Knowledge, attitudes and uptake related to influenza vaccine among healthcare workers during the 2018–2019 influenza season in Tunisia

Influenza is an acute respiratory infection that is highly contagious and considered one of the most challenging public health problems worldwide [1, 2]. It may range from mild to severe illness causing hospitalizations and deaths mainly among high-risk groups. Globally, an estimated 1 billion cases of influenza occur each year, with 3 to 5 million cases of severe illness and 290,000 to 650,000 influenza-related deaths [1, 3]. In Tunisia, an average of 130,000 to 272,000 cases of influenza-like illness are recorded each year at influenza sentinel surveillance sites, representing 6.5 to 12.9% of all outpatient visits [4]. In addition, 119 cases of severe acute respiratory illness due to influenza and 48 influenza-related deaths were reported from the beginning of the 2017–2018 influenza season to the end of January 2018 [5].

Given their close and regular contact with ill patients, healthcare workers (HCWs) are at a high risk of developing influenza and may transmit the disease to their patients. As such, HCW infections may result in nosocomial outbreaks, with an increased risk of mortality among immunocompromised hospitalized patients [6]. Influenza infection among health professionals was also associated with a high economic burden mainly related to absenteeism [7].

Influenza vaccines (IVs) have been available since 1945 and remain the most effective tool to prevent influenza infection and its complications [1, 8]. HCWs immunization is a cost-effective method proven to reduce influenza-related deaths among high-risk patients [9, 10]. Furthermore, vaccination of HCWs can protect patients who cannot receive the vaccine or those who respond poorly to vaccination [11].

Given the aforementioned reasons, the World Health Organization (WHO) and the U.S. Advisory Committee on Immunization Practices (ACIP) have recommended annual vaccination of HCWs [1, 11]. Despite these recommendations and the efficacy of HCW influenza vaccination in improving self and patients’ safety, vaccine coverage among healthcare professionals remains low mainly in developing countries [12, 13]. Although the IV is provided free of charge to health professionals in Tunisia, the estimated vaccination uptake proportion among HCWs remains low [14]. However, this indicator has never been accurately assessed at the national level and its determining factors are not fully understood.

We performed this nationwide study to measure the vaccine uptake and to understand the knowledge and attitudes related to influenza vaccination among HCWs, in order to propose evidence-based strategies to address these gaps in Tunisia.

Overall, 1359 HCWs were approached to participate in the survey. Among them, 1264 accepted to respond to the questionnaire (Response rate = 93%). Among the collected questionnaires, 33 were removed owing to high percentages of missing responses and not meeting the inclusion criteria. The remaining 1231 questionnaires (97%) were eligible for analysis. Most of the participants were women (80.0%). Their mean age was 44.5 ± 9.3 years, ranging from 22 to 64 years. More details on the participants’ profession and sociodemographic characteristics are presented in Table 1.

Among respondents, 36.6% [33.9–39.4] reported receiving the IV at least once in their lives, while 27.6% [25.1–30.2] had received the IV at least once during the 4 years preceding the 2018–2019 influenza season and 15.3% [13.3–17.4] were vaccinated during the 2018–2019 influenza season. Most of participants 75.9% [73.4–78.3] reported that the IV is available for free to HCWs at their workplace. More than half of the respondents (53.8% [50.9–56.6]) declared their unwillingness to receive the IV even if recommended to HCWs and provided for free at their workplace and 65.3% [62.6–68.0] reported low confidence regarding vaccine efficacy in preventing influenza among healthcare personnel while 79.1% [76.7–81.3] declared their willingness to recommend or prescribe the IV to patients if available.

According to participants, the main three reasons leading to vaccine acceptance were: self-protection from influenza (73.8% [71.2–76.2]), family and colleagues’ protection (49.2% [46.4–52.1]) and protection of patients (28.2% [25.7–30.9]). Fear of the vaccine side effects (48.0% [45.2–50.9]), not feeling at risk of influenza (31.8% [29.2–34.5]) and doubt about vaccine efficacy (31.6% [28.9–34.3]) were the most frequent cited reasons leading to IV refusal.

Most participants believed that influenza may result in severe illness or death (80.0% [77.6–82.2]) and that they could transmit it to their family members (91.9% [90.3–93.4])). More than half agreed that vaccinating HCWs could reduce work absenteeism, severe illness and deaths among patients (54.9% [52.1–57.7] and 52.7% [49.8–55.5] respectively). However, almost half (48.5% [45.6–51.3]) of the participants believed that the IV could cause influenza. In addition, 29.2% [26.7–31.8] of respondents were aware that HCWs are a target group for influenza vaccination and almost three-quarters (74.5% [72.0–76.9]) knew that the IV was recommended annually for HCWs.

Univariate analysis showed that HCWs belonging to primary healthcare centers were 2.4 times more likely to be vaccinated against influenza in 2018–2019 than those working in regional and district hospitals (p < 0.001). We also observed a significant association between the participants’ educational level and vaccination status (p = 0.005), with the highest percentage of vaccine uptake among those with the lowest educational level. Besides that, the vaccination rate increased with age (p < 0.001), professional experience (p < 0.001) and with the average number of patients seen per day (p = 0.038). Gender and type of occupation were not significantly associated with 2018–2019 vaccination uptake (Additional file 1: Appendix A.2).

HCWs who highly trust the vaccine efficacy in preventing influenza, and those who believed that HCW vaccination against influenza could reduce severe illness and deaths in patients, as well as those who support a mandatory IV among HCWs were more likely to be vaccinated than their counterparts (OR = 3.5, p < 0.001; OR = 1.7, p = 0.001 and OR = 2.8, p < 0.001 respectively).

Respondents who were aware that annual influenza vaccination is recommended for HCW had significantly higher vaccination rates than other respondents (p < 0.001) and vaccine uptake in 2018–2019 was higher among those who had received the vaccine at least once in the four preceding seasons (42.2% vs 5.0%) (Table 2).

The independent factors associated with IV uptake in 2018–2019 among Tunisian HCWs are summarized in Table 3. Variables included in the initial multivariate model were: Educational level, age, average number of patients seen per day, health facility type, previous IV uptake, confidence regarding vaccine efficacy in preventing influenza, willingness to vaccinate or recommend IV to patients, availability of IV for free, believing that HCWs are a target for influenza vaccination, that IV is indicated annually for HCWs, that influenza may result in severe illness or deaths, that HCWs can transmit influenza to their family members, that IV should be mandatory for HCWs and that it can reduce work absenteeism and severe illness among patients.

We assessed IV coverage among Tunisian healthcare professionals working in primary healthcare centers, district and regional hospitals in the 2018–2019 season and described HCW knowledge and attitudes regarding influenza and IV. Fewer than half of respondents (36.6%) have received the vaccine at least once in their lives and only 15.3% were vaccinated in the 2018–2019 influenza season. Moreover, more than half of the participating HCWs reported their unwillingness to receive the IV even if provided for free. The most commonly cited reason for vaccine refusal was fear of vaccine side effects. Multivariate analysis revealed a significant association between IV uptake in 2018–2019 and previous IV receipt, educational level, belief that the IV should be mandatory for HCWs, and confidence regarding IV efficacy in preventing influenza.

Globally, influenza vaccination rates previously reported among HCWs studies have varied [12, 13, 15‐25]. The reported vaccine uptake among our respondents for the 2018–2019 season was much lower than those reported in studies conducted in some countries of the Middle East and North Africa (MENA) region, where the IV is provided freely to health professionals. In Saudi Arabia, two studies conducted in similar healthcare settings reported an increase in HCW vaccination rates between the 2012–2013 and 2016–2017 seasons – from 38 to 67.6% [22, 23]. Similarly, a study conducted in a community hospital in Qatar found that more than half of health professionals were vaccinated against influenza in 2011–2012 and exceeded 70% during the 2012–2013 influenza season [26]. In addition, the administrative vaccination coverage of health professionals against influenza in Morocco was estimated 54% in 2016 [27].

Despite international recommendations for annual vaccination of health professionals and the provision of IV free of charge to HCWs in Tunisia, the vaccination rate is low. This might be explained by the lack of appropriate flu awareness campaigns in Tunisian health care facilities. Thus, health authorities should pay more attention to raise awareness of health professionals toward the necessity of influenza immunization through annual educational programs that could be delivered online. Facilitating access to influenza immunization by making time of vaccine delivery more flexible should also be considered [28]. Reminder messages through social networks and media before and during the influenza season may also help to increase vaccine coverage [28].

The most important predictor of IV uptake was the previous vaccination during the previous 4 years. However, we did not observe a significant association between vaccination status and professional category. Surprisingly, HCWs with the lowest educational level were more likely to be vaccinated against influenza in 2018–2019 compared to their counterparts. Our results are in contrast to those reported by Hammour et al. [29], in which HCW vaccine uptake increased with educational level. In our study, the highest vaccine uptake among those with the lowest educational level might be explained by a lower concern about IV side effects than those with higher education level. Vaccine uptake in 2018–2019 was higher among healthcare professionals working in primary care centers than among those working in regional and district hospitals despite their more frequent contact with patients at high risk of complications. This could be explained by higher exposure of general practitioners to the recommendations of the national influenza control program. Therefore, national educational programs should focus mainly on health professionals in contact with vulnerable patients.

Vaccine uptake among HCWs was associated with their willingness to recommend IV to their patients (p = 0.001). Our results are consistent with those of Joseph et al. [16] who reported a positive association between IV uptake among French general practitioners and vaccine coverage among patients aged 65 years and above. Other studies, conducted among elderly, adults with chronic diseases and pregnant women, found that recommendations from healthcare providers are one of the leading causes of IV vaccine acceptance and receipt among patients [30‐32] and that they are the main source of information about influenza [31]. The low influenza immunization coverage in Tunisia may be partly attributed to low level of confidence regarding vaccine efficacy which is translated in low vaccine acceptance among prescribers. In agreement with Petek et al. [18], we observed an independent positive association between high confidence in vaccine efficacy and IV uptake in the 2018–2019 season (OR: 2.07).

Main barriers to vaccine acceptance for HCWs were fear of IV side effects, low perceived risk of severe influenza disease and doubt about vaccine efficacy. As expected, these reasons corroborate those reported globally [17‐19, 21, 23, 25, 33] and support the presence of misconceptions regarding influenza and influenza vaccines among HCWs. Indeed, almost half of our study sample believed that IV could cause a person to develop influenza. These results are in agreement with those from Saudi Arabia, where we found that 48.2% of health professionals believed mistakenly that the IV included live virus and could cause influenza [23]. Although IV containing live viruses does exist, it cannot cause influenza. Indeed, viruses contained in these vaccines are attenuated [34].

Despite the ACIP and WHO recommendations, less than one-third of Tunisian respondents identified HCWs as a target group for influenza immunization. These results are in contrast with previous studies in India and Saudi Arabia, in which the majority of surveyed HCWs were aware that the IV was recommended to HCWs [12, 22, 23]. Similarly, a study conducted during the 2018–2019 influenza season among healthcare providers working in critical care units in Italy found that more than half (64.1%) of participants knew that IV is recommended for HCWs [25].

Our results underscore the urgent need to educate HCWs about IV target groups and the vaccine composition. Tunisian vaccination awareness programs should also include information on the rates of IV side effects in addition to those of severe illnesses and deaths averted due to vaccination to raise HCW confidence regarding influenza immunization. In addition, COVID-19 pandemic might be a great opportunity to promote IV. Indeed, COVID-19 and influenza are both infectious respiratory diseases that have some symptoms and complications in common causing respiratory distress, hospitalization in intensive care units and even deaths mainly among vulnerable persons. HCWs encouraging the use of a vaccine against SARS-COV-2 just released after emergency use authorization, may find it hard to justify their negative attitude regarding flu shot that is already available for decades.

As educational programs alone may not be sufficient to increase vaccine uptake among health professionals, the Healthcare Infection Control Practices Advisory Committee (HICPAC) and the ACIP recommend the requirement of a signed declination from HCWs if they refuse to receive the IV without having any medical contraindications [35].

Mandatory vaccination of Tunisian health workers may be a solution to increase the uptake of IV among HCWs; however, only 42.8% of the present study respondents agreed with this action. Other studies observed higher percentages of mandatory vaccine acceptance among healthcare providers [13, 36].

Although more than half of respondents believed that vaccinating HCWs can reduce severe illness and deaths among patients, fewer than one-third mentioned patient protection as a main reason for vaccine acceptance. Indeed, self and family protection appeared to be more motivating than patient safety. These results are consistent with those of other studies, in which self-protection was identified as the main reason for vaccine acceptance [21, 37].

Despite recommendations, the vaccination rates were low among Tunisian health professionals. The low vaccination uptake may be related to a lack of confidence regarding IV efficacy and misconceptions about influenza immunization. These findings highlight the need for educational programs to raise HCWs’ awareness of vaccine efficacy and safety. Mandatory vaccination policies in healthcare facilities may also be considered. Findings from the present study can be useful to overcome potential barriers against the uptake of COVID-19 vaccine among HCWs which are identified as a priority group.