Determinants of 2009 A/H1N1 influenza vaccination among pregnant women in Hong Kong

Assessment of knowledge and attitude toward influenza vaccinations within the adult population of Riyadh, Saudi Arabia

BACKGROUND

The most cost-effective measure for preventing the infectious disease, influenza, is vaccination. The purpose of this research was to evaluate knowledge levels, familiarity, and attitude toward influenza and influenza vaccination of the Riyadh adult population.

MATERIALS AND METHODS

A cross-sectional study was carried out in Riyadh and data was collected between December 2017 and March 2018. Five hundred participants were interviewed in person using a closed-ended questionnaire. Participants comprised the general population, students, and healthcare workers (HCWs), and were recruited from shopping malls, parks, Princess Nourah Bint Abdulrahman University, and King Abdullah Bin Abdulaziz University Hospital. A pilot study was conducted among 15 participants from the general population, students, and HCWs who gave verbal consent. Participants were asked if they comprehended the questionnaire and whether they felt comfortable participating. Descriptive statistics were used to describe the sample. Statistical significance was determined using t-test for quantitative variables and Chi-square test for qualitative variables.

RESULTS

Most participants in all groups had poor knowledge. The least informed was the general population (8.8%), followed by the students (11.8%), and the most aware were the HCWs (18.5%). The social media (35%) was the main source of participants' knowledge, followed by doctors and health educators in hospitals (33%). Only 15.6% of participants had been vaccinated this year. Even fewer (8.8%) stated that they took the vaccination every year. The most important reasons for getting vaccinated were the recommendations by the Ministry of Health or by their doctors (77.8% for each). The key barrier to vaccination was a lack of perceived benefit (the participants did not usually get influenza so they felt vaccination was unnecessary [66.2%]). About 34% of participants reported that they had the children in their families vaccinated. The main reason given was to protect their children from influenza complications (80.6%).

CONCLUSION

Within the Riyadh adult population, there was both low compliance to take the influenza vaccinations owing to a lack of perceived benefit and insufficient knowledge of the risks of influenza.

The long road of pandemic vaccine development to rollout: A systematic review on the lessons learnt from the 2009 H1N1 influenza pandemic

BACKGROUND

The 2009 Influenza A(H1N1) pandemic prompted one of the largest public health responses in history. The continuous emergence of new and deadly pathogens has highlighted the need to reflect upon past experiences to improve pandemic preparedness. The aim of this study was to examine the development and rollout of 2009 influenza A(H1N1) pandemic vaccine and knowledge challenges for the effective implementation of vaccination programs for COVID-19 and future influenza pandemics.

METHODS

A systematic review was conducted searching EMBASE (inception to current date) and PUBMED (from January 2009 to current date) databases for relevant published studies about influenza A(H1N1) pandemic vaccines. A Google search was conducted to identify relevant documents from gray literature. Selected Studies were reviewed and summarized.

RESULTS

A total of 22, comprising of 12 original studies and 10 relevant documents met the inclusion criteria. Fourteen papers reported an initial high demand that outweighed production capacity and caused vaccine shortages. Vaccine procurement and supply were skewed toward high-income countries. Low vaccination rates of about 5%-50% were reported in all studies mainly due to a low-risk perception of getting infected, safety concerns, and the fear of adverse effects.

CONCLUSIONS

Safety concerns about the approved H1N1 vaccines resulted in many unsuccessful vaccination campaigns worldwide. Understanding the factors that influence people's decision to accept or refuse vaccination, effective risk communication strategies, adequate resources for vaccine deployment initiatives and building local capacities through shared knowledge and technology transfer may help to improve COVID-19 vaccine uptake and accelerate pandemic control.

Factors Impacting Vaccine Uptake during Pregnancy: A Retrospective Analysis

BACKGROUND AND OBJECTIVE

Vaccine uptake rates during pregnancy remain below target goals due to a convergence of factors. In particular, women of lower socioeconomic means and racial minorities typically have reduced rates of vaccine acceptance. This study aims to identify additional factors contributing to vaccine acceptance within a sample population of women receiving prenatal care in Houston, Texas, United States of America.

METHODS

We performed a retrospective cross-sectional analysis of 11,500 pregnant women covered by Medicaid or ChipPerinate who received prenatal care during 2013-2021, assessing influenza (flu) and combined Tetanus, Diphtheria, Acellular Pertussis (TDAP) vaccine acceptance in the patient population. We examined temporal trends in flu and TDAP vaccination rates using Joinpoint regression analyses and evaluated the factors associated with single or concomitant vaccine acceptance during the study period and during the COVID-19 pandemic using adjusted log-binomial regression models.

RESULTS

In our population, 54% of patients received flu vaccination, and 76.1% received TDAP. TDAP rates increased from 2013-2015 but have shown an overall decline since then, as with the flu vaccine. Earlier entry to prenatal care (Prevalence Ratio [PR] 6.32; Confidence Interval [CI] 3.28-12.24) and pregnancy comorbidity such as gestational diabetes (PR 1.32; CI 0.82-2.19) were positively associated with uptake. In contrast, the NH-Black race was negatively associated with vaccine acceptance (PR 0.51 CI; 0.25-0.99). Otherwise, age and history of pre-pregnancy comorbidities were not significant predictors.

CONCLUSION AND GLOBAL HEALTH IMPLICATIONS

Within demographic groups identified as at-risk for vaccine refusal, modifying factors further impact vaccine hesitancy. Identifying these elements will guide targeted patient efforts to promote vaccine uptake, both for routine prenatal recommendations and for COVID vaccination.

Programme costs for introducing age/gestation-based universal influenza vaccine schedules for young children and pregnant women in Hong Kong

BACKGROUND

Hong Kong experiences year-round influenza activity with winter and summer peaks. The government's Vaccination Subsidy Scheme (VSS) provides vaccine to high-risk groups prior to the larger winter peak. The VSS is predominantly administered through the private sector. This study aimed to cost the two theoretical routine influenza vaccination schedules using both northern and southern hemisphere vaccines, administered according to child's age and women's gestation, from a governmental perspective; and compare these costs to the costs of government's seasonal VSS assuming equivalent coverage estimates to determine the budget impacts of these influenza vaccination programmes in Hong Kong.

METHODS

We used the World Health Organization's Flutool Plus to estimate the incremental annual costs for immunising young children aged 6 months to 2 years and pregnant women with influenza vaccine during 2021, assuming the latter group accesses the public system for some antenatal care. Inputs were based on literature review, publicly available data and expert opinions. Sensitivity analyses were done with various coverage rates and vaccine costs.

RESULTS

The annual incremental cost (including vaccine price) to vaccinate young children with three doses of influenza vaccine during the first two years of life was estimated at USD 1,175,146 (per-dose-cost of USD 10.55) at 75% coverage while that to vaccinate pregnant women with one dose at 60% coverage was estimated at USD 398,555 (per-dose-cost of USD 13.39). Across a range of sensitivity analyses we predict that routine year-round schedules could be cost-saving to the government compared to the VSS. Implementing routine immunisation to both risk groups equates to USD 1,573,701, i.e., 0.012% of Hong Kong's annual healthcare spending.

CONCLUSION

Proposed year-round universal schedules providing influenza immunisation according to the child's age or the woman's gestation are predicted to be cost-saving compared to the current seasonally administered subsidised vaccine programme.

The Rate of Influenza Vaccination after Face-to-Face Interview in Pregnancy

PURPOSE

Most societies recommend routine influenza vaccine to all pregnant women. In Turkey, the Ministry of Health provides the influenza vaccine free of charge to pregnant women during the second and third trimesters. Pregnant women may not be willing to accept vaccination despite their knowledge and attitudes. We aimed to investigate the rate and determining factors of influenza vaccine acceptance after receipt of face-to-face information.

METHODS

Pregnant women were informed about the benefits of the influenza vaccine and asked if they would get the vaccine.

RESULTS

A total of 353 Turkish women were involved, and 191 (54.1%) accepted influenza vaccination. There was no statistically significant difference in terms of maternal age, body mass index, gravida, number of children, socioeconomic status, smoking and occupation between groups. Women in the third trimester had lower vaccination rates compared to first- and second-trimester pregnancies (35.7% vs. 67.7-64.2%). Women with at least a university degree also had lower vaccine uptake rates (58.1% vs. 59.5-36.8%). While 82.2% of women who accepted vaccination believed the benefit of the vaccine to the baby, the rate was 54.9% in the non-vaccinated group. The most common reason for refusal was the belief that influenza was not a serious disease. Vaccination uptake was higher especially for women who understood the benefits of the influenza vaccine for the baby (OR=3.79, 95%Cl=2.34-6.14).

CONCLUSION

Women who had enough information, who had a lower education level, who had a previous history of influenza infection, and who had decided to have their babies vaccinated were more likely to accept influenza vaccine.

Factors that influence vaccination decision-making among pregnant women: A systematic review and meta-analysis

BACKGROUND

The most important factor influencing maternal vaccination uptake is healthcare professional (HCP) recommendation. However, where data are available, one-third of pregnant women remain unvaccinated despite receiving a recommendation. Therefore, it is essential to understand the significance of other factors and distinguish between vaccines administered routinely and during outbreaks. This is the first systematic review and meta-analysis (PROSPERO: CRD 42019118299) to examine the strength of the relationships between identified factors and maternal vaccination uptake.

METHODS

We searched MEDLINE, Embase Classic & Embase, PsycINFO, CINAHL Plus, Web of Science, IBSS, LILACS, AfricaWideInfo, IMEMR, and Global Health databases for studies reporting factors that influence maternal vaccination. We used random-effects models to calculate pooled odds ratios (OR) of being vaccinated by vaccine type.

FINDINGS

We screened 17,236 articles and identified 120 studies from 30 countries for inclusion. Of these, 49 studies were eligible for meta-analysis. The odds of receiving a pertussis or influenza vaccination were ten to twelve-times higher among pregnant women who received a recommendation from HCPs. During the 2009 influenza pandemic an HCP recommendation increased the odds of antenatal H1N1 vaccine uptake six times (OR 6.76, 95% CI 3.12-14.64, I2 = 92.00%). Believing there was potential for vaccine-induced harm had a negative influence on seasonal (OR 0.22, 95% CI 0.11-0.44 I2 = 84.00%) and pandemic influenza vaccine uptake (OR 0.16, 95% CI 0.09-0.29, I2 = 89.48%), reducing the odds of being vaccinated five-fold. Combined with our qualitative analysis the relationship between the belief in substantial disease risk and maternal seasonal and pandemic influenza vaccination uptake was limited.

CONCLUSIONS

The effect of an HCP recommendation during an outbreak, whilst still powerful, may be muted by other factors. This requires further research, particularly when vaccines are novel. Public health campaigns which centre on the protectiveness and safety of a maternal vaccine rather than disease threat alone may prove beneficial.

Review of the status and challenges associated with increasing influenza vaccination coverage among pregnant women in China

Influenza vaccination coverage in pregnant women in China remains low. In this review, we first provide an overview of the evidence for the use of influenza vaccination during pregnancy. Second, we discuss influenza vaccination policy and barriers to increased seasonal influenza vaccination coverage in pregnant women in China. Third, we provide case studies of successes and challenges of programs for increasing seasonal influenza vaccination in pregnant women from other parts of Asia with lessons learned for China. Finally, we assess opportunities and challenges for increasing influenza vaccination coverage among pregnant women in China.

Does the availability of influenza vaccine at prenatal care visits and of immediate vaccination improve vaccination coverage of pregnant women?

Introduction

Although vaccination against influenza is recommended for pregnant women in France because it exposes them to a risk of death and severe respiratory complications, their vaccination coverage in 2016 was estimated at 7%. This study's principal objective was to assess the association between the availability of influenza vaccination at prenatal care visits and vaccination coverage.

Material and methods

This multicenter survey took place in 3 Paris-area public hospital (AP-HP) maternity wards (A, B, and C). Only maternity ward A offered the vaccine and vaccination without charge at prenatal visits. Data were collected from parturients during 10 days in January 2017 by a self-administered anonymous questionnaire.

Results

Data from 248 women showed overall vaccination coverage of 19.4% (48/248): 35.4% (46/130) in maternity unit A, 2.7% (2/75) in B, and 0% (0/43) in C (P<0.01). After adjustment for socio-demographic characteristics, women at maternity ward A were significantly more likely to be vaccinated than those at B and C (aOR 25.52, 95%CI [5.76–113.10]). Other factors significantly associated with higher vaccination coverage were the mother’s French birth (aOR 2.37 CI [1.03–5.46]) and previous influenza vaccination (aOR 3.13, 95%CI [1.25–7.86]). Vaccinated women generally considered they had received adequate information (aOR 4.15 CI [2.10–8.22]), principally from the professional providing their prenatal care. Nonvaccination was attributed to the absence of an offer of vaccination (81.5%), fear of fetal side effects (59.5%), and inadequate information (51.4%).

Conclusion

Our results show that availability of influenza vaccination, free of charge, at prenatal consultations at the maternity ward increases vaccination coverage significantly.

Acceptance and uptake of influenza vaccines in Asia: A systematic review

In Asia, the public health burden of influenza is significant despite the existence of efficacious influenza vaccines. Annual seasonal influenza vaccination can reduce the incidence of influenza significantly, yet influenza vaccination coverage remains low in this part of the world. As a densely populated region with varying climatic zones and a larger proportion of developing countries compared to the West, Asia is at increased risk of influenza. To provide a more comprehensive and nuanced understanding of the Asian region, the key objective of this systematic review is to examine the determinants of vaccination uptake in Asia, beyond that of existing studies that have largely been western-centric. We carried out a systematic review of peer-reviewed scientific research, examining the key determinants, acceptance and uptake of influenza vaccinations across Asia. A comprehensive search strategy was defined to capture studies that met the inclusion criteria of articles published in English, from 2008 to 2018, focusing on adult populations within Asia. A total of 83 relevant studies were appraised in this review. Analyses of the extant data confirmed that vaccination rates within Asia are low, and that most countries lack scientific research on vaccination behaviours. Studies were categorised into four different population groups: healthcare workers, high risk groups, general population and uniform groups. The motivators and deterrents for vaccine uptake varied according to population groups and characteristics. Both general populations and healthcare workers were concerned with vaccine safety and efficacy, and recommendations from health authorities were influential in vaccine uptake within the other populations. The findings suggest that further research is needed within a broader range of Asian countries to garner greater in-depth knowledge of vaccination behaviours in the region. In particular, influenza vaccination programs within Asia should focus on improving engagement more effectively, through greater relatability and transparency of data when educating the public.

Increasing influenza vaccine uptake in children: A randomised controlled trial

BACKGROUND

Influenza vaccine is not included in the Hong Kong Government's universal Childhood Immunisation Programme but eligible children can receive subsidised vaccine through the private sector using the Vaccination Subsidy Scheme (VSS). This study examined whether a simple intervention package can increase influenza vaccine uptake in Hong Kong children.

METHODS

Two study samples were enrolled: families of children who had participated in a previous knowledge, attitudes and practices study; and mother-infant pairs recruited from postnatal wards. Control groups received publicly available leaflets about VSS. Intervention groups additionally received: (1) a concise information sheet about influenza and its vaccine; (2) semi-completed forms to utilise the subsidy; (3) contacts of VSS clinics that did not charge above the subsidy; and (4) text message reminders for vaccination. Enrolled mothers were contacted when children were approximately 1 and 2 years old to determine influenza vaccination status of the families and their plan to vaccinate their children. Mothers' attitudes towards influenza vaccine were assessed at enrolment and at the end of the study.

RESULTS

A total of 833 eligible mother-infant pairs were enrolled from the two samples. The intervention package improved influenza vaccine uptake by 22% at one year and 25% at two years of age. Maternal influenza vaccine uptake in intervention group was higher during this two-year period in those who had never been previously vaccinated. Mothers' self-efficacy regarding the use of influenza vaccine in her child i.e. belief and confidence in her own ability to make a good decision, was also improved with the intervention.

CONCLUSIONS

A four-component intervention package could improve influenza vaccine uptake in Hong Kong children and their mothers during the first two years of life and depending on vaccine effectiveness could potentially reduce influenza-associated hospital admissions in children below 2 years old by 13-24%.

Barriers of Influenza Vaccination Intention and Behavior - A Systematic Review of Influenza Vaccine Hesitancy, 2005 - 2016

BACKGROUND

Influenza vaccine hesitancy is a significant threat to global efforts to reduce the burden of seasonal and pandemic influenza. Potential barriers of influenza vaccination need to be identified to inform interventions to raise awareness, influenza vaccine acceptance and uptake.

OBJECTIVE

This review aims to (1) identify relevant studies and extract individual barriers of seasonal and pandemic influenza vaccination for risk groups and the general public; and (2) map knowledge gaps in understanding influenza vaccine hesitancy to derive directions for further research and inform interventions in this area.

METHODS

Thirteen databases covering the areas of Medicine, Bioscience, Psychology, Sociology and Public Health were searched for peer-reviewed articles published between the years 2005 and 2016. Following the PRISMA approach, 470 articles were selected and analyzed for significant barriers to influenza vaccine uptake or intention. The barriers for different risk groups and flu types were clustered according to a conceptual framework based on the Theory of Planned Behavior and discussed using the 4C model of reasons for non-vaccination.

RESULTS

Most studies were conducted in the American and European region. Health care personnel (HCP) and the general public were the most studied populations, while parental decisions for children at high risk were under-represented. This study also identifies understudied concepts. A lack of confidence, inconvenience, calculation and complacency were identified to different extents as barriers to influenza vaccine uptake in risk groups.

CONCLUSION

Many different psychological, contextual, sociodemographic and physical barriers that are specific to certain risk groups were identified. While most sociodemographic and physical variables may be significantly related to influenza vaccine hesitancy, they cannot be used to explain its emergence or intensity. Psychological determinants were meaningfully related to uptake and should therefore be measured in a valid and comparable way. A compendium of measurements for future use is suggested as supporting information.

Brief education to promote maternal influenza vaccine uptake: A randomized controlled trial

BACKGROUND

Although pregnant women are the highest priority group for seasonal influenza vaccination, maternal influenza vaccination rates remain suboptimal. The purpose of this study was to evaluate the effect of a brief education intervention on maternal influenza vaccine uptake.

METHODS

During the 2013-14 and 2014-15 influenza seasons, we recruited 321 pregnant women from the antenatal clinics of 4 out of 8 public hospitals in Hong Kong with obstetric services. Hospitals were geographically dispersed and provided services to pregnant women with variable socioeconomic backgrounds. Participants were randomized to receive either standard antenatal care or brief one-to-one education. Participants received telephone follow-up at 2 weeks postpartum. The primary study outcome was self-reported receipt of influenza vaccination during pregnancy. The secondary outcomes were the proportion of participants who initiated discussion about influenza vaccination with a health care professional and the proportion of participants who attempted to get vaccinated.

RESULTS

Compared with participants who received standard care, the vaccination rate was higher among participants who received brief education (21.1% vs. 10%; p=0.006). More participants in the education group initiated discussion about influenza vaccination with their HCP (19.9% vs. 13.1%; p=0.10), but the difference was not statistically significant. Of participants who did not receive the influenza vaccine (n=271), 45 attempted to get vaccinated. A significantly higher proportion of participants who attempted to get vaccinated were in the intervention group (82.2% vs. 17.8%; p<0.001). If participants who had attempted vaccination had received the vaccine, vaccination rates would have been substantially higher (44.1% vs. 15%; p<0.001). Twenty-six participants were advised against influenza vaccination by a healthcare professional, including general practitioners, obstetricians, and nurses.

CONCLUSION

Although brief education was effective in improving vaccination uptake among pregnant women, overall vaccination rates remain suboptimal. Multicomponent approaches, including positive vaccination recommendations by healthcare professionals, are needed to promote maternal influenza vaccination.

CLINICAL TRIAL REGISTRATION

www.clinicaltrials.gov (NCT01772901).

Effect on Baby-Friendly Hospital Steps When Hospitals Implement a Policy to Pay for Infant Formula

BACKGROUND

The Baby-Friendly Hospital Initiative requires hospitals to pay market price for infant formula. No studies have specifically examined the effect of hospitals paying for infant formula on breastfeeding mothers' exposure to Baby-Friendly steps.

OBJECTIVES

To investigate the effect of hospitals implementing a policy of paying for infant formula on new mothers' exposure to Baby-Friendly steps and examine the effect of exposure to Baby-Friendly steps on breastfeeding rates.

METHODS

We used a repeated prospective cohort study design. We recruited 2 cohorts of breastfeeding mother-infant pairs (n = 2470) in the immediate postnatal period from 4 Hong Kong public hospitals and followed them by telephone up to 12 months postpartum. We assessed participants' exposure to 6 Baby-Friendly steps by extracting data from the medical record and by maternal self-report.

RESULTS

After hospitals began paying for infant formula, new mothers were more likely to experience 4 out of 6 Baby-Friendly steps. Breastfeeding initiation within the first hour increased from 28.7% to 45%, and in-hospital exclusive breastfeeding rates increased from 17.9% to 41.4%. The proportion of mothers who experienced all 6 Baby-Friendly steps increased from 4.8% to 20.5%. The risk of weaning was progressively higher among participants experiencing fewer Baby-Friendly steps. Each additional step experienced by new mothers decreased the risk of breastfeeding cessation by 8% (hazard ratio = 0.92; 95% CI, 0.89-0.95).

CONCLUSION

After implementing a policy of paying for infant formula, breastfeeding mothers were exposed to more Baby-Friendly steps, and exposure to more steps was significantly associated with a lower risk of breastfeeding cessation.

Factors associated with a successful expansion of influenza vaccination among pregnant women in Nicaragua

BACKGROUND

Pregnant women are at risk of severe influenza disease and are a priority group for influenza vaccination programs. Nicaragua expanded recommendations to include influenza vaccination to all pregnant women in the municipality of Managua in 2013.

METHODS

We carried out a survey among 1,807 pregnant women who delivered at public hospitals in the municipality of Managua to evaluate the uptake of influenza vaccination and factors associated with vaccination.

RESULTS

We observed a high (71%) uptake of influenza vaccination among this population, with no differences observed by age, education or parity of the women. Having four antenatal visits and five or more visits were associated with receipt of influenza vaccination (AORs: 2.58; 95% CI: 1.15, 5.81, and 2.37; 95% CI: 1.12, 5.0, respectively). Also, receipt of influenza vaccination recommendation from a health care provider was positively associated with receipt of influenza vaccination (AOR: 14.22; 95% CI: 10.45, 19.33).

CONCLUSIONS

The successful expansion of influenza vaccination among pregnant women in the municipality of Managua may be due to ready access to free medical care and health care providers' recommendation for vaccination at health care clinics that received influenza vaccine.

Perceptions of Hong Kong Chinese women toward influenza vaccination during pregnancy

INTRODUCTION

Pregnant women are the highest priority group for seasonal influenza vaccination. However, their vaccination uptake remains suboptimal. The purpose of this study is to explore Hong Kong women's perceptions of the threat of influenza infection during pregnancy, the risks and benefits of influenza vaccination, and their decision-making processes.

METHODS

We used a qualitative descriptive design and recruited women who had just given births to a live infant from April to June 2011. Participants were recruited from a large teaching hospital in Hong Kong and were interviewed in the immediate postpartum period.

RESULTS

A total of 32 postpartum women were interviewed, and two had been vaccinated during pregnancy. Following thematic analysis, three themes emerged: perceived risk of influenza infection, perceived risk of influenza vaccine, and decision-making cues. Overall, participants held negative impressions about influenza vaccination during pregnancy, and they underestimated the threat of influenza to themselves and their fetus. They were also confused about the safety and efficacy of the influenza vaccine and the differences between preventive strategies and treatment for influenza. Most participants reported that their health care providers (HCPs) did not offer or recommend vaccination. Because of negative media reports about vaccination, participants were hesitant to receive the vaccine. Motivating forces for vaccine acceptance were a perceived high prevalence of circulating influenza during their pregnancy and HCP recommendations and reassurances that the vaccination was safe, effective, and beneficial for the fetus.

CONCLUSION

Vaccination promotion strategies need to focus on encouraging HCPs to take the initiative to discuss vaccination with their pregnant clients and provide accurate and unbiased information about the risks of influenza and the benefits of vaccination.

Interventions to increase the uptake of seasonal influenza vaccination among pregnant women: A systematic review

BACKGROUND

Pregnant women and their infants under 6 months of age infected with influenza have a high risk of serious morbidity and mortality. Influenza vaccine during pregnancy offers 3-for-1 benefits to pregnant women, fetuses and newborn infants. Current vaccination uptake rates during pregnancy, however, are often lower than other high-risk groups and the general population.

METHODS

We systematically reviewed evidence on the effectiveness of interventions to improve influenza vaccination coverage in pregnant women. Risk differences (RDs) were calculated from the included studies.

RESULTS

Eleven studies were included in the review, of which four were randomized controlled trials (RCTs). Three cohort studies assessed provider-focused interventions while four RCTs and one cohort study evaluated pregnant women-focused interventions. Two cohort studies and a prospective intervention study assessed the effectiveness of bundled interventions. No study solely assessed the effectiveness of interventions to enhance access to influenza vaccination. One moderate quality RCT showed that an influenza pamphlet, with or without a verbalized benefit statement, improved the vaccination rate (RD=0.26; RD=0.39). The other reviewed RCTs showed discordant results, with RDs ranging from -0.15 to 0.03. Although all observational studies significantly improved vaccination rates (RDs ranged from 0.03 to 0.44), the quality of the evidence varied.

CONCLUSIONS

There is a lack of effective interventions to increase the influenza vaccination rate in pregnant women. Based on the existing research, we recommend that clinicians provide influenza pamphlets to pregnant women with a verbalized statement about the benefits of influenza vaccine to newborns. Further high-quality RCTs are needed to develop successful maternal influenza vaccination programs. Increased clarity in reporting the content of interventions would help to improve the comparability and generalizability of the published studies.

2010 A(H1N1) vaccination in pregnant women in Brazil: identifying coverage and associated factors

We studied vaccination coverage and its associated factors in the 2010 pandemic influenza vaccination of Brazilian pregnant women. A cross-sectional study of pregnant women who had given birth was performed in a municipality in southern Brazil, in 2010. Data about vaccination against A(H1N1) and sociodemographic characteristics, morbidities and prenatal care were collected. Statistical analysis was performed using a Poisson regression. Coverage was 77.4%. Most were vaccinated in the public sector (97.6%) and in the second trimester (47%). Associated factors that increased vaccination were marriage, older age, first income quartile, prenatal care and influenza before pregnancy. Education and skin color were not significantly associated with vaccination. The vaccination campaign was extensive and exhibited no inequality. Prenatal care was the factor that most affected vaccination coverage, reflecting its importance for vaccination campaign success.

Effect of a hospital policy of not accepting free infant formula on in-hospital formula supplementation rates and breast-feeding duration

Objective

To investigate the effect of public hospitals in Hong Kong not accepting free infant formula from manufacturers on in-hospital formula supplementation rates and breast-feeding duration.

Design

Prospective cohort study.

Setting

In-patient postnatal units of four public hospitals in Hong Kong.

Subjects

Two cohorts of breast-feeding mother–infant pairs (n 2560). Cohort 1 (n 1320) was recruited before implementation of the policy to stop accepting free infant formula and cohort 2 (n 1240) was recruited after policy implementation. Participants were followed prospectively for 12 months or until they stopped breast-feeding.

Results

The mean number of formula supplements given to infants in the first 24 h was 2·70 (sd 3·11) in cohort 1 and 1·17 (sd 1·94) in cohort 2 (P<0·001). The proportion of infants who were exclusively breast-fed during the hospital stay increased from 17·7 % in cohort 1 to 41·3 % in cohort 2 (P<0·001) and the risk of breast-feeding cessation was significantly lower in cohort 2 (hazard ratio=0·81; 95 % CI 0·73, 0·90). Participants who non-exclusively breast-fed during the hospital stay had a significantly higher risk of stopping any or exclusive breast-feeding. Higher levels of formula supplementation also increased the risk of breast-feeding cessation in a dose–response pattern.

Conclusions

After implementation of a hospital policy to pay market price for infant formula, rates of in-hospital formula supplementation were reduced and the rates of in-hospital exclusive breast-feeding and breast-feeding duration increased.

A comprehensive review of influenza and influenza vaccination during pregnancy

Influenza is a highly infectious respiratory disease that can impose significant health risks leading to increased morbidity and mortality. Receiving influenza vaccination is the most important and effective means of preventing the infection and its related complications. During pregnancy, physiological changes increase susceptibility to influenza infection, and women contracting infectious diseases during pregnancy are more likely to have adverse pregnancy and neonatal outcomes. Influenza vaccination during pregnancy is safe for both pregnant women and their fetus, and pregnant women are now the highest priority group for vaccination. Despite the accumulated evidence of the benefits and safety of influenza vaccination during pregnancy, uptake among pregnant women remains suboptimal. Concerns about the vaccine's safety persist, and the fear of birth defects remains the predominant barrier to vaccination. Targeted interventions have been shown effective in enhancing influenza vaccination uptake among pregnant women. Reluctance to be vaccinated should be addressed by offering accurate information to counteract the misperceptions about the risk of influenza infection during pregnancy as well as to educate mothers about the safety and benefits of influenza vaccination. High-quality randomized controlled trials are recommended to evaluate the effectiveness of individual or multifaceted approaches to increase vaccine uptake.

Determinants of uptake of influenza vaccination among pregnant women - a systematic review

BACKGROUND

Pregnant women have the highest priority for seasonal influenza vaccine. However, suboptimal coverage has been repeatedly noted in this population. To improve vaccine uptake, reviewing the determinants of vaccination is of increasing importance.

METHODS

A detailed literature search was performed up to November 30, 2013 to retrieve articles related to uptake of influenza vaccination during pregnancy.

RESULTS

Forty-five research papers were included in the review. Twenty-one studies assessed the coverage of seasonal influenza vaccination, 13 studies assessed coverage of A/H1N1 pandemic vaccination and 11 studies assessed both. Vaccination uptake ranged from 1.7% to 88.4% for seasonal influenza, and from 6.2% to 85.7% for A/H1N1 pandemic influenza. Many pregnant women were unaware that they were at high risk for influenza and its complications during pregnancy. They were also more likely to underestimate the threat of influenza to themselves and their fetus. Moreover, they had substantial concerns about the safety and efficacy of the influenza vaccine during pregnancy. Negative media reports contributed to the perception that influenza vaccination during pregnancy was risky and could result in adverse pregnancy outcomes. Although health care providers' (HCPs) recommendations were consistently associated with vaccine uptake, most did not recommend the vaccine to their pregnant clients.

CONCLUSIONS

Influenza vaccination uptake among pregnant women is suboptimal and HCPs rarely recommend it. Positive vaccination recommendations from HCPs as well as direct access to the vaccine would likely substantially improve vaccination acceptance.

Burden of influenza infection in hospitalised children below 6 months of age and above in Hong Kong from 2005 to 2011

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Incidence of hospital admission with a diagnosis of influenza was highest in infants aged 2 month to <6 months (1762 per 100,000 person-years).

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Incidence of hospital admission with a diagnosis of influenza for children <18 y.o. was highest when A(H1N1)pdm09 was circulating in Apr 09/Mar 10.

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Laboratory confirmed influenza at one sentinel site was obtained in 1.6% of admissions aged 6 days to <6 months and in 5.2% aged 6 days to <18 years.

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.

Population-based hospitalization burden of influenza a virus subtypes and antigenic drift variants in children in Hong Kong (2004-2011)

OBJECTIVES

We aim to document and analyze influenza hospitalization burden in light of antigenic changes in circulating influenza viruses in Hong Kong.

METHODS

The pediatric age-specific rates of influenza A hospitalization in Hong Kong for 2004-2011 which encompassed the emergence of H1N1pdm09 were extrapolated from admissions to 2 hospitals that together catered for 72.5% of all pediatric admissions on Hong Kong Island. Influenza A was detected by immunofluorescence, culture and/or PCR on nasopharyngeal aspirates.

RESULTS

Influenza A caused high rates of hospitalization in children with year to year fluctuations. The highest hospitalization burden was seen with H1N1pdm09 in 2009. Additional factors affecting hospitalization were the proportion of viral circulation among different subtypes, and antigenic drifts. Taking these into effect, an H3N2 dominated year was not always associated with more hospitalizations than a 'seasonal' H1N1 year. Hospitalization burden was higher in seasons when drifted viruses of H1N1 or H3N2 dominated. No hospitalization was documented in infants <6 months of age during years when an undrifted virus circulated (2006 for H1N1 and 2008 for H3N2) but significant hospitalization was observed with a drifted or shifted virus (2004, 2005, 2007 and 2010 for H3N2, and 2009 for H1N1pdm09).

CONCLUSIONS

We documented a consistently high pediatric hospitalization burden of influenza A. Knowledge of antigenic changes and their proportion of circulation aids in the interpretation of impact of the subtypes. Year-to-year variation in hospitalization rates in young infants appeared to correlate with antigenic variation, lending support to the role of protection from maternal antibodies.

Brief education to increase uptake of influenza vaccine among pregnant women: a study protocol for a randomized controlled trial

Background

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.

Methods

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%.

Discussion

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.

Trial registration

This trial is registered with the Clinical Trials Registry at www.clinicaltrials.gov(NCT01772901).

Prevalence and predictors of maternal seasonal influenza vaccination in Hong Kong

BACKGROUND

Pregnant women infected with influenza virus are more likely to experience severe complications when compared with their non-pregnant peers. Yet influenza vaccine uptake is low among pregnant women. The purpose of this study was to assess the prevalence of seasonal influenza vaccine uptake among pregnant women in Hong Kong and to identify predictors of vaccine uptake.

METHODS

Using a multi-center cross-sectional design, we recruited 2822 new mothers during their immediate postpartum stay from all eight public obstetric hospitals in Hong Kong. We assessed antenatal maternal influenza vaccination status as well as health beliefs and perceptions toward influenza and influenza vaccination. Bivariable and multivariable logistic regression was used to identify the predictors of vaccination uptake.

RESULTS

Only 49 (1.7%; 95% CI 1.3-2.3%) participants were vaccinated during their pregnancy. Fear that the vaccine would cause harm to the fetus or themselves were the most common reasons for not being vaccinated. Being aware of the vaccination recommendations (OR=2.69; 95% CI 1.06-6.82), being advised by a health-care provider (OR=6.30; 95% CI 3.19-12.46), history of vaccination (OR=2.47; 95% CI 1.25-4.91), perceived susceptibility to influenza infection (OR=3.67; 95% CI 1.64-8.22), and perceived benefits of influenza vaccination (OR=9.98; 95% CI 3.79-26.24) were all independently associated with vaccination. Perceived barriers to vaccination (OR=0.17; 95% CI 0.07-0.40) were strongly associated with failure to vaccinate.

CONCLUSIONS

Low seasonal influenza vaccination uptake among Hong Kong pregnant women was related to a number of factors, all of which are amenable to interventions. Vaccination promotion strategies need to focus on encouraging health-care providers to discuss vaccination with their pregnant clients and in providing pregnant women with accurate and unbiased information about the risks of influenza infection and the benefits of vaccination.

The epidemiological and public health research response to 2009 pandemic influenza A(H1N1): experiences from Hong Kong

In recent years, Hong Kong has invested in research infrastructure to appropriately respond to novel infectious disease epidemics. Research from Hong Kong made a strong contribution to the international response to the 2009 influenza A (H1N1) pandemic (pH1N1). Summarizing, describing, and reviewing Hong Kong’s response to the 2009 pandemic, this article aimed to identify key elements of a real‐time research response. A systematic search in PubMed and EMBASE for research into the infection dynamics and natural history, impact, or control of pH1N1 in Hong Kong. Eligible articles were analyzed according to their scope. Fifty‐five articles were included in the review. Transmissibility of pH1N1 was similar in Hong Kong to elsewhere, and only a small fraction of infections were associated with severe disease. School closures were effective in reducing pH1N1 transmission, oseltamivir was effective for treatment of severe cases while convalescent plasma therapy has the potential to mitigate future pandemics. There was a rapid and comprehensive research response to pH1N1 in Hong Kong, providing important information on the epidemiology of the novel virus with relevance internationally as well as locally. The scientific knowledge gained through these detailed studies of pH1N1 is now being used to revise and update pandemic plans. The experiences of the research response in Hong Kong could provide a template for the research response to future emerging and reemerging disease epidemics.