Vaccine Hesitancy in Women of Childbearing Age and Occupational Physicians: Results from a Cross-Sectional Study (Italy, 2022)

: Italian occupational physicians (OPs) are instrumental in promoting vaccination practice in occupational settings, and this study aims to characterize their attitudes, knowledge, and practices (collectively, KAP) towards immunization practice in women of childbearing age. A convenience sample of 120 OPs (50.8% males, mean age of 48.2 ± 5.9 years old) completed a structured online


Introduction
Where implemented by the national legal framework, occupational physicians (OPs; please refer to Table A1 for a full summary of acronyms) are the medical professionals responsible for health surveillance and promotion across the workplaces [1,2]. Well before the inception of the SARS-CoV-2 pandemic, Italian OPs were actively involved in the implementation of specifically tailored preventive measures against biological risk factors [3][4][5], including prescription and/or delivery of appropriate vaccinations [2,6]. Not coinciden-Women 2023, 3 238 tally, Italian OPs have been extensively involved in the implementation of SARS-CoV-2 vaccination campaigns [7].
Even SARS-CoV-2 vaccines have been recently addressed by official recommendations that support their delivery in pregnant women. While initially recommended for breastfeeding mothers and pregnant women at higher risk of exposure to the virus or at greater risk of developing a severe illness, since the second half of 2021, SARS-CoV-2 mRNA vaccines have been extended to all pregnant women in their second and third trimester who wish to be vaccinated [43][44][45][46][47][48]. More precisely, national vaccination guidelines prioritize women at greater risk of contracting SARS-CoV-2 infection because of their occupational exposures (e.g., HCWs) and/or at greater risk of developing severe COVID-19 disease (women with risk factors such as age >30 years, BMI >30, comorbidities, women from countries where the migration pressure is high) [43][44][45].
In such a setting, the role of OPs may be of particular interest, as they could contribute to the promotion of recommended vaccination in working age groups, which in women largely coincide with childbearing age. Unfortunately, previous studies have reported a high occurrence of false beliefs about vaccinations and a lack of knowledge about national vaccination policies among Italian OPs [2,6,46,47]. Interestingly, similar shortcomings have been reported also in other national settings [1,20,48].
As a consequence, the main endpoint of this study was to assess knowledge (how much the respondents understand a certain topic), attitudes (that is the feelings of sampled individuals towards the assessed subject, as well as any preconceived ideas they may have towards it), and practices (the ways in which they demonstrate their knowledge and attitude through their actions; collectively, KAP) of a sample of OPs about vaccinations and vaccination policies in women of childbearing age and pregnant women. The understanding of general and specific recommendations was specifically focused on, as well as how the KAP of sampled professionals related to these recommendations. Our results may contribute to identifying areas that may be potentially targeted by specific informative and educative campaigns dedicated to OPs.

Descriptive Analysis
As reported in Figure 1, a total of 120 OPs (5.9% of the original population of 2034 OPs) participated in the inquiry.
As reported in Figure 1, a total of 120 OPs (5.9% of the original population of 2034 OPs) participated in the inquiry. Overall, 50.8% of the participants were of the male gender, and their mean age was 48.2 ± 5.9 years (30.0% aged 50 years old or more), with average seniority as OPs of 16.3 ± 10.1 years (75.0% of them, with a seniority of 10 years or more). Of these, the large majority had offspring (86.7%) and worked as OPs in healthcare facilities (71.7%) ( Table 1).

Assessment of Knowledge Status
Knowledge status was assessed by means of a series of 25 true-false questions, whose internal consistency was good (Cronbach's alpha = 0.873). After percent normalization, the corresponding cumulative score (general knowledge score, or GKS) was generally high (74.5% ± 18.2; actual range 28.6-100%; median 78.6%). A skewed distribution was identified at visual inspection (Figure 2), and the Gaussian distribution was rejected by the D'Agostino-Pearson test (K2 = 22.17, p < 0.001). Overall, 50.8% of the participants were of the male gender, and their mean age was 48.2 ± 5.9 years (30.0% aged 50 years old or more), with average seniority as OPs of 16.3 ± 10.1 years (75.0% of them, with a seniority of 10 years or more). Of these, the large majority had offspring (86.7%) and worked as OPs in healthcare facilities (71.7%) ( Table 1).

Assessment of Knowledge Status
Knowledge status was assessed by means of a series of 25 true-false questions, whose internal consistency was good (Cronbach's alpha = 0.873). After percent normalization, the corresponding cumulative score (general knowledge score, or GKS) was generally high (74.5% ± 18.2; actual range 28.6-100%; median 78.6%). A skewed distribution was identified at visual inspection (Figure 2), and the Gaussian distribution was rejected by the D'Agostino-Pearson test (K2 = 22.17, p < 0.001). Detailed results of the knowledge test are reported in Table A2. More precisely, substantial uncertainties were associated with items represented by Q19, as only 37.5% of respondents were aware that no RSV vaccine has been to date commercially made available; and Q23, as only 47.5% of participants had any understanding that mRNA vaccines against SARS-CoV-2 vaccines can be employed also in women with a previous history of deep vein thrombosis. Interestingly, even though a large share of participants had a proper understanding of official recommendations that allow the use of vaccines in pregnancy (Q16, 91.7%), similar knowledge gaps affected the recommendations for the delivery of the Tdap vaccine to all pregnant women (Q15, 54.2%) and for avoiding live-attenuated vaccines in pregnancy (Q17, 54.2%).
Moreover, a substantial share of participants exhibited some uncertainties regarding the role of vaccine additives in human health (Q01, 66.7% of correct answers) and the potential resurgence of secondary cases with epidemic potential after vaccinations with liveattenuated vaccines (Q21, 67.5%). Around a third of respondents also exhibited knowledge gaps about the potential vaccine-related induction of encephalitis lethargica (Q04, 66.7%), subacute sclerosing panencephalitis (Q03, 67.5%), and autoimmune Hashimoto's thyroiditis (Q06, 63.3%). Conversely, the large majority of participants properly acknowledged the efficacy of vaccines (Q11), understood the role of smallpox vaccination in the progressive eradication of the pathogen (Q10; 95.8% for both statements), and correctly reported that tetanus vaccination should be delivered in all adults every 10 years (Q18, 91.7%). The large majority of respondents also agreed on the lack of secondary effects of childhood immunization on their resistance to infectious diseases (Q12, 93.3%), and that vaccines do not increase the risk of developing autism (Q07, 91.7%), being of substantial value in promoting the control of infectious disease (Q09, 91.7%). Detailed results of the knowledge test are reported in Table A2. More precisely, substantial uncertainties were associated with items represented by Q19, as only 37.5% of respondents were aware that no RSV vaccine has been to date commercially made available; and Q23, as only 47.5% of participants had any understanding that mRNA vaccines against SARS-CoV-2 vaccines can be employed also in women with a previous history of deep vein thrombosis. Interestingly, even though a large share of participants had a proper understanding of official recommendations that allow the use of vaccines in pregnancy (Q16, 91.7%), similar knowledge gaps affected the recommendations for the delivery of the Tdap vaccine to all pregnant women (Q15, 54.2%) and for avoiding live-attenuated vaccines in pregnancy (Q17, 54.2%).
Moreover, a substantial share of participants exhibited some uncertainties regarding the role of vaccine additives in human health (Q01, 66.7% of correct answers) and the potential resurgence of secondary cases with epidemic potential after vaccinations with liveattenuated vaccines (Q21, 67.5%). Around a third of respondents also exhibited knowledge gaps about the potential vaccine-related induction of encephalitis lethargica (Q04, 66.7%), subacute sclerosing panencephalitis (Q03, 67.5%), and autoimmune Hashimoto's thyroiditis (Q06, 63.3%). Conversely, the large majority of participants properly acknowledged the efficacy of vaccines (Q11), understood the role of smallpox vaccination in the progressive eradication of the pathogen (Q10; 95.8% for both statements), and correctly reported that tetanus vaccination should be delivered in all adults every 10 years (Q18, 91.7%). The large majority of respondents also agreed on the lack of secondary effects of childhood immunization on their resistance to infectious diseases (Q12, 93.3%), and that vaccines do not increase the risk of developing autism (Q07, 91.7%), being of substantial value in promoting the control of infectious disease (Q09, 91.7%).

Risk Perception
Risk perception scores (RPS) for natural infections and vaccine-related side effects were calculated as the mathematical product of perceived severity (potential range 0 to 5) and perceived incidence (potential range 0 to 5) of the assessed condition ( Figures A1 and A2). Briefly, the greatest RPS on natural infections was associated with SARS-CoV-2 (52.7% ± 32.9), followed by rubella (

Attitudes towards Vaccination
When participants were asked about the perceived barriers towards vaccination of pregnant women (Table 2), the most frequently reported one was the inappropriate risk perception by pregnant women (83.3%), followed by their appropriate understanding of official recommendations (79.2%), the fear of side effects (70.8%), the inappropriate understanding of official recommendations by medical professionals (62.5%). Moreover, 45.9% of participants claimed that other medical professionals may not perceive maternal vaccinations as a priority and that vaccination services may be scarcely available given the specificities of pregnant women (37.5%). Only 12.5% of participants reported any complaints about the high costs of vaccines. Overall, the majority of participants recommended any of the SARS-CoV-2 vaccines (i.e., mRNA, subunit, or adenovirus-based formulates) in women of childbearing age (74.2%), followed by Tdap (70.8%), SIV (66.7%), and hepatitis B virus vaccine (54.2%) ( Table 3). On the contrary, less than 50% of participants actively recommended MPR (45.8%), and varicella (41.7%) immunizations.

Multivariable Analysis
Multivariable analysis was modeled including the variables that in univariate analysis were significantly associated (p < 0.05) with the active promotion among female workers of childbearing age of SIV (Model 1), Tdap (Model 2), and SARS-CoV-2 vaccines (Model 3), and more precisely (Table A6) 20.14). On the contrary, it was less frequently reported by participants who reportedly worked as OPs in healthcare facilities (aOR 0.03, 95%CI 0.01 to 0.43) and who reported higher RPS on the vaccine (aOR 0.04, 95%CI 0.01 to 0.35). Table 6. Multivariable analysis of factors associated with a better individual attitude towards seasonal influenza vaccine (SIV), diphtheria, tetanus, and pertussis formulate (Tdap), and SARS-CoV-2 vaccination among 120 occupational physicians participating in the survey. The assessed models included the favorable attitude towards the individual vaccine as the outcome variable, and assessed as explanatory variables all factors that in univariate analysis were associated (p < 0.05) with the corresponding outcomes.

Discussion
In our cross-sectional study, we assessed the KAP of a small sample of Italian OPs (120 respondents in total) about vaccinations and vaccination policies in female workers of childbearing age. As HCWs, OPs can reasonably represent a model for the general population, but because of their exclusive role in the occupational settings, they are also potentially instrumental in overcoming vaccine hesitancy (delay in acceptance or refusal of vaccines irrespective of their actual availability) [49][50][51] across workplaces and in high-risk occupational groups [52]. Consequently, when OPs improperly share false beliefs among the workers they care for, they may even become detrimental to the global efforts to achieve and maintain high vaccination rates, not only for "new" vaccines such as SARS-CoV-2 [1,2,36,53] but also for more conventional ones such ad Tdap and SIV [36,48,54,55]. In our study, the majority of respondents exhibited a relatively good performance on the knowledge test (74.5% ± 18.2) and a somehow discrete positive attitude towards SIV (66.7%), Tdap (70.8%), and SARS-CoV-2 (74.2%). It is often believed that the attitudes towards vaccines of medical professionals (including OPs) should not be negative and that they cannot be affected by substantial vaccine hesitancy. Even though these results are obviously desirable, they cannot be taken for granted [17,[56][57][58].
In our study, the aforementioned vaccinations were associated with quite distinctive predictive variables. On the one hand, a better knowledge status was consistently characterized as a predictive variable (aOR 12 Our estimates are therefore somewhat consistent with most of the available KAP studies on immunizations [2,6,7,29,33,53,[59][60][61][62][63][64][65][66], where the domain of knowledge has been often acknowledged as a main predictor for attitudes and practices of medical professionals. It should be stressed that similar results have been repetitively but not consistently reported in occupational studies, particularly in those performed on OPs [1,2,6,7,36,53]. Particularly when dealing with KAP studies on biological risk in occupational settings, knowledge represents a key factor that should be specifically addressed. As previously stressed by Betsch et al. in a sample of German professionals [1], OPs are not spared by substantial knowledge gaps and misunderstanding of biological risk agents. Similar estimates were reported from several Italian studies [2,7,53,67], and a likely explanation for these knowledge gaps may be tentatively identified in the core curriculum of OPs. Until recently, despite the underlying legal framework, and the substantial burden represented by pathogens such as HBV, HCV, and HIV, the formal education and the medical training of Italian OPs have often prioritized other topics (e.g., work-related musculoskeletal diseases, occupational pulmonary diseases, occupational neoplasia) over biological risk [15,37,39,68]. In other words, despite their professional role, scientific background, and medical training, not only may OPs fail to overcome the gaps between official recommendations and vaccine objectors [1,2,7,67,69], but their knowledge gaps could even lead to a certain degree of vaccine hesitancy [2,6,7,53,59].
In addition, the negative attitude towards the promotion of SIV among female workers of childbearing age could be explained in terms of potential false beliefs, particularly on the actual efficacy and safety profile of the available vaccines [29,32,70,71]. During the previous decade, the reporting of three deaths within 48 h of vaccination with the Fluad ® vaccine led to a sustained reduction in vaccination rates between 2014 and 2017 [72,73], also among medical professionals [72,74], with a sustained lack of trust in this preventive intervention [29,53]. Even in our study, SIV was associated with an RPS that exceeded other immunizations, notably including varicella and rubella immunizations. Both vaccines are represented by live-attenuated pathogens: even though reactivation of vaccine strains is usually acknowledged as somewhat unusual for both varicella and rubella, for the safety of mother and children, their delivery is usually avoided in pregnant women [19,[75][76][77][78][79]. Moreover, the reported mismatch between antigens contained in the SIV and the circulating pathogens in several winter seasons has presumptively led to the diffuse underscoring of the actual preventive role of SIV [46,80,81]. Nonetheless, we cannot rule out that a certain disregard for SIV could be associated with the misunderstanding of the actual aims of this intervention. While vaccines included in Tdap are aimed to avoid the clinical syndromes associated with the natural infection of the primary pathogens, the primary aim of SIV is avoiding complications of the natural infection, likewise with SARS-CoV-2 immunization [24,74,82,83]. Interestingly, the effectiveness of SIV in avoiding sick leave in certain settings, such as healthcare facilities, although proven [84], has been inconsistently reported in several Italian studies [53,83,84]. In other words, some professionals may have failed to properly appreciate the actual cost-benefit ratio of this medical intervention, particularly in individuals such as pregnant women, where the clinician should not only target the health and safety of the patient (i.e., the pregnant woman) but care also for the unborn child. Not coincidentally, being an occupational physician in medical facilities was a negative predictor for a positive attitude towards SIV [26,33,[85][86][87][88].
The inappropriate attitude of participating OPs towards SIV is particularly unsatisfactory when keeping in mind that vaccination of pregnant women remains globally low [85], and that there is a certain base of evidence that the failure of HCW to recommend, offer, promote, and perform influenza vaccination represents a substantial barrier to antenatal influenza vaccination [85][86][87]. A more effective contribution of OPs in overcoming usual barriers to maternal vaccination would be therefore both appreciable and necessary, as previously recommended for other medical professionals interacting with pregnant women [26,33,85,[88][89][90][91].
In our study, the eventual promotion of the SARS-CoV-2 vaccine among pregnant women was remarkable (74.2%) and quite similar to the overall acceptance of mRNA formulates in a precedent report on Italian OPs (89.8% of 166 professionals) [7]. Moreover, the overall risk perception for these vaccines was comparable to other assessed immunizations, with the notable exception of adenovirus-based formulates. In this regard, a worse acceptance of these formulates was reported even in the aforementioned preliminary report (i.e., 51.2% vs. 89.8%) [7]. In fact, participating OPs appeared to be up-to-date in terms of general recommendations towards SARS-CoV-2 vaccines, with the notable exception of the exemption for women previously reporting cases of deep vein thrombosis. During the first SARS-CoV-2 vaccination campaign, several claims of an increased risk of deep vein thrombosis after SARS-CoV-2 vaccination shots urged for a critical reappraisal of these vaccines in groups potentially at high-risk, including individuals with previous episodes of deep vein thrombosis, women using birth control pills or hormone replacement therapy, and pregnant women [92][93][94][95][96]. Still, most of the reported cases were actually associated with adenovirus-based formulates [92,93,97], while mRNA vaccines and subunit vaccines have shown a safer profile [92,95,96]. Even though SARS-CoV-2 immunizations performed by means of an adenovirus carrier were discontinued during 2021, the overall attitude towards this immunization was actually associated with a quite higher RPS than that reported for mRNA formulates (19.9% ± 19.8 vs. 15.7% ± 19.4) and for SARS-CoV-2 vaccines based on the subunit technology (15.2% ± 16.1). The similar appraisal of mRNA and subunit vaccines-at least in this specific sample-may contribute to our understanding of the unsatisfying uptake of subunit formulates during vaccination campaigns in 2021 and 2022. Even though substantial vaccine hesitancy had previously affected similarly designed vaccines targeting hepatitis B and Neisseria meningitidis ACWY [31,[98][99][100][101], subunit formulates have been initially welcome as "more conventional" drugs that could contribute to overcoming most of the concerns about the innovative mRNA technology [102]. However, according to an official report from the Italian National Health Service, by 26 September 2022, a total of 140,689,960 doses of SARS-CoV-2 vaccines had been delivered among Italian residents; of these, only 0.03% were represented by subunit formulates [103]. In other terms, our results seemingly suggest that interventions improving the understanding of actual guidelines among OPs may also improve their acceptance and proactive attitude towards SARS-CoV-2 vaccines even in pregnant women.
Limits and Strengths. Despite its potential significance, our study is affected by several limitations and is not generalizable because of shortcomings affecting the sampling strategy and generalizability of the sample.
In the first place, our sample was quite small, as it included a total of 120 OPs, which is around 1.5% of all Italian occupational physicians at the time of the survey (n = 7826), and only 5.9% of the potential recipients. Therefore, the sample is not likely to be representative of all OPs. Moreover, because of the limited number of sampled professionals, and the similarly limited response rate across the targeted and invited OPs, the present study was also affected by reduced statistical power, urging for a very cautious appraisal of the results we were able to collect. More precisely, assuming as a reference the acceptance of influenza (68.5%), Tdap (52.7%), and SARS-CoV-2 (90.4%) by Italian OPs from some similarly designed studies [7,36,53], a Type I error of 5% (0.05), and a power of 95%, a minimum sample size ranging between 133 for SARS-CoV-2, 332 for SIV, and 383 for Tdap could be calculated [7]. In other words, the present study only collected one-third of the sample size it would have required in order to gather sufficient statistical power. Still, as the specific topic of immunization of childbearing-age women in occupational settings has been assessed in only a limited fashion, particularly in Italy, and available evidence has been mostly collected from healthcare workers [7,29,[104][105][106][107], our preliminary results could provide some insight for potential interventions aimed to improve the overall delivery of vaccines by OPs.
Second, our research was designed as an internet-based survey, whose implicit limits have been previously addressed [108][109][110]. Similarly designed studies are acknowledged as reliable and cost-effective, but they are also affected by an extensive double "self-selection" of participating individuals. On the one hand, as participating individuals are recruited through social media platforms, the sample will only include individuals familiar with new media [36,109,[111][112][113]. In turn, this could lead to the oversampling of individuals more accustomed to sharing personal information through internet access, usually more frequently reported among younger age groups. In effect, our sample included a reduced share of respondents aged 50 years or older (30.0% of the total sample), and these figures are quite inconsistent with the Italian medical workforce [114,115]. On the other hand, this sampling strategy would lead to the oversampling of subjects having greater knowledge and/or interest in the assessed topic [29,32,116,117], while not participating could be understood as a negative attitude or a lack of knowledge about the targeted topic [109], and that may impair the overall reliability and generalizability of collected results. Nonetheless, our study deliberately targeted a relatively homogenous subgroup of medical professionals (i.e., OPs) in order to mitigate as much as possible the potential self-selection of the participants and minimize or even rule out the eventual effect of individual factors such as occupational background and educational level.
Thirdly, we cannot rule out that some of the respondents did not fully adhere to our selection criteria, further compromising the actual representativity of the sample. In order to cope with this potential shortcoming, our study only included participants that were drawn from discussion groups, whose participation was limited to individuals having previously received a specific invitation from the manager and answered specific "selection" questions [118]. Moreover, we do not know how often sampled participants are usually requested to contribute to workers' vaccinations, and more specifically to the vaccination practice of pregnant women [7,29,36,53,[104][105][106][107].
Fourth, even though the core of this study, i.e., the knowledge test, was based on a reliable model and characterized by a high degree of internal consistency [1,119], we cannot rule out that some of the items assessed might have been affected by some degree of social desirability bias, whereby some participants reported some answers in terms of "common sense", prioritizing more "socially appropriate" answers over their true understanding of certain topics. Interestingly, such potential bias has been repeatedly identified in previous KAP studies on OPs [1,2,36,53,108], including some surveys performed with a quite similar sample. Therefore, we cannot rule out that our results could have ultimately overstated the share of individuals having an effective understanding of vaccine-associated issues, but also actually acknowledging the reported and assessed vaccinations as recommended and promoted in pregnant women and women of childbearing age. In order to attempt a certain quantification of participants affected by social desirability bias, the knowledge test specifically reported the still commercially unavailable maternal RSV vaccination [118,120]. Interestingly, only 37.5% of participants correctly ruled out this option, suggesting the need for a critical appraisal of overall results from the knowledge test and individual attitudes towards reported vaccines.
Finally, our study deliberately assessed the KAP of recruited participants on a selected set of immunizations, but women of childbearing age could be targeted by other interventions of some occupational interest, including but not limited to vaccines for Neisseria meningitidis and Mycobacterium tuberculosis (i.e., BCG) for healthcare workers, Hepatitis A virus, typhoid vaccines, and tick-borne encephalitis vaccine for workers traveling to parts of the world where these pathologies are common, and even rabies vaccines for professionals involved in laboratory and veterinary practice [30,31,[121][122][123][124][125][126][127]. Moreover, workplaces may represent an appropriate setting for improving the acceptance of immunizations with a more limited occupational interest, such as pneumococcus, and mostly human papillomavirus (HPV) vaccines. In effect, the pneumococcal vaccine is currently indicated only for individuals having certain chronic medical conditions or other risk factors, and routine medical surveillance by OPs may provide an ideal opportunity for reaching potential recipients and/or addressing their vaccine hesitancy [128,129]. Similarly, OPs could contribute to the shared effort for improving HPV vaccination rates. HPV is not only the current most common sexually transmitted disease in the world but it is also acknowledged as the main risk factor for cervical cancer in women with an estimated 570,000 new cases per year [130][131][132][133]. According to the current guidelines, the HPV vaccine is currently recommended for everyone through age 26 years if not adequately vaccinated when younger, and OPs, during medical surveillance, could properly identify and address women that can potentially benefit from catch-up vaccination [134]. According to the total worker health approach, future interventions should be therefore tailored in order to include a more extensive list of assessed vaccinations, not strictly limited to the interventions associated with occupational settings [135,136].

Study Design
The present study was designed as a cross-sectional questionnaire-based study according to the STROBE statement (see STROBE checklist as Supplementary File S1) and performed between 1 April 2022 and 30 April 2022. The study was delivered across seven private Facebook group pages and four closed forums focusing on occupational medicine, whose applications were officially limited to OPs. According to the built-in statistics of the parent social media, by 1 April 2022, the group pages had a total of 2034 members. Still, no information could be retrieved about cross-membership and the number of actual, active users.
In order to share the study with the group members, the chief researcher (MR) preventively contacted the administrators of the groups, requesting preventive authorization for posting an invitation link to the questionnaire. Users who clicked on the invitation texts were then provided with a page reporting (a) the full study information; (b) the informed consent (authors' translation of the informed consent is available as Supplementary File S2); and (c) a web link to the first page of the survey (Google Forms; Google LLC; Menlo Park, California, CA, USA).
On the first page of the survey, participants were initially asked whether they (a) were or not living and working in Italy and (b) were working as an OP at the time of the survey. Only participants sharing two positive answers to these checkpoint items received the full questionnaire, while in all other cases, the survey was closed, and no further data were retained. The questionnaire was compiled anonymously: personal data (e.g., name, IP address, email address), and all personal information unnecessary to the survey were not requested, saved, or tracked.

Questionnaire and Availability of Data and Material
The questionnaire was originally formulated in Italian, being designed as a followup to an instrument originally validated in obstetrics and gynecology [29]. The final questionnaire included the following sections: 1.
Individual characteristics: age, seniority as OPs, gender, and whether they (a) had any professional experience as an occupational physician with any healthcare provider (yes vs. no) and (b) had any child.

2.
Knowledge test: participants received a 31-item questionnaire on vaccination in pregnancy [29] that was based on previous KAP studies in occupational settings [137,138]. Briefly, the questionnaire included a series of true/false items based on the current understanding and guidelines on vaccinations in pregnancy, specifically focusing on (a) general issues about vaccinations and (b) official recommendations on SARS-CoV-2, SIV, and Tdap. GKS was calculated as the sum of correctly and incorrectly marked recommendations: for all correct answers, +1 was added to a sum score, while a missing/"don't know" answer or a wrong indication added 0 to the cumulative score.

3.
Risk perception: participants were initially asked to rate by means of a fully labeled 5-point Likert scale (range: 1, "of no significant concern in daily practice", to 5, "of very high concern in daily practice") the perceived severity (C) and the perceived frequency (I) of a series of vaccine-preventable disorders in pregnant women: seasonal influenza, tetanus, diphtheria, pertussis, measles, parotitis, rubella, varicella, hepatitis B, SARS-CoV-2. Similarly, participants were then asked to rate how they perceived a series of vaccinations (i.e., against seasonal flu, tetanus, diphtheria, pertussis, measles, parotitis, rubella, varicella, hepatitis B virus, SARS-CoV-2 delivered as mRNA formulate, adenoviral vector-based formulates, and subunit vaccine) when delivered to pregnant women in terms of the perceived severity (C) and frequency (I) of their side effects.
As previously suggested by Yates, a quantitative estimate of perceived risk can be defined as the mathematical product of the perceived probability of an event and its expected consequences [1,139], and the corresponding RPS for vaccines and natural infection was therefore calculated as: RPS = I × C

4.
Attitudes and practices: we initially inquired of participants whether they had previously received any of the following vaccinations: seasonal influenza virus, Tdap or dT, MPR, varicella (either as a single formulate or within an MPR-V vaccine), hepatitis B virus, SARS-CoV-2 (any). Similarly, participants were asked whether, during the last 12 months, they had recommended any of the aforementioned vaccines in women of childbearing age. Finally, we reported a series of potential barriers towards vaccinations in women of childbearing age (i.e., fear of side effects; costs of vaccinations; not being perceived as a priority by other medical professionals; inappropriate risk perception by pregnant women; vaccination services are scarcely available; inappropriate understanding of official recommendations by pregnant women; inappropriate understanding of official recommendations by medical professionals), and participants were asked to rate their perceived significance through a 5-point Likert scale ranging from 1 (not agreeing at all) to 5 (totally agreeing).
All questions were self-reported and not externally validated. The internal consistency or reliability of each of the sections of the questionnaire was assessed with the Cronbach alpha test, the results of which were interpreted in accordance with the literature. An English translation of the questionnaire is available on request to the study Authors.

Ethical Approval
Before giving their consent to the survey, participants were briefed that the principles and guidelines of the Helsinki Declaration would be followed across all steps of this study. More precisely, data were gathered anonymously and handled confidentially, being stored for a limited timeframe, in order to only allow aggregate data analysis. Participation was strictly voluntary, and no monetary or other compensation was offered to the participants. Moreover, only subjects who had expressed consent for study participation were able to provide the questionnaire for data analysis. As individuals cannot be identified based on the presented material, this study caused no plausible harm or stigma to participants. The study was deliberately designed with an anonymous, observational approach, and it did not include clinical data. Moreover, demographic data were deliberately limited to very generic items (i.e., age, seniority, and gender). According to Italian law (Gazzetta Ufficiale no. 76, dated 31 March 2008; Supplementary File S3), a preliminary evaluation by an ethical committee was not required.

Data Analysis
Cumulative scores (RPS, GKS) were initially normalized to percent value, being then dichotomized by median value as "high" (i.e., >median) and "low" (≤median) groups. All continuous variables were reported as mean ± standard deviation. After visual inspection, their distributions were assessed by means of the D'Agostino-Pearson K2 test and compared through the Student's t-test for unpaired data or ANOVA for K2 test p value > 0.100 (i.e., normally distributed variable), or through the Mann-Whitney or Kruskal-Wallis test for K2 test p value < 0.100 (i.e., not normally distributed variable). According to the distribution of variables, their correlation was then assessed by Pearson's correlation coefficient (i.e., normally distributed variables) or through Spearman's ranks test (i.e., not normally distributed variable).
In order to properly characterize explanatory variables of the outcome variables represented by a somewhat positive attitude towards recommending SIV, Tdap, and SARS-CoV-2 vaccine, a multivariable analysis was modeled as follows. Firstly, univariate analysis of all of the categorical variables was performed in respect of the aforementioned outcome variables through a chi-squared test in order to test variables to be included in the multivariable analysis. All variables that at univariate analysis were significantly (p < 0.05) associated with a somewhat positive attitude towards recommending SIV, Tdap, and SARS-CoV-2 vaccines were then included in a stepwise binary logistic regression analysis model in order to calculate multivariate odds ratios (aOR) and their respective 95% confidence intervals (95%CI). We opted for a more restrictive stepwise approach over an a priori modeling as in a small dataset the latter could find many false associations that happen only by chance [140]. All statistical analyses were performed by means of IBM SPSS Statistics 26.0 for Macintosh (IBM Corp. Armonk, NY, USA).

Conclusions
OPs are called upon to play a dual key role, i.e., reconciling the right to work and protecting and promoting workers' health at the same time. Despite a generally favorable attitude towards vaccines among our OP respondents, the results of our study suggest substantial knowledge gaps and a need for better training in the area of immunization of pregnant women. Because of the low response to the survey, however, these results remain preliminary. Institutional Review Board Statement: The study was conducted according to the guidelines of the Declaration of Helsinki. A preventive ethical review and approval were waived for this study because of its anonymous, observational design and due to the lack of clinical data about patients that could configure the present research as a clinical trial. Participants were also guaranteed that retrieved data would be stored only for the time required by data analysis. The study, therefore, did not configure itself as a clinical trial, and a preliminary evaluation by an ethical committee was not required, according to Italian law (Gazzetta Ufficiale no. 76