Many parents around the U.S. are asking what to do about a possible measles exposure with a baby at home who is too young to be immunized. Should they stay home? Can they travel? Should they cancel that trip to Utah or to Vermont or even to Disney next month? Can they head out to the store without worry? Are they “safe”?
I hate that I can’t completely say they are safe. 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 is low (more than 90 percent of us won’t get measles because we’re vaccinated so we also won’t spread it to you!). Some parents are also wondering about getting the vaccine before the baby turns 1 year because they’ve heard the recommendation for infants traveling abroad: infants traveling outside the U.S. are recommended to get an MMR (measles, mumps, rubella) shot if they are over 6 months of age (of note, babies who get the shot as an infant also get the usual shot again at 12 months of age). Without travel plans, we wait to immunize babies with their first MMR vaccine until they are 12 months of age. Over 95 percent of babies who get the shot at 12 months of age are protected against measles, and over 99 percent are protected for a lifetime after the 2nd dose (at least one month later). Wow, right?
“This is not going to be the end-all-be-all post on protecting your infant or child from measles’,” Dr. Matthew Kronman, a pediatric infectious disease expert at Seattle Children’s, reminded me as we chatted. Advice and guidance for protecting babies and children will change as we learn again how to protect our population from measles infection while unvaccinated pockets of people remain.
The CDC warns that the outbreak could grow and nationally there’s a palpable dialog going on between the herd (those immunized) and those not. Politicians are involved: Governor Christie talked about “choice;” Obama is urging parents to immunize right alongside the president of the American Academy of Pediatrics who released another urgent statement. Pediatricians, family docs, nurse practitioners and health workers everywhere are encouraging parents to get shots up-to-date to protect their own children and vulnerable populations (this includes infants). Here’s a bit of evidence and information that can hopefully curb anxiety for parents to babies. I teamed up with Dr. Edgar Marcuse, a lifelong scholar with vaccines and an emeritus professor of pediatrics at the University of Washington, and Dr. Matthew Kronman. Here are seven tips about infants and families that may help shape your thinking:
7 things to consider during a measles outbreak
1. For babies under six 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 breastfeeding. Those antibodies provide protection for young infants and typically are thought to protect infants for up to 6 months or more. 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.
2. Babies over six months of age. MMR shots for all infants over six months of age are not recommended at this time. The current outbreak has not changed recommendations on when to get MMR vaccine for children in the U.S. If the outbreak turns to an epidemic, it is possible recommendations would change. Babies who get a MMR shot between 6 and 12 months of age after a measles exposure or for travel will still need to get their MMR shot at 12 months of age.
3. Disney? Safe to go? Yes, it is. Parents have asked if babies, age 6 to 12 months should get the MMR shot prior to a trip to Disneyland. No. Dr. Marcuse frames it nicely saying, “While Disneyland was the site of exposure for what is turning out to be a remarkable number of cases, the visitors who transmitted measles and those exposed during the original cases during December have dispersed.” Currently, there isn’t an ongoing outbreak in Disneyland. Dr. Marcuse again explains, “While secondary cases are still being reported, particularly in California and some among Disneyland employees, these do not meet the criteria for an epidemic or continued extensive [person-to-person] transmission which would warrant immunization of infants 6-12 months of age.” So for now it’s still a great plan to explore and take a holiday, and there’s no need to get an early MMR shot for your infant.
4. OK to go to the grocery or have a playdate 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 (Southern California, Orange County, for example, has had 22 cases alone) you may take more caution 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 2 hours after an infected individual is there, so it’s tricky to provide solid guidelines of how to avoid it if it’s around. If 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 planning on visiting with guests or sharing in on a playdate, why not ask parents to children involved, “Is everyone here immunized against measles that can be?
5. If traveling with or living with children should I get labs (“titers”) to prove my children’s MMR shot worked? For those who have 2 documented doses of MMR vaccine blood testing for immunity is not recommended. If an individual has 2 documented doses of MMR vaccine and has blood testing that is done that finds a negative or equivocal measles titer results (unsure proof of immunity), it is still not recommended that the person receive an additional dose of MMR vaccine. Officially, recommendations suggest that, “such persons should be considered to have presumptive evidence of measles immunity.” Dr. Marcuse clarifies, “Documented age-appropriate vaccination supersedes the results of subsequent blood testing.” This official recommendation is from the CDC recommendations for healthcare workers. Further, it should also be noted that additional doses of measles vaccine are not harmful so in some cases a clinician may decide to provide another immunization to trigger an immune response.
One expert Dr. Marcuse conferred with only performs measles titers in immunocompromised patients, regarding such testing in others as “a slippery slope.” Reason being, the best test for measles immunity is a neutralizing antibody titer, whereas commercial labs report enzyme immunoassay (EIA) that may not be as accurate. Note that the guidelines discussed here were created in the spirit of protecting the public at large. Unfortunately Dr. Marcuse reminds, “Occasionally, a person who meets the criteria for presumptive immunity can acquire and transmit disease.” This is rare as the vaccine is so wildly successful and durable. Simply put Dr. Kronman says, “2 doses of the shot is presumptive immunity, so there’s no place is recommending getting titers if you have had both shots.” Reason being, the most commonly used test for blood proof (titers) isn’t the best measure of immune status. Having low titers can occur even in a person who still is protected from measles and may create false worry.
6. 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 immunizaton for medical or philosophical reasons) are tracked. In Washington State, parents can check to see what percent of children are up to date on immunizations in kindergarten by searching SchoolDigger or the VaxNorthwest website (on the right side) by school name. When I checked my own son’s school, it had data for the 2012-2013 school year, which I found reassuring. Because vaccination status is tracked at the state level, many other states provide this service (some are up on School Digger). To find your data, start at school digger or try a search at the state’s Department of Health website for more. If you’ve run into a roadblock or can’t find the information, it’s always your right to request the numbers from school administration or the school nurse.
7. 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, most of us all got the shot as children. In 1989 we also started to do a 2nd dose of MMR to get more people protected (closer to 100 percent of population). Only adults working with vulnerable populations and in health care need to go and get 2nd dose now. If you have ZERO written documentation anywhere that you’ve had MMR shot, talk with your doctor. In addition, if pregnant now, no MMR shot until after the baby’s born if you’re concerned you may not be protected. You can get a MMR shot safely while breastfeeding. Here’s a nice post for parents from Dr. Burgert, a pediatrician in Kansas City with more.
Wendy Sue Swanson is a pediatrician who blogs at Seattle Mama Doc. She is the author of Mama Doc Medicine: Finding Calm and Confidence in Parenting, Child Health, and Work-Life Balance.