Thanks to an intensive federal vaccination campaign in the 1990’s, measles was eliminated in the United States about 15 years ago (meaning that the virus no longer spreads freely in the population). While cases imported by travelers from overseas have appeared from time to time, high rates of immunization have generally stopped the virus in its tracks. But a rising number of unvaccinated U.S. residents — tied to a misguided anti-vaccination movement — threatens to undo much of the progress we’ve made against measles and other vaccine-preventable diseases.
The ongoing Disneyland measles outbreak, which has now spread to 87 people in 7 states plus Mexico, underscores the critical importance of immunizations for the health of individuals and the public, serving as a sober reminder that we are still highly vulnerable, as a society, to the infectious diseases that we are fortunate enough to be able to forget about.
As the current outbreak continues to grow, here are 10 things you should know about the disease, vaccinations, and how to best protect yourself and your family against measles:
1. What is a measles?
Measles is a highly contagious respiratory disease caused by a virus in the paramyxovirus family. According to the Centers for Disease Control and Prevention, the disease is so contagious that 9 out of 10 people who have close contact with a measles patient will become infected themselves, unless they are immune. There is no specific treatment for measles; supportive care is used to help relieve symptoms and address complications such as bacterial infections, but there are no antivirals for the disease.
2. How is measles transmitted?
The measles virus is an airborne pathogen, meaning that it can spread very easily by air or through direct contact. It passes through droplets in the air, usually from someone sneezing or coughing, but it can also live for up to two hours on a surface or in an airspace where an infected person coughed or sneezed. If other people breathe the contaminated air or touch the infected surface, then touch their eyes, noses, or mouths, they can become infected. Tight spaces like elevators are common points of transmission, as are schools, churches, and daycare facilities. It’s also possible to catch measles from someone before they even know they’re sick; infected people can spread measles to others up to four days before the first symptoms appear (and four to five days afterwards).
3. What are the symptoms of measles?
The first sign of measles is usually a high fever, which begins about 10 to 12 days after exposure to the virus, and lasts 4 to 7 days. A runny nose, a cough, red and watery eyes, and small white spots inside the cheeks can develop in the initial stage. After several days, a telltale rash erupts, usually on the face and upper neck. Over about 3 days, the rash spreads, eventually reaching the hands and feet. The rash lasts for 5 to 6 days, and then fades. On average, the rash occurs 14 days after exposure to the virus (within a range of 7 to 18 days).
The telltale symptom of measles is a bright red rash that appears about 2 weeks after exposure to the virus.
4. How serious are the symptoms?
In most people, the symptoms go away in one or two weeks. However, even in previously healthy children, measles can cause serious illness requiring hospitalization, and complications are not uncommon among certain vulnerable groups, including children under a year old (who are too young to have been vaccinated), pregnant women, and people with compromised immune systems (such as older adults and those getting treated for cancer).
The CDC estimates that 1 in 10 children with measles will develop ear infections that can result in permanent hearing loss, while 1 in 20 will develop pneumonia — the most common cause of death from measles in children. Other serious complications include: acute encephalitis, which often results in permanent brain damage; respiratory and neurologic damage; and subacute sclerosing panencephalitis (SSPE), a rare but fatal degenerative disease of the central nervous system characterized by behavioral and intellectual deterioration and seizures that generally develop 7 to 10 years after measles infection.
Globally, measles is one of the leading causes of preventable death among young children. In 2013, there were 145,700 measles deaths worldwide, according to the World Health Organization.
5. How common is measles?
Before the first measles vaccination program started in 1963, about 3 to 4 million people got measles each year in the United States. Of those people, 400 to 500 died, 48,000 were hospitalized, and 4,000 developed encephalitis (brain swelling) from measles. Although the disease was eliminated in 2000, cases are on the rise again: in 2008, 2011, 2013 and 2014, there were more reported measles cases compared with previous years. Last year, 644 cases were confirmed, accounting for a nearly two-decade high.
6. How can I protect myself against measles?
First and foremost: get vaccinated. Measles is prevented through the combination MMR (measles, mumps, and rubella) shot. The CDC recommends that children get two doses:
- The first dose, at 12 through 15 months of age.
- The second dose, at 4 through 6 years of age.
The vaccine is known to be extremely safe and very effective: it contains a live but weakened version of the virus, and it causes your immune system to produce antibodies against the virus. Should you be exposed to actual measles, those antibodies will then fire up to protect against the disease. According to the CDC, two doses of the MMR vaccine are about 97 percent effective at preventing measles. Immunity from the vaccine lasts for decades, but you should ask your health provider about booster shots if you’re an adult.
As with any virus, good personal hygiene is also important to help prevent the spread of disease, including washing hands regularly, covering your mouth when coughing or sneezing (with a tissue or your sleeve, not your hands), disposing of used tissues, and not sharing eating utensils or drinks. The best prevention, however, is vaccination.
7. Is the vaccine safe?
The MMR vaccine has been used safely and effectively since the 1970s. According to the CDC, side effects from the vaccine are rare and mostly very mild. For example, low-grade fevers after the MMR vaccine occur in one out of six people, and mild rashes, in one in 20. More severe problems are virtually non-existent: serious allergic reactions happen in less than one in a million cases. Deafness, seizures, and permanent brain damage are “so rare that it is hard to tell whether they are caused by the vaccine.” So the benefits of the vaccine — the protection of children and the communities they live in — vastly outweigh the harms.
The MMR vaccine has been shown to be extremely safe and effective at preventing measles.
8. Is anyone who has been vaccinated safe from measles?
Most Americans who are older than 51 were exposed to measles in childhood, when the virus was common in the United States, and so developed immunity. Beginning in 1963, children received one dose of the vaccine, which was about 93 percent protective. In the late 1980s, researchers discovered that a second dose bumped the protectiveness up to about 98 percent. Since then, American children have been given two doses, one at 12-15 months and the second no later than ages four to six.
The people who received only one dose, who are now mainly in their 30s and 40s, have slightly less protection than younger or older people. It’s also possible that some people, particularly those vaccinated outside the United States, where the supply of vaccine might not have been kept continuously cold, didn’t get an effective dose. Doctors may recommend vaccination before traveling overseas to a country where the disease is present.
Individuals who have not received their vaccinations or are unsure, or those who travel internationally, should speak with their primary care physician. Doctors can perform a simple blood test to determine whether or not you need a booster shot to ensure immunity.
9. Why do some parents refuse to vaccinate their children?
The modern anti-vaccination movement was sparked by the work of now-discredited British physician Dr. Andrew Wakefield, who claimed to have found a link between the MMR vaccine and autism. Although the original study was published in 1998, news of Wakefield’s claims did not become popularized until 2005. But once it caught on, the pseudoscience of the anti-vaccine movement attracted supporters nationwide, even capturing the attention of celebrity supporters like Jenny McCarthy.
Despite clear evidence that vaccines are safe — and do not cause autism — many parents still refuse to vaccinate their children based on the discredited theory.
Yet the anti-vaccine movement carries on, despite the wealth of scientific research proving that the federal vaccination schedule is safe and effective for children. And it’s incredibly difficult to change those parents’ minds about vaccines. Research has found that there’s no amount of scientific fact that can convince them that vaccines aren’t linked to autism, largely because the people who resist vaccination are distrustful of scientists’ opinions on the subject. One recent study found that even disease outbreaks, like the current spread of measles, aren’t enough to convince more people to inoculate their kids.
10. What are the consequences of refusing to vaccinate against measles?
People who choose not to vaccinate their children are taking a risk both for their own child and for the larger community. As more and more children are withheld from immunizations, the risk of contracting infectious diseases increases for everyone.
Vaccinations prevent diseases through two mechanisms: they help to protect vaccinated individuals from contracting the disease, and they also reduce the risk of widespread disease transmission by producing “herd immunity.” Herd immunity is the term used to describe community-wide protection from disease that is accomplished when a critical percentage of the population is immunized. For highly contagious diseases like measles, this percentage is around 96% of the population; if the number drops any lower, we lose the protective benefits of herd immunity.
This is particularly important for those who are immunocompromised, too young to be vaccinated, or otherwise medically ineligible for vaccination; these vulnerable groups are also most likely to have severe cases of measles. If immunization rates drop below the critical mass, the risk of disease transmission in the community increases substantially.