Page 40 - Christiana Care Focus June July 2018

Pharmacy Services | Therapeutic Notes
Effectiveness of a third dose of MMR vaccine
Mumps is a single-stranded RNA virus from the genus Rubulavirus and Paramyxovirus family.
Mumps often presents with symptoms including a low-grade fever, headache, muscle aches, respiratory problems, loss of appetite and swelling of the salivary or parotid glands known as parotitis.
Symptoms typically appear 16-18 days after infection and can vary greatly in severity from asymptomatic to more severe complications. The virus is spread by respiratory droplets when an infected person coughs, sneezes or talks. In the United States, pediatric patients receive a standard immunization series as recommended by the Centers for Disease Control (CDC). The measles-mumps-rubella (MMR) vaccine is among these recommended childhood vaccinations. The first of the two dose series is typically given at 12–15 months, followed by a second dose at four–six years. If a person is delayed in getting the first dose at the recommended age then the 2nd dose may be given as early as four weeks after the first dose.
Cases of mumps have dropped by 99 percent since the introduction of a vaccine in 1967. Unlike measles and rubella, however, mumps has not yet been eradicated in the United States. Large outbreaks of mumps continue to appear in pockets of the population including camps, colleges, etc. Outbreaks have often occurred within the high- density of college campuses where students are living, socializing and learning in close quarters. Of particular interest, outbreaks have occurred even when greater than 90 percent of students had received two-doses of the MMR vaccination. Outbreaks among college students may be due to several key factors including gradual weakening of vaccine-induced protection, a two-dose MMR vaccine
Kristen Audley, Pharm.D and Ashley Scopelliti, Pharm.D
effectiveness of 88 percent against mumps, and a high risk of exposure generated by the close proximity of susceptible young adults. In 2015, 90.7 percent of U.S. adolescents had received the two dose MMR vaccine series. With such high compliance, there may be fewer opportunities for natural boosting of immunity and thus an increase in breakthrough mumps cases in highly vaccinated populations. Outbreaks in previously vaccinated individuals have brought into question the possible utility of a third dose of the
MMR vaccine.
Limited data exists on the utility of a third dose of MMR making it difficult to provide effective health care guidance to the public. To combat this lack of evidence, researchers Cardemil and colleagues tested the effectiveness of a third dose of the MMR vaccine at the University of Iowa and assessed whether time-dependent decreasing immunity of the second vaccine dose played a role in the 2015 outbreak. The University of Iowa set up vaccination clinics on campus that targeted students younger than 25 years of age, for a third dose of MMR vaccine. Of 20,496 university students who were enrolled during the 2015–2016 academic year, mumps was diagnosed in 259 students. During the outbreak, 4,783 students received a third dose. The table below demonstrates the age and time of administration of the MMR vaccine among students revaccinated during the outbreak period.
There was a direct relationship between an increase in time from the second MMR dose and an increase in the risk and the occurrence of mumps. In students who had received at least two previous MMR doses, those who had received the second dose within 12 years had a
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