ABSTRACT
Pregnant women and young infants are at increased risk for influenza-associated severe disease, complications and hospitalizations. In Greece influenza vaccination during pregnancy remains extremely low. We studied the knowledge about influenza and the adherence to the recommendations for influenza vaccination of pregnant women following an educational intervention in a large maternity hospital. A standardized questionnaire was used. A knowledge score was calculated for each woman. A total of 304 pregnant women were studied [mean age: 31.5 years (standard deviation (SD): 5.4 years), mean gestational age: 27.8 weeks (SD: 9.6 weeks)]. Their mean knowledge score was 87%. Sixty pregnant women (19.5%) were vaccinated against influenza at a mean gestational age of 24.6 weeks (SD: 7.5 weeks). Multiple regression analysis revealed that previous influenza vaccination and information about the need to get vaccinated were the only significant factors associated with an increased probability for influenza vaccination during pregnancy (47% versus 17% in women with and without a history of influenza vaccination in the past, respectively; odds ratio = 3.6; p-value = 0.016, and 32% versus 4% in women informed compared to those uninformed about the need for vaccination during pregnancy, respectively; odds ratio = 17.8; p-value<0.001). Seventy women provided a reason for refusing influenza vaccination. “Fear of adverse events” (for them or the fetus) was the prevalent reason for refusing influenza vaccination (19 women; 27%), followed by the statements “influenza vaccination is not necessary” (13; 18.5%) and “not at risk to get influenza” (9; 13%). In conclusion, an educational intervention was associated with an influenza vaccination rate of 19.5% among pregnant women compared to <2% the past years. In order to improve vaccine uptake by pregnant women and protect them and their babies, more intensified interventions should be explored.
Introduction
The impact of influenza on pregnant women, neonates and young infants was recognized rather recently. Influenza during pregnancy is associated with a higher risk for hospitalization, complications for the fetus and neonate, and influenza-associated mortality compared to influenza in non-pregnant women, especially during the second and third trimester and in women with co-morbidities.Citation1 In addition, influenza is associated with an increased risk of serious illness, complications, outpatient visits, and death among infants younger than six months old compared to older age groups, while influenza-associated hospitalization rates in the former age group are similar to those noted in persons older than 65 years old with high-risk conditions.Citation2
Maternal vaccination against influenza during pregnancy is associated with significantly fewer episodes of febrile respiratory illness and laboratory-confirmed influenza among mothers and infants, fewer small for gestational age infants and higher mean birth weight during the influenza season, compared to infants whose mothers did not receive the influenza vaccine.Citation3–Citation6 Despite the benefits of influenza vaccination during pregnancy for both mothers and young infants, influenza vaccine uptake rates by pregnant women remain low globally.Citation7–Citation12 Studies indicate that main barriers to influenza vaccine acceptance in pregnancy are related to perceived risk of influenza to pregnant women and their fetus, to perceived vaccine safety and perceived vaccine efficacy.Citation13–Citation16 In Greece influenza vaccination of pregnant women is recommended by the Ministry of Health since the 2009 H1N1 influenza pandemic however vaccine uptake rates remain extremely low (<2%). Influenza vaccination is recommended to pregnant women regardless of trimester and it is provided free-of-charge.
The current cross-sectional study was conducted in order to evaluate the knowledge about influenza and influenza vaccine and the adherence to recommendations for influenza vaccination of pregnant women in Greece, following an education intervention by their obstetricians, which constitute the main source of advice for pregnant women.
Results
During the study period, 308 pregnant women were invited to participate. Four of them were excluded because their influenza vaccination status was unknown. Finally, 304 pregnant women with a mean age of 31.5 years (range: 13–48 years, SD: 5.4 years) and a mean gestational age of 27.8 weeks (range: 5–40 weeks, SD: 9.6 weeks) were studied. shows their characteristics. Their mean knowledge score was 87%.
Table 1. Characteristics of 304 pregnant women.
One hundred and seven of 271 pregnant women (39.5%) reported that they were already informed about the recommendations to get vaccinated against influenza. Their obstetrician was the prevalent source of information (61 cases, 58%), followed by internet/newspaper/TV (27 cases, 25.5%), other healthcare professionals (26 cases, 25%), and friends or relatives (10 cases, 9.5%). Of 272 pregnant women who answered this question, 155 (57%) stated that they intended to get vaccinated and received a prescription. Of them, 95 (31%) were not vaccinated despite the fact that they got the vaccine; their main reason for not being vaccinated was “being sick” (77 women; 81%).
Overall, 60 of 304 participating pregnant women (19.5%) were vaccinated against influenza at a mean gestational age of 24.6 weeks (range: 12–37 weeks, SD: 7.5 weeks). shows the results of univariate analysis. Multiple regression analysis revealed that influenza vaccination in the past and information about the need to get vaccinated against influenza were the only significant factors associated with an increased probability for influenza vaccination during pregnancy (47% versus 17% in those with and without a history of influenza vaccination in the past, respectively; odds ratio = 3.6; p-value = 0.016, and 32% versus 4% in those with and without being informed about the need for influenza vaccination during pregnancy, respectively; odds ratio = 17.8; p-value<0.001).
Table 2. Influenza vaccination rate of pregnant women by characteristic (univarite analysis).
Among 70 pregnant women who provided the reason for refusing influenza vaccination, fear of adverse events (for them or the baby) was the prevalent reason (19 women; 27%), followed by the statement “influenza vaccination is not necessary” (13; 18.5%), “not at risk to contract influenza” (9; 13%), against all vaccinations (8; 11.5%), “need more time to think about vaccination” (5; 7%) and other (16; 23%).
Discussion
Successful vaccination policies rely largely on their acceptance by both healthcare professionals and the target population. The aim of the current study was to assess the knowledge about influenza and influenza vaccine of pregnant women in Greece, their adherence to the national recommendations for influenza vaccination and the reasons for declining vaccination. Following an obstetrician-based active educational intervention approximately 20% of them were vaccinated. Although this rate is low, it represents an exceptional (10-fold) raise of vaccine uptake from <2% recorded in Greece the past years. Low influenza vaccination rates among pregnant women have been also reported in Italy (9.7%), Germany (19.5%), Thailand (25%), and Spain (40.5%).Citation7,Citation8,Citation10,Citation11 In the United States influenza vaccine uptake rate by pregnant women was 53.6% during the 2016–2017 season.Citation12 In this latter country, reported vaccine uptake rate was 70.5% when vaccination was offered by their healthcare provider, 43.7% when it was recommended but not offered and 14.8% when it was not recommended,Citation12 which underlines the role of healthcare professionals as well as of on-site vaccination.Citation13,Citation17,Citation18
In the current study, influenza vaccination in the past was associated with a 3.6-fold increased probability to get vaccinated. This is in accordance with others.Citation7,Citation9 In this study pregnant women who were already informed about the recommendation for influenza vaccination had a 17.8-fold increased probability to get vaccinated compared to those who were not informed. Similarly, a history of vaccination recommendation was also significantly associated with higher vaccination rates by others.Citation7,Citation8,Citation11 Socioeconomic factors have been also found as associated with a higher probability to get vaccinated,Citation11 however this was not the case in this study.
Fear of adverse events was reported by more than one fourth of women who declined vaccination, and in half cases they worried about adverse events to their babies. In a study conducted in the same hospital few years ago, 73.7% of women accepted to get the influenza vaccine early post-partum in order to protect their young babies (cocooning strategy)Citation18 compared to 19.5% uptake rate by pregnant women in the current study; this difference indicates that safety fears for the baby is a significant barrier to vaccine uptake during pregnancy. Safety concerns also impacted influenza vaccination decisions by pregnant women as well as by healthcare workers in other studies also,Citation10,Citation14–Citation16 while perceived vaccine safety, efficacy and disease susceptibility were associated with intention to get the influenza vaccine.Citation14 Similar to others,Citation10,Citation13 several women declined vaccination because they believe that vaccination is not necessary or that they are not at risk to get influenza, while a non-negligible number of women (11.5%) had anti-vaccination beliefs. Of note, although more than half (57%) of the participating women stated that they intended to get vaccinated and despite the fact that they got the vaccine, almost one third were not vaccinated because of “being sick”. An overall very good mean score of 87% was recorded in the studied cohort of pregnant women, which indicates that the majority of them were well-informed about the influenza-associated complications for them and their babies.
The main strength of the current study was the inclusion of almost all pregnant women who visit the Outpatient Clinic of a large maternity hospital. The fact that we estimated the real vaccine uptake and not the intention to get vaccinated is also important. Several reasons for vaccination refusal were also explored. To the best of our knowledge, this is the first study to address issues of acceptance of vaccination with the quadrivalent vaccine by pregnant women. The applicability of the findings of the current study to other pregnant populations globally is a potential issue. The fact that only 70 women who refused vaccination provided the reasons for doing so is a limitation.
In conclusion, an obstetrician-based active educational intervention was associated with an increase of influenza vaccine uptake by pregnant women from <2% to 19.5% in a maternity hospital in Greece. The current study indicates that history of influenza vaccination and information about the need to get vaccinated were significantly associated with an increased probability for influenza vaccination during pregnancy. Fear of adverse events for them and their babies was the prevalent barrier to vaccine acceptance. In this hospital discussion with their obstetrician was the key factor for promoting vaccine uptake. In order to further increase vaccine uptake by pregnant women and influenza vaccination to become the standard of care within the following years, more intensified educational interventions should be explored.
Materials and methods
The study was conducted at Alexandra General Hospital (Athens, Greece). A pilot assessment of the standardized questionnaire in 10 pregnant women preceded the study. Approximately 300–350 pregnant women, regardless of socioeconomic, clinical or other characteristics, visit the Outpatient Clinic of the hospital every month for follow-up. Pregnant women who attended the Outpatient Clinic from October 15 throught December 31, 2017 were consecutively invited to participate, regardless of their characteristics. Only pregnant women who could communicate in Greek or English participated.
The educational intervention consisted of the following: A leaflet (available upon request) with information about the complications of influenza during pregnancy and infancy and the efficacy and safety of influenza vaccine in pregnant women was distributed to them at the waiting room of the Outpatient Clinic. The expected benefits of influenza vaccination were also presented by their obstetrician. Pregnant women also discussed with their obstetrician their concerns (if any) about vaccination. The 2017–2018 quadrivalent inactivated influenza vaccine was prescribed to all pregnant women who intended to get vaccinated. Their influenza vaccination status (= if they did receive the prescribed vaccine) was confirmed in their next follow-up visit.
Data were collected using one standardized form per woman. Women who refused influenza vaccination were asked the reason for doing so. In addition, there were 11 questions in order to assess the participants’ knowledge about the impact of influenza on pregnant women, neonates and young infants and the safety of influenza vaccine (Questionnaire). Informed consent was requested by all participating women. The study was approved by the Ethics Committee of the hospital.
Statistical analyses were performed using the R statistical software (version R 3.4.2). Frequency tables were used to describe the categorical data while mean, range and SD were used to describe the continuous data. In univariate tests, T-test checked the statistical relation of vaccination (yes-no) with the continuous variables of the study, while χ2 test checked the statistical relation of vaccination (yes-no) with the categorical variables. Multiple logistic regression (stepwise selection) was applied to investigate the statistical relation between influenza vaccination with the following independent variables: age, area of residence, immigrant, education level, number of household members, number of children <5 years old, underlying disease, number of parities, gestational age, pregnancy complications, scheduled cesarian section, smoking, intention to breastfeed, history of influenza vaccination in the past, already informed about the recommendations for influenza vaccination, and knowledge score about influenza and influenza vaccine. P-values of ≤ 0.05 were considered statistically significant. In addition there were 11 questions about the women knowledge about influenza and influenza vaccine in the questionnaire. The rate of knowledge regarding influenza and influenza vaccine was computed as follows: [(number of correct answers)/11]*100.
Disclosure of potential conflicts of interest
No potential conflicts of interest were disclosed.
Additional information
Funding
References
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