Immunization history available on 85% of cases revealed that 73% had received one dose of MMR vaccine and 7% were unvaccinated, and 64% of all vaccinated patients had a history of two doses.
Laboratories were able to communicate those results to clinicians, but at times, there weren't enough qualified workers or materials to perform the necessary testing. After the testing, it wasn't clear how to interpret negative results and how to convince local authorities that it was still mumps.