The population of the Russian Federation has been divided into 5 groups according to their immunity to measles; the epidemiological importance of this division for the prognosis of measles morbidity for the next decade has been substantiated. As revealed in this study, children under 6 years and born in 1966-1978 who have received only one immunization are least protected from measles and make up the main socio-epidemiological nucleus of the population which will determine the level of measles morbidity in the next decade. The conclusion has been made on the necessity of mass immunization (revaccination) of high school and college students and groups of servicemen not later than 1995 in order to eliminate measles by the year of 2000.
Observations over the measles epidemic process in Leningrad showed that the sporadic morbidity level reached in 1974--4.1 per 100 000 residents; however periodic elevation and decline of morbidity and tis seasonal variations persisted. A rise of morbidity in 1972--1973, and by preliminary data--in 1975, occurred on account of the older age groups. There was revealed no dependence of the disease incidence among the persons vaccinated on the time lapse after their vaccination. Individual batches of live measles vaccine issued in 1963--1969 were not up to the standard, this serving as one of the cases of the occurence of group incidence of the infection in some foci.
With vaccination having become usual practice in health care, the incidence rate of measles in the Donetsk region has fallen 53.6-fold versus the prevaccination period. Bet there are also negative processes in the epidemiology of measles; of these, ever more frequent occurrence of the infection under consideration in persons of mature years is worthy of particular mention. The specific weight of juveniles and grown ups had come to be 68.65% in 1998 vs 6.3% in 1975. Since 1993 the case rate of measles is noted to be at its greatest among children less than two years of age and among adolescents, which fact can be referred to effects on the level of immunity of different factors including that of time of more than five years having elapsed since the previous immunization. The administration in 1997-1998 of vaccines to non-vaccinated persons and to unprotected ones permitted the incidence rate of measles to be kept down in juveniles and adults but the age brackets of sick persons were in fact the same as before the additional vaccinations done. The state of things discribed above attests to the need for development of cardinal measures to raise the level of individual and collective immunity in juveniles and adults.
An outbreak of measles that occurred in Anchorage, Alaska, in 1998 resulted in 33 diagnosed cases: 26 were laboratory confirmed and 7 were clinically confirmed. Twenty-nine (88%) of 33 cases occurred in individuals who had not been immunized with at least two measles-mumps-rubella (MMR) vaccinations; 25 (76%) of 33 occurred in school-age children, 0 to 19 years of age. This study identifies the difference in the incidence of measles between the civilian school-age population, who was not completely immunized (two MMR vaccinations given at least 30 days apart), and the military dependent population who had been completely immunized. All cases occurred among civilians, and most (25 of 33 confirmed cases) were associated with school attendance. The authors conclude that a two-dose regimen of MMR vaccine is required to adequately protect individuals against measles.
The study of measles morbidity in Donetsk Province in 1960-1984 and the study of antimeasles immunity in different groups of the population have shown that the problem of the liquidation of measles cannot be solved by immunizing the population in a single administration of the vaccine. To enhance the effectiveness of the immunoprophylaxis of measles and its influence on the epidemic process, a number of problems must be solved with the aim to improve the quality of the vaccine, especially its thermal stability, to establish the possibility of shifting the beginning of immunization from 15-17 months to 12 months of age, to increase the coverage of children with immunization against measles by decreasing the number of groundless exemptions from immunization and by immunizing children in risk groups according to individual schedules and dosage, to carry out selectively the booster immunization of persons who have lost their postvaccinal immunity, as revealed by laboratory test, or in whom such loss may be supposed, to introduce the objective method (indirect hemagglutination test) for controlling the state of immunity among different groups of the population into laboratory practice at sanitary and epidemiological stations. As to the possibility of the liquidation of measles, the statement of this problem is correct, but for its solution a complex of additional prophylactic and epidemic-control measures should be taken.
In the present article there are considered the features of the formation of post-vaccination immunity in dependence on the level of anthropogenic load. The level of anthropogenic load on urban and rural areas on the base of the database of the Regional Foundation for Socio-hygienic monitoring of the Orenburg region has been determined. The assessment of the state of post-vaccination immunity was performed on average long-term indices in the indicator groups of children and adults. The distribution of the population throughout the strength of immunity to measles in dependence on area of residence has been determined. The relationship between the formation of post-vaccination immunity area of the residence has been established. In the population residing in urban areas the number of post- vaccination antibodies was significantly lower than that of the population in rural settlements.
Anamnestic data in respect to measles failed to correspond to the results of serological examination of contacts at the foci of the given infection. The collective immunity level in children's institutions is inadequate for the prevention of measles outbreaks. The incidence of the disease depended both on the level of immunity among the children and on the duration of presence of the source of infection in the focus. Live measles vaccine protected 90 percent of the vaccinated children from contracting the disease in the foci. At the very beginning of the postvaccinal period immunization defects were revealed in 26.5 percent of the vaccinated children who fell ill with measles. Morbidity index among the vaccinated individuals constituted 3.8 percent. One of the causes of measles contraction by the vaccinated individuals was the loss of postvaccinal immunity. Systematic control over the antimeasles immunity level with the aid of serological investigations is necessary for the purpose of detection of persons sensitive to measles in children's collective bodies.
WHO has adopted a goal of eliminating indigenous measles from the European Region by the year 2007. The strategy focuses on reducing the proportion of susceptible individuals in the population to low levels and maintaining these low levels of susceptibility. Routine vaccination against measles for children aged 13-15 months was introduced in Poland in 1975, and a second dose added in 1991. High coverage (> 95%) is achieved with both doses. In order to assess progress towards measles elimination in Poland, a serological survey was performed to evaluate the impact of vaccination on the susceptibility profile of population. Three thousand residual serum samples from individuals aged 1-30 years were collected from hospitals in six selected voivodeships (administration units) in Poland. These were tested for measles-specific IgG using a commercial ELISA. Overall 4% (120/3000) were negative for measles virus antibody. The highest proportion of negatives (8.2%) occurred among cohorts born 1977-81--the only cohorts in which susceptibility exceeded the WHO targets. 'Catch-up' vaccination strategies should target these cohorts.