Brief education to increase uptake of influenza vaccine among pregnant women: a study protocol for a randomized controlled trial.
ABSTRACT: Pregnant women are the highest priority group for annual influenza vaccination. Studies have shown unacceptably low uptake of both seasonal and pandemic A/H1N1 influenza vaccination among pregnant women. This paper will describe the study protocol and methodology of a randomised controlled trial designed to assess the effectiveness of a brief educational intervention in improving the uptake of seasonal influenza vaccine among pregnant women in Hong Kong.A randomised controlled trial will be conducted with pregnant women in at least the second trimester of pregnancy from four publicly funded hospital antenatal clinics in Hong Kong. Participants will be randomly assigned to either one of the two treatment groups: standard care (control) or standard care plus brief education (intervention). Pregnant women in the standard care group will receive the usual antenatal care with an educational pamphlet developed by the Hong Kong Centre for Health Protection and those in the intervention group will be provided with usual care plus a brief ten-minute education intervention. Content of the education session will cover four core components recommended in the research literature. The primary study outcome will be the proportion of participants who have received influenza vaccine during their pregnancy. A total of 184 pregnant women (92 per group) will be required to give an 80% power to detect a treatment effect of 15%.Most intervention studies aimed at improving influenza vaccination rates in pregnant women have targeted obstetric-care providers and the results of the two patient-oriented RCT interventions are conflicting. The high priority for vaccination given to pregnant women and the low influenza vaccination rate among pregnant women worldwide strongly indicates a need for interventions to improve uptake.
Project description:The World Health Organization recommends vaccination of pregnant women for seasonal influenza that can also protect infants aged below 6 months. We estimated incidence and disease burden of influenza in hospitalised children below and above 6 months of age in Hong Kong during a 6 year period. Discharge diagnoses for all admissions to public Hong Kong Hospital Authority hospitals, recorded in a central computerised database (Clinical Management System, CMS), were analysed for the period April 2005 to March 2011. Incidence estimates of influenza disease by age group were derived from CMS ICD codes 487-487.99. Laboratory-confirmed influenza infections from a single surveillance hospital were then linked to the CMS entries to assess possible over- and under-diagnosis of influenza based on CMS codes alone. Influenza was recorded as any primary or any secondary diagnosis in 1.3% (1158/86,582) of infants aged above 6 days to below 6 months and 4.3% (20,230/471,482) of children above 6 days to below 18 years. The unadjusted incidence rates per 100,000 person-years based on any CMS diagnosis of influenza in all admission to Hong Kong public hospitals were 627 in the below 2 months of age group and 1762 in the 2 month to below 6 month group. Incidence of hospitalisation for influenza in children was highest from 2 months to below 6 months. In the absence of vaccines for children below 6 months of age, effective vaccination of pregnant women may have a significant impact on reducing influenza hospitalisations in this age group.
Project description:School-based vaccination, as a means to mitigate seasonal influenza outbreak, depends on attaining adequate coverage rate. We evaluated the potential of a fully subsidized school outreach vaccination (SOV) program to achieve epidemic prevention potential in Hong Kong. The purpose of this study was to evaluate the impact of SOV program 2018-2019 on influenza vaccination rates and influenza-like illness (ILI) in the primary school students and their household members during the influenza season. The vaccination rate was significantly higher in the schools offering SOV (intervention schools) (69.2% vs. 34.3%) than those not offering SOV (control schools) (p < .0001). The ILI rate was significantly reduced from 14.1% among non-vaccinated to 7.7% among vaccinated students (p < .0001). Influenza vaccine effectiveness against ILI was 45.3%. The vaccination rates of the household members were the same in both intervention and control schools except in the sub-group of preschool household members with the intervention significantly higher than the control group (43.8% vs. 32%, p < .0001). SOV program significantly improved influenza vaccine coverage, and the vaccine reduced ILI incidence. Extension of SOV program to all primary schools as well as kindergartens in Hong Kong could achieve epidemic prevention potential and should be evaluated.
Project description:BACKGROUND:Influenza vaccination during pregnancy benefits mothers and children. Kenya and other low- and middle-income countries have no official influenza vaccination policies to date but are moving towards issuing such policies. Understanding determinants of influenza vaccine uptake during pregnancy in these settings is important to inform policy decisions and vaccination rollout. METHODS:We interviewed a convenience sample of women at antenatal care facilities in four counties (Nairobi, Mombasa, Marsabit, Siaya) in Kenya. We described knowledge and attitudes regarding influenza vaccination and assessed factors associated with willingness to receive influenza vaccine. RESULTS:We enrolled 507 pregnant women, median age was 26 years (range 15-43). Almost half (n = 240) had primary or no education. Overall, 369 (72.8%) women had heard of influenza. Among those, 288 (78.1%) believed that a pregnant woman would be protected if vaccinated, 252 (68.3%) thought it was safe to receive a vaccine while pregnant, and 223 (60.4%) believed a baby would be protected if mother was vaccinated. If given opportunity, 309 (83.7%) pregnant women were willing to receive the vaccine. Factors associated with willingness to receive influenza vaccine were mothers' belief in protective effect (OR 3.87; 95% CI 1.56, 9.59) and safety (OR 5.32; 95% CI 2.35, 12.01) of influenza vaccines during pregnancy. CONCLUSION:Approximately one third of pregnant women interviewed had never heard of influenza. Willingness to receive influenza vaccine was high among women who had heard about influenza. If the Kenyan government recommends influenza vaccine for pregnant women, mitigation of safety concerns and education on the benefits of vaccination could be the most effective strategies to improve vaccine acceptance.
Project description:In winter 2018, schools in Hong Kong were closed 1 week before the scheduled Chinese New Year holiday to mitigate an influenza B virus epidemic. The intervention occurred after the epidemic peak and reduced overall incidence by ?4.2%. School-based vaccination programs should be implemented to more effectively reduce influenza illnesses.
Project description:BACKGROUND:The protection conferred by influenza vaccination is generally thought to last less than a year, necessitating annual revaccination. However, the speed with which influenza vaccine effectiveness might decline during a year is unknown, which is of particular importance for locations with year-round influenza activity. We aimed to assess how influenza vaccine effectiveness changes by time intervals between vaccination and admission to hospital, taking advantage of almost year-round circulation of influenza in Hong Kong. METHODS:In this test-negative case-control study, we analysed vaccine effectiveness in children (aged 6 months to 17 years) who were admitted to hospital in Hong Kong over 5 consecutive years (2012-17). We included those who were admitted to general wards in four public hospitals in Hong Kong with a fever (?38°C) and any respiratory symptom, such as runny nose, cough, or sore throat. We used direct immunofluorescence assay and reverse transcription PCR to detect influenza virus infection, and recorded children's influenza immunisation history. We compared characteristics of positive cases and negative controls and examined how vaccine effectiveness changed by time between vaccination and admission to hospital with regression analyses. FINDINGS:Between Sept 1, 2012, and Aug 31, 2017, we enrolled 15?695 children hospitalised for respiratory infections, including 2500 (15·9%) who tested positive for influenza A or B and 13?195 (84·1%) who tested negative. 159 (6·4%) influenza-positive cases and 1445 (11·0%) influenza-negative cases had been vaccinated. Most vaccinations were done by December of each influenza vaccination season. Influenza-related admissions to hospital occurred year-round, with peaks in January through March in most years and a large summer peak in 2016; pooled vaccine effectiveness for children of all ages was 79% (95% CI 42-92) for September to December, 67% (57-74) for January to April, and 43% (25-57) for May to August. Vaccine effectiveness against influenza A or B was estimated as 79% (95% CI 64-88) within 0·5-2 months of vaccination, 60% (46-71) within >2-4 months, 57% (39-70) within >4-6 months, and 45% (22-61) within >6-9 months. In separate analyses by type and subtype, we estimated that vaccine effectiveness declined by 2-5 percentage points per month. INTERPRETATION:Influenza vaccine effectiveness decreased during the 9 months after vaccination in children in Hong Kong. Our findings confirm the importance of annual vaccination in children. Influenza vaccines that provide broader and longer-lasting protection are needed to provide year-round protection in regions with irregular influenza seasonality or lengthy periods of influenza activity. FUNDING:Health and Medical Research Fund, Hong Kong and the Research Grants Council, Hong Kong.
Project description:OBJECTIVES:The current study was conducted to use a developed framework to appraise the public primary care response to pandemic 2009 influenza A H1N1 virus in Hong Kong in 2009. METHODS:A cross-sectional survey was conducted of 300 doctors working in public primary care clinics. In addition, a qualitative study was conducted in two selected general outpatient clinics (GOPCs) with 10 doctors between September and December 2009. RESULTS:We found that there was an increase in clinical service demand for public primary care doctors and that there was lower compliance with hand washing as compared to the wearing of masks among GOPC doctors during the study period. CONCLUSIONS:Since hand hygiene and influenza vaccination are effective methods to prevent the spread of influenza infection, future studies should explore the reasons for non-compliance with these preventive behaviors among doctors. More education and training in dealing with influenza A H1N1 infection may be needed.
Project description:BACKGROUND:Influenza and pneumococcal vaccine uptake in the older population aged 65?years or over of Hong Kong dramatically increased since the 2003 SARS outbreak. This study is aimed to evaluate the impact of increased coverage of influenza and pneumococcal vaccines by comparing the change of disease burden in the older population of Hong Kong, with the burden in the older population of Brisbane with relatively high vaccine coverage in the past fifteen years. METHODS:Time series segmented regression models were applied to weekly numbers of cause-specific mortality or hospitalization of Hong Kong and Brisbane. Annual excess rates of mortality or hospitalization associated with influenza in the older population were estimated for the pre-SARS (reference period), post-SARS and post-pandemic period, respectively. The rate ratios (RRs) between these periods were also calculated to assess the relative change of disease burden. RESULTS:Compared to the pre-SARS period, excess rates of mortality associated with influenza during the post-SARS period in Hong Kong decreased for cardiorespiratory diseases (RR?=?0.90, 95% CI 0.80, 1.01), stroke (RR?=?0.74, 95% CI 0.50, 1.09), and ischemic heart diseases (RR?=?0.45, 95% CI 0.34, 0.58). The corresponding RRs in Brisbane were 0.79 (95% CI 0.54, 1.15), 0.33 (0.13, 0.80), and 1.09 (0.62, 1.90), respectively. Only the mortality of ischemic heart diseases showed a greater reduction in Hong Kong than in Brisbane. During the post-pandemic period, excess rates of all-cause mortality increased in Hong Kong, but to a lesser extent than in Brisbane (RR?=?1.41 vs 2.39). CONCLUSION:A relative decrease (or less of an increase) of influenza disease burden was observed in the older population of Hong Kong after increased coverage of influenza and pneumococcal vaccines in this population, as compared to those of Brisbane where vaccination rates remained stable. The lack of significant findings in some disease categories highlights the challenges of evaluating the benefits of vaccination at the population level.
Project description: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.
Project description:Influenza infection in pregnant women is associated with increased risk of morbidity and mortality. Despite recommendations for all women to receive the seasonal influenza vaccine during pregnancy, vaccination rates among pregnant women in the U.S. have remained around 50%. The objective of this study was to evaluate clinical and demographic factors associated with antenatal influenza vaccination in a medically underserved population of women. We conducted a retrospective cohort study at Grady Memorial Hospital, a large safety-net hospital in Atlanta, Georgia, from July 1, 2016, to June 30, 2018. Demographic and clinical characteristics were abstracted from the electronic medical record. The Kotelchuck index was used to assess prenatal care adequacy. Relative risks and 95% confidence intervals for associations between receipt of influenza vaccine and prenatal care adequacy, demographic characteristics, and clinical characteristics were calculated using multivariable log-binominal models. Among 3723 pregnant women with deliveries, women were primarily non-Hispanic black (68.4%) and had Medicaid as their primary insurance type (87.9%). The overall vaccination rate was 49.8% (1853/3723). Inadequate prenatal care adequacy was associated with a lower antenatal influenza vaccination rate (43.5%), while intermediate and higher levels of prenatal care adequacy were associated with higher vaccination rates (66.9-68.3%). Hispanic ethnicity, non-Hispanic other race/ethnicity, interpreter use for a language other than Spanish, and preexisting diabetes mellitus were associated with higher vaccination coverage in multivariable analyses. Among medically underserved pregnant women, inadequate prenatal care utilization was associated with a lower rate of antenatal influenza vaccination. Socially disadvantaged women may face individual and structural barriers when accessing prenatal care, suggesting that evidenced-based, tailored approaches may be needed to improve prenatal care utilization and antenatal influenza vaccination rates.
Project description:PURPOSE: Women who are pregnant, planning to become pregnant in the influenza season or caring for infant 6-59 months of age are identified as priority groups for influenza vaccination. Vaccination rate is presumed to be low in those women. The purpose of this study was to investigate perceptions of childbearing age women about influenza vaccination. MATERIALS AND METHODS: Childbearing age women visiting the department of Obstetrics and Gynecology in 3 University hospitals in Seoul and Gyeonggi-do province were surveyed. Individual interviews were performed to them with questionnaire for 2 months from April to May 2012. Demographic data, Immunization history, general understanding and factors associated with vaccination were asked. RESULTS: Three hundred fifty-five (71.0%) of total 500 reproductive age women had the experience of influenza vaccination. Among 343 women who has been pregnant at least once, 48 women (16.4%) had vaccination during pregnancy, and 46 of them got vaccination since 2009. One hundred ninety women of total 500 women responded that they would get vaccination if pregnant in the next influenza season (38.0%). In multivariate analysis, statistically significant factors associated with plans of influenza vaccination in pregnancy were as follows: experience of childbirth (odds ratio [OR], 1.97; 95% CI, 1.32 to 2.93), high level of education (OR, 1.96; 95% CI, 1.22 to 3.15), previous influenza vaccination (OR, 1.88; 95% CI, 1.17 to 3.01). CONCLUSION: Influenza vaccine coverage on childbearing age women including pregnant women is low because of misperception of vaccination during pregnancy. It is necessary for healthcare provider to correct misunderstanding and to recommend vaccination actively.