Reading: Do You Need a Measles Booster?

Annual flu shot aside, I haven’t really worried about who needs to get vaccinated for what since my now grown-up kids transitioned from their pediatricians to internists. Ok. I did recently succumb to the shingles vaccine on my doctor’s urging. But the MMR (Measles, Mumps, Rubella)? Like most adults, I thought I had put that particular vaccine behind me.

However, a dramatic rise of measles in countries around the world — and in pockets of the US — has prompted health officials to recommend that certain adults consider getting re-vaccinated.

This year, the United States experienced its worst measles outbreak since the disease was declared eradicated here back in 2000. Since January, more than 1200 people in 31 states have come down with the measles, and some have gone on to develop serious complications like pneumonia and encephalitis.

“The likelihood is that people born before 1957 had measles and are immune — and that those who went to school in the US in the 1980s or later, when we had immunization requirements in most states, were probably vaccinated,” according to Walter A. Orenstein, MD, Associate Director of the Emory University Vaccine Center. But there are exceptions, he says, and even those who were vaccinated once may need to be re-vaccinated according to CDC (Center for Disease Control) recommendations. How do you know if you need a booster?

Who Needs To Be Re-Vaccinated

Measles, considered one of the world’s most contagious diseases, is spread by airborne droplets produced when an infected person breathes, sneezes or coughs. The virus can remain infectious in the air for up to two hours; in fact, nine out of ten susceptible people with close contact to a measles patient develop the disease.

Who’s susceptible?

According to the World Health Organization, anyone who has not been vaccinated with two doses of measles vaccine can potentially become infected. One measles shot is 93 percent effective in inducing immunity against the disease, says Dr. Orenstein. Two shots are 97 percent effective. Indeed, measles outbreaks in the late 1980s led both the CDC and the American Academy of Pediatrics to recommend in 1989 that all children receive a second dose of the vaccine for added insurance.

The CDC advises that all adults born in 1957 and later should have at least one dose of the vaccine in the unlikely event that they haven’t already received one. The measles vaccine was introduced in the US in 1963, so people born between 1957 and 1963 may not have been vaccinated.

In addition, while most people have received the “live” version of the vaccine, some people born in the sixties received a “killed” version, which not only wasn’t as effective — it has also been associated with more severe infections in those exposed, notes Dr. Orenstein. People born between 1963 and 1968 who received the killed vaccine should get a live booster. Though fewer than one million people received the killed vaccine, if you are in this age group and do not know which type of vaccine you received — or if you are born in 1957 or after and aren’t sure of your vaccination status, you should talk to your doctor about getting re-vaccinated.

According to the CDC, adults who will be in settings that pose a high risk for measles transmission should get re-vaccinated if they do not have records showing that they’ve received two doses of the vaccine or laboratory evidence (from a blood test) confirming immunity.  This includes students or staff at post-high school education institutions, healthcare personnel, and those traveling internationally.

Measles Shots for Travel

Getting a measles shot is not typically on the to-do list of those about to travel, but this summer, the CDC issued a Global Measles Outbreak Notice advising those planning to leave the country to confirm their vaccination status.

“Measles is crossing borders,” says Manisha Patel, MD, Team Lead for Mumps, Measles and Rubella at the CDC. “Not only is the global burden of measles increasing, but more travel is occurring. Two thirds of our measles cases are United States residents who have traveled to other countries.” And it’s not just developing countries that pose a risk, she adds.

WHO recently warned of a “dramatic resurgence” in measles across Europe: Britain, Greece, Albania and the Czech Republic have all lost their measles-free status in recent months, joining 12 other countries (including France, Germany, Poland, Romania and Russia) where the disease is endemic. In fact, measles is still commonly transmitted in many parts of the world, including Asia, Africa, the Americas and the Middle East.

Even in high income countries, complications result in hospitalization in up to a quarter of cases, and can lead to lifelong disability, including blindness, hearing loss, and even brain damage. Large outbreaks have been reported in recent years in popular travel destinations like Israel, Thailand and Italy, though even countries that don’t report outbreaks pose a risk.

“For measles, it’s not helpful to look at which countries have outbreaks,” notes Dr. Patel. “India, for example, is not going to list that they have a measles outbreak, because measles is endemic there.” That’s why “your default should be I should be vaccinated against measles,’’ she says.

How The Vaccine Protects

The measles vaccine protects against the disease in two ways, explains Dr. Orenstein. “One is by inducing an active immune response in the vaccinee, so that that person is protected if exposed to the measles virus. The other way that vaccines protect is indirectly.” In order for measles to sustain itself, he says, it needs a chain of human-to-human transmission. In other words, a person with measles needs to come into contact with susceptible individuals. “If the transmitting case only comes into contact with immune individuals, the chain is broken,” he says. What is known as “herd immunity” is achieved when 90-95 percent of a community is vaccinated.

Unfortunately, certain groups of people in the US (and around the world) have been reluctant to give their children the MMR, for fear it could lead to autism, a concern based on a 1998 study in the journal Lancet that suggested an association. This study has since been retracted — and multiple studies have disproven such a link. Yet misinformation persists. In fact, the recent resurgence of measles around the world is partly due to the growing number of people refusing to get vaccinated, experts say.

When cases of measles land in communities with many susceptible people, it spreads. The majority of recent cases in this country occurred in areas where large groups of people were unvaccinated (i.e. the outbreak in Brooklyn, NY, which according to NYC health officials finally ended in early September, as well as the ongoing outbreak in Rockland County, NY, were heavily concentrated in Orthodox Jewish communities which had lower than average vaccination rates.)

“When someone gets vaccinated against measles, they are not only doing it for their own protection but for the community’s protection,” notes Dr. Orenstein. “By getting vaccinated, you can indirectly protect people who can’t get vaccinated.” This includes babies under six months, pregnant women, adults who are immune-compromised (because of cancer treatment, for example) and those allergic to components of the vaccine, such as neomycin or gelatin. So if you have a new baby in the family, or a pregnant or chronically ill family member, knowing your vaccination status is especially important.

Ensuring Immunity

If you are unsure of your measles vaccine status, an alternative to getting the booster is getting a blood test to determine if you are immune. “The benefit of the blood test is that you can document immunity: Two doses of the vaccine is about 97 percent effective, so that means it’s 3 percent ineffective,” says Dr. Orenstein. “The big disadvantage is that if you are susceptible, you have to make an extra visit to get the vaccine. If you are immune, getting the vaccine is harmless, so it’s generally easier to just get a dose.”

Side effects of the MMR are minimal, and may include fever and a transient rash about 7 to 12 days after vaccination. Adults (as well as children under two) are most at risk for complications from actually getting the disease, so it’s worth making sure that you are protected.

“Most of us in the US are vaccinated,” says Dr. Patel. “But if there is one thing I want to get across to readers it’s that if you are traveling to another country, you have to make sure. Because when you bring measles back to the US, there may be susceptible people around you and that’s how it spreads.”

Anyone planning to travel out of the country should visit their healthcare provider at least a month before travel to ensure they are protected. If you require two doses, make that six weeks ahead, as doses have to be given 28 days apart and it takes about two weeks to develop immunity.