A Randomized Controlled Trial of an Educational Intervention to Promote Influenza Vaccine Uptake Among Pregnant Women

Transcription

1 A Randomized Controlled Trial of an Educational Intervention to Promote Influenza Vaccine Uptake Among Pregnant Women Valerie W. Y. Wong RN MPH Daniel Y. T. Fong PhD Marie Tarrant RN MPH PhD School of Nursing, University of Hong Kong

2 Background Pregnant women at greater risk for increased morbidity and mortality from influenza infection during pregnancy. Compared with non-pregnant women, risk of influenzarelated hospital admission: ~50% higher from weeks ~5-fold higher in weeks 37-42

3 Background Risk is than for persons years with chronic diseases or those at highrisk or. Pregnant women susceptible to influenza during pregnancy because of physiological and immunological changes.

4 Background Physiological changes: Alterations in the chest shape and dimensions and elevation of the diaphragm dyspnea, O 2 consumption & tidal volume, functional residual capacity susceptibility to respiratory pathogens Immunological changes: Maternal immune system suppresses cell-mediated immunity to tolerate fetal antigens during pregnancy. susceptibility to intracellular pathogens such as viruses and bacteria

5 Background HK infants 6 months have hospital admission rates for influenza. Infants 6 months have influenza-associated mortality. Infants 6 months of age cannot receive influenza vaccine maternal vaccination can provide protection for first 6 months.

6 Background Benefits of Vaccination: respiratory illnesses among pregnant women by 36%. 15% to 20% in LBW, SGA, preterm birth, and stillbirth in vaccinated mothers. Maternal influenza vaccine can hospitalization from influenza infection in infants 6 months of age by >90%.

7 Background Despite the benefits, vaccine rate is low around 20-40% in most countries. HK studies show rates are low in pregnant women: In rate was 3.9%. In rates of H1N1 vaccination was 6.2%. In rate was 1.7%.

8 Research Aims Designed a RCT to evaluate the effectiveness of a brief education intervention on maternal influenza vaccine uptake Primary outcome: influenza vaccination rate during pregnancy Secondary outcome: proportion of participants seeking out influenza vaccine

9 Methods Recruited pregnant women from 4 public antenatal clinics Inclusion criteria were: Singleton pregnancy 18 years of age 2 nd trimester Cantonese speaking Hong Kong resident No serious medical or obstetrical complications Has not received the influenza vaccine this pregnancy Staying in Hong Kong for 2 weeks after birth Followed up by telephone at 2 weeks postpartum

10 Methods Randomized to receive: Standard antenatal care or Routine maternal and foetal health checks + health education to promote a healthy pregnancy Printed pamphlet on benefits of influenza vaccine widely available in antenatal clinics Standard care + one-to-one brief (10 mins) education session Overview of the safety and benefits of the vaccine to pregnant women, the foetus, and the newborn baby Randomized at 1:1 ratio w/ block randomization random block sizes of two to eight

11 Methods Intervention focused on four key recommendations from US preventative task force: inform pregnant women of vaccination recommendations encourage discussion with their healthcare practitioners increase accessibility of vaccine by making referral to clinics where vaccine can be obtained provide credible information from the government official website

12 Allocation Assessed for eligibility (n=489) Analysis Follow-up Enrollment Standard care (n=160) Lost to follow-up (n=6) Intention-to-Treat (n=160) Per Protocol (n=154) Randomized participants (n=321) Excluded (n=168) Did not meet inclusion criteria (n=28) Declined to participate (n=140) Brief Education (n=161) Lost to follow-up (n=10) Intention-to-Treat (n=161) Per Protocol (n=151)

13 Table 1: Baseline Characteristics of Participants by Treatment Group Characteristic Standard Care N (%) N=160 Brief Education N (%) N=161 p-value Maternal age, years M(SD) Maternal education.26 Compulsory secondary 64 (40.0) 64 (42.2) Upper secondary 22 (13.8) 31 (19.3) University degree or above 74 (46.3) 62 (38.5) Parity (61.9) 92 (57.1) 1 53 (33.1) 60 (37.3) 2 8 (5.0) 9 (5.6) Family income.56 Below median 44 (27.5) 49 (30.4) Above median 116 (72.5) 112 (69.6) Pre-existing chronic disease.006 No 149 (93.1) 134 (83.2) Yes 11 (6.9) 27 (16.8) Medical condition during pregnancy.99 No 125 (78.1) 126 (78.3) Yes 35 (21.9) 35 (21.7) Advised by HCP to receive vaccine.66 No 151 (94.4) 150 (93.2) Yes 9 (5.6) 11 (6.8)

14 Results 11.8% had a pre-existing chronic disease high-risk for influenza infection. 21.8% had pregnancy-related health problem. Only 6.2% were advised by HCP to receive the vaccine.

15 % % Influenza Vaccination Rate Per Protocol Analysis ITT Analysis 25 P < P < Standard Care Brief Education 0 Standard Care Brief Education Adjusted OR: 2.45; 95% CI 1.28, 4.68 Adjusted OR: 2.52; 95% CI 1.32, 4.82

16 Results Among non-vaccinated participants, 17% (n=45) reported asking HCP about the vaccine. Intervention group participants more likely to attempt to get vaccinated (33.0% vs. 5.9%; p<0.001) 47% (n=21) were given anti-vaccination advice by HCP.

17 % % Expected Influenza Vaccination Rate Per Protocol Analysis ITT Analysis 35 P = P < Standard Care Brief Education 0 Standard Care Brief Education

18 Discussion Intervention significantly improved vaccine uptake, but the overall impact was not substantial. Vaccination rates remain suboptimal. However, vaccination rates in standard care group (~10%) higher than previously reported in this population.

19 Discussion A positive recommendation by obstetric HCP is strong predictor of vaccination. Failure of obstetric HCPs to recommend vaccination to pregnant women is main contributor to low uptake. <10% of pregnant women had received a vaccine recommendation Not uncommon that HCPs give anti-vaccination advice to pregnant women.

20 Discussion Multicomponent approaches should be evaluated to maternal influenza vaccination: Brief maternal education + HCP vaccination recommendations On-site vaccination Education programs should target both pregnant women and HCPs

21 Strengths and Limitations Strengths RCT with adequate study power Followed CONSORT guidelines Measured actual uptake of vaccination and not intention 100% intervention fidelity Low loss to follow-up (<5%) Limitations Generalizability of public hospital patients to larger population. Participants may have been more receptive to message higher uptake in standard care group. Vaccination status assessed by self-report data potential for recall bias.

22 Acknowledgements Funded by: Health and Medical Research Fund (Grant no ). Clinical Trial Registration: NCT Ethical Approval by: HKU/HKW Cluster IRB & REC at all study sites

23 Publications Wong, W. Y. V., Fong, D. Y. T., & Tarrant, M. (2014). Brief education to increase uptake of influenza vaccine among pregnant women: A study protocol for a randomized controlled trial. BMC Pregnancy & Childbirth, 14(19). Wong, W. Y. V., Fong, D. Y. T., Lok, K. Y. W., Sing, C., Choi, A. Y. Y., Yuen, C. Y. S., & Tarrant, M. Brief education to promote maternal influenza vaccine uptake: A randomized controlled trial. In progress.

24 References 1. Neuzil KM, Reed GW, Mitchel EF, Simonsen L, Griffin MR (1998) Impact of influenza on acute cardiopulmonary hospitalizations in pregnant women. Amer J Epidemiol 148: Schanzer DL, Langley JM, Tam TWS (2007) Influenza-attributed hospitalization rates among pregnant women in Canada JOGC 29: Jamieson DJ, Honein MA, Rasmussen SA, Williams JL, Swerdlow DL, et al. (2009) H1N influenza virus infection during pregnancy in the USA. Lancet 374: Dubar G, Azria E, Tesnière A, Dupont H, Le Ray C, et al. (2010) French experience of 2009 A/H1N1v influenza in pregnant women. PLoS One 5: e Hanslik T, Boelle P-Y, Flahault A (2010) Preliminary estimation of risk factors for admission to intensive care units and for death in patients infected with A(H1N1)2009 influenza virus, France, PLoS Currents 2: RRN Anzic Influenza Investigators and Australasian Maternity Outcomes Surveillance System (2010) Critical illness due to 2009 A/H1N1 influenza in pregnant and postpartum women: population based cohort study. BMJ 340: c Knight M, Pierce M, Seppelt I, Kurinczuk JJ, Spark P, et al. (2011) Critical illness with AH1N1v influenza in pregnancy: a comparison of two population-based cohorts. BJOG 118: Shahab SZ, Glezen WP (1994) Infleunza virus. In: Gonik B, editor. Viral diseases in pregnancy. Berlin: Springer-Verlag. pp Goodnight WH, Soper DE (2005) Pneumonia in pregnancy. Crit Care Med 33: S390-S Bhatia P, Bhatia K (2000) Pregnancy and the lungs. Postgrad Med J 76: Jamieson DJ, Theiler RN, Rasmussen SA (2006) Emerging infections and pregnancy. Emerg Infect Dis 12: Dodds L, McNeil SA, Fell DB, Allen VM, Coombs A, et al. (2007) Impact of influenza exposure on rates of hospital admissions and physician visits because of respiratory illness among pregnant women. CMAJ 176:

25 References 13. Nelson EAS, Ip M, Tam JS, Mounts AW, Chau SL, et al. (2014) Burden of influenza infection in hospitalised children below 6 months of age and above in Hong Kong from 2005 to Vaccine. 14. Bhat N, Wright JG, Broder KR, Murray EL, Greenberg ME, et al. (2005) Influenza-associated deaths among children in the United States, NEJM 353: Zaman K, Roy E, Arifeen SE, Rahman M, Raqib R, et al. (2008) Effectiveness of maternal influenza immunization in mothers and infants. NEJM 359: Källén B, Olausson PO (2012) Vaccination against H1N1 influenza with Pandemrix during pregnancy and delivery outcome: a Swedish register study. BJOG 119: Steinhoff MC, Omer SB, Roy E, Arifeen SE, Raqib R, et al. (2012) Neonatal outcomes after influenza immunization during pregnancy: a randomized controlled trial. CMAJ 184: Benowitz I, Esposito DB, Gracey KD, Shapiro ED, Vazquez M (2010) Influenza vaccine given to pregnant women reduces hospitalization due to influenza in their infants. Clin Inf Dis 51: World Health Organization (2012) Vaccines against influenza WHO position paper - November Wkly Epidemiol Rec 87: Yuen CY, Tarrant M (2014) Determinants of uptake of influenza vaccination among pregnant women - A systematic review. Vaccine 32: Lau JT, Yeung NC, Choi KC, Cheng MY, Tsui HY, et al. (2010) Factors in association with acceptability of A/H1N1 vaccination during the influenza A/H1N1 pandemic phase in the Hong Kong general population. Vaccine 28: Tarrant M, Wu KM, Yuen CY, Cheung KL, Chan VH (2013) Determinants of 2009 A/H1N1 Influenza Vaccination Among Pregnant Women in Hong Kong. Matern Child Health J 17: Yuen CYS, Fong DYT, Lee ILY, Sing C, Siu ESM, & Tarrant M (2013) Prevalence and predictors of maternal seasonal influenza vaccination in Hong Kong. Vaccine 31: