Medical Director Notes
Dr. Kristen Feemster is the Medical Director of the Philadelphia Department of Public Health’s Immunization Program.
Spring, Measles and Mumps
2019 is on track to have the highest number of measles cases since the disease was declared eliminated from the U.S. in the year 2000. Why are we seeing these outbreaks and what can we do to protect our community?
This has been a busy spring for vaccine-preventable diseases! Temple University is experiencing a mumps outbreak among students and reported almost 150 cases as of mid-April. While, across the nation, the Centers for Disease Control and Prevention (CDC) reports more than 600 cases of measles so far this year. While we have not yet had any measles cases in Philadelphia, some of the largest outbreaks are right next door. The MMR vaccine prevents both measles and mumps, and most schools require it for entry. Despite that, 2019 is on track to have the highest number of measles cases since the disease was declared eliminated from the U.S. in the year 2000. Why are we seeing these outbreaks and what can we do to protect our community?
Between January 2016 and July 2017, there were 150 mumps outbreaks (9,200 cases) across the country. Half of these outbreaks took place on college campuses despite the majority of students being vaccinated. Why? The effectiveness of two doses of MMR vaccine is 88% for mumps, meaning that out of 100 people, 12 may still get sick if exposed. Additionally, it appears that protection against mumps may decrease over time. How easy is it to be exposed to mumps? Mumps spreads through contact with saliva or respiratory droplets from an infected person. In a community like a college campus, where young students live in dormitories and socialize frequently, there are many opportunities for the mumps virus to spread. And, unfortunately, people with mumps can start spreading the virus before they know for sure that they are sick. The virus can be spread up to two days before developing the most common symptom, a swollen, painful jaw. The ability to spread the mumps virus before one knows that they are sick along with close personal contact inherit to dorm style living and college life, and a decreased protection from the MMR vaccine creates the ideal conditions for an outbreak.
Unlike mumps, measles outbreaks are primarily occurring among unvaccinated individuals. The majority of our current measles cases are in New York City and state where returning travelers brought measles to some Orthodox Jewish communities where vaccination rates are low. Large outbreaks have also occurred in Oregon where there are high rates of vaccine refusal among parents. The measles virus is so highly contagious, it is easy for it to spread quickly through a community if there are any unprotected people. How well does MMR vaccine work for measles? The effectiveness of 2 doses of MMR is 97% against measles AND immunity is lifelong. If we can maintain 95% or higher MMR vaccination rates we can prevent the spread of measles.
While there is no explicit content barring vaccination in major religious texts and no evidence of any association between vaccines and autism, some parents still seek exemption on these grounds.
If MMR vaccine has been a part of the routine immunization schedule for decades, why do some communities have low MMR vaccination rates? In every state, MMR is one of the vaccines required for school attendance. And, nationally, MMR rates are greater than 90%. Yet, despite requirements, almost every state allows exemptions based upon personal or religious beliefs. And there are a wide range of reasons some parents refuse vaccination or choose to pursue an exemption. For example, some religious communities refuse vaccines based upon interpretation of religious teachings. And some parents refuse MMR vaccine because of vaccine safety concerns related to autism. While there is no explicit content barring vaccination in major religious texts and no evidence of any association between vaccines and autism, some parents still seek exemption on these grounds.
Simply, the best prevention tool that we have for both is the MMR vaccine.
What can we do to prevent or stop mumps and measles outbreaks? Simply, the best prevention tool that we have for both is the MMR vaccine. Be sure that your patients, whether children or adults, are up to date as per current recommendations. Early identification of cases of mumps and measles is also important. When we suspect cases, we can use appropriate isolation practices to prevent further spread. We can also identify contacts to make sure they are protected.
For mumps specifically, it is time to implement requirements that all university and college students are up to date on their MMR vaccine and provide documentation of vaccine receipt. It is also important to consider a third MMR booster dose for people who are at risk of being exposed to mumps cases when there is an outbreak. At Temple, this has meant setting up vaccination clinics to provide MMR vaccine to students.
For measles, we are encouraging providers to remain vigilant and consider measles when seeing patients with fever and a rash, especially if they have traveled domestically or internationally. Talk to your patients and their families about any vaccine-related concerns, especially if they have a history of vaccine refusal. Know about resources to help address specific questions, such as concerns about vaccine safety. And consider partnering with community leaders to communicate the importance of vaccination.
Healthcare providers should also use our immunization registry, Philavax, to check your patients’ immunization histories and keep patients, especially students, up to date on their MMR. The Vaccines for Children (VFC) program can help you provide vaccines for publicly, under – or uninsured kids up to the age of 19.
Working together we can keep measles and mumps from spreading any further this spring and keep everyone healthy to enjoy this wonderful weather.