Australian and New Zealand Journal of Obstetrics and Gynaecology 2015; 55: 131–137
DOI: 10.1111/ajo.12292
Original Article
Antenatal care provider’s advice is the key determinant of influenza vaccination uptake in pregnant women Donna B. MAK,1,2 Annette K. REGAN,1,3 Sarah JOYCE,4 Robyn GIBBS1 and Paul V. EFFLER1,3 1
Department of Health, Communicable Disease Control Directorate, Department of Health, Western Australia 2School of Medicine, University of Notre Dame, Fremantle, 3School of Pathology and Laboratory Medicine, University of Western Australia, and 4 Epidemiology Branch, Department of Health, Western Australia
Background: Although influenza vaccination is an important component of antenatal care and is recommended and funded by the Australian government, vaccination uptake has been low. Aims: This study compared seasonal influenza vaccination uptake among pregnant Western Australian (WA) women and identified factors associated with vaccination uptake. Materials and Methods: Adult women who were pregnant during the 2012 and 2013 influenza vaccination seasons were selected at random and invited to complete a computer-assisted telephone interview survey about whether they received influenza vaccination during pregnancy. Data analyses were weighted to the age distribution of women of reproductive age in WA. Multivariate logistic regression was used to identify factors associated with vaccination uptake. Results: Between 2012 and 2013, the proportion of WA women whose antenatal care provider recommended influenza vaccination increased from 37.6 to 62.1% and vaccination uptake increased from 23.0 to 36.5%. The antenatal care provider’s advice to have influenza vaccine was the single most important factor associated with vaccination (OR 11.1, 95% CI 7.9–15.5). Most women (63.7%) were vaccinated in general practice, 18.8% in a public hospital antenatal clinic and 11.0% at their workplace. Wanting to protect their infant from infection (91.2%) and having the vaccine recommended by their GP (60.0%) or obstetrician (51.0%) were commonly reported reasons for vaccination; worrying about side effects was a common reason for nonvaccination. Conclusions: To optimise maternal and infant health outcomes, Australian antenatal care providers and services need to incorporate both the recommendation and delivery of influenza vaccination into routine antenatal care. Key words: human, influenza, pregnancy, prenatal care, vaccination.
Background Preventing influenza during pregnancy is considered an important part of antenatal care because pregnant women are at increased risk of serious illness due to influenza.1 Excess morbidity and mortality in pregnant women with seasonal and pandemic influenza compared with nonpregnant women of similar age with influenza have been well documented.2,3 The most effective strategy for preventing influenza in pregnant women is annual vaccination which is recommended for all pregnant
Correspondence: Prof Donna B. Mak, Health Department of Western Australia, Communicable Disease Control Directorate, PO Box 8172 Perth Business Centre, WA 6849, Grace Vaughan House, 227 Stubbs Tce, Shenton Park, WA 6008, Australia. Email: [email protected] Received 24 August 2014; accepted 25 October 2014.
women regardless of gestation.1 Influenza vaccination is estimated to prevent 1–2 hospitalisations per 1000 women vaccinated during the second or third trimester.1 Active placental transfer of maternal antibodies makes influenza vaccine during pregnancy a highly effective measure to protect infants from influenza during the first six months of life.4,5 Both maternal and infant benefits are now well recognised, with an estimated one case of serious maternal or infant respiratory illness prevented for every 5 pregnant women who are vaccinated.5 Furthermore, the safety of influenza vaccination during pregnancy is well established; no study to date has shown an adverse consequence of inactivated influenza vaccine in pregnant women or their children.6,7 Inactivated influenza vaccine has been recommended for Australian pregnant women since 2003, but has been government funded only since the H1N1 (swine flu) pandemic of 2009.1 The Royal Australian and New Zealand College of Obstetricians and Gynaecologists
© 2014 The Royal Australian and New Zealand College of Obstetricians and Gynaecologists The Australian and New Zealand Journal of Obstetrics and Gynaecology
131
D. B. Mak et al.
(RANZCOG) publicly endorsed routine vaccination of all pregnant women against influenza in November 2011.8 In 2013, Australian Health Ministers approved a national woman-held pregnancy record which includes antenatal influenza vaccination as a routine part of antenatal care9 and the World Health Organization recommended pregnant women as the highest priority group for seasonal influenza vaccination.10 Since March 2012, the Health Department of Western Australia (WA Health) has had Operational Directives supporting antenatal influenza vaccination of pregnant women.11,12 However, only 23% of pregnant women in WA received antenatal influenza vaccine in 2012, although 74% reported that they would have been vaccinated if it was recommended by their antenatal care provider.13 In response to these findings, WA Health updated its Operational Directive (OD 0423/13) to authorise nurses and midwives in public hospitals to administer influenza vaccine and distributed information sheets and consent forms for antenatal influenza vaccination, stickers reminding private obstetricians to recommend antenatal influenza vaccination; referral forms for private obstetricians to refer antenatal patients back to their general practitioner (GP) for influenza vaccination; and promotional posters for patient waiting rooms and print advertisements.12 Although influenza vaccination uptake in pregnant women in WA improved from 6.9 to 10.3% in 200914,15 to 23.0% in 2012,13 this level of coverage is far from ideal and much lower than has been achieved in other Australian and international settings where coverage rates in the order of 40–60% were observed when influenza vaccine was routinely recommended and offered by antenatal care providers.16–18 This study aimed to compare seasonal influenza vaccination uptake among pregnant WA women in 2012 and 2013 and identify factors associated with vaccination uptake. Given the statewide public health interventions described, we hypothesised that antenatal influenza vaccination coverage would increase between 2013 and 2012.
Materials and Methods Data collection methods used in 2012 have been described previously.13 A random sample of 1142 adult women who gave birth to a live baby between 07/04/2013 and 06/10/ 2013 (i.e were pregnant during 2013 influenza vaccination season) was selected from the WA Midwives’ Notification System, a statutory database of attended births. As the total sample size in 2013 was doubled from 2012, it was not necessary to oversample women from country areas in order to make comparisons between metropolitan and country uptake. The sample size provides a maximum relative standard error of 3.5% at the standard 95% confidence interval. Women were posted a letter informing them about the study and giving them the opportunity to opt-out of being contacted for a 5- to 10-min computer-assisted telephone 132
interview survey about whether they were vaccinated during pregnancy and whether they were offered/ recommended influenza vaccine during pregnancy by a healthcare provider. For those women who reported that they had been vaccinated, consent was obtained to contact the woman’s healthcare provider for the purpose of confirming her antenatal influenza vaccination status. Published literature regarding the accuracy of selfreported vaccination status in adults indicates that falsepositive self-reports are not uncommon, whereas falsenegative self-reports are extremely rare.19–22 Therefore, positive self-reported influenza vaccination status was verified by: 1 Asking for date and brand of vaccine administered from the written record of vaccination given to her at the time of vaccination or for those women would could not provide this information, 2 Checking against the Antenatal Influenza Vaccination Database (includes consent information, faxed to WA Health by some vaccination providers) or for those women not on the database and 3 Contacting the vaccination provider nominated by the woman. The survey instrument in 2013 was similar to 2012.13 In 2013, questions about knowledge of, and attitudes to, influenza vaccination in pregnancy were omitted to allow for an increased sample size and higher statistical precision. Data from 2012 and 2013 were aggregated and analysed using SAS version 9.3 (SAS Institute, Cary, NC, USA). Data analyses were weighted to the age and geographical distribution of women of reproductive age in WA for the study years of interest. Weighted frequencies of vaccination status were compared across years using Rao Scott chi-square tests. The odds of vaccination in 2012 and 2013 were modelled by multivariate logistic regression, adjusting for age group (18–29 vs 30+ years), metropolitan versus rural residence, antenatal care provider, whether the woman was advised to have vaccination and education attainment (by four strata as defined in Table 1); socio-economic status was not included in the model as it is closely related to education attainment. Variables significant at P < 0.1 level in crude models were included in the multivariate regression model in order to control for the other potential explanatory variables. Ethics approval was obtained from WA Health’s Human Research Ethics Committee.
Results Of women who were pregnant during the 2013 influenza vaccination season and randomly selected for inclusion in the study, 28 (2.5%) of 1142 women opted out and were not contacted further. An additional 110 women were excluded from data collection (telephone not connected (n = 88), incorrect contact details (n = 21), infant deceased (n = 1)), and 18 women did not need to be contacted after the target of 830 interviews had been
© 2014 The Royal Australian and New Zealand College of Obstetricians and Gynaecologists
Antenatal care providers key to vaccination
Table 1 Demographic characteristics of study participants by year, 2012–2013
Characteristic
2012, n = 407 Number (%)
Age*: 18–29 years 198 (48.6) ≥30 years 209 (51.4) Location*: Country 201 (49.4) Metropolitan 206 (50.6) Highest level of education completed: Primary/high 129 (31.7) school TAFE 114 (28.0) University 90 (22.1) undergraduate University 70 (17.2) postgraduate Socioeconomic status*: Quintile 5 (least 51 (12.5) disadvantaged) Quintile 4 110 (27.0) Quintile 3 160 (39.3) Quintile 2 45 (11.1) Quintile 1 38 (9.3) (most disadvantaged) Chronic conditions: No 350 (86.0) Yes 57 (14.0) Antenatal care mostly from: Public hospital 138 (33.9) GP 129 (31.7) Private 127 (31.2) obstetrician
2013, n = 831 Number (%)
Chisquare P-value
321 (38.6) 510 (61.4)
DOI: 10.1111/ajo.12292
Original Article
Antenatal care provider’s advice is the key determinant of influenza vaccination uptake in pregnant women Donna B. MAK,1,2 Annette K. REGAN,1,3 Sarah JOYCE,4 Robyn GIBBS1 and Paul V. EFFLER1,3 1
Department of Health, Communicable Disease Control Directorate, Department of Health, Western Australia 2School of Medicine, University of Notre Dame, Fremantle, 3School of Pathology and Laboratory Medicine, University of Western Australia, and 4 Epidemiology Branch, Department of Health, Western Australia
Background: Although influenza vaccination is an important component of antenatal care and is recommended and funded by the Australian government, vaccination uptake has been low. Aims: This study compared seasonal influenza vaccination uptake among pregnant Western Australian (WA) women and identified factors associated with vaccination uptake. Materials and Methods: Adult women who were pregnant during the 2012 and 2013 influenza vaccination seasons were selected at random and invited to complete a computer-assisted telephone interview survey about whether they received influenza vaccination during pregnancy. Data analyses were weighted to the age distribution of women of reproductive age in WA. Multivariate logistic regression was used to identify factors associated with vaccination uptake. Results: Between 2012 and 2013, the proportion of WA women whose antenatal care provider recommended influenza vaccination increased from 37.6 to 62.1% and vaccination uptake increased from 23.0 to 36.5%. The antenatal care provider’s advice to have influenza vaccine was the single most important factor associated with vaccination (OR 11.1, 95% CI 7.9–15.5). Most women (63.7%) were vaccinated in general practice, 18.8% in a public hospital antenatal clinic and 11.0% at their workplace. Wanting to protect their infant from infection (91.2%) and having the vaccine recommended by their GP (60.0%) or obstetrician (51.0%) were commonly reported reasons for vaccination; worrying about side effects was a common reason for nonvaccination. Conclusions: To optimise maternal and infant health outcomes, Australian antenatal care providers and services need to incorporate both the recommendation and delivery of influenza vaccination into routine antenatal care. Key words: human, influenza, pregnancy, prenatal care, vaccination.
Background Preventing influenza during pregnancy is considered an important part of antenatal care because pregnant women are at increased risk of serious illness due to influenza.1 Excess morbidity and mortality in pregnant women with seasonal and pandemic influenza compared with nonpregnant women of similar age with influenza have been well documented.2,3 The most effective strategy for preventing influenza in pregnant women is annual vaccination which is recommended for all pregnant
Correspondence: Prof Donna B. Mak, Health Department of Western Australia, Communicable Disease Control Directorate, PO Box 8172 Perth Business Centre, WA 6849, Grace Vaughan House, 227 Stubbs Tce, Shenton Park, WA 6008, Australia. Email: [email protected] Received 24 August 2014; accepted 25 October 2014.
women regardless of gestation.1 Influenza vaccination is estimated to prevent 1–2 hospitalisations per 1000 women vaccinated during the second or third trimester.1 Active placental transfer of maternal antibodies makes influenza vaccine during pregnancy a highly effective measure to protect infants from influenza during the first six months of life.4,5 Both maternal and infant benefits are now well recognised, with an estimated one case of serious maternal or infant respiratory illness prevented for every 5 pregnant women who are vaccinated.5 Furthermore, the safety of influenza vaccination during pregnancy is well established; no study to date has shown an adverse consequence of inactivated influenza vaccine in pregnant women or their children.6,7 Inactivated influenza vaccine has been recommended for Australian pregnant women since 2003, but has been government funded only since the H1N1 (swine flu) pandemic of 2009.1 The Royal Australian and New Zealand College of Obstetricians and Gynaecologists
© 2014 The Royal Australian and New Zealand College of Obstetricians and Gynaecologists The Australian and New Zealand Journal of Obstetrics and Gynaecology
131
D. B. Mak et al.
(RANZCOG) publicly endorsed routine vaccination of all pregnant women against influenza in November 2011.8 In 2013, Australian Health Ministers approved a national woman-held pregnancy record which includes antenatal influenza vaccination as a routine part of antenatal care9 and the World Health Organization recommended pregnant women as the highest priority group for seasonal influenza vaccination.10 Since March 2012, the Health Department of Western Australia (WA Health) has had Operational Directives supporting antenatal influenza vaccination of pregnant women.11,12 However, only 23% of pregnant women in WA received antenatal influenza vaccine in 2012, although 74% reported that they would have been vaccinated if it was recommended by their antenatal care provider.13 In response to these findings, WA Health updated its Operational Directive (OD 0423/13) to authorise nurses and midwives in public hospitals to administer influenza vaccine and distributed information sheets and consent forms for antenatal influenza vaccination, stickers reminding private obstetricians to recommend antenatal influenza vaccination; referral forms for private obstetricians to refer antenatal patients back to their general practitioner (GP) for influenza vaccination; and promotional posters for patient waiting rooms and print advertisements.12 Although influenza vaccination uptake in pregnant women in WA improved from 6.9 to 10.3% in 200914,15 to 23.0% in 2012,13 this level of coverage is far from ideal and much lower than has been achieved in other Australian and international settings where coverage rates in the order of 40–60% were observed when influenza vaccine was routinely recommended and offered by antenatal care providers.16–18 This study aimed to compare seasonal influenza vaccination uptake among pregnant WA women in 2012 and 2013 and identify factors associated with vaccination uptake. Given the statewide public health interventions described, we hypothesised that antenatal influenza vaccination coverage would increase between 2013 and 2012.
Materials and Methods Data collection methods used in 2012 have been described previously.13 A random sample of 1142 adult women who gave birth to a live baby between 07/04/2013 and 06/10/ 2013 (i.e were pregnant during 2013 influenza vaccination season) was selected from the WA Midwives’ Notification System, a statutory database of attended births. As the total sample size in 2013 was doubled from 2012, it was not necessary to oversample women from country areas in order to make comparisons between metropolitan and country uptake. The sample size provides a maximum relative standard error of 3.5% at the standard 95% confidence interval. Women were posted a letter informing them about the study and giving them the opportunity to opt-out of being contacted for a 5- to 10-min computer-assisted telephone 132
interview survey about whether they were vaccinated during pregnancy and whether they were offered/ recommended influenza vaccine during pregnancy by a healthcare provider. For those women who reported that they had been vaccinated, consent was obtained to contact the woman’s healthcare provider for the purpose of confirming her antenatal influenza vaccination status. Published literature regarding the accuracy of selfreported vaccination status in adults indicates that falsepositive self-reports are not uncommon, whereas falsenegative self-reports are extremely rare.19–22 Therefore, positive self-reported influenza vaccination status was verified by: 1 Asking for date and brand of vaccine administered from the written record of vaccination given to her at the time of vaccination or for those women would could not provide this information, 2 Checking against the Antenatal Influenza Vaccination Database (includes consent information, faxed to WA Health by some vaccination providers) or for those women not on the database and 3 Contacting the vaccination provider nominated by the woman. The survey instrument in 2013 was similar to 2012.13 In 2013, questions about knowledge of, and attitudes to, influenza vaccination in pregnancy were omitted to allow for an increased sample size and higher statistical precision. Data from 2012 and 2013 were aggregated and analysed using SAS version 9.3 (SAS Institute, Cary, NC, USA). Data analyses were weighted to the age and geographical distribution of women of reproductive age in WA for the study years of interest. Weighted frequencies of vaccination status were compared across years using Rao Scott chi-square tests. The odds of vaccination in 2012 and 2013 were modelled by multivariate logistic regression, adjusting for age group (18–29 vs 30+ years), metropolitan versus rural residence, antenatal care provider, whether the woman was advised to have vaccination and education attainment (by four strata as defined in Table 1); socio-economic status was not included in the model as it is closely related to education attainment. Variables significant at P < 0.1 level in crude models were included in the multivariate regression model in order to control for the other potential explanatory variables. Ethics approval was obtained from WA Health’s Human Research Ethics Committee.
Results Of women who were pregnant during the 2013 influenza vaccination season and randomly selected for inclusion in the study, 28 (2.5%) of 1142 women opted out and were not contacted further. An additional 110 women were excluded from data collection (telephone not connected (n = 88), incorrect contact details (n = 21), infant deceased (n = 1)), and 18 women did not need to be contacted after the target of 830 interviews had been
© 2014 The Royal Australian and New Zealand College of Obstetricians and Gynaecologists
Antenatal care providers key to vaccination
Table 1 Demographic characteristics of study participants by year, 2012–2013
Characteristic
2012, n = 407 Number (%)
Age*: 18–29 years 198 (48.6) ≥30 years 209 (51.4) Location*: Country 201 (49.4) Metropolitan 206 (50.6) Highest level of education completed: Primary/high 129 (31.7) school TAFE 114 (28.0) University 90 (22.1) undergraduate University 70 (17.2) postgraduate Socioeconomic status*: Quintile 5 (least 51 (12.5) disadvantaged) Quintile 4 110 (27.0) Quintile 3 160 (39.3) Quintile 2 45 (11.1) Quintile 1 38 (9.3) (most disadvantaged) Chronic conditions: No 350 (86.0) Yes 57 (14.0) Antenatal care mostly from: Public hospital 138 (33.9) GP 129 (31.7) Private 127 (31.2) obstetrician
2013, n = 831 Number (%)
Chisquare P-value
321 (38.6) 510 (61.4)
