Influenza and hepatitis B vaccination coverage among healthcare workers in Croatian hospitals: a series of cross-sectional surveys, 2006–2011

Rok Civljak 2 3 Neven Papic 3 Valerija Stamenic 1 Smilja Kalenic 4 Ilija Kuzman 2 3 Josip Car 0 0 School of Public Health, Imperial College London , Reynolds building, London , UK 1 Department for Projects and Programs, Directorate for Medical Affairs, Ministry of Health , Ksaver 200a, 10 000 Zagreb , Croatia 2 Department of Infectious Diseases, Medical School, University of Zagreb , Salata 3, 10 000 Zagreb , Croatia 3 Dr. Fran Mihaljevic University Hospital for Infectious Diseases , Mirogojska 8, 10000 Zagreb , Croatia 4 Department of Bacteriology, Virology and Parasitology, Medical School, University of Zagreb , Salata 3, 10000 Zagreb , Croatia Background: Healthcare workers (HCWs) are at an increased risk of exposure to and transmission of infectious diseases. Vaccination lowers morbidity and mortality of HCWs and their patients. To assess vaccination coverage for influenza and hepatitis B virus (HBV) among HCWs in Croatian hospitals, we conducted yearly nationwide surveys. Methods: From 2006 to 2011, all 66 Croatian public hospitals, representing 43-60% of all the HCWs in Croatia, were included. Statistical analysis was performed using the Kruskal-Wallis analysis of variance, Dunn's multiple comparison analysis and the chi-square test, as appropriate. Results: The median seasonal influenza vaccination coverage rates in pre-pandemic (2006-2008) seasons were 36%, 25% and 29%, respectively. By occupation, influenza vaccination rates among physicians were 33 21%, 33 22% among graduate nurses, 3034% among other HCWs, 26 21% among housekeeping and the lowest, 23 17%, among practical nurses (p < 0.01). In 2009-2010 season, seasonal influenza vaccination coverage was 30%, while overall vaccination coverage against pandemic influenza was fewer than 5%. Median vaccination coverage in the post-pandemic seasons of 2010-2011 and 2011-2012 decreased to 15% and 14%, respectively (reduction of 24% and 35%, respectively, p < 0.0001). Meanwhile, the median mandatory HBV vaccination coverage was 98%, albeit with considerable differences according to work setting (range 19-100%) and occupation (range 4-100%). Conclusions: We found substantial year-on-year variations in seasonal influenza vaccination rates, with reduction in post pandemic influenza seasons. HBV vaccination is satisfactory compared to seasonal influenza vaccination coverage, although substantial variations by occupation and work setting were observed. These findings highlight the need for national strategies that optimize vaccination coverage among HCWs in Croatian hospitals. Further studies are needed to establish the potential role of mandatory vaccination for seasonal influenza. - Background Healthcare workers (HCWs), due to direct and indirect contact with patients, are at an increased risk of exposure to and transmission of infectious diseases [1-5]. In Croatia, the majority of vaccine-preventable infectious diseases, such as diphtheria, tetanus, pertussis, poliomyelitis, measles, mumps, rubella and tuberculosis, are covered by the national mandatory immunization program for children [6-8]. Vaccination of HCWs against hepatitis B virus (HBV) began to be introduced in Croatia in the 1990s and for many years has been mandatory and free of charge [9,10]. It is performed using a vaccine obtained from a surface antigen of the hepatitis B virus through genetic engineering that is administered in three doses according to a scheme of 0, 1 and 6 months. The immunization of persons who have been exposed to contaminated material is performed by injecting four doses of vaccine according to a scheme of 0, 1, 2 and 12 months. The annual plan of immunization against infectious diseases is conducted according to the immunization program, which is adopted by the Minister of health at the proposal of the Department of Infectious Disease Epidemiology of the Croatian National Institute of Public Health (CNIPH). The vaccine is provided by the CNIPH to the epidemiology departments, including hospital settings. All HCWs, including medical/nursing students and all new employees, are covered, so all HCWs are supposed to be vaccinated at least by the time they begin their professional careers [9,10]. An ordinance on the prevention and control of hospital infections from 2002 places special emphasis on the education and protection of new medical professionals, which has resulted in stricter enforcement measures, especially among newly recruited employees who cannot be hired until they have been vaccinated against hepatitis B. HBV vaccination and post-exposure management after occupational exposure became integral components of a comprehensive program to prevent infections following bloodborne pathogen exposure and important elements of workplace safety [2,3,11,12]. Our study represents the first assessment of this program. On the other hand, the first official recommendations for influenza vaccination and free immunization programs for HCWs have been in existence since 1984, when the Advisory Committee on Immunization Practices in the USA recommended annual influenza vaccination as the first and best protection against influenza [13]. However, the vaccination of HCWs against influenza is indicated not only for the personal protection of the vaccinated HCWs but also because it contributes to the prevention of influenza among unvaccinated persons in their environment, including their patients and family members [14-17]. A number of studies demonstrated that influenza vaccination of HCWs lowers morbidity and mortality in their patients [15-18]. Despite long-standing recommendations, overall vaccination rates for HCWs in many countries remain unacceptably low, near 40% [5,19-21]. The gap is magnified when one considers the estimate that influenza immunization rates of 80% or higher are essential for providing the herd immunity necessary to reduce healthcare-associated influenza infections substantially, which is generally not the case where vaccination is voluntary [22]. In an effort to combat the low rates of vaccination among HCWs, a growing number of professional medical organizations and healthcare facilities are adopting policies mandating influenza vaccination for individuals who work with patients [23]. This decision is justified by the fact that maximum protection of patients can only be achieved with a high rate of HCWs vaccination [24]. This recommendation is reflected in a 2009 European Union recommendation that set a goal of 75% coverage for this population by 2015 [25]. Mandatory vaccination has been implemented in many countries, thereby demonstrating that an opt-out strategy for influenza immunization significantly improved vaccination rates compared to an opt-in approach and influenza vaccination rates of more than 95% were sustained [26-29]. The CNIPH recommends seasonal influenza vaccination for particularly vulnerable population groups, including HCWs. According to the mandatory immunization program, seroproph (...truncated)