[Wide spread inflammation of the parotid glands (mumps): underestimated disease. I. Epidemiology of the mumps and its medical meaning in Poland].

: Mumps is commonly considered a "mild" infectious disease in children because death due to mumps is very rare. However, mumps causes a high rate of complications in young adults, and its burden should not be underestimated. Before the introduction of vaccine, mumps was a common infectious disease with high incidence rates which exceeded 100 per 100,000 population in most countries. Poland continues to belong to the group of countries, which do not use mumps vaccine. In Poland, the number of reported mumps cases per year ranges from 40,000 to 220,000, yielding an annual incidence rates of 110 and 570 per 100,000 population. It is estimated that each year in Poland, mumps causes 1000 cases of aseptic meningitis (range 400 to 2,200), 100 cases of encephalitis, 250 to 1375 cases of epidymo-orchitis in post-pubertal men, 50-275 cases of oophoritis in women. The age distribution of mumps cases is characteristic for a country that does not use mumps vaccine. For more that 20 years, the highest mumps incidence has occurred in children aged 5-9 years. In many countries the number of reported cases has declined significantly following the introduction of mumps vaccine, and in several countries the incidence has fallen to less than 1 per 100,000 population. Several countries using mumps vaccine have reported a shift in the age distribution of mumps cases, with an increased incidence in older children and young adults. Countries with high levels of coverage with measles-mumps-rubella (MMR) vaccine have nearly eliminated encephalitis associated with these diseases. A few countries using mumps vaccine have experienced relative resurgence of the disease, either due to incomplete vaccine coverage of certain age groups (USA) or problems with the long-term immunogenicity of mumps vaccine based on the Rubini strain (Portugal, Switzerland).