Impact of the COVID-19 Pandemic on Measles Vaccination Coverage and Estimated Catch-up Efforts for Serbia.

BACKGROUND: Measles is highly infectious, requiring ≥95% vaccine coverage rate (VCR) to prevent outbreaks. This study aimed to understand the impact of the COVID-19 pandemic on routine measles-containing vaccine (MCV) VCRs in Serbia and estimate national and regional catch-up vaccination required to prevent outbreaks. METHODS: A multiplier model was used to calculate annual MCV dose 1 (MCV1) and MCV dose 2 (MCV2) VCRs for children 1-6 and 6-12 years of age, respectively, for 2011-2022. Postpandemic (2023-2024) VCRs were modeled. The numbers of administered doses were compared to prepandemic and postpandemic, and monthly catch-up rates were calculated for 12-, 18- and 24-month campaigns. RESULTS: Between prepandemic and pandemic periods, national MCV1 VCR decreased from 88% to 81%, while MCV2 VCR decreased from 92% to 89%, corresponding to 20,856 missed MCV1 and 8760 missed MCV2 doses. Assuming national VCRs returned to prepandemic levels post-2022, 18% of children 1-6 years of age and 11% of children 6-12 years of age would have missed their MCV1 and MCV2 doses, respectively, by 2024. To catch up missed doses under this scenario, most regions would require monthly catch-up rates of 25%, 16% or 12% for MCV1 and 14%, 9% or 7% for MCV2, considering 12-, 18- or 24-month campaigns, respectively. CONCLUSIONS: The pandemic negatively impacted MCV VCRs in Serbia, leaving a sizeable proportion of children with missed doses. Significant catch-up efforts are required to recover VCRs to prepandemic levels and avoid future measles outbreaks, with increased monthly administration rates versus those in prepandemic periods.

Overview of the Implementation of the First Year of Immunization against Human Papillomavirus across Different Administrative Units in Serbia and Montenegro.

Despite the availability of a safe and effective vaccination, uptake of human papillomavirus (HPV) vaccination remains low worldwide. We aimed to analyze the coverage of HPV immunization during the first year of the immunization program and the sociodemographic characteristics across different administrative units in Serbia and Montenegro. Coverage of HPV vaccination in Serbia for females aged 9-14 and 15-19 years was 5.5% and 5.9%, respectively. The coverage rate of immunization against HPV in Montenegro for girls aged 9-14 years was 22.1%. Within Serbia, only one administrative region (Moravica) had HPV immunization coverage in girls 9-19 years old above 10%, 11 districts had coverage from 5 to 10%, while 13 districts had coverage below 5%. As per Montenegro, two administrative units, Cetinje and Berane, reported the highest coverage, with 39% and 36.4% of vaccinated eligible girls, respectively. When we explored the coverage of HPV immunization among girls aged 9-19 years across different regions in Serbia, we observed that the level of coverage did not correlate with the number of pediatricians or with the population density. In Montenegro, we observed a similar situation. On the other hand, we noticed a statistically significant moderate negative correlation (r = -0.446; p = 0.026) between HPV immunization coverage and the percentage of illiterate women in the administrative units. Comparing the coverage between the two countries we found that the higher coverage in Montenegro corresponded with a smaller number of female populations aged 9-14 years, with higher average net monthly income, with smaller population density and smaller number of pediatricians, among divorced persons, and among those without formal education or incompletely primary education. Taking into account the experiences in Montenegro, increasing immunization coverage in Serbia could be achieved through a more vigorous educational campaign targeting schools, the general population, and healthcare workers as well as by additionally incentivizing those engaged in these activities.

Are pediatricians responsible for maintaining high MMR vaccination coverage? Nationwide survey on parental knowledge and attitudes towards MMR vaccine in Serbia.

AIM: To assess parental knowledge and attitudes related to MMR vaccination and to determine factors associated with parental decision whether to vaccinate their child with MMR vaccine in Serbian population. METHODS: The selection of participants was performed using multi-phase sampling. Seventeen out of the total 160 public health centers on the territory of Republic of Serbia were randomly selected. All parents of children up to the age of 7 who visited the pediatrician at the public health centers from June to August 2017 were recruited. Parents filled in an anonymous questionnaire regarding their knowledge, attitudes and practices in immunization with MMR vaccine. The relative contribution of different factors was explored by univariable and multivariable logistic regression analysis. RESULTS: The majority of parents were female (75.2%), with mean age of 34.3 ± 5.7 years, and the average age of children was 4.7 ± 2.4 years, 53.7% of them were girls. In the multivariable model, getting information on vaccination from a pediatrician was associated with 7.5 fold increased probability to vaccinate child with MMR vaccine (OR = 7.52; 95% CI 2.73-20.74; p<0.001), while previous vaccination of the child increased this chance two times (OR = 2.07; 95% CI 1.01-4.27; p = 0.048), and having two children was associated with 84% increase in chance of vaccinating child with MMR vaccine compared to having one child or three or more children (OR = 1.84; 95% CI 1.03-3.29; p = 0.040). CONCLUSION: Our study emphasized the key role of pediatricians in the formation of parental attitude on MMR vaccination of their child.

Understanding vaccination communication between health workers and parents: a Tailoring Immunization Programmes (TIP) qualitative study in Serbia.

Vaccine communication between health workers and parents affects parental acceptance, so understanding this is particularly important when vaccination rates drop. This paper presents the findings of a qualitative research study conducted in Serbia as part of a Tailoring Immunization Programmes (TIP) project. The aims were to explore the process of vaccination communication between health workers and parents (accepting, indecisive, delaying, refusing), and identify barriers and drivers to effective communication. In-depth interviews with 14 health workers were supplemented and qualified by observations of 40 consultations, using thematic analysis. Study sites were two community health centers in two Belgrade municipalities where a significant drop in childhood vaccination rates had occurred. Key findings were: (1) communication mainly took place between pediatricians and parents, while nurses focused on administering vaccines. (2) Health workers were confident in their skills to communicate and address concerns of accepting and indecisive parents, successfully applying specific strategies. (3) When interacting with delaying and refusing parents, they sometimes agreed to delay vaccination to maintain relationships, confident that most parents would vaccinate in due course. (4) Some refusing parents asked questions grounded in a socio-political agenda regarding vaccines or vaccination. Such questions exceeded the domain of health workers' expertise, which affected the communication between them. (5) Health workers' behavior in consultations was sometimes affected by parents' (dis) trust in their recommendations about vaccination. The study revealed that health workers in Serbia require additional skills and techniques to respond to parents who refuse and wish to delay vaccination, to secure timely vaccination.

Trend in mandatory immunisation coverage: linear and joinpoint regression approach, Serbia, 2000 to 2017.

BackgroundAnalyses of temporal trends in immunisation coverage may help to identify problems in immunisation activities at specific points in time. These data are essential for further planning, meeting recommended indicators, monitoring, management and advocacy.AimThis study examined the trends of mandatory vaccination coverage in the period 2000-2017 in Serbia.MethodsData on completed immunisations were retrieved from annual national reports of the Institute of Public Health of Serbia during the period 2000-2017. To assess the trends of immunisation coverage, both linear and joinpoint regression analyses were performed. A probability p < 0.05 was considered significant.ResultsOver the period 2000-2017 linear regression analysis showed a significant decline in coverage with the primary vaccination against poliomyelitis, diphtheria, tetanus, pertussis and measles, mumps, rubella (MMR) (p ≤ 0.01). In the same period, coverage of all subsequent revaccinations significantly decreased, namely, first revaccination for pertussis (p < 0.01); first, second and third revaccination against diphtheria, tetanus and poliomyelitis (p < 0.01); and second dose against MMR before enrolment in elementary school (p < 0.05). Although linear regression analysis did not show change in vaccination coverage trend against tuberculosis (Bacillus Calmette-Guérin; BCG), hepatitis B (HepB3) in infants and diseases caused by Haemophilus influenzae type b (Hib3), the joinpoint regression analysis showed that the coverage declined for BCG after 2006, HepB3 after 2010 and Hib3 after 2008.ConclusionTo achieve and keep optimum immunisation coverage, it is necessary to address barriers to immunisation, such as the availability of all vaccines and vaccine-hesitancy among parents and healthcare workers in Serbia.

Epidemiological, clinical and laboratory characteristics of the measles resurgence in the Republic of Serbia in 2014-2015.

The Republic of Serbia is a country with ongoing endemic transmission of measles. The aim of this study is to summarize the main characteristics of the measles resurgence that occurred in Serbia in 2014-2015. The national surveillance data on measles was analysed in relation to the clinical, epidemiological and laboratory data. Between November 2014 and December 2015 a measles resurgence with 420 cases was observed in Serbia. Measles virus was initially introduced by and spread among citizens of Bosnia and Herzegovina with temporary residence in Serbia, before spreading to the resident population. Of the 223 patients with available medical records, 173 (77.6%) were unvaccinated. The overall measles incidence during the outbreak was 5.8/100.000. The highest age-specific incidence rate was recorded in children aged ≤4 years (25.9/100.000), but most cases (67.9%) were ≥20 years old. Hospitalization rate was high (32.9%) and included two cases of encephalitis associated with measles. In total, 42 health-care workers and 22 related cases including hospitalized patients (n = 13) contracted measles. The overall percentage of laboratory confirmed cases was 81.7% (n = 343/420). All measles virus sequences except one (D9) belonged to genotype D8, suggesting interruption of transmission after the previous outbreak in 2010-2011 caused by genotype D4 viruses. The growing number of adult patients as compared to previous epidemics, suggests an urgent need for supplementary immunization activities targeting susceptible health care workers, unvaccinated or incompletely vaccinated adults as well as people without vaccination records. The comprehensive investigation of the 2014/2015 measles resurgence will contribute to decisions about appropriate countermeasures to stop the future measles resurgences in Serbia.

Predictors of hepatitis B vaccination status in healthcare workers in Belgrade, Serbia, December 2015.

Despite the availability of a safe and effective vaccine since 1982, overall coverage of hepatitis B vaccination among healthcare workers (HCWs) has not reached a satisfactory level in many countries worldwide. The aim of this study was to estimate the prevalence of hepatitis B vaccination, and to assess the predictors of hepatitis B vaccination status among HCWs in Serbia. Of 380 randomly selected HCWs, 352 (92.6%) were included in the study. The prevalence of hepatitis B vaccination acceptance was 66.2%. The exploratory factor analyses using the vaccination-refusal scale showed that items clustered under 'threat of disease' explained the highest proportion (30.4%) of variance among those declining vaccination. The factor analyses model of the potential reasons for receiving the hepatitis B vaccine showed that 'social influence' had the highest contribution (47.5%) in explaining variance among those vaccinated. In the multivariate adjusted model the following variables were independent predictors of hepatitis B vaccination status: occupation, duration of work experience, exposure to blood in the previous year, and total hepatitis B-related knowledge score. Our results highlight the need for well-planned national policies, possibly including mandatory hepatitis B immunisation, in the Serbian healthcare environment.

Risk factors for hepatocellular carcinoma: a case-control study in Belgrade (Serbia).

AIMS AND BACKGROUND: The objective of this case-control study was to test the existing hypotheses about factors related to the occurrence of hepatocellular carcinoma in the population of Belgrade (Serbia). METHODS AND STUDY DESIGN: The investigation was conducted between 2004 and 2007 and consisted of 45 newly diagnosed, histologically confirmed hepatocellular carcinoma patients and 90 individually gender- and age-matched hospital controls. Conditional univariate and multivariate logistic regression analyses were applied. RESULTS: A highly statistically significant association (P = 0.001) was demonstrated between hepatocellular carcinoma and HBsAg positivity and the presence of hepatitis C virus antibodies. Diabetes mellitus was significantly (P = 0.018) associated with an increased risk of hepatocellular carcinoma. A statistically significant inverse association was shown between low parity and the risk of hepatocellular carcinoma (P = 0.033). The risk increased significantly with a longer history of cigarette smoking (P = 0.044), as well as the daily consumption of hard liquor (P = 0.049). A weekly intake of fish (P = 0.003) and yogurt (P = 0.003) and daily intake of boiled vegetables (P = 0.001) were reported more frequently by controls than hepatocellular carcinoma cases. In the current study, a high intake of salty food also significantly increased the risk of hepatocellular carcinoma (P = 0.027). Based on multivariate analysis, the presence of hepatitis C virus antibodies (OR = 24.6, P = 0.001) and duration of smoking > or =25 years (OR = 3.8, P = 0.020) were significantly related to hepatocellular carcinoma, whereas the daily consumption of boiled vegetables (OR = 0.1, P = 0.011) was inversely associated with the risk of hepatocellular carcinoma. CONCLUSIONS: The findings obtained in the current study support the hypotheses that non-viral factors, such as lifestyle factors, reproductive factors, and a history of diabetes, might be involved in the etiology of hepatocellular carcinoma.