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Another measles outbreak: A pediatrician answers your vaccine questions


Wendy Sue Swanson, a pediatrician with Seattle Children’s Hospital, wants parents to know immunizations are safe, necessary and effective. As a mother of two boys (ages 10 and 12), she understands why parents get nervous. “I think anybody who hears a scary story about vaccines has questions, and I think that’s natural and human,” she says. But as a doctor and a mother, she knows how safe and important vaccines are.

“I never hesitated. My kids got their MMR [measles, mumps and rubella] as soon as they could. They got the flu vaccine as soon as they can. We were one of the first in line for the H1N1 because I had a baby at home,” she says. “I’m an enthusiast of vaccines because the science is so clear.”

‘It will take off like a wildfire’: The unique dangers of the Washington state measles outbreak

Yet there’s an outbreak of measles right now in the Northwest. “Outbreaks like this really show there are risks of non-intervention,” Swanson says. Measles is highly contagious. If a child isn’t immunized against measles, and they’re in a room even two hours after someone who had the measles was there, “they are likely to get it.”

Here is an edited excerpt of a helpful blog post Swanson wrote at Seattle Mama Doc for Seattle Children’s Hospital about why we need to vaccinate our children:


There is a measles outbreak unfolding in Washington state. Unfortunately, there have been multiple outbreaks across the United States in the past few months. Here’s info about outbreaks in 2018, as well.

The MMR vaccine is safe and effective. If you’ve hesitated or declined the vaccine in the past, please reconsider the science and risk to your child and their community now.

The first thing to know, which I know I already said, is that the MMR vaccine, which protects children and adults against measles, mumps and rubella, is safe and highly effective. If your children are immunized there is very little to worry about during a measles outbreak. The first dose (and second dose for those infants and children who didn’t respond to the first) of the vaccine work to trigger lifelong immunity. Typically after the first dose at 12 months old, 95 percent of people are protected for life. The second dose at age 4 protects those not protected from the first dose and brings protection to 97-99 percent.

If your child hasn’t had a second dose of the MMR vaccine and you live where widespread measles infections are being reported, you can get the second dose of MMR now as long as it’s been one month since the first dose. Call your pediatrician to inquire if you’re interested.

The bottom line: Immunized children can play and go to school and go to assemblies and even visit a clinic safely during an outbreak because the vaccine is so effective. Hurrah for science!

What to know about babies too young to be immunized for measles (MMR):

I hate that I can’t say infants are perfectly safe during an outbreak. Infants are a vulnerable population during a measles outbreak. Measles is wildly contagious, and during an outbreak, it can spread, especially to older infants who aren’t vaccinated yet. The good news is that risk of exposure (outside of areas during an outbreak) is low. More than 90 percent of us won’t get measles because we’re vaccinated, so we also won’t spread it to your baby. Here’s an even more comprehensive post I wrote about this from 2015.

  • For babies younger than 6 months of age: If a baby’s mother has had her MMR shots and/or had measles infection in her life, she passed antibodies to her baby during fetal development while in-utero and continues to pass them passively while breast-feeding. Those antibodies provide protection for young infants and typically are thought to protect infants for up to 6 months or more. However, exactly how long for each baby is not ever known. Immunity wanes for these babies as they age and the mom’s antibodies fail to persist. The reason babies don’t get the MMR shot sooner than a year of age is because of the persistence of these maternal antibodies — if you put a vaccine in while maternal antibodies are still around the vaccine won’t stimulate the baby’s own immune system to respond, it will just get soaked up by the maternal antibodies doing their job.
  • Okay to go to the grocery store or have a play date with your infant? Yes! With a few caveats, of course. If you’re in a county where multiple cases of active measles have been recently reported, you may take more caution, by disallowing strangers to hold your baby and/or steering clear of anyone with a cough. Measles is infectious on surfaces and in the air for two hours after an infected individual has been in the space, so it’s tricky to provide solid guidelines of how to avoid it if it’s around. If there is ever any concern for exposure, call your pediatrician to discuss a visit. Like everything in life we balance risk with benefit and being out and about in the world. If you are planning on visiting families with children, ask the parents involved, “Is everyone here immunized against measles that can be?" 
  • Is my child’s school protected against a measles outbreak? In many states, you can track vaccination status for your child’s school because exemptions (those opting out of immunizations for medical or philosophical reasons) are tracked. To find your data, start at School Digger or try a search on the state’s Department of Health website. If you can’t find the information, it’s your right to request the numbers from school administration or the school nurse. Outbreaks like this are one of the reasons California discontinued allowing children to attend school without up-to-date immunizations. Their non-protection puts other children at risk.
  • As a parent, do I need another MMR shot? What If I’m pregnant? It’s unlikely you need more MMR shots if you were born after 1957, when vaccination was universal. In 1989 we also started to do a second dose of MMR to get more people protected (closer to 100 percent of the population). Only adults working with vulnerable populations and in health care need to get a second dose now. If you have zero written documentation anywhere that you’ve had an MMR shot, talk with your doctor. In addition, if you’re pregnant now, do not get an MMR shot until after the baby’s born. You can get an MMR shot safely while breast-feeding.
  • Traveling internationally with infants: If you’re planning to travel abroad with your infant and they are between 6 and 12 months of age, it’s recommended they get an MMR shot before travel to protect against measles. They’ll need to repeat that MMR dose at 1 year of age, and the last shot at age 4, but they will be better protected during travel to higher-risk areas while they are still an infant.

If your child is up-to-date on MMR vaccination they can play and go to school and live as they normally would during an outbreak. The MMR vaccine provides lifelong immunity for almost all who get it.

Wendy Sue Swanson is a mother, a pediatrician and chief of digital innovation at Seattle Children’s Hospital. Follow her on Twitter @SeattleMamaDoc. Her blog is SeattleMamaDoc.

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