SAN FRANCISCO — Most parents of teenagers at a high school in Texas where a mumps outbreak occurred did not follow recommendations for immunizing their child with a third dose of the measles, mumps and rubella immunization, or MMR, according to research presented at IDWeek 2018.
A third dose of the vaccine is recommended by the Advisory Committee on Immunization Practices (ACIP) during mumps outbreaks.
“When the third dose MMR is recommended by public health officials, employers and schools impacted by mumps outbreaks should strongly consider making receipt of this vaccination mandatory for applicable employees and students in order to achieve more rapid curtailment of the outbreak,” Wendy Chung, MD, MS, chief epidemiologist in Dallas County Health and Human Services’ department of acute communicable disease epidemiology, told Infectious Diseases in Children.
After all students without mumps were offered a free third dose at school-based vaccination clinics, the researchers surveyed parents about their knowledge and attitudes about the third MMR dose. Additionally, Chung and colleagues collected data regarding their child’s vaccination status, exposure history and illness characteristics from medical records and interviews with the child.
Between February and May 2017, the researchers observed 12 probable mumps cases and 28 PCR-confirmed cases. All cases were identified at one high school (24.3 cases per 1,000 students). Nearly all students at this high school (99.8%) — including all suspected or confirmed cases — had received two doses of MMR before the outbreak.
Despite public health recommendations, only 17.6% of students chose to receive the third dose of MMR. The researchers observed one case of mumps among students who received a third dose. Chung and colleagues speculated that this was likely due to mumps exposure before receiving the third MMR dose.
Despite extensive outreach to parents through advisory letters, emails, and phone or media communications, 42% of surveyed parents of children who did not receive a third dose stated that they were unaware of the recommendations. According to Chung, one-third of these parents stated that they did not realize that a third MMR dose was offered in school-based clinics, and 26% did not believe their child was at risk for mumps. Chung said that even when parents are not concerned about the safety and efficacy of a vaccine, public uptake of vaccination recommendations faces barriers, including the lack of perceived personal risk for mumps.
“These results may be generalizable to similar outbreak settings affecting groups — such as adolescents — who may be anticipated to have poor or slow voluntary response rates to public health vaccination recommendations,” Chung added. “In outbreak settings where the implementation of vaccination mandates simply may not be feasible, the efficacy of other options could be studied, such as requiring signed declinations to ensure that public health recommendations have at least been received and understood by at-risk individuals.” – by Katherine Bortz
Chung W, et al. Abstract 659. Presented at: IDWeek 2018; October 3-7, 2018; San Francisco.
The authors report no relevant financial disclosures.