Vaccination against influenza and attitudes towards seasonal vaccination of medical students from the Medical University of Silesia

Influenza is a highly contagious and virulent virus that kills 290,000 to 650,000 people worldwide [1]. Classic symptoms of infection include fever, myalgia, headache, sore throat, and dry cough. However, seasonal influenza is thought to cause a wide range of illnesses, including pneumonia, exacerbation of underlying lung disease, and extrapulmonary symptoms affecting the gastrointestinal and neurological systems [2, 3]. In 2019, 225 influenza-related deaths were registered in Poland [4]. Once symptoms of infection appear, antiviral drugs are the preferred treatment. There is also primary prevention in the form of vaccination, which is recommended for all people 6 months of age and older, including pregnant and postpartum women, unless there is a contraindication. Vaccination should be given at the beginning of the influenza season (usually in October) and repeated annually due to the high mutation rate of the virus [3]. Worldwide, there are two types of influenza vaccination, trivalent and quadrivalent. In Poland, quadrivalent vaccines are available in two forms: inactivated intramuscular/subcutaneous vaccines or live intranasal vaccines. Both types cause active immunization against the four strains of influenza virus (two strains of virus A and two strains of virus B) contained in a given vaccine [5]. The following influenza vaccines were offered in Poland for the 2022/2023 season: Influvac Tetra, Vaxigrip Tetra, Fluarix Tetra, Fluenz Tetra. Quadrivalent vaccines have been shown to reduce morbidity, mortality, and healthcare utilization compared to trivalent vaccines [3]. Both types of vaccines utilize humoral and cellular immunity. Intranasal vaccination is the preferred form in children because it is better tolerated this way. The attenuated virus administered into the nasopharynx replicates in mucosal tissues, simulating a physiological infection. Moreover, nasal administration results in higher secretory IgA titers than intramuscular administration of the inactivated vaccine [6]. In contrast, according to a meta-analysis of studies, the efficacy of the inactivated vaccine was 59% (95% CI 51–67) in the population aged 18–65 years [5].

On average, influenza vaccination rate in the EU was low compared with the WHO target of 75% for at-risk groups and healthcare workers set as an EU target in the 2009 Council Recommendation on seasonal influenza vaccination. The most recent data from 2018 show that influenza vaccination rates in the EU are approximately 41% among persons aged 65 years and older [7,8,9]. In contrast, influenza vaccination rates in Poland in recent seasons have ranged from only 4% in the general population to 15.1% in those aged 65 years and older [10].

Due to the effectiveness of influenza vaccination in reducing the number and severity of influenza complications, WHO gives high priority to preventive vaccination of healthcare workers who are in constant contact with pathogens during the influenza season, including through free vaccination programs [1]. At the same time, the issue of vaccination of medical students as a group of future healthcare workers is becoming increasingly common [11]. According to previous reports, the percentage of vaccinated healthcare workers in Poland is only 5% [12].

The aim of this study is to investigate the behavior of students regarding their willingness to be vaccinated against influenza and the attitudes influencing their approval or disapproval of influenza vaccination.

In our study, the percentage of vaccinated students during the study season was 33.4%. The largest group among the vaccinated was medical students (59.1%), especially those who had already had the opportunity to participate in clinical classes (59.4%). We showed the factors influencing participants’ decision to vaccinate or not, including a worrying lack of awareness about the threat posed by influenza (22.9%). It was also observed that free vaccination campaigns can significantly increase the number of vaccinations in Poland, which may influence a change in vaccination policy.

As mentioned previously, the largest percentage of students vaccinated against influenza were medical students. Similarly, among healthcare workers, doctors more often decide to vaccinate against influenza than do nurses [9]. In the study group, 59.1% of medical students who had been vaccinated for influenza showed an upward trend compared to previous studies, in which the level of vaccination among medical students was 18.9% and 36.5%, respectively [1, 9].

Awareness of the possibility of easy transmission of infection in the hospital environment may vary, especially among students in different years and courses. Our study revealed that a significant difference was observed among those vaccinated between students participating in clinical classes in direct contact with the patient and students in earlier years of study, which coincides with the research from 2020 [1]. Because the majority of clinical-year students were vaccinated, we can attribute this to increased awareness and knowledge of infectious diseases and their prevention gained in later years of education. Being in a higher year of study was an important predictor in the US for clinical students (69% of clinical students vs. 34% of preclinical students) [15]. Other studies have found similar correlations between these two groups. For example, in Strasbourg, the vaccination rates were higher for students higher than the 4th year [16]. Similarly, in Cyprus, more clinical students were vaccinated and showed higher levels of knowledge about vaccination [17]. These results reveal the importance of educating students during the early years of their studies.

Our thesis may also be supported by the fact that after medical students, the next largest groups of vaccinated students are physiotherapy (15%) and midwifery (11.8%) students, who also take a large number of clinical classes in direct contact with patients as part of their education. Moreover, the findings of another study showed a higher percentage of vaccinated healthcare workers than students and nonmedical hospital employees [7]. However, an inverse relationship was presented in a British study, where a significantly higher percentage of vaccinated students was recorded in the group of students in preclinical education (84%) than in the group of students attending clinical classes (65%) [18]. Furthermore, a higher level of education has an overall significant effect on the chances of vaccine uptake, which has been shown in various studies [19,20,21].

Low awareness of the risks may, therefore, influence the decision not to vaccinate. The three most common reasons for not vaccinating in the study group were a lack of fear of influenza (22.9%), no recommendation to vaccinate (21.9%), and the view that vaccination is pointless (21.4%). At the turn of the years, the lack of fear of becoming sick remained the most important argument for a negative decision. This has been shown successively by Polish studies from 2015 to 2020 [12].

Our results show that medical students are not afraid of the course or complications of influenza. This may indicate a lack of knowledge regarding various aspects of influenza. In comparison, among Chinese students, the most common reasons for refusing vaccination were a low level of knowledge about the vaccination itself (46%), declared lack of need due to good health (45%), and fear of side effects (33%) [22]. Saudi students who refused vaccination claimed that they were not at risk of becoming ill with influenza (37.9%) and were afraid of the side effects of the vaccination itself (28.9%) [23].

The survey found that the second most common reason for refusing influenza vaccination was that the vaccine was not recommended by family doctors (21.9%). The authors of another Polish study believed that students may not have a family doctor in the city where they study, making it difficult to access one during medical school. However, some physicians may not recommend, or may even advise against, annual influenza vaccination [12].

Considering factors that may have influenced the uptake of the vaccine, unvaccinated participants were also asked what could change their decision. The most frequently mentioned argument was the possibility of free vaccination at the university (26%). Free vaccination policies are a positive factor for higher global influenza vaccination rates [24].

However, in Strasbourg, where vaccination is free of charge, the percentage of immunized students is fairly low (29.7%) [24]. There is a need to describe this problem and find an effective solution, such as offering free vaccinations in conjunction with parallel educational campaigns. In addition, 88.8% of French midwifery students believed that vaccination directly at the university would increase the percentage of vaccinated students [25]. Improving the accessibility of the vaccination in time and space is a suggestion of medical students from the University of Zaragoza [26]. On-campus vaccination campaigns may be the only opportunity for many busy students to be vaccinated. Hence, one possible way to increase vaccination rates would be to hold several vaccination days on the university campus at the beginning of the flu season with the opportunity to receive vaccination free of charge. Signing up via an online form for a specific date and time before attending classes in the academic year would also be convenient.

Another argument is financial, as 26% of the surveyed students who have not been vaccinated would change their minds if the cost of vaccination was lower. Cost is also a barrier for 7.7% of Southern California public health students [27]. Another reason why students changed their decision to vaccinate was to make vaccination mandatory for healthcare workers (16%). A cross-sectional study conducted in Spanish university hospitals reported that influenza vaccination rates in hospitals where vaccination is not compulsory are below the standards recommended by the WHO, whereas the highest vaccination rates are observed in medical schools where vaccination is compulsory [28]. It is worth noting that 51% of the surveyed MUS students were in favor of introducing the obligation to vaccinate healthcare workers, while the group of European medical students and junior doctors who were in favor of mandatory vaccinations for medical staff (86.0%) and medical students (82.7%) were much larger [29].

The decision to vaccinate against influenza was also influenced by the duration of the COVID-19 pandemic. In our study, 71% of those vaccinated with at least one booster dose against COVID-19 were also vaccinated against influenza, which may indicate a positive effect of disseminating knowledge about vaccination during the COVID-19 pandemic. In 2020, 35% of the surveyed healthcare workers in the Upper Silesia Agglomeration (where the Medical University of Silesia is located) declared that they had been vaccinated against influenza [14]. In Lebanon, among healthcare workers, during the COVID-19 pandemic, the influenza vaccination rate more than doubled, from 33.1% in 2019/20 to 80.2% in the 2020/21 season [30]. In a pan-European study of medical students and junior doctors, despite the almost undisputed agreement of the respondents regarding the effectiveness of influenza vaccination (97.2%), only 68% of the respondents had ever been vaccinated against influenza; however, only 22.1% declared vaccination every year or every other year [29].

On the other hand, the unsatisfactory percentage of people vaccinated and declaring vaccination may also be related to the pandemic: it may be related to the process of dissemination of the topic of infectious diseases and epidemics. After the initial fear of an escalating pandemic and an increase in the number of vaccinations [1], almost three years later, we can see the opposite trend – a downward trend. For example, this is indicated by the fact that only 22.5% of MUS students surveyed received full COVID-19 vaccination (primary vaccination and two booster doses), while 4% of respondents were not vaccinated at all. The overall low coverage of influenza vaccination may be related to the prevailing negative perceptions of vaccination in the media. We speculate that this is also because of the widespread perception that influenza is not a dangerous disease. Many patients may be unaware of the number of flu complications, so they are reluctant to be vaccinated.

Furthermore, our study showed that the percentage of students who received influenza vaccination in the past was 42.1%, and in the current influenza season (autumn 2022) is 33.4%. The current trend of increasing vaccination rates among Polish medical students is therefore promising, although still at an inadequate level compared to vaccination rates in the United Kingdom, for example, where the percentage has reached 76% [12]. Although the Italian study indicated a percentage of vaccinated students of 20.9% [31] and a similar rate was found among Saudi students (20.7%) [23], Chinese researchers reported a vaccination rate of less than 10% in the same group [22]. In France, the vaccination coverage rate was 47.9% [11]. Considering students from other medical faculties, for example, in France 47.9% of midwifery students declared that they had received influenza vaccination, citing as the main reason the need to protect patients from infection [25]. Similarly, among the staff of the Swiss maternity hospital, despite the low percentage of people vaccinated against influenza (15%), 82% of those vaccinated cited the need to protect patients as the reason, 75% to protect themselves, and 61% to protect their families [32]. A similar situation was presented in the analysis of vaccination motives declared by German physicians, 80.6% of whom were vaccinated to protect their patients against influenza virus infection [8].

In our study, less than 6% of the surveyed students indicated that the analogous motive for vaccination was the most important. The most frequently given argument persuading the surveyed students to vaccinate against influenza was the belief in the effectiveness of vaccination (35.6%); the same answer was given most often among medical students in 2020 [12]. For Italian students, the most important factors in deciding to vaccinate were receiving a personal invitation for vaccination (aOR = 3.8; CI:1.2–12.3) and participation in training on preventive vaccination (aOR = 3.4; CI:1.7–6.7) [31]. Similarly, Saudi students considered training and recommendations of the National Health Department as the most important motivators for vaccination [23].

In turn, an increasing number of medical students do not believe in the effectiveness of vaccination, and this is worrying. According to studies conducted among medical students, the prevalence was 19.5% in 2015 and 10% in 2020. However, our study showed that by 2022, this group was already at a level of 21.4%.

It should be noted, however, that the group of respondents included students from other medical faculties, as well as students from medical courses. In a French study from 2019, 21.3% of obstetric students showed a lack of confidence in the effectiveness of vaccines [25]. An Italian study conducted in the same year at the University of Palermo showed that 10.02% of nursing students held the same position [33]. Conversely, 88% of California public health students reported that they were encouraged to receive a flu vaccination during their studies, but only 43% took up the opportunity to get vaccinated. Nearly half of the students who had refused vaccination believed that it could cause influenza in them [34].

Our study has some limitations: a relatively small research sample and the non-representativeness of some fields of medical studies. Nevertheless, the results of the study indicate a certain tendency in the behavior of medical students and their motivation in the area of seasonal influenza infection prevention.

The relatively high percentage of vaccinated medical students (64.4%) significantly differed from the general percentage of influenza-vaccinated students in other medical-related courses (33.4%). The results obtained in this study indicate the need to introduce changes in the field of broader education on the effectiveness of vaccinations in reducing the number of influenza virus infections among medical students. However, more education should be paid to students in other medical courses where the percentage of vaccinated students is lower.