Streptococcus pneumoniae serotype distribution in Vojvodina before the introduction of pneumococcal conjugate vaccines into the National Immunization Program.

Introduction: Streptococcus pneumoniae is the most common causative agent of bacterial pneumonia and meningitis. Mandatory childhood immunization against pneumococcal diseases is introduced in the new Law on Protection of Population against Communicable Diseases in Serbia. Objective: The objective of this study was to determine the prevalence of pneumococcal serotype distribution in Vojvodina region before routine use of pneumococcal conjugate vaccine in Serbia. Methods: A total of 105 isolates of Streptococcus pneumoniae were collected in the period from January 2009 to April 2016. Based on the results of serotyping in the National Reference Laboratory, we analyzed distribution of circulating serotypes and coverage of conjugate and 23-valent polysaccharide pneumococcal vaccines in different age groups. Results: Among 105 isolates, a total of 21 different serotypes of Streptococcus pneumoniae were determined. The most frequent serotypes were 3 (21.9%), 19F (20.0%), and 14 (10.5%). The serotype coverage of pneumococcal conjugate vaccines (PCV7, PCV10, and PCV13) was 48.6%, 54.3%, and 84.8%, respectively, while pneumococcal polysaccharide vaccine (PPV23) covered 89.5% of the total number of isolates in all age groups. Serotypes included in PCV7, PCV10, and PCV13 represented 72.0%, 76.0%, and 88.0% of the total number of isolates in children ≤5 years, respectively. Vaccine serotype coverage of PCV13 and PPV23 ranged from 87.1% to 90.3% in adults 50­64 years of age, and 77.8% to 85.2% in adults ≥65 years old. Conclusion: Serotype distribution of Streptococcus pneumoniae in the population fairly overlaps with the serotypes contained in pneumococcal vaccines, so that implementation of childhood immunization is justified. The study was done in the Province of Vojvodina but the findings may be applied to Serbia as a whole.

A Mumps Outbreak in Vojvodina, Serbia, in 2012 Underlines the Need for Additional Vaccination Opportunities for Young Adults.

In 2012, mumps was introduced from Bosnia and Herzegovina to Vojvodina, causing an outbreak with 335 reported cases. The present manuscript analyses the epidemiological and laboratory characteristics of this outbreak, identifies its main causes and suggests potential future preventive measures. Sera of 133 patients were tested for mumps-specific antibodies by ELISA and 15 nose/throat swabs were investigated for mumps virus RNA by RT-PCR. IgG antibodies were found in 127 patients (95.5%). Mumps infection was laboratory-confirmed in 53 patients, including 44 IgM and 9 PCR positive cases. All other 282 cases were classified as epidemiologically-confirmed. More than half of the patients (n = 181, 54%) were 20-29 years old, followed by the 15-19 age bracket (n = 95, 28.4%). Twice as many males as females were affected (67% versus 33%). Disease complications were reported in 13 cases (3.9%), including 9 patients with orchitis and 4 with pancreatitis. According to medical records or anamnestic data, 190 patients (56.7%) were immunized with two doses and 35 (10.4%) with one dose of mumps-containing vaccine. The Serbian sequences corresponded to a minor genotype G variant detected during the 2011/2012 mumps outbreak in Bosnia and Herzegovina. Vaccine failures, the initial one-dose immunization policy and a vaccine shortage between 1999 and 2002 contributed to the outbreak. Additional vaccination opportunities should be offered to young adults during transition periods in their life trajectories.

[Analysis of suspected adverse reactions following immunization against pandemic influenza].

INTRODUCTION: The surveillance on adverse reaction following immunization was aimed at recording all adverse events possibly related with vaccines. During the implementation of immunization strategy against pandemic influenza A(H1N1) in 2009. the post-marketing comprehensive surveillance was suggested to be conducted due to limited clinical experience in applying this particular vaccine and because of the fact that some vaccines had been licensed only on the basis of the data regarding their quality. MATERIAL AND METHODS: The passive surveillance on adverse events following immunization was conducted simultaneously with immunization campaign against pandemic influenza in the Autonomous Province of Vojvodina. Reporting of adverse events was conducted by health care service through a specially designed questionnaire. RESULTS: In the period from December 17th 2009 to February 7th 2010, of the total number of 55720 people who were vaccinated, 50433 received one dose and 5287 received two doses of vaccine. The total number of doses administered was 61007. During the observed period, some adverse reactions were recorded in 37 people, the rate of occurrence of adverse reactions being 6.6 per 10.000 vaccinated. Since the majority of patients had several symptoms and signs, the number of recorded clinical manifestations was much higher (140) than the number of patients with reactions. The dominant symptoms and signs were fever (51.4%), weakness/fatigue (48.6%), headache (40.5%) and myalgia (31.5%). The reactions in the majority of patients were mild and transient. Only two patients sought medical care and one was hospitalised. Since the immunization coverage was very small, it was not possible to record rare adverse events, whose expected incidence is, anyway, very low. CONCLUSION: Surveillance on adverse reaction following immunization represents an important component of immunization program, especially when new vaccines are introduced. Therefore, this form of surveillance in our country needs further improvement in order to provide more complete information on occurrence and characteristics of adverse reactions following immunization.

Overview of the winter wave of 2009 pandemic influenza A(H1N1)v in Vojvodina, Serbia.

AIM: To analyze the epidemiological data for pandemic influenza A(H1N1)v in the Autonomous Province of Vojvodina, Serbia, during the season of 2009/2010 and to assess whether including severe acute respiratory illness (SARI) hospitalization data to the surveillance system gives a more complete picture of the impact of influenza during the pandemic. METHODS: From September 2009 to September 2010, the Institute of Public Health of Vojvodina conducted sentinel surveillance of influenza-like illnesses and acute respiratory infections in all hospitalized patients with SARI and virological surveillance of population of Vojvodina according to the European Centers for Disease Control technical document. RESULTS: The pandemic influenza outbreak in the province started in October 2009 (week 44) in students who had returned from a school-organized trip to Prague, Bratislava, and Vienna. The highest incidence rate was 1090 per 100000 inhabitants, found in the week 50. The most affected age group were children 5-14 years old. A total of 1591 patients with severe illness were admitted to regional hospitals, with a case fatality rate of 2%, representing a hospitalization rate of 78.3 per 100000 inhabitants and a mortality rate of 1.6 per 100000. Most frequently hospitalized were 15-19 years old patients, male patients, and patients with pneumonia (P<0.001). The highest case fatality rate was found among patients with acute respiratory distress syndrome (P<0.001). Nasal/throat swabs were obtained for polymerase chain reaction test from 315 hospitalized patients and 20 non-hospitalized patients, and 145 (46%) and 15 (75%) specimens, respectively, tested positive on A(H1N1)v. CONCLUSION: Sentinel influenza-like illness and SARI surveillance, both followed with virological surveillance, seem to be the optimal method to monitor the full scope of the influenza pandemic (from mild to severe influenza) in Vojvodina.

[Epidemiological characteristics of hepatitis A in Vojvodina from 1988 to 2009].

INTRODUCTION: Hepatitis A represents a significant epidemiological problem in many regions of the world. This research was aimed at analyzing trends and distribution of hepatitis A in the Autonomous Province of Vojvodina in Serbia. MATERIAL AND METHODS: The authors used data on individual cases and outbreak reports in the period from 1988 to 2009 obtained from the Registry of Communicable Diseases kept at the Center for Disease Control and Prevention, Institute of Public Health of Vojvodina. RESULTS: The total of 10.471 cases was recorded with average incidence of 23.4/100.000 and with a decreasing trend. This disease occurs as an endemoepidemic with a cyclic increase in the incidence in time intervals of 3, 4 and 6 years. The disease has seasonal character and is most frequently observed in autumn and winter with the highest percentage of cases in October-November after the beginning of school year and forming of school collectives. The age-specific incidence is highest in school age children due to agglomeration of susceptible population. During the observed period, the total of 160 outbreaks was recorded with over 5,000 reported cases. The highest number of outbreaks was recorded in school collectives and then in peri-urban settlements with poor hygiene. Two outbreaks occurred at institutions for people with special needs. Outbreaks were progressive in course and contact was the dominant mode of transmission. CONCLUSION: Although hepatitis A incidence trend is decreasing, this disease still has endemoepidemic character of occurrence. Such an epidemiological situation is most probably caused by slow and limited impact of hygienic measures. A significant contribution to further incidence reduction could be achieved by active immunization.

[Importation and spread of pandemic influenza virus A(H1N1) in autonomous province of Vojvodina in preepidemic period].

INTRODUCTION: Influenza is the most frequently reported communicable disease, having epidemic and pandemic potential. The first influenza pandemic in this century started in Mexico and spread quickly throughout the world. This paper analyses importation of pandemic influenza cases and local transmission among population in the Autonomous Province of Vojvodina. MATERIAL AND METHODS: According to the WHO guidelines and national recommendations, the influenza surveillance activities were conducted in Vojvodina in order to detect, isolate and treat affected international travelers and their close contacts. Patients whose pandemic influenza infection was laboratory confirmed were classified as confirmed cases, while those with symptoms who were epidemiologically linked with confirmed cases were classified as probable cases. RESULTS: During the period from the 24th of June to 17th of August 2009, 123 pandemic influenza cases were recorded in Vojvodina. Infection was imported through international travelers and our citizens coming from countries affected by influenza outbreaks. Majority of cases had mild clinical picture. Most frequently reported symptoms were high fever (above 38 degrees C) (85.6%), and cough (61.6%). Difficulty in breathing was recorded in 20 (16.0%) cases, while pneumonia developed in 4 (3.2%) cases but none of the cases required mechanical ventilation. CONCLUSION: The imported cases of pandemic influenza in the pre-epidemic period led to limited local transmission in general population and caused a small outbreak among visitors of International music festival called EXIT.

[Effects of the immunization program in Vojvodina].

INTRODUCTION: With the widespread use of active immunization, significant results have been achieved in the control and prevention of numerous communicable diseases. The Expanded Programme on Immunization of the World Health Organization is intended to strengthen national programs for the reduction in the incidence and mortality rates and global elimination or eradication of communicable diseases. The aim of this paper is to analyze results of the immunization program in Vojvodina. MATERIAL DND METHODS: The results of the immunization program were analyzed on the basis of the incidence rates, since the introduction of the mandatory reporting system, till 2006. The analysis included immunization coverage against diphtheria, tetanus, pertussis, poliomyelitis and measles as well as reported cases of missed opportunities in the period from 1997 to 2006. RESULTS: Poliomyelitis has not been reported in Vojvodina since 1963, diphtheria since 1978 and measles in the period from 2001 to 2006. Sporadic cases of pertussis have been reported in unimmunized children of the youngest age, and tetanus in unimmunized elderly population. Vaccination coverage against poliomyelitis, diphtheria, tetanus and pertussis was above 96%. Vaccination coverage against measles was lower (95% vaccination, 87% revaccination). The highest proportion of missed opportunities was caused by not responding to immunization calls (46.6%). CONCLUSION: These results can be maintained by up-to-date (UTD) immunization and high vaccination coverage without territorial and population differences. Data on the total number of children without up-to-date vaccination cannot be obtained on the basis of administrative coverage follow-up. It is necessary to establish follow-up mechanisms for UTD immunization, which would reveal the number of children at risk from vaccine preventable diseases and characteristics of unimmunized population.

[Epidemiological characteristics of tetanus in Vojvodina].

INTRODUCTION: Vojvodina is an endemic area for tetanus. MATERIAL AND METHODS: Epidemiological characteristics of tetanus were analyzed based on registered cases of disease and death in the period 1960-2004, and epidemiological investigation of 50 registered cases during the last 10 years of this period. Epidemiological characteristics were analyzed chronologically, demographically and topographically. RESULTS AND DISCUSSION: During the period of observation, the incidence rate of tetanus declined steadily. Due to immunization and extremely high coverage, tetanus has been practically eliminated in the age group of younger than 29 years. Neonatal tetanus and tetanus in the age group 30-59 years has been reduced to individual cases. Today, tetanus is a problem of the elderly population. Tetanus deaths occur statistically more often among persons older than 66 years. The average case fatality rate during the period of observation was 33.1%. The vaccination history in the majority of investigated cases was unknown (52%) or they have never been vaccinated (28%) because they were mainly elderly people born before introduction of mandatory immunization. Tetanus most often occurs after minor wounds, because of which patients do not seek medical attention. In the majority of cases tetanus occurred after limb injuries. CONCLUSION: Tetanus in Vojvodina is a problem among unimmunized elderly people. It mostly occurs after minor injuries or after contamination of chronic skin lesions. Mandatory vaccination of older age groups should contribute to further reduction in the incidence rate of tetanus.

Maintaining the cold chain for vaccines.

Cold chain for vaccines a is a system for storing and transporting vaccines at very low temperatures to maintain their effectiveness before use. Because vaccines are sensitive biological substances, their exposition to high temperatures directly affects the quality of vaccines and safety of immunization. The goal of this study was to assess the safety of cold chain for vaccines within the cold chain system in two services of Health Center Novi Sad. Cold Chain Monitors (CCM) and Freeze Watch (FW) indicators were used. A total of 155 (94.5%) Cold Chain Monitors (CCM) and 100 (95.2%) Freeze Watch (FW) indicators were analyzed. Only one CCM showed a breack in cold chain. A total of 3 CCMs indicated risk of vaccine wastage. A total of 9 CCMs were colorized without risk of vaccine wastage. FWs were positive in a high percentage in both services of Health Center Novi Sad. FWs were exposed to low temperatures during transport. Statistically significant differencies in the number of exposed CCMs to high temperatures and the number of exposed FWs to low temperatures were observed in these two services. A statistically significant difference in number of FWs exposed to low temperatures was observed in regard to the period of transport and the period of storage at the vaccination stations. The study shows high level of safety of the cold chain in two services of Health Center Novi Sad Cold Chain Monitor is a reliable indicator of the quality of cold chain for vaccines. Freeze Watch is a reliable indicator of the quality of cold chain during storage of vaccines, but not during their transport.