Keywords

1 Introduction

Influenza viruses are Orthomyxoviridae and are classified into three distinct types: A, B, and C. Epidemics of influenza A and B occur annually during the winter season in temperate regions of the northern hemisphere, including Poland, while influenza C viruses cause sporadic respiratory tract infections. Influenza viruses cause a broad spectrum of respiratory tract diseases, ranging from asymptomatic infection to pneumonia and acute respiratory distress syndrome, and they are responsible for significant morbidity, hospitalizations, and mortality worldwide. During the latest influenza season of 2016/2017, approximately 3.79 m cases of influenza-like illness were registered in Poland, with 13,000 hospitalizations and 24 deaths being attributed to influenza (National Influenza Center 2017).

Influenza A has a potential to cause global pandemics. Five pandemics occurred in the last century: A/H1N1 (‘Spanish flu’ in 1918), A/H2N2 (‘Asian flu’ in 1957), A/H3N2 (‘Hong Kong flu’ in 1968), A/H1N1 (‘Russian flu’ in 1977), and most recently, A/H1N1pdm09 (‘Swine flu’ in 2009) (RCPCH 2016; CDC 2015, 2016). The threat of a new influenza pandemic is always present. For the aforementioned reasons, knowledge of influenza, possible complications, treatment, and prevention is crucial for healthcare practitioners. The effective prevention with immunization and a rapid diagnosis, followed by administration of antivirals when necessary, and the isolation of infectious patients are fundamental for the limiting of influenza spread and burden. The annual influenza vaccination is the most effective preventive measure. Polish and other national guidelines are updated regularly and, in recent years, indications for the vaccine use have become broader and cover, apart from the healthy population aged over 6 months, such risk groups as pregnant women and immunocompromised individuals (Grohskopf et al. 2016). Despite the broad indications, influenza vaccination rate remains very low in Poland, amounting to 2.2–3.4% of the general population. In more detail, vaccination rate is about 9% among healthcare professionals, 0.5–1% in children aged 6 months to 4 years, and 7–13% among the elderly aged over 65 (Czarkowski et al. 2016). Since healthcare professionals are crucial to the implementation and execution of recommendations for the vaccination, its low coverage rate may be related to their unsatisfactory knowledge of influenza, poor recognition of immunization benefits, and unjustified fears of side effects. To address these issues, we examined physicians’ knowledge of influenza, its complications and treatment, and the indications and contraindications to vaccination.

2 Methods

This survey-type study was approved by the Ethics Committee of Warsaw Medical University in Poland and it was conducted in accord with the principles of the Declaration of Helsinki for Human Research of the World Medical Association. The population sample surveyed consisted of 495 random healthcare professionals from Poland, mostly women (70%). Four hundred and eleven respondents (83%) were physicians, notably general practitioners, while rheumatologists and cardiologists were the most commonly represented subspecialists. Table 1 summarizes the basic demographic information and characteristics of the participants.

Table 1 Demographics and professional qualifications of study participants
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An online questionnaire consisting of 18 mostly multiple-answer, closed-ended items was designed explicitly for the purpose of this study by two members of the Polish Expert Committee of the National Program for Influenza Prevention. The items contained a variable list of correct choices. When more than one choice was correct, all correct choices in an item had to be checked off to include the item into correct responses. The questionnaire items, along with the responses provided by the interviewees, are displayed in Table 2. The survey was conducted on-line via social media or email among a varied group of healthcare professionals. The questionnaire was anonymous and voluntary, and the participants were informed about its aim. Answers were scored as correct based on published literature and current recommendations of the Advisory Committee on Immunization Practices (ACIP) of the Centers for Disease Control and Prevention (CDC).

Table 2 Survey results
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3 Results

On average, respondents gave correct answers to 4.8 out of the 18 survey items, i.e., each item was correctly addressed by about a quarter of respondents (133/495 or 26.9%). The majority of correct responses (88.5%) concerned the contraindications to influenza vaccination and the recommendations for use of antivirals in influenza treatment (63.0%). More than half of respondents (56.6%) knew the cardiovascular indications for immunization against influenza, but a sunstantial number (44.4%) failed to recognize the general recommendations for immunization as set out in the Polish Immunization Program of 2014.

The knowledge of subspecialists about influenza virus was far from being sufficient as well, with just 5% of respondents being able to correctly name the virus type that was responsible for ‘avian flu’. Only did 8.9% of respondents give correct answers concerning the transmission routes of influenza virus. Outstandingly, the majority appeared unaware of the possibility of vertical transmission, for instance from mother to child. The gaps in practical knowledge were particularly worrisome in some specific areas such as influenza complications in pregnant women (10.3% of correct answers), vaccine administration routes (11.3% of correct answers), influenza diagnosis tests (12.1% of correct answers), and interpretation of rapid test (13.9% of correct answers). Only did 9.7% of respondents give correct answers concerning the symptoms raising a specter of a severe or progressive course of influenza. Healthcare professionals also had a difficulty in defining the proper vaccine dosing in the pediatric population (16.3% of correct answers). However, a low number of pediatricians participating in the study (4% of respondents) could bear on this matter. Finally, only did 10% of respondents pass the survey with the threshold set at 50% of correct answers (Table 2).

4 Discussion

Every year, approximately 5–20% of the population acquires influenza. Although the majority of influenza infections are benign, self-limiting, and require only symptomatic care, a substantial number of cases result in complications, hospitalizations, and deaths. The analysis of long-term data in the US population of approximately 300 m people has revealed that the number of annual influenza-related deaths from respiratory and circulatory causes ranged from 3349 to 48,614, with an average of 23,607 deaths (CDC 2010, 2015). In the EU, the annual number of individuals of all ages infected with influenza is estimated at 25–100 m, with approximately 38,500 deaths (CDC 2016). In Poland, there were 3,793,770 cases of influenza and influenza-like illness reported in the most recent 2016/17 epidemic season, with 13,779 hospitalizations or 0.36% of patients being hospitalized, and 24 deaths. The incidence was estimated at 9842 per 100,000 people (National Influenza Center 2017). Although these figures change in a variable manner every next year, there is a consistent impression that the disease incidence increases (Table 3), which may likely be due to persistently low vaccination rate. These data, even though they are likely underestimated due to the imperfect, passive reporting system, show that influenza is now the most dangerous infectious disease and one of the most significant threats to public health. The US ACIP, the European CDC, and the WHO recommend vaccination as the most effective preventive measure for seasonal influenza and as the first-line intervention to control the impact of seasonal influenza on public health (Grohskopf et al. 2016; WHO 2016b; European Commission 2014; Council of the European Communities 2009). The Polish National Immunization Program recommends the annual influenza vaccination for all individuals without medical contraindications who are 6 months of age and older. High-risk individuals, their close contacts, and healthcare workers remain the high-priority target groups for immunization. Despite clear and broad recommendations, the percentage of individuals vaccinated against influenza in the general population has been highly unsatisfactory, ranging from 2 to 5% in 2005–2014 (Czarkowski et al. 2015). One of the underlying reasons is that vaccines have become not only a domain of medical knowledge but also a subject of a heated public debate in recent years. The anti-vaccination movements and the popularization of pseudo-scientific contents on the Internet seem to significantly influence both medical professionals’ opinions and the decision-making process concerning immunization. The main inclination observed is to stoke fear and overstate the side effects of vaccines while to understate the risk of vaccine-preventable diseases and, in extreme cases, denying their existence (NWO Report 2017; Verger et al. 2016; BeWellBuzz 2015; Healy et al. 2014). In 2011, the WHO definition of vaccine hesitancy was coined as ‘delay in the acceptance or refusal of vaccines despite the availability of vaccination services’ and a working group on vaccine hesitancy has been established (WHO 2014, 2016a). Vaccine hesitancy is a complex and emerging global problem that requires local monitoring. In Poland, the number of people questioning (negating) mandatory vaccinations in Poland tripled in 2011–2014.

Table 3 Influenza-related morbidity and mortality in Poland in recent epidemic seasons
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The impact of vaccine hesitancy on the vaccination rate has been observed in many countries and noted with concern by the Strategic Advisory Group of Experts on Immunization. The present survey revealed three main problems. Firstly, the unsatisfactory level of healthcare professionals’ knowledge of influenza and influenza immunizations, which can be partly explained by the information glut that it is difficult to navigate through to draw a sensible meaning, a deluge of highly-specialist information, and other, not strictly factual but time-consuming activities, e.g., frequently changing reimbursement rules, healthcare professionals should be aware of. The insufficient knowledge of vaccination against influenza among healthcare professionals is a phenomenon present in numerous countries, being confirmed by a low vaccination rate that remains persistently lower than the population target of 75% (Hulo et al. 2017; Newcombe et al. 2016; Nutman and Yoeli 2016; Kassianos 2015; Castilla et al. 2013; Opstelten et al. 2008). Secondly, there appears a striking disproportion between the good knowledge of healthcare professionals on contraindications to vaccination and poor knowledge on indications to immunization, influenza complications, and the risk groups. Undoubtedly, this incomplete knowledge contributes to the low vaccination rate against influenza in Poland. Lastly, there is an issue of the universal trivialization of influenza infection. As a result, healthcare professionals are not well aware of symptoms pointing to the possible presence of a severe disease or of poor prognostic factors. General practitioners mostly see ambulatory patients with a benign disease course. Their personal experience may tame the true perception of influenza severity and burden, and may result in disease trivialization, often confused with a common cold. The present study also showed that most respondents could not properly define the risk groups, the signs and symptoms of severe influenza, and the predictors of its complications. In all likelihood, this is also reflected in a low vaccination rate specifically concerning the healthcare professionals in Poland, amounting to barely 6% in 2007/08 and 9% in the most recent 2016/17 season. A number of studies have examined the decision-making process regarding vaccinations. The results indicate that one of the most important factors influencing one’s decision to become vaccinated is the attitude of the physician providing advice to the patient (Arriola et al. 2015; WHO 2014; Leask et al. 2012; Cooper et al. 2008; Schmitt et al. 2007). Healthcare professionals’ knowledge and attitudes about vaccines determine the intention to recommend the vaccine to patients and thus also vaccine uptake by patients (Nessler et al. 2014; Flicoteaux et al. 2014; Clark et al. 2009; Hollmeyer et al. 2009; Posfay-Barbe et al. 2005).

We believe the present study has identified the essential reason for a low influenza vaccination rate in Poland, which is the poor knowledge of a disease threat, with the undue perception of contraindications to immunization and an excessive fear of adverse effects. In 2016, European recommendations concerning the diagnosis and prevention of seasonal influenza were ‘harmonized to better identify influenza outbreaks and to move towards reaching the target vaccination rate of 75% throughout Europe’ (Kassianos et al. 2016). Hopefully, the harmonizing of recommendations will facilitate the assimilation of knowledge, but it cannot substitute for the continuing medical education.

5 Conclusions

The study identified the most important reasons for a low influenza vaccination rate in Poland, which are the disease trivialization and unsatisfactory knowledge among healthcare professionals of influenza and influenza immunization, combined with the perception of an exaggerated relevance of side effects of, and contraindications to, vaccination. All healthcare workers should be provided with continuous education programs focused on influenza complications, poor prognostic factors, risk groups, and the indications for vaccination. Subspecialists should be educated that influenza can exacerbate diseases in their field of specialization, which can be prevented with a vaccine.