratory system. Symptoms include a blotchy or lacy rash, cough, runny nose and eyes, high fever sometimes topping 104ºF, and a sore throat. Spread by droplets through the air, or germs on contaminated surfaces, measles is so contagious that 90% of unvaccinated persons exposed to someone with an active case of measles will catch the infection.
Prior to the development of a safe, effective vaccine for measles, most young adults contracted measles before the age of 15. Between three and four million people got the measles each year in the US, requiring 50,000 hospitalizations, and about 4,000 cases of swelling of the brain, called encephalitis. An estimated 500 people die each year from the infection. Even today, there is no treatment for the illness, other than supportive measures, and about 100,000 children die each year of measles around the world.
At all ages, measles is a dangerous infection. According to the Centers for Disease Control and Prevention (CDC), people under age five, and those over age 20, are at higher risk to develop complications, and overall, one to two children per 1,000 will die from the disease. Complications can include:
- Diarrhea: About one in ten patients develop diarrhea during the course of the measles.
- Ear infections: Also afflicting about one in ten people, ear infections from the measles can be serious, resulting in permanent loss of hearing.
- Pneumonia: As the most common cause of death in children with the measles, pneumonia is a serious lung infection that afflicts about one in 20 children who contract the measles.
- Encephalitis: Impacting about one in every thousand patients with measles, swelling of the brain can cause convulsions, hearing loss, and permanent intellectual impairment.
- Subacute sclerosing panencephalitis (SSPE): Attacking the central nervous system, patients who contract measles can suffer with SSPE for up to 10 years after they were infected with the measles. Of every 100,000 measles patients, between four to 11 may eventually develop the condition. SSPE is a progressive, disabling disease that causes personality changes, physical disability, and eventually death, and it impacts males more than females.
Measles was "eliminated" from the US in 2000. So why is a measles still a problem in this country?
As defined by the CDC, the elimination of the measles means the infection is no longer present in this country. While it is carried to the US by unvaccinated travelers, and may cause an outbreak, measles is not considered to be endemic to this country any longer.
In the roughly two months between January and February 2017, a total of 21 cases of measles were reported. In 2014, among 23 other outbreaks, a large outbreak took the Ohio Amish community by surprise. Unvaccinated adult men returning from a missionary trip to the Philippines spread the infection to 383 of their community members. As an isolated, unvaccinated community, the Amish represent a group ripe for infectious outbreak, although vaccination numbers may increase over time, due to the recent outbreak.
While measles case counts in the US are currently low, that could change. In mid-March, public health authorities in Romania reported more than 3,400 cases of the measles. In addition to Romania, the European Centre for Disease Prevention and Control (ECDC) noted measles outbreaks of varying size since the first of the year in Austria, Belgium, Denmark, France, Germany, Spain, and Sweden.
In an assessment, the ECDC states the size of the current measles outbreak in Romania could result in export and transmission of measles to other countries with vaccination rates too low to protect the general population.
In the US, people still catch the measles due to these factors:
- Low vaccination rates in some communities leads to outbreaks. Parents and individuals who refuse to obtain vaccinations for themselves and their children sometimes live closely to others in their communities. These pockets of unvaccinated people offer opportunity for outbreak. The higher the community vaccination rate, the better protection is provided to all. Vaccination rates between 90% and 95% are required to stop, or at least slow, the spread of a wild measles outbreak. Conversely, declining vaccination levels mean the virus can gain a foothold more easily.
- Wild measles is endemic in many parts of the world. At present, measles outbreaks in the US are caused by contagious travelers and groups of unvaccinated people. With large outbreaks in other countries, there is increased possibility of the global spread of the virus.
As part of a global community, it is likely most people in the US will be exposed to measles during the course of their lifetime. Yet people routinely choose not to vaccinate, endangering themselves, and their neighbors.
Some people are hesitant about being vaccinated, or about vaccinating their children. Some of the reasons for their concern include religious objections, lack of trust in the safety of vaccinations, or lack of knowledge about how vaccinations work, leading them to believe vaccines could overwhelm the immune system.
A primary event that fueled anti-vaccination campaigns targeting the measles-mumps-rubella (MMR) vaccine was the publication of a research paper in the British journal Lancet in 1998. The paper suggested that the MMR could predispose children to autism-spectrum disorders. In Great Britain, the paper led to a decline in vaccinations and a jump in cases of measles.
In 2010, the journal retracted the paper. While all vaccinations carry some risk, no scientific study ever reproduced its results, and investigators revealed significant scientific and ethical concerns, including financial fraud.
As reported in the New York Times, an author on the study, Andrew Wakefield, was partially paid for the research by lawyers representing parents suing vaccine makers. Dr. Wakefield also patented his own measles vaccine in the event public tide turned against the MMR. A regulatory board, the British General Medical Council, later ruled Dr. Wakefield guilty of four counts of dishonesty and 12 counts of abuse of children, and he is barred from practicing medicine in the United Kingdom. Despite the findings, many people remain uncomfortable with vaccinations because of Wakefield's poor scientific conduct.
A recent study mathematically modeled the likelihood that a state like Colorado, with one of the lowest vaccination rates for measles in the country, could experience an outbreak. The research found Colorado was 140% to 190% more likely to experience an outbreak than states with tougher legislation around vaccination exemptions for school age children.
For school age children, laws concerning vaccinations are changing, and legislation may make it harder for parents to choose not to vaccinate their children. Because proof of routine vaccination is required for school registration, most children are vaccinated by the time they enter school. Mississippi, West Virginia, and most recently, California, have enacted legislation that prohibits all except medical exemptions for routine vaccinations—the measles, mumps, tetanus, diphtheria, whooping cough, rubella, and others.
In California, where the new law allows only medical exemptions, parents with religious or philosophical objections to vaccinations can choose to school their children at home. The California legislation resulted from the 2014 measles outbreak at the Disneyland theme park in Anaheim, where measles was able to spread to 125 people, many who were either unvaccinated, or had not had a full course of vaccinations.
Measles is a highly infectious, sometimes virulent disease. There is a safe vaccine to keep communities protected against outbreak. No child, or adult, is immune to measles without a vaccination. And even one life is too many to lose to an infection that is preventable.