Introduction Measles is highly contagious, but preventable viral disease. adults of 19-38 years old at 55.68%. The group of the oldest patients (70-101 years old) had the highest ratio of seropositive subjects (100%), while adults of 60-69 years old had a seropositivity ratio of 97.22%. Conclusions These data suggest that the group of young adults who were vaccinated with one or two doses of MMR vaccine in childhood are the most susceptible for infection, and when working in contact with other people, should be re-vaccinated for protection against measles. = 13, before obligatory vaccination at age 13-14 month); 2) 1.3-16 years old (= 17, children who should be vaccinated with two doses of MMR vaccine); 3) 19-38 years old (= 88, young adults who should be vaccinated with two doses of MMR vaccine); 4) 39-45 years old (= 61, adults who should be vaccinated with one dose of MMR vaccine); 5) JTC-801 46-59 years old (= 131, adults who were not covered by an obligatory vaccination programme, occupationally active); 6) 60-69 years old (= 36, adults who were not covered by an obligatory vaccination programme, partially occupationally active); 7) JTC-801 70-101 years old (= 16, adults who were not covered by an obligatory vaccination programme, retired). In the group of adult subjects, the percentage of seropositivity was estimated at 80.12% (95% CI: 75.48-84.07). The distribution of anti-measles IgG in each age group is presented in Table 1. Table 1 Characteristic of studied groups with exact results of measles-specific IgG prevalence and values = 0.033). An age JTC-801 dependence of antibody concentrations was observed (Fig. 1) and divided into three groups based on distribution: two with the lowest and one with the highest concentration of antibodies. The first group included patients with the lowest values in the 0-1 years old group. The second group included 20-45 years old patients, and the third group included patients older than 45 years, in which anti-measles IgG concentrations reached the highest values (Fig. 1). Individuals aged 20-45 had the most diversified distribution of results. Open in a separate window Fig. 1 Distribution of IgG anti-measles antibodies according to patients age. Red circles show the population with seronegativity, the green circle shows the group with the highest level of immunization, and the blue group showed the highest diversity A significantly higher number of seronegative patients were in the male group than in the women group (= 0.04). The studied groups differed significantly in measles-specific IgG values, which are presented in Table 1 and Figure 2. There was also a significant difference in the seronegativity/seropositivity ratio between examined aged groups, with the lowest seropositivity TSPAN6 ratio in the group of subjects that were 19-38 years old (Fig. 3). Open in a separate window Fig. 2 Median values of measles-specific IgG concentration is selected patient groups (*< 0.05, ****< 0.0001) Open in a separate window Fig. 3 Numbers of seropositive and seronegative subjects in the studied age groups. The difference is statistically significant, < 0.0001 Discussion The results showed that 78.02% of patients enrolled in the study had positive titres of measles-specific IgG antibodies. The lowest ratio of seropositivity was found in a group of adult patients who were covered by an immunization schedule with two doses of MMR vaccination in childhood, and in a group of children aged 0-1 who were not covered by vaccination. This observation is consistent with the results from other studies . According to the immunization schedule appropriate for each study group, a second vaccination should have been administered at the age of 7-10, which means that the time between the last vaccination and the test for the presence of specific IgG was 9-28 years. Interestingly, the seropositivity ratio was higher in a group that, according to immunization schedule, should have administered one dose of MMR; however, we cannot exclude that this group also involved non-vaccinated subjects, since coverage of vaccination in 1978 was estimated at 50% and in 1981 it was ~80% . The seropositivity ratios observed in our study between vaccinated once and twice are not accordant with the results from a study performed in Japan . Here, we show a significantly lower titer of antibodies in the group vaccinated twice than after one dose of MMR. In addition, the seropositivity ratio was the highest.