Probability of exposure to the wild measles virus in adult population - Estimation from seroepidemiology and historical data

Vaccination against measles is one of the most effective public health interventions which has saved millions of lives and interrupted circulation of the natural virus in the population. However, it is widely accepted that the immunity after vaccination can wane, especially in those who have had no contact with the virus. This study aimed to classify the particular birth cohorts of adults with regard to their exposure to the wild measles virus in the population with a long history of mandatory vaccination. We introduced two methods. In the first, we estimated the probability of exposure to the wild virus through an analysis of antibody levels from the Immunologic Survey performed in the Slovak Republic in 2018, while the second was based on historical epidemiological data. Both methods resulted in similar estimations. Cohorts born in Slovakia before 1964 can be considered to be cohorts in which most people were exposed to the wild measles virus. Cohorts born after 1977 can be designated as cohorts that most likely did not come into the contact with the wild virus. Cohorts born between 1965 and 1976 are composed of a mixture, with a decreasing proportion of people exposed to the wild virus with increasing year of birth. The proposed methods can help identify potential immunity gaps in the adult population. They can be applied in other countries with high measles vaccination coverage to estimate the probability of exposure to the wild measles virus in particular birth cohorts.

Quantification of Waning Immunity After Measles Vaccination-Evidence From a Seroprevalence Study

We aimed to quantify rates of waning immunity after measles vaccination from seroprevalence data collected in a study of a population with high vaccination coverage and a fixed vaccination schedule. Data were collected during a national survey (the Immunological Survey) carried out in the Slovak Republic in 2018. The average rate of waning immunity against measles after the first dose of measles, mumps, and rubella (MMR) vaccine (ages 1.5-10 years) was 9.7% per year from the geometric mean titer value of 2,634 mUI/mL. The average waning rate after the second dose of MMR vaccine (ages 10-33 years) was significantly lower: 4.8% per year from the lower geometric mean titer of 1,331 mUI/mL. This decline in antibody levels suggests that vaccine-induced protection may be compromised and results in an increase in the proportion of seronegative/borderline individuals. These outcomes may provide a valuable source for critical assessment of direct and indirect effects of MMR vaccination.

Association of the role of personal variables and nonoccupational risk factors for work-related carpal tunnel syndrome

OBJECTIVES

The purpose of this study was to identify personal variables and nonoccupational risk factors for carpal tunnel syndrome and to analyse the strength of association of these factors.

METHODS

We performed a case-control study with 162 cases and 300 controls. We studied consecutive patients with an electrophysiologically confirmed diagnosis of symptomatic carpal tunnel syndrome. Univariate analysis was performed in the case group and control comparing them for presence of various risk factors. Multivariate analysis was carried out through logistic regression.

RESULTS

The mean BMI and age were greater in the case group than in the control. Multivariate analysis showed that BMI (OR = 1.05, 95% CI = 1.01-1.11) and arterial hypertension (OR = 4.63, 95% CI = 2.88-7.44) were the only factors significantly associated with carpal tunnel syndrome. The age, cigarette smoking and alcohol drinking were at the edge of significance.

CONCLUSIONS

Carpal tunnel syndrome is the most common peripheral neuropathy and has been related to occupational activities in some but not all studies. Clarifying this relationship has important implications for workers' compensation systems. Based on our findings, BMI and arterial hypertension are considered to be the most significant risk factors of carpal tunnel syndrome in our study.

MATHEMATICAL MODELLING OF VARICELLA SPREAD IN SLOVAKIA

AIM

Varicella is a highly contagious disease. In Slovakia, 15,000-30,000 cases are reported annually. However, vaccination against varicella is not widely used in Slovakia. The aim of this paper is to predict the influence of vaccination administrated in different ages on the disease occurrence in different age groups.

METHODS

Deterministic, age-stratified SIR (susceptible-infected-recovered) model with stable population was used for prediction of varicella spread in Slovakia.

RESULTS

Vaccination of a group designated as 0 influences the proportion of susceptible and infected persons in all age groups, vaccination of 10 years old ones affects only the proportion of susceptible and infected individuals older than 10 years.

CONCLUSION

The increase of vaccination coverage should have a positive impact on the incidence of varicella in Slovakia. In case of vaccination coverage of 0 group in the range of 30-75%, it is necessary to pay attention to the protection of older children and adults.

[Occupational tuberculosis in Slovakia and in the Czech Republic]

STUDY OBJECTIVE

To conduct a retrospective 15-year study to monitor trends in the number of employees at risk for occupational tuberculosis (TB) (levels III and IV) in the Slovak Republic, and in particular in the sector of economic activities Q (health care and social assistance). Furthermore, to analyze reported cases of occupational TB and to compare the incidence and sex-specific and age-specific prevalence with the data reported in the Czech Republic.

MATERIAL AND METHODS

Data on the number of employees at risk of exposure to occupational TB were derived from the Automated Risk Classification System of the Slovak Republic. Data on cases of occupational TB were taken from health statistics (Institute of Health Information and Statistics/National Health Information Center in the Slovak Republic and the National Institute of Public Health in the Czech Republic). A retrospective analysis was conducted (for 1998-2012) of reported cases of occupational TB, selected from Article 24 of the List of occupational diseases (infectious and parasitic diseases except tropical infectious and parasitic diseases and diseases transmissible from animals to humans). The selection criterion was a TB diagnosis according to ICD-10. In the Czech Republic, the data were derived from Article 5.1.02 (tuberculosis), Chapter V. of the List of Occupational Diseases. The data obtained were analyzed by methods of descriptive statistics.

RESULTS

The numbers of employees with a level III risk of exposure to occupational TB in the Slovak Republic declined by 30% over the 15 years of study and by 40% in category Q. In 2012, 2027 employees were classified in category III and 1442 of them belonged to group Q. Females accounted for 81-84% of employees at risk of exposure to occupational TB. Eighty-six and 181 cases of occupational TB were reported in the Slovak Republic and in the Czech Republic, respectively, in 1998-2012, with the incidence showing a downward trend in both countries. TB of the respiratory tract was reported most often (83.7% of the total of reported cases of occupational TB). As expected, more cases occurred in females than in males (1.9 times as many cases in females as in males in the Slovak Republic and three times as many cases in females as in males in the Czech Republic). The incidence of occupational TB was the highest in sector Q, with the highest absolute numbers reported in nurses. In 2012, the incidence rates of occupational TB were 0.22 cases per 100,000 sick benefit policy holders in the Slovak Republic and 0.13 cases per 100,000 sick benefit policy holders in the Czech Republic.

CONCLUSION

The incidence of occupational TB has a downward trend in both countries, similarly to TB incidence in the general population. A negative aspect in both countries is the incidence of occupational TB at the middle productive age, in contrast to the population occupationally non-exposed to TB. Slovakia is surrounded by higher prevalence countries, with the exception of the Czech Republic. It cannot be ruled out that, in addition to the known factors influencing the prevalence of TB, including occupational TB, migration from eastern countries, including job search migration, can also play a role in increase in TB cases. It is vital to continue epidemiological surveillance and to reduce the risk of TB as much as possible also in healthcare settings by adhering to barrier nursing practices. Cases of active TB need early and adequately long, controlled treatment in order to reduce, among others, the incidence of multi-drug resistant TB.

Occupational viral hepatitis in the Slovak and the Czech Republic

BACKGROUND

The proportion of occupational infectious diseases (ID) in the total number of occupational diseases reported in the Slovak Republic (SR) and the Czech Republic (CR) was decreasing from 1973 to 2010. Our study presents a longitudinal analysis of the occurrence of occupational infectious diseases in the Slovak Republic and the Czech Republic in the period from 1973-2010 with special focus on viral hepatitis.

METHODS

The sources of data were national health statistics of Czechoslovakia, the Czech Republic and the Slovak Republic. Descriptive statistical methods were used for data analysis. Incidence rate of reported diseases was calculated per 100,000 general population or per 100,000 people insured.

RESULTS

During the studied period, a total of 2,931 and 8,318 cases of occupational viral hepatitis (VH) were reported in the Slovak Republic and the Czech Republic, respectively. The incidence culminated in the late 1970s when hepatitis represented almost 50% of all reported occupational infectious diseases. Most cases of occupational hepatitis occurred in health and social services. Since the early 1980s, a steep decrease in the incidence of hepatitis has been observed due to the gradual implementation of mandatory vaccination against hepatitis A and B in risk groups. In SR in 1973, the incidence rate of occupational infectious diseases and that of occupational viral hepatitis was 10.85/100,000 and 1.86/100,000, respectively. In 2010, these rates decreased to 0.74/100,000 and 0.20/100,000, respectively. In CR, the incidence rates of occupational infectious diseases and that of occupational viral hepatitis reported in 1973 were 11.75/100,000 and 3.69/100,000. In 2010, reported incidence rates were 1.71/100,000 and 0.10/100,000, respectively.

CONCLUSION

Although the incidence of occupational viral hepatitis has dramatically decreased in the Slovak and the Czech Republic as well as in other Visegrad group countries during the studied period, we emphasize the necessity of continuing epidemiological surveillance of hepatitis, especially with regard to the recent incidence increase of viral hepatitis C.