[G1 mumps virus outbreak in the province of Almeria in 2005].

BACKGROUND Despite high levels of triple MMR vaccinations being recorded on Spain, epidemic mumps outbreaks are still being reported. This study is aimed at describing an outbreak reported in the province of Almeria in 2005 and of evaluating the degree to which the vaccinated population was affected. METHODS Descriptive study of reported cases. VARIABLES STUDIED Basic Health District, municipality, age, sex, type of population (Spanish-born and foreign), date of symptom onset, symptoms, complications, vaccination status, vaccine strain and diagnostic testing. INFORMATION SOURCES disease reporting files, epidemiological surveys, microbiological data, vaccination card, District vaccine software and Andalusian Institute of Statistics demographic data. Rates per 100,000 inhabitants were calculated by age groups and population type. The Student's t-test was used for comparing means. RESULTS A total of 145 cases from 17 municipalities were reported. A total 63.4% were males. The group showing the highest incidence was that of 10-14 years of age, with a rate of 405 per 100,000. The highest rate was among the Spanish-born population (128.7). A total of 52.4% of the cases were found to have been administered some dose of vaccine, 69.7% of them with two doses and 71.1% some Jeryl Lynn strain. Mumps virus was confirmed in 43 cases, the G1 genotype having been identified in 6 cases. CONCLUSIONS An outbreak of G1 genotype mumps virus is confirmed, the Spanish-born population of different age groups having been affected to a greater extent. Over half of the cases were vaccinated individuals.