Drug Information System in the Czech Republic.

The Drug Information System (DIS) enables to monitor: incidence (the numbers of newly registered problem drug users); prevalence (the numbers of existing problem users visiting treatment/contact centres in a certain time period or as of a certain date); types of used drugs, manner of their application, frequency of use, their availability, purity; health (but also social consequences) of drug use (hepatitis, HIV; social and economic consequences); demographic profile of affected persons (age, sex, employment, education, etc.); time trends showing potential changes of the above specified indicators, including changes in the geographic distribution. Hygienic Service was mandated to create and operate the DIS in the Czech Republic. The system has been in operation since 1 January 1995 and it is based on the monitoring of basic health indicators.

Trends in the incidence of problematic drug addicts in the Czech Republic, 1995-1996.

During 1996 there were 3,252 newly registered problematic drug users (incidence 31.5/100,000 inhabitants) while in 1995 it was only 2,470 drug users (23.9/100,000 inhabitants). Trends in the incidence of problematic drug users and their age structure and regional distribution between 1995-1996 characterise the current drug scene in the Czech Republic as follows: Slightly upward trend of the incidence of problematic drug users with prevalent position of pervitin. Dramatic increase in heroin use in 1995 has changed in slower growth of the number of new users in 1996. Proportion of men to women is totally 2:1 with major differences between individual drug types. Gradual decrease in the average age of problematic users, especially women, and decrease in the age of first use of primary drug. The most affected age group are young people between 15 and 19. Increasing number of problematic users under 15 is also alarming. Major differences in the incidence of problematic users and in the different representation of individual types of drugs in regions with prevalence of Northern Bohemia and Prague. High and gradually upward trend of injection drug users; national average nears to 60% and thus exceeds Prague and Northern Bohemia regions. Injection users under 19 represent 1/3 of all registered problematic users and approximately 50-60% of all injection users.

Prevalence study of serious substance abusers in the Czech Republic.

In October of 1995, a prevalence study of serious substance abusers was carried out in the Czech Republic. The prevalence study focused on: 1. persons hospitalized because of drug addiction as of 31.10.1995; 2. persons who visited one of the treatment/contact centres during October of 1995. Data on serious addictive substance abusers were collected from 142 treatment/contact centres. The overall prevalence in the 15-39-year age group is 30.3/100,000 inhabitants, the highest in Prague (115.0/100,000 inhabitants), followed by Northern Bohemia (34.1) and Northern Moravia (32.0). The most frequently used primary drug remains pervitin (349 users, i.e. 35.5%), followed by heroin in the second place (126, i.e. 12.9%), marihuana in the third place (94, i.e. 9.4%) and toluene in the fourth place (81, 8.1%). The 15-19-year age group is the most affected, and corresponds to 36.9% of all users. In this age category, women predominate (47.2% of all users). Heroin is equally used in the 15-19-year and 20-24-year age groups, while pervitin is used most in the 15-19-year age group, as are marihuana and toluene; the frequency of gambling increases more or less with age. Heroin is used most in Northern Bohemia (48.4%) and Prague (24.6%), and pervitin in Prague (34.7%) and Northern Moravia (18.9%). Data on injection administration of drugs, which is dangerous because of the possibility of transmission of hepatitis and HIV, confirm that almost two thirds of all users prefer this means of application. The great majority of all serious abusers are persons with only elementary schooling.

[The present epidemiologic status and prognosis in measles]. / Soucasná epidemiologická situace a prognóza spalnicek.

During 1990 and partly also 1991, after a practically 10-year zero incidence of measles on the territory of the Czech Republic a measles epidemic broke out. The most severely affected group were adolescents aged 15-19 years who were immunized only by a single dose of vaccine. Conversely the lowest morbidity was recorded in 2-9-year-old children who were immunized already with two doses. The cause of the epidemic was primary failure of the vaccine leading to a low level of collective immunity in some population age brackets. The authors discuss and explain the strategy of immunization against measles involving two doses of vaccine after a 6-10-month interval. In the conclusion possibilities to achieve permanent elimination of measles on our territory are discussed.

Expanded program on immunization and its implementation in the Czech Socialist Republic.

National immunization programs carried out in the CSR are here confronted with the EPI regional targets for Europe, a component of the WHO global program "Health for all by the year 2000". The EPI target diseases to be brought under control in Europe by 1990 include measles, poliomyelitis, diphtheria and neonatal tetanus; control of congenital rubella infection is to be achieved by the year 2000. The presented data show that Czechoslovakia has succeeded in implementing this program much ahead of the WHO time schedule. The elimination of measles infection was achieved in 1982, poliomyelitis was brought under control in 1961, and the effective diphtheria control has been in effect since the mid-1960s. Cases of neonatal tetanus are absent in the CSR since 1965, the annual incidence of postnatal tetanus is permanently 0.1-0.2 per 100,000 population. The goal of achieving the rubella-free status and thus the elimination of congenital rubella cases at country level is expected to be reached in the early 1990s. Implementation of the remaining WHO recommendations pertinent to infections other than EPI target diseases appears also satisfactory. Regular immunization against whooping cough, one of the oldest immunization programs in Czechoslovakia, succeeded in effectively eliminating this infection in the early 1970s. Selective immunization campaigns against influenza infection, introduced many years ago, help protect, together with a large-scale use of available chemoprophylactics, some 200,000 individuals every year in CSR. The hepatitis B immunization program was started in 1983 and is primarily limited to health service staff, which is in line with the existing WHO recommendations. Inception of the regular immunization program against mumps is planned for the beginning of 1987.

Four years of measles elimination in the Czech Socialist Republic.

In 1982, Czechoslovakia succeeded in eliminating measles infection throughout the country. The paper describes the strategy of the measles immunization program following its introduction in 1969, showing it to reflect the objective epidemiological situation as revealed by the regular immunological surveys carried out in a broad population sample. As it turned out, decisive for achieving and maintaining a permanent measles elimination in the country was the introduction of second vaccination into the regular immunization schedule. Since 1982, its timing of is from 6 to 10 months after primary immunization. Over the 4-year period between 1982 and 1985, confirmed measles occurred only sporadically in the CSR, 115 cases altogether, and of these as many as 67 were classified as imported or their immediate contacts (38 measles patients were tourists from abroad). Of these 115 measles cases, 52 had had vaccination prior to acquiring the disease, 46 were individuals who had never before been vaccinated and in the remaining 17 patients no vaccination data were available. The vaccine failures, at least in 18 cases, could have been explained by the primary immunization prior to reaching 15 months of age. According to the estimates, at least 670 thousand cases of measles, 470 deaths, 100 thousand complications and some 33 thousand hospitalizations had been averted between 1972 and 1985 on the territory of CSR as a result of the introduction of the measles immunization program in Czechoslovakia.

Detection of postvaccination mumps virus antibody by neutralization test, enzyme-linked immunosorbent assay and sensitive hemagglutination inhibition test.

A group of 251 children aged 2-3 years given live attenuated mumps virus vaccine PAVIVAC of Czechoslovak production were tested for antiparotitis antibody levels in pre- and postvaccination sera by neutralization test (NT), enzyme-linked immunosorbent assay (ELISA) and sensitive hemagglutination inhibition test, enhanced by heterologous antibody to human immunoglobulin G (E-HIT). The prevaccination findings were as follows: positive ELISA IgG titres, neutralization antibodies and hemagglutination inhibition antibodies were present in, respectively, 35%, 25.9% and 27.9% of the sera. Postvaccination seroconversions were evaluated in 159 susceptible vaccinees whose prevaccination sera had been negative by all three tests. The lowest seroconversion was detected by NT (74.2%), seroconversions by ELISA and E-HIT were appreciably higher (82.4% and 86.8%, respectively). The seven children showing a seroconversion by E-HIT but not by ELISA had a 4 fold increase of anti-mumps ELISA IgG antibodies as well, but the rise of antibody titres was at a level falling in the range below the positivity criterion for ELISA. The statistically evaluated detection rate for antibodies was significantly higher (significance test "t") by ELISA as compared with neutralization test. However, antibody levels (geometric mean titres) were 8-10 times lower in postvaccination sera than in convalescent sera of 30 children with mumps in all three tests.

Control of measles in Czechoslovakia (CSSR).

Mass immunization against measles in the Czechoslovak Socialist Republic (CSSR) began in 1969 and utilized the Czechoslovak vaccine, which corresponds in its parameters to the further-attenuated measles vaccines. The immunization rate for relevant age groups of the population (i.e., children born in 1968-1980) is already 98%-99% in 1982. Measles morbidity decreased to less than 2% of the incidence before the introduction of immunization, and the mortality now is practically negligible. The decade 1972-1982 produced significant changes in epidemiologic characteristics of measles. Of importance is the gradual shift in the age distribution of affected children to older, nonimmunized age groups. Results of yearly immunologic surveys of a broad, randomly selected population sample have become the decisive criteria for evaluation of vaccine efficacy. The program of revaccination of all children was chosen as the optimal strategy for maintaining measles elimination. This program aims at ensuring a level of herd immunity in the whole population of greater than or equal to 95%.