Vaccination of pregnant women: modelling the knowledge and attitudes of Polish nurses and midwives – a preliminary study

INTRODUCTION

It is believed that pregnant women should be vaccinated if a safe vaccine is available for them and if they are at risk of being exposed to a disease endangering them or their baby. It is also suggested that the period of pregnancy is optimal for vaccination to prevent diseases such as influenza and pertussis in women and newborns [1, 2].
Presently in Poland there is no approved compulsory vaccination schedule for pregnant women. There are programmes of maternal immunization, in which vaccinations against hepatitis B, influenza and pertussis are recommended [3]. Despite the recommendations and strong support from professional organizations, vaccinations in pregnant women are rare, especially in low- and middle- income countries, which include Poland. It has been speculated that, like in many developing countries, this is due to concerns about the safety of vaccines in pregnant women, expressed by both women and by medical personnel [4].
Vaccination during pregnancy is still not a common intervention in Poland. Surveys showed, however, that patients recognize the benefits of vaccination and would be willing to accept it to protect themselves and their children. At the same time, less than half of the respondents believe that vaccination during pregnancy is safe [5].
All women should be fully informed about vaccinations and have the opportunity to be vaccinated with easy access to immunization services [6, 7]. Healthcare workers have a crucial role in informing women, recommending vaccinations, implementing recommended diagnostic and therapeutic practices, and infection control procedures [8, 9]. Strong associations between women’s perceptions of vaccination and their uptake by healthcare workers have been previously reported [10, 11]. Polish surveys show that medical personnel, especially obstetricians, hold a lot of authority in the decision-making process of women [5]. Midwives in Poland, while unable to prescribe vaccinations, play a vital role in informing women and actively participating in the decision-making process. Understanding barriers faced by obstetricians and midwives is crucial for boosting vaccination rates among pregnant women.
The aim of the study is to assess the attitudes of Polish nurses and midwives to maternal vaccinations and to assess their state of knowledge in this field.

MATERIAL AND METHODS

This cross-sectional study was conducted between October and December of 2019 on Polish nurses and midwives. The study used a diagnostic survey with a questionnaire prepared by the authors. The questionnaire was prepared by research midwives on the basis of an analysis of scientific evidence [12-15] and validated by one of the co-authors – a Polish authority in vaccinology, infectious diseases and paediatrics. It included background questions (gender, age, profession, and job seniority) and questions assessing knowledge and attitude regarding the subject of the study.
The attitudes of medical staff to maternal immunization were assessed based on two questions on recommendations for the vaccination of pregnant women, and points were awarded accordingly (Webappendix 1). Based on the sum of the awarded points, the respondents fell into the following groups:
1) positive attitude toward maternal vaccination: 1 or 2 point(s),
2) neutral attitude toward maternal vaccination: 0 points,
3) negative attitude toward maternal vaccination: –1 or –2 point(s).
We assessed knowledge using 12 questions concerning influenza, MMR, BCG, smallpox, poliomyelitis, hepa­titis A, Tdap, HPV, rabies, typhoid and meningitis vaccinations in the context of pregnancy (Webappendix 1). The questions were constructed as the single best answer type, with an “I don’t know” option as an additional answer. The respondents were awarded one point for each correct answer. The maximum score was 12. Three levels of knowledge were defined: low (0-4 points), medium (5-8 points) and high (9-12 points). Participants were also asked for their own assessment of their knowledge about vaccinations, on a scale from 1 to 5.
The study group was selected based on the following criteria:
– inclusion: people who: expressed their willingness to complete the questionnaire, with Polish reading and writing skills; were a nurse or a midwife;
– exclusion: people who were both a nurse and a midwife; had no language skills in Polish.
The participants were recruited using two methods: online, Google Forms based computer-assisted web interview (CAWI) questionnaire shared on social media platforms, and the paper and pen personal interview (PAPI) – a traditional paper version handed out before the start of a Polish scientific congress on vaccinations. This congress was organized by the Chamber of Nurses and Midwives for medical staff related to Primary Health Care. The online CAWI questionnaire had a built-in function which made all questions compulsory.
Before starting to fill in the questionnaire, a declaration of anonymity and the information that completing the questionnaire also constitutes informed consent to participate in the study were given to the respondents. Participants did not provide any identification data and could discontinue participation in the study at any stage.
The level of statistical significance was p < 0.05. After establishing the lack of normal distribution with the Shapiro-Wilk test, quantitative variables were compared with the Mann-Whitney U test. Qualitative variables were compared using the chi-square test with a correction for low frequencies and quantitative variables with the Kruskal-Wallis ANOVA test (with Tukey’s post-hoc test). Correlations between variables were examined with Spearman’s test. The Kuder-Richardson Formula 20 test of internal consistency reliability had a value of 0.77. To establish the impact of the variables on the level of knowledge and on beliefs multinomial logistic regression models were constructed. The examined power of the tests was >0.90 for our analysis. The calculations were performed using Statistica 13.1 and Stata 17.0 software.
The study was not classified as a medical experiment and did not require the opinion of the Bioethics Committee. The study was performed in compliance with the principles outlined in the Declaration of Helsinki. Respondents participated in the study in a voluntary and anonymous manner.

RESULTS

We collected 285 questionnaires. Twenty-two questionnaires were found to be incomplete and were subsequently rejected, leaving 263 responses for further analysis.
The study involved 152 nurses and 111 midwives. Congress participants (n = 126) included 21 midwives and 105 nurses, and 90 midwives and 47 nurses responded to online surveys (n = 137). Most of the respondents (n = 261, 99.2%) were women. The largest group in terms of age was between 21 and 34 years old (n = 113, 43%). The majority of study participants had over 15 years of job seniority (n = 117, 44.5%).
A positive approach to maternal vaccination was reported more often by nurses than by midwives (n = 135, 89% vs. n = 81, 73%, p = 0.002). Also, the respondents who took part in the congress were more likely to express a positive attitude toward the discussed prevention method among pregnant women than the medical staff who completed the study questionnaire on the Internet (n = 121, 96% vs. n = 95, 69%, p < 0.001) (Table 1).
The mean score for assessing all participants’ knowledge based on 12 questions was 5.92 (±2.92) and the median was 6 (min. 0, max. 11). Median scores of nurses (n = 152) were 7 (min. 0, max.11) points, while the median score of midwives (n = 111) was 5 (min. 0, max. 11) points. The median score of nurses’ and midwives’ knowledge about vaccinations was 7 (n = 126, min. 0, max. 11) among those participating in the congress. It was statistically significantly higher than that of the respondents filling in the study questionnaire on the Internet (n = 137, Median = 5, min. 0, max. 11, Z = –0.840, p < 0.001).
Table 2 shows the study participants’ knowledge of specific maternal vaccinations. Most of them demonstrated good knowledge of benefits of vaccination against influenza and MMR in pregnancy. A lower level of knowledge was recorded for vaccines against rabies, typhoid and meningitis used in pregnant women. The nurses had a statistically significantly better level of knowledge about vaccinations against smallpox, poliomyelitis, hepatitis A and HPV when compared to the midwives.
The average own assessment of knowledge about vaccinations in the entire study group was 2.77 (±1.01) and median 3 (min. 1, max. 5). The median for both nurses (n = 152) and midwives (n = 111) was 3 (min. 1, max. 5) points. The median level of nurses’ and midwives’ own assessment of knowledge was 3 (n = 126, min. 1, max. 5) among those participating in the congress. It was significantly higher than that of the respondents completing the study questionnaire on the Internet (n = 137, Median = 2, min. 1, max. 5, Z = –5.719, p < 0.001).
There were no statistically significant correlations between the age of nurses and the level of their knowledge about vaccinations (r = 0.065, p = 0.423), the age of midwives and their knowledge about vaccinations (r = −0.017, p = 0.859) or the age of whole study group and their level of knowledge about vaccinations (r = −0.084, p = 0.933). Furthermore, no statistically significant correlation was found between the age and level of knowledge about vaccinations among the respondents participating in the congress (r = −0.092, p = 0.306) and completing the online questionnaire (r = −0.097, p = 0.8260). There were no statistically significant correlations between job seniority and the level of knowledge about vaccinations in the whole group (n = 263, r = 0.103, p = 0.096), among the midwives (n = 111, r = −0.013, p = 0.883), or among the nurses (n = 152, r = −0.065, p = 0.423). There were no statistically significant correlations between the age of nurses and the level of their own assessment of knowledge about vaccinations (rho = 0.080, p = 0.330), the age of midwives and their own assessment of knowledge about vaccinations (r = 0.132, p = 0.167). Furthermore, a weak statistically significant correlation between the age of the entire study group and their own assessment of knowledge about vaccinations (r = 0.236, p < 0.001) was found.
Figure 1 shows a comparison of knowledge on maternal vaccinations in groups with a negative, neutral and positive attitude toward this form of prevention. Post-hoc tests established that the level of knowledge among the participants with a positive attitude towards vaccinations in pregnancy was significantly different from the other groups both in the entire study group (p < 0.001) and in nurses (p = 0.005). The midwives’ group presented a statistically significant difference between negative and positive (p = 0.009) attitudes. In the group of respondents filling in the Internet questionnaire their knowledge was statistically significantly higher among persons with a positive attitude in the whole study group (p = 0.001) and in the group of nurses (p = 0.018) and midwives (p = 0.032).
Table 3 shows a multinomial logistic regression model which presents the impact of variables on the level of knowledge (low, medium, high). The impact of each variable is described by two equations which concern the risk of the level of knowledge 2 vs. 1 and the level of knowledge 3 vs. 1. The Attitude assessment variable was introduced as a dummy variable with a base category of 1 (positive).
The univariate models indicate the existence of a statistically significant relationship between the level of knowledge and the Internet and congress group, profession, attitude and own knowledge’s assessment. However, in the multivariate model a significant relationship for the level of knowledge was found only for age and own assessment. The relative risk of possessing medium relative to low knowledge decreases 1.05 (= 1/0.955) times (p = 0.007) when age increases by 1 year (or decreases by 4.5% (1-0.955) when age increases by 1 year). The relative risk of possessing medium relative to low knowledge increases 4 times (p < 0.001) when own assessment increases by 1 point. The relative risk of possessing high compared to low knowledge increases 8.3 times (p < 0.001) when own assessment increases by 1 point.
Table 4 shows the multinomial logistic regression model which presents the impact of variables on the attitude to vaccinations (1 – positive, 2 – neutral, 3 – nega­tive). The impact of each variable is described by two equations establishing the risk of attitude 2 vs. 1 and attitude 3 vs. 1. Univariate models indicate the existence of a statistically significant relationship between attitude to vaccinations and the Internet and Congress group, profession, attitude and own assessment of knowledge. However, in the multivariate model a significant association between attitude to vaccinations was found only for age and own assessment of knowledge. The relative risk of a neutral attitude compared to a positive attitude is 4.88 (= 1/0.21) times lower (p = 0.047) for the Congress than for the Internet. The relative risk of a negative attitude compared to a positive attitude is 13.89 (= 1/0.07) times lower (p = 0.002) for the Congress than for the Internet. The relative risk of a negative attitude compared to a positive attitude increases 1.05 times (p = 0.036) when age increases by 1 year (or increases by 5% when age increases by 1 year).
The relative risk of a negative attitude compared to a positive attitude decreases 1.24 (= 1/0.81) times (p = 0.041) when total knowledge increases by 1 point. The relative risk of a neutral attitude compared to a positive attitude decreases 3.28 (= 1/0.305) times (p = 0.001) when own assessment increases by 1 point.
The participants indicated different sources of knowledge on vaccinations in pregnancy. They were most likely to use their co-workers’ experiences in this area (n = 191, 72.6% among all study participants). Conferences and workshops (n = 131, 49.8%) were a source of knowledge for almost half of the respondents. The nurses and midwives participating in the congress were more likely to acquire knowledge from conferences and workshops (p < 0.001), training or courses (p < 0.001), brochures (p < 0.001) and scientific articles (p = 0.010) than online participants. Midwives more often sought support from their co-workers in this field than nurses (p < 0.001).

DISCUSSION

Clinicians’ knowledge and beliefs significantly influence their recommendations for immunization. As medical staff enhance their understanding, they exhibit more positive attitudes towards immunization, align with subjective norms, and perceive greater behavioural control, ultimately leading to increased vaccine recommendations. Also, the quality of their vaccine recommendation improves [16-18]. The majority of conducted studies focus on the knowledge of prevention of diseases and attitudes towards vaccination expressed by obstetricians and gynaecologists as well as physicians [19]. Our study focused on medical professionals who play a crucial role in antenatal and postnatal care – nurses and midwifes. The results show that the respondents with good knowledge on the subject also had a positive attitude towards vaccination in pregnancy. In our study a weak positive correlation between knowledge and attitude was found in all participants (r = 0.360, p < 0.001). Regression models reveal a link between knowledge level, self-assessment, and attitudes toward vaccination in pregnant women. Notably, respondents with the highest knowledge attended vaccination congresses and completed questionnaires beforehand, demonstrating greater self-assessment. Similar results concerning subject knowledge and attitudes of medical staff were obtained in other studies worldwide [20, 21].
The nursing and midwifery students at the Medical University of Lodz in Poland have less frequently indicated that influenza vaccines are recommended for pregnant women than for other specific groups such as older people, patients with chronic diseases, and children. Therefore, it is important to provide continuous education and training to students in order to ensure their pro-health attitudes [22]. Lack of students’ knowledge about maternal immunization against influenza may negatively impact vaccine recommendations in their future clinical practices and may require them to undertake additional postgraduate education in this subject. Also, it was observed that the longer the job experience of midwives and nurses was, the more they knew about vaccinations [23, 24]. However, our study demonstrated no significant correlation between the respondents’ job seniority and their level of knowledge about maternal immunization.
Our respondents had the highest knowledge about maternal immunization against influenza and MMR as compared to vaccines against other diseases listed in the questionnaire. Both professional groups were the least aware of the option of immunization against meningitis during pregnancy. Most of the studies demonstrate a high awareness of medical professionals of maternal vaccination. However, these studies focus on influenza and pertussis vaccines [25-27], which are recommended in many European countries [28]. A study conducted by Vilca et al. [29] indicated that a vast majority (> 90%) of 194 maternal care providers (obstetrician- gynaecologists and midwives) from Catalonia in Spain knew what the recommendations were for influenza and pertussis vaccines in pregnancy. Ricco and co- authors studied obstetricians and gynaecologists from North-Western Italy. 91.2% of the surveyed professionals knew that the Italian National Immunization Plan recom­mends the use of vaccines during pregnancy. Knowledge of the principles of maternal vaccinations against influenza was reported by 79.4% of respondents [27].
Some studies underline the necessity for vaccinology education to be focused on medical professionals, in order to increase their knowledge and confidence in the promotion of maternal immunization [30] and to increase the positive impact of participation in training on the self-assurance of midwives and nurses [31]. Smith et al. [24] found in their study that midwives with formal immunization training had greater knowledge and were more likely to recommend the vaccines than those who lacked such education.
Our study group indicated colleagues’ experiences in vaccinology prevention as the most popular source of information on this issue. It was observed previously that societal and collegial support was observed to have a positive impact on recommendation of vaccinations by healthcare providers [16]. Our respondents completing the online questionnaire relied on the knowledge of others more often than the persons participating in the congress. This may be caused by the fact that midwives and nurses report having limited time to attend training or workshops, as described in a study by Veeramah et al. [32]. Similar conclusions were drawn from a study focused on midwifery students in Australia. The students reported having 2-4 hours of vaccinology during the entirety of their education. Such limited training in obstetric immunization may in later clinical practice prove insufficient for educating and counselling pregnant women about the subject [33]. According to Frawley et al. [34], the vast majority of Australian midwives considered their education in vaccinology inadequate. They reported looking for the possibility to attend additional courses in order to increase their knowledge about vaccinations and looked up to their colleagues’ experiences with regard to this issue. In Poland, education standards include general classes on immunization in the undergraduate programme, which focus on neonatal vaccinations against HBV as perioperative prevention and HPV [35]. What is more, classes on preventive immunizations are scheduled in postgraduate education in certain specialist courses for midwives and nurses (about 10 hours). However, maternal immunization constitutes just a small element discussed in this field [36-38]. According to the Polish Act on Nurse and Midwife Professions (Journal of Laws of 2011 no. 174, item 1039), midwives and nurses are required to adhere to a continuous professional development schedule [39], but the decision about undertaking some kind of additional postgraduate education depends on midwives’ preferences and on their employers’ specific requirements. In our study, the respondents recruited during the congress knew more about maternal immunization than the participants recruited online. Moreover, almost 40% (n = 105) of the respondents reported participating in courses or training activities as their source of information. Training is essential for up-to-date medical knowledge. Respondents who indicated training as their information source demonstrated higher knowledge levels. Understanding maternal vaccination is critical for healthcare professionals, enabling effective education and vaccine promotion. This effort contributes to raising awareness among pregnant women. For instance, Spanish medical students recognized the importance of vaccinology education. In their view, medical staff, especially nurses, should be better educated and have more knowledge concerning vaccinations as future health promoters [40]. Positive attitudes to vaccinations in healthcare workers should be encouraged and developed as soon as practicable, for instance, during undergraduate medical studies [22].

LIMITATIONS

The results obtained from our study represent a preliminary investigation. As such, the sample of respondents is not fully representative of Polish nurses and midwives. Unfortunately, we lack data regarding their specific workplaces (whether they work in antenatal settings or vaccination clinics) and their educational backgrounds. Additionally, some participants were recruited during a vaccination congress, potentially over-representing individuals with higher vaccine acceptance and introducing bias into our study. We encountered challenges in assembling our study group and received incomplete questionnaires (7.7% of all responses). This may be due to hesitancy among medical staff to verify their knowledge.
Furthermore, the questions related to knowledge in our study tool underwent internal validation by a co-author who is an expert in vaccinology. Moving forward, our main study will address these limitations. The revised questionnaire will also incorporate information about COVID-19 vaccinations which emerged after the preliminary study was conducted.

CONCLUSIONS

Our study revealed that conferences and workshops were the sources of information about vaccination most frequently cited by midwives and nurses. This underscores the urgent need for well-organized courses, training activities, and workshops based on current scientific findings.
Furthermore, our modelling analysis demonstrated a strong correlation between knowledge levels, self-assessment, and attitudes toward maternal vaccination among respondents. Notably, positive attitudes were predominantly expressed by those surveyed during the congress.

ACKNOWLEDGEMENTS

The publication of the results was covered by the EU- financed InterDoktorMen project (POWR.03.02.00-00-I027/16).

CONFLICTS OF INTEREST

The authors declare no conflict of interest.

References