A measles outbreak among people with measles vaccination history in Beijing

A measles outbreak occurred in Beijing in 2013. 5 cases were diagnosed, they all received more than 2 doses of measles vaccine 8-12 years ago. The serological detection indicated that measles IgM were negative in all cases and measles IgG titers in convalescent phase were 4 times higher than that in acute phase in 2 cases. Nucleic acid testing for swab specimens confirmed that the pathogen was measles virus genotype H1. Secondary measles immunization failure might be the main cause of vaccinated people to be affected in this outbreak. Virus nucleic acid detection plays an important role in the diagnosis of measles due to secondary immunization failure.