Introduction

Healthcare workers (HCWs) are at increased risk for influenza infection. Influenza vaccination remains the best intervention to prevent influenza infection. The World Health Organization (WHO) considers HCWs to be a priority group for annual influenza vaccination [1].

Influenza vaccination provides direct protection to HCWs by reducing the risk of symptomatic illness and severe complications [2,3]. Vaccinated HCWs are also less likely to transmit influenza to patients, thereby lowering the risk of nosocomial infections, particularly among vulnerable populations such as the elderly or immunocompromised [4,5]. Furthermore, higher vaccination coverage among HCWs has been associated with reduced absenteeism during influenza seasons, supporting continuity of care and mitigating strain on healthcare services [6,7].

However, annual influenza vaccine uptake among HCWs varies widely across countries and regions. A recent meta-analysis reported an overall global influenza vaccination rate of 41.7% among HCWs. Regional coverage ranged from 67.1% in the Americas (USA, Canada, Peru and Costa Rica) to 6.5% in Africa (Morocco, Egypt and Sierra Leone) [8].

HCWs’ attitudes, perceptions, and confidence in vaccines influence vaccination decisions [9]. Understanding factors associated with influenza vaccination uptake among HCWs, including attitudes and perceptions about influenza vaccine, may help inform targeted efforts to promote vaccine uptake among HCWs.

In recent years, variability in vaccination uptake has increasingly been examined through the concept of vaccine hesitancy, defined as delay in acceptance or refusal of vaccines despite availability of vaccination services [10]. Vaccine hesitancy is a complex and context-specific phenomenon influenced by factors such as confidence in vaccine safety and effectiveness, perceived risk of disease, and access to vaccination services [10,11].

Studies conducted during the COVID-19 pandemic demonstrated that vaccine hesitancy also occurs among HCWs and is associated with sociodemographic characteristics, profession, trust in health authorities, and previous vaccination behaviour, including influenza vaccination history [12–14].

More recent reviews continue to highlight the importance of vaccine confidence, perceived safety, and institutional trust as key determinants of vaccination behaviour among HCWs [15–17].

Georgia is an upper-middle income country in the South Caucasus region with a population of 3.7 million people. The Georgia Ministry of Health recommends influenza vaccination for HCWs [18]. In 2019, influenza coverage among HCWs in Georgia reported annually through the WHO/UNICEF Joint Reporting Form on Immunization was 64% [19].

From 2021–2024, the National Center for Disease Control and Public Health, Georgia (NCDC) together with WHO Regional Office for Europe conducted a prospective cohort study among HCWs in six Georgian hospitals to measure COVID-19 and influenza vaccine effectiveness (VE) [20]. We used data from this VE study with the aim of evaluating sociodemographic factors and attitudes about influenza vaccine associated with influenza vaccine uptake in at least one of the three seasons (2021–2022, 2022–2023, and 2023–2024) among Georgian HCWs.

Methods

Results

Characteristics of participants

Overall, of the 1606 HCWs who were enrolled in Year 1, 403 (25%) participants had complete data, were still enrolled in Year 3, and were included in our analysis. The median age was 46 (IQR = 36–54), 364 (90%) were female, 168 (42%) were nurses or midwives, 85 (21%) were support or janitorial staff, 75 (19%) were doctors and 75 (19%) were other unspecified staff. A third of HCWs [134 (33%)] reported having at least one underlying condition, 131 (33%) reported smoking currently or in the past, and 289 (72%) reported their self-rated health status as “excellent,” “very good,” or “good” (Table 1).

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Table 1. Sociodemographic characteristics of HCWs (N = 403) overall and by influenza vaccination status, Georgia, 2021–2024.

https://doi.org/10.1371/journal.pone.0356495.t001

Most participants reported having regular contact with patients [319 (79%)] and providing hands-on medical care to patients [210 (52%)]. Less than half of participants reported performing aerosol-generating procedures [157 (39%)]. Most participants worked in inpatient or outpatient units/services [322 (80%)], and most participants [320 (79%)] reported living with family members. Overall, 289 (72%) participants received influenza vaccine in at least one of the 3 seasons, while 114 (28%) participants were never vaccinated against influenza in any season. Of the 289 participants who reported having received influenza vaccine in at least one of the 3 seasons, 81/289 (28%) had received vaccine in all 3 seasons, 110/289 (38%) received vaccine in two seasons and 98/289 (34%) received vaccine in only one season.

Attitudes towards influenza vaccination

Most participants [351 (87%)] said they thought that influenza vaccine was “extremely effective” or “very effective” or “somewhat effective” in preventing influenza, and most participants [357 (89%)] “strongly” or “mildly” agreed that influenza vaccination was safe. More than three-quarters of participants [320 (79%)] were not worried about becoming ill with influenza during the next 12 months. The large majority [373 (93%)] of HCWs strongly or mildly agreed with the statement, “If I am fully vaccinated against influenza, I will be less likely to miss work because of becoming ill with influenza” (Table 2).

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Table 2. Attitudes towards influenza vaccination overall and by influenza vaccination status, Georgia, 2021–2024.

https://doi.org/10.1371/journal.pone.0356495.t002

In the univariable analysis we evaluated 14 sociodemographic, occupational, and attitudinal variables. Of these, 7 variables met criteria to be included in the multivariable analysis, of which 4 remained significant in the multivariable analysis (Table 3).

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Table 3. Univariable and partially adjusted analysis of factors associated with uptake of influenza vaccine in at least one of the three study seasons among health care workers, Georgia, 2021–2024.

https://doi.org/10.1371/journal.pone.0356495.t003

Compared to HCWs aged 18–29 years, HCWs in the age group 40–49 years were more likely to get vaccinated (adjusted odds ratio (aOR): 2.67, 95% CI 1.09–6.59). While older HCWs in other age group categories were also more likely to have received influenza vaccine, the aORs were not statistically significant (Table 4).

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Table 4. Multivariable analysis of factors associated with uptake of influenza vaccine in at least one of the three study seasons among health care workers, Georgia, 2021–2024.

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HCWs who did not believe influenza vaccine was safe (aOR: 0.27, 95% CI 0.11–0.68), HCWs who thought that influenza vaccine was not effective (aOR: 0.36, 95% CI 0.14–0.89), and HCWs who worked in Hospital B (aOR: 0.06, 95% CI 0.02–0.23) were less likely to get vaccinated.

In a sensitivity analysis restricted to influenza vaccination uptake during the 2023–2024 season (the year in which attitudes were measured), perceived vaccine safety and perceived effectiveness in preventing missed work remained strongly associated with vaccination uptake. Institutional differences were also observed. Results were consistent with the primary analysis (S1 Table).

Reasons for getting and not getting influenza vaccine in 2022–2023 season

HCWs who did not get vaccinated in the 2022–2023 season, cited as the main reason for not getting vaccinated “even if I get the flu, it won’t be severe, so I don’t need vaccination” [97 (66%)] followed by “I do not trust the official recommendations” [84 (58%)] (Table 5). Among HCWs who did get vaccinated, the main reason reported was “to protect my health” [211 (99%)] (Table 6).

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Table 5. Reasons for not getting influenza vaccine, Georgia, 2022–2023.

https://doi.org/10.1371/journal.pone.0356495.t005

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Table 6. Reasons for getting influenza vaccine, Georgia, 2022–2023.

https://doi.org/10.1371/journal.pone.0356495.t006

Discussion

In our study of factors associated with influenza vaccine uptake among Georgian HCWs over a three-year period, we found that older HCWs were more likely to be vaccinated, while doubts about influenza vaccine safety and effectiveness were associated with lower vaccination uptake. These findings highlight not only the patterns of vaccination behaviour but also the underlying beliefs that may shape HCW decision-making. These findings, which combine three seasons of influenza vaccination history among HCWs in six Georgian hospitals, can be used to tailor messaging to emphasize influenza vaccine safety and effectiveness. In addition, the findings highlight the need to increase vaccine promotion among younger HCWs in Georgia.

Our finding that doubts about influenza vaccine safety were associated with lower vaccine uptake among HCWs has been reported in other studies conducted mostly in high-income countries. For example, in a global meta-analysis Kong et al. (2022) found that safety concerns were a common barrier to influenza vaccination among HCWs across multiple studies [23]. Likewise, a study among Lebanese physicians by Farah et al. (2025) identified vaccine safety perceptions as a key determinant influencing influenza vaccination uptake [24]. Consistent with this, a multi-country study reported that vaccine acceptance varied substantially depending on the vaccine’s perceived efficacy and safety profile [25]. These findings suggest that vaccine hesitancy among HCWs is not solely a matter of access or awareness, but reflects cognitive evaluations of risk and trust in health authorities and vaccines. Our findings, like previous studies, underscore the importance of emphasizing messages about influenza vaccine safety among HCWs. Influenza vaccine has been shown to be safe in several studies [26,27]. Strengthening post-vaccination surveillance and pharmacovigilance systems can further help address concerns about adverse events following immunization and build vaccine confidence [28]. HCWs are known to be a trusted source of information for patients [29]. Therefore, improving their awareness about vaccine safety for themselves could also help improve vaccine safety awareness among patients [30].

Similarly, doubts about influenza vaccine effectiveness were associated with lower uptake, echoing findings from post-pandemic studies, where perceived vaccine effectiveness was shown to be a strong driver of vaccine uptake decisions. For example, a German study found doubts about vaccine effectiveness as one of the most common reasons for non‑vaccination among HCWs [31]. Likewise, a study from Italy among HCWs found that confidence in the vaccine’s ability to prevent illness was the main reason for missed annual revaccination [32]. These findings indicate that HCWs’ behaviour regarding influenza vaccination is influenced by perceived utility: if the protective benefit is uncertain, motivation to vaccinate declines. From a behavioural perspective, interventions should focus on communicating the effectiveness of vaccination. Educational strategies that clearly communicate effectiveness in reducing disease severity and reducing transmission may be critical in improving coverage rates in HCWs.

Although our findings indicate that concerns about influenza vaccine safety and effectiveness were associated with lower vaccine uptake among HCWs, these perceptions represent broad constructs that may encompass different types of beliefs. Safety concerns may include evidence-based scientific reservations about vaccine adverse effects, general vaccine hesitancy, anxiety related to prior vaccination experiences, or misinformation circulating through social or professional networks. Previous qualitative research among HCWs has shown that vaccine hesitancy can stem from concerns about side effects, perceived insufficient testing of vaccines, or mistrust towards pharmaceutical companies or health authorities [29]. Future research using qualitative or mixed-methods approaches—such as in-depth interviews or focus groups—would help better characterize the specific beliefs and informational gaps underlying these perceptions among HCWs in Georgia. Such evidence could inform the development of more targeted communication strategies and vaccination promotion programs.

Age was a significant predictor of vaccine uptake in our study: HCWs in all age groups ≥ 30 years old had trends of increased odds of reported vaccination uptake compared to those in the 18–29-year group. This trend may reflect greater professional experience, heightened awareness of influenza risks, or prior exposure to institutional vaccination campaigns among older HCWs. Our finding is in line with other studies from Italy and Jordan that found that older age was significantly associated with higher influenza vaccine uptake among HCWs [33,34]. While young HCWs may be at less risk of getting severe disease from influenza virus infection, they still get ill from influenza, miss work, and they are at risk of transmitting the virus to vulnerable patients, all of which are messages that can be used to encourage influenza vaccination in this population.

The markedly lower uptake observed in Hospital B may reflect institutional factors such as differences in vaccine promotion practices, leadership engagement, workplace culture, vaccine accessibility, or local perceptions regarding vaccination. Although we did not evaluate these factors in participating hospitals, previous studies have demonstrated that organisational climate, leadership support, and institutional vaccination policies can strongly influence HCW vaccination behaviour [35,36]. Further facility-level investigations are warranted.

Our finding that there was no significant difference in influenza vaccine uptake by sex among HCWs is consistent with existing literature. For instance, Sallam et al. (2022) found that sex was not a significant predictor of influenza vaccination uptake among Jordanian HCWs [9]. Similarly, Anwar et al. (2023) reported no association between sex and vaccine uptake among HCWs in tertiary care hospitals in Bangladesh [37].

While our study population was predominantly female (90%), this gender distribution is consistent with the high proportion of women employed in nursing and allied health professions in Georgia. Annual national statistics reports in the country have consistently shown that women comprise the vast majority of the healthcare workforce; in 2022, 84.4% of physicians and 94% of nurses were women [38]. Gender-specific concerns, including perceptions related to pregnancy, fertility, or vaccine safety, could have influenced vaccination attitudes and behaviours in our survey, but could not be explored in this analysis.

While our study did not identify an association between occupational category and influenza vaccine uptake, research conducted in Germany and the United States reported significant differences in vaccination rates across different health service disciplines. The U.S. study found that physicians had significantly higher vaccination rates compared to other healthcare professionals [39]. Likewise, the German study reported that physicians had influenza vaccination rates two to three times higher than those of nurses [40].

Finally, our analysis of HCWs’ self-reported reasons for vaccination decisions underscores the role of perceived disease severity and personal health protection in decisions related to vaccination. Perception of influenza as a non-severe disease was the main reason HCWs reported for not getting the influenza vaccine in 2022–2023 season, while the desire to protect one’s own health was the main reason for getting the vaccine. These findings indicate that risk perception strongly shapes behaviour and that messages to promote vaccination should explicitly connect influenza vaccination to both individual health and patient safety outcomes. Our findings are similar to studies in Greece, the UK and Saudi Arabia, where unvaccinated HCWs reported low perception of influenza severity as a main reason for not getting vaccinated, and vaccinated HCWs reported that one of the primary motivators to get vaccinated was a desire to protect their own health [41–43]. While it is true that most young, healthy HCWs do not get severe illness from influenza virus infection, HCWs still commonly get influenza-like symptoms — including moderate illness — which poses a clear risk for transmitting infections like influenza to vulnerable patients [44].

Our study has a number of strengths. For our analysis we used data collected from a prospective cohort study among HCWs in six Georgian hospitals over three seasons, and therefore we were able to include influenza vaccination uptake data over multiple seasons. In addition, because we collected our data in a rigorously conducted prospective vaccine effectiveness study, the data were regularly checked for inconsistencies and completeness to ensure high quality.

Several limitations should be considered when interpreting our findings. First, the external validity of our study may be limited. Our analysis was conducted among HCWs in six large, secondary care hospitals in major urban centres. Therefore, these results may not be fully representative of the attitudes and vaccination behaviours of HCWs in primary care and rural medical facilities across Georgia. Our study had a high attrition rate, only 25% (403/1606) of the initial cohort providing complete data across all three years. While this longitudinal approach allowed for a robust assessment of long-term vaccination patterns, the loss of participants may have introduced selection bias; while 42% of eligible HCWs were enrolled in the prospective VE study in the six hospitals, only one-third of those HCWs were included in this analysis, as we required them to participate in all three years. Participants who remained in the study may have differed from those lost to follow-up in ways that could influence vaccination behaviour, such as greater engagement in research activities, stronger health awareness, or more positive attitudes towards vaccination. As a result, the findings may not fully represent all HCWs initially enrolled in the cohort. The causal strength of the factors we found to be associated with vaccine uptake is limited due to the observational nature of the study. While we found statistically significant associations between age, perceived vaccine safety/effectiveness, and vaccine uptake, these results demonstrate association rather than direct causality. Given the three-year study period, recall bias may have occurred, as participants may not accurately remember their vaccination history. Furthermore, social desirability bias may have influenced self-reported vaccination behaviour, potentially leading to overestimation of uptake.

Additional limitations include the relatively small sample size, as a result of which we may not have had the power to detect some true associations. Because of the limited sample size of participants with complete data across three years, we analysed receipt of influenza vaccination in at least one season as our primary outcome. As a result, individuals vaccinated once were analytically grouped with those vaccinated annually, which may limit interpretation regarding consistency of vaccination behaviour, as it does not distinguish between sporadic and consistent annual vaccination.

While our study found that HCWs at one hospital (Hospital B) had lower odds of influenza vaccination, we were not able to explore reasons that could explain the low uptake in this hospital; this is something that should be investigated in the future.

We asked participants questions about their attitudes about influenza vaccination in the Year 3 questionnaire (2023), while we used vaccination status data over the 3 previous seasons. However, the findings in our sensitivity analyses restricted to Year 3 vaccination uptake were consistent with our main findings, suggesting that temporal misclassification did not materially alter conclusions.

Finally, we did not include a comprehensive assessment of broader dimensions of vaccine hesitancy, such as trust in vaccine development and manufacturing processes, confidence in health authorities, or exposure to anti-vaccination narratives. Vaccine hesitancy is increasingly recognised as a complex and multidimensional phenomenon influenced by psychological, social, and institutional factors, particularly highlighted during the COVID-19 pandemic. While our study assessed several attitudes towards influenza vaccination, these broader determinants were beyond the scope of the survey. Future studies incorporating validated measures of vaccine hesitancy and vaccine confidence could provide additional insights into factors influencing influenza vaccine uptake among HCWs.

In conclusion, we observed that in Georgia, younger HCWs, HCWs who doubted influenza vaccine safety and influenza vaccine effectiveness, and HCWs who worked at one of the six hospitals were less likely to get vaccinated against influenza. Addressing these barriers is essential for improving vaccine uptake. Hospital-level assessments may help identify structural or organisational barriers to vaccination. Evidence from previous studies suggests that targeted educational interventions and multifaceted vaccination campaigns—such as tailored communication, on-site vaccination opportunities, and promotional activities—can increase influenza vaccination coverage among HCWs [45–47]. Implementing targeted educational programs addressing vaccine safety and effectiveness concerns, particularly among younger HCWs, could help increase vaccine uptake in Georgia. In addition, healthcare institutions in Georgia could consider expanding workplace vaccination strategies, such as on-site vaccination services, peer-led promotion, and tailored communication campaigns, to improve influenza vaccination uptake among HCWs.

Supporting information

Acknowledgments

The authors acknowledge the contributions of all study participants. We also thank the research team for their support and assistance in conducting the study and analysing the data. Their efforts were essential for the completion of this work.