Vaccination against pandemic influenza A/H1N1 among healthcare workers and reasons for refusing vaccination in Istanbul in last pandemic alert phase

Coverage of the HCWs as target population is one of the important determinants for the impact of vaccination. To determine the vaccination against the pandemic influenza A/H1N1 among HCWs, we conducted a cross-sectional questionnaire survey in a public hospital in Istanbul from December 7 to December 22, 2009. Out of total 941 HCWs 718 (76.3%) completed the questionnaires. Nearly one-fourth (23.1%) of the participants were vaccinated against pandemic influenza A/H1N1. Occupation (being a doctor), receiving seasonal influenza vaccine in 2009, agreement with safety of pandemic influenza A/H1N1 vaccine and being comprehend that HCWs have a professional responsibility for getting vaccinated was the strongest independent predictive factor for accepting the pandemic influenza A/H1N1 vaccine (p < .0001). The most frequent reasons for refusing pandemic vaccine were fear of side effects and doubts about vaccine efficacy. Among HCWs 59.6% were recommending pandemic influenza vaccination to a patient even if indicated. In conclusion vaccination against pandemic influenza A/H1N1 is insufficient among HCWs. Misinformed or inadequately informed HCWs are important barrier to pandemic influenza vaccine coverage of the general public also. Educational campaigns concerning HCWs should include evidence based and comprehensible information about possible adverse effects and their incidence besides the advantages of vaccine.     

Correlates of 2009 pandemic H1N1 influenza vaccine acceptance among middle and high school teachers in rural Georgia

BACKGROUND: Teachers play an essential role in the school community, and H1N1 vaccination of teachers is critical to protect not only themselves but also adolescents they come in contact within the classroom through herd immunity. School‐aged children have a greater risk of developing H1N1 disease than seasonal influenza. The goal of this study was to assess the relationship between attitudes toward H1N1 vaccination and vaccine acceptance among middle and high school teachers in rural Georgia. METHODS: Participants were recruited from 2 counties participating in a school‐based influenza vaccination intervention in rural Georgia. Data were collected from surveys distributed to middle and high school teachers in participating counties in September 2009 prior to implementing the interventions to increase vaccination against seasonal influenza. Multivariate logistic regression was used to assess the association between teachers' attitudes toward H1N1 vaccination and H1N1 vaccine acceptance, controlling for demographic variables. RESULTS: Among participants, 52.9% indicated that they would get the H1N1 vaccine. In multivariate analyses, H1N1 vaccine acceptance was associated with male gender (odds ratio[OR] = 3.67, p = .016), fear of contracting H1N1 (OR = 3.18, p = .025), and receipt of a seasonal influenza vaccine in the past year (OR = 3.07, p = .031). H1N1 vaccine acceptance was not significantly associated with age, race, perceived severity of H1N1, belief that the H1N1 vaccine would cause illness, or talking about H1N1 with friends. CONCLUSIONS: Teachers may play a pivotal role in school‐based H1N1 vaccinations. Understanding and addressing teachers' attitudes toward H1N1 vaccination may assist in future immunization efforts.     

Relationship between intention of novel influenza A (H1N1) vaccination and vaccination coverage rate

We carried out this study to describe the difference between intention to receive vaccine against influenza A (H1N1) before the vaccination campaign and actual vaccine coverage rate after vaccination campaign; and to find out the factors affecting the acceptability. We analyzed data on intention to receive vaccine against influenza A (H1N1) and actual vaccination coverage rate from IR (immunization registry). In a survey of pre-vaccination, the sample size was 1042 and the survey results were weighted with gender and age distribution for sample distribution to be similar to population distribution. Although the intention to receive vaccine against influenza A (H1N1) was high, the actual vaccination coverage was lower than their intention. The factors affecting their intention were the degree of fear for novel influenza A (H1N1), the possibility to be infected with the virus, priority for production of novel influenza vaccine between timing and safety, and belief for effectiveness of novel influenza vaccine. Besides 2009 influenza A (H1N1) vaccination experience developing to resolve the effecting factors on intentions to receive vaccine, which would be the effective way to prepare for anther pandemic in the future.     

The perceptions of and disincentives for receiving influenza A (H1N1) vaccines among chronic renal disease patients in Hong Kong

This article aims to demonstrate the perceptions of patients with chronic renal disease in Hong Kong towards the new vaccine for influenza A (H1N1), as well as the main disincentives. Little is known about the views of chronically ill patients on the H1N1 vaccine and even less about the underlying factors that motivate its low acceptance by this group. To explore these issues, this study adopted a qualitative approach by conducting in-depth, semi-structured interviews with 40 chronic renal disease patients in Hong Kong from December 2009 to March 2010. The participants were selected by purposive sampling from a patient with renal disease self-help alliance, which has over 4000 members with chronic renal diseases coming from nine public hospitals. Data were analysed using thematic content analysis. Although vaccination was portrayed as one of the most effective methods to prevent influenza A (H1N1), chronically ill participants in this study showed reluctance towards it. Six disincentives for them to receive H1N1 vaccines were identified: perceptions of H1N1 vaccine as unsafe, cultural perception of vaccines as harmful, the belief that seasonal influenza vaccines provided immunity against influenza A (H1N1), inaccessibility for receiving the H1N1 vaccine, worries in contracting infectious diseases from vaccination locations and the financial cost. As chronically ill patients are one of the high-risk groups who can suffer from severe complications from influenza, understanding the underlying social, cultural and perceptual factors that prevent their immunisation is crucial to the design of a public health policy responsive to their needs.     

Coverage and side effects of influenza A(H1N1) 2009 monovalent vaccine among primary health care workers

In June 2009, WHO declared the maximum phase alert against H1N1 pandemic flu. Health care workers (HCWs) are considered a strategic target for prevention of the occurrence of H1N1 influenza since they had the greatest risk of acquiring infection. The objectives of our study were (1) identifying the uptake of influenza A(H1N1) 2009 monovalent vaccine by primary health care workers in the southern part of Cordoba, and (2) reporting of the adverse events occurred after vaccination. We followed 240 HCWs in 12 primary health care centres at southern part of Cordoba for vaccine uptake and the occurrence of adverse events. The coverage rate with H1N1 vaccine was 20.5% which was lower compared to seasonal influenza vaccination rate 44.2% in 2009. Males had higher H1N1 vaccination rate compared to females with no significant difference. Senior HCWs complied more with seasonal influenza vaccine while this finding was not consistent with H1N1 vaccination. Multivariate analysis showed that the only independent variable that affected H1N1 vaccine was the compliance to the seasonal flu vaccine in the past three years with OR 5.1 and 95% CI (2.4-10.8). Adverse events occurred among 26.5% of those who complied with H1N1 vaccination. Those were local pain, irritation and induration at site of injection (38.5%), fever (15.4%), fever cough and rhinorrhea (15.4%) generalized pain and lumber pains (23.1%). The low vaccination rate in this study is consistent with previous studies done in many parts of the world and in Spain. Further studies should be done to explore the factors that hindered the uptake and resistance of HCWs to vaccination to H1N1 vaccine.     

Serologic survey of pandemic influenza A (H1N1 2009) in Beijing, China

Objective

To examine the frequency and distribution of antibodies against pandemic influenza A (H1N1 2009) [H1N1] in populations in Beijing and elucidate influencing factors.

Methods

In January 2010, a randomized serologic survey of pandemic influenza A (H1N1 2009) was carried out. Six districts that were randomly selected with a total of 4601 participants involved in the survey have their antibody level tested by hemagglutination inhibition assay.

Results

Among the 4601 participants, the overall seropositive rate for pandemic influenza A (H1N1 2009) antibodies was 31.7%. The seropositivity prevalence in participants who received the pandemic H1N1 vaccination was 60.9%. Only 53.1% of the pandemic influenza A (H1N1 2009) seropositive individuals who had not received the vaccination experienced respiratory tract infection symptoms. Multivariate logistic regression revealed that factors such as age, occupation, dwelling type, whether the participant's family included students in school, and the vaccination history with pandemic influenza A (H1N1 2009) were associated with antibody titers (p < 0.05).

Conclusions

Our data indicated that almost 30.0% of the residents had appropriate antibody titers against pandemic influenza A (H1N1 2009) in Beijing, and these titers may provide an immune barrier.     

成都市青羊区首批甲型H1N1流感疫苗接种回访调查

目的回访调查了解甲型H1N1流感疫苗应急接种率,以及接种对象接受或拒绝应急接种的原因和自述的疫苗接种后不良反应发生情况。方法采用分层抽样和问卷调查的方式,在疫苗接种后第14天对应接种对象进行回访调查。结果 4225名被访者中,2595人(61.42%)接受甲型H1N1l流感疫苗应急接种,其中399人(15.38%)的受种者在接种后14d内出现各种身体不适。在拒绝接种人群中32.82%的被访者认为新型疫苗安全性尚不可靠。结论首批接种对象接受接种率不高,部分拒绝接种者对疫苗安全性、可靠性不信任。接种的甲型H1N1流感疫苗接种后不良反应发生率与产品说明书标识的不良反应基本一致。     

Correlates of 2009 H1N1 influenza vaccination among day care-aged children, Miami-Dade County

Background

The aim of this study was to assess factors influencing 2009 H1N1 influenza vaccination among a demographically diverse group of day care-aged children. Day care children were chosen because they were an initial target group for vaccination and are at higher risk of influenza infection than children cared for at home.

Methods

A cross-sectional study was conducted from March to May 2010 among parents of day care aged children in 13 day care facilities in Miami-Dade County. Data was collected by an anonymous self-administered two-page 20 question survey which consisted of demographic variables and information regarding 2009 H1N1 influenza vaccine knowledge, attitude and acceptance. Data was analyzed using SAS to conduct both bivariate and multivariate analyses.

Results

There were 773 participants in the study. The response rate ranged from 42% to 72.2% among day care centers. A total of 172 parents (22.3%) and 225 (29.1%) children had received the 2009 H1N1 influenza vaccine. Non-Hispanic White and Black parents were more likely to vaccinate their children than Hispanic and Haitian parents. Primary reasons for non-vaccination included vaccine safety (36.7%) and side effects (27.1%). Among parents who spoke with a health care professional, 274 (61.4%) stated the health care professional recommended the vaccine.

Conclusion

Misperceptions about influenza vaccination among parents created a barrier to 2009 H1N1 influenza vaccination. Parents who got the vaccine, who believed the vaccine was safe and whose children had a chronic condition were more likely to immunize their children. Clear, reliable and consistent vaccine information to the public and health care providers and initiatives targeting minority groups may increase vaccination coverage among this population.     

Vaccination for 2009 pandemic H1N1 influenza A did not induce conserved epitope-specific memory CD8 T cell responses in HIV+ northern Thai children

The influenza virus causes severe illness in susceptible populations, including children and people living with human immunodeficiency virus (HIV). Here, we investigated cell-mediated immune responses (CMI) against influenza CD8 T cell conserved epitopes in HIV-infected (HIV+) northern Thai children following the 2009 pandemic H1N1 influenza A vaccination. Sixty HIV+ children were vaccinated with two doses of the 2009 pandemic influenza vaccine and their CD8 T cell responses were assessed. We found no significant differences in the increase of cytokines-producing and CD107a-expressing CD8+ T cells or CD8+ memory T cells in response to pooled conserved epitopes stimulation in vitro between children with different serologic responses to the vaccine at all time points of the study. Our results suggest that the 2009 pandemic H1N1 vaccine did not induce the conserved epitope-specific immune responses in HIV+ children. Vaccine design and vaccination strategy against influenza in these populations warrant further studies.     

Monitoring pandemic influenza A(H1N1) vaccination coverage in Germany 2009/10 - results from thirteen consecutive cross-sectional surveys

To monitor pandemic influenza A(H1N1) vaccine uptake during the vaccination campaign in Germany 2009/10, thirteen consecutive cross-sectional telephone-surveys were performed between November 2009 and April 2010. In total 13,010 household-interviews were conducted. Vaccination coverage in persons >14 years of age remained low, both in the general population (8.1%; 95%CI: 7.4-8.8) and in specific target groups such as healthcare workers and individuals with underlying chronic diseases (12.8%; 95%CI: 11.4-14.4). Previous vaccination against seasonal influenza was a main factor independently associated with pandemic influenza vaccination (Odds ratio = 8.8; 95%CI: 7.2-10.8). The campaign failed to reach people at risk who were not used to receive their annual seasonal influenza shot.     

Pandemic H1N1 vaccine requires the use of an adjuvant to protect against challenge in naïve ferrets

In the context of an A/H1N1 influenza pandemic situation, this study demonstrates that heterologous vaccination with an AS03-adjuvanted 2008/2009 seasonal trivalent and pandemic H5N1 monovalent split vaccine conferred partial protection in influenza-naïve ferrets after challenge with the influenza pandemic H1N1 A/The Netherlands/602/09 virus. Further, unlike saline control and non-adjuvanted vaccine, it was shown that immunization of naïve ferrets with an AS03-adjuvanted pandemic H1N1 A/California/7/09 influenza split vaccine induced increased antibody response and enhanced protection against the challenge strain, including significant reduction in viral shedding in the upper respiratory tract and reduced lung pathology post-challenge. These results show the need for vaccination with the adjuvanted vaccine to fully protect against viral replication and influenza disease in unprimed ferrets.     

AF03-adjuvanted and non-adjuvanted pandemic influenza A (H1N1) 2009 vaccines induce strong antibody responses in seasonal influenza vaccine-primed and unprimed mice

Pandemic influenza vaccines have been manufactured using the A/California/07/2009 (H1N1) strain as recommended by the World Health Organization. We evaluated in mice the immunogenicity of pandemic (H1N1) 2009 vaccine and the impact of prior vaccination against seasonal trivalent influenza vaccines (TIV) on antibody responses against pandemic (H1N1) 2009. In naïve mice, a single dose of unadjuvanted H1N1 vaccine (3 μg of HA) was shown to elicit hemagglutination inhibition (HI) antibody titers >40, a titer associated with protection in humans against seasonal influenza. A second vaccine dose of pandemic (H1N1) 2009 vaccine strongly increased these titers, which were consistently higher in mice previously primed with TIV than in naïve mice. At a low immunization dose (0.3 μg of HA), the AF03-adjuvanted vaccine elicited higher HI antibody titers than the corresponding unadjuvanted vaccines in both naïve and TIV-primed animals, suggesting a potential for antigen dose-sparing. These results are in accordance with the use in humans of a split-virion inactivated pandemic (H1N1) 2009 vaccine formulated with or without AF03 adjuvant to protect children and young adults against influenza A (H1N1) 2009 infection.     

Acceptance of vaccination during pregnancy: experience with 2009 influenza A (H1N1) in the Netherlands

Objectives

In 2009, the Dutch government advised pregnant women to get vaccinated against influenza A (H1N1). A study was set up to gain insight into vaccination coverage and reasons why pregnant women seek vaccination or not.

Methods

We invited 14,529 pregnant women to complete an internet survey on vaccination during pregnancy in general and against 2009 influenza A (H1N1). Differences in background characteristics between unvaccinated and vaccinated women were investigated. Prediction analyses were carried out to determine which survey statement had the greatest impact on vaccination status or intention to get vaccinated during pregnancy.

Results

Of the 2993 included respondents, 63% reported to be vaccinated against 2009 influenza A (H1N1). Vaccination coverage was higher among older birth cohorts, women who had been pregnant before, women with underlying medical conditions, and women who reported no defined ‘life philosophy’. Protection of the child (after birth), the government's advice and possible harmful effects of the vaccine for the unborn child had the greatest predictive value for vaccination status. With regards vaccination during future pregnancies, 39% had a positive intention to obtain vaccination and 45% were neutral. The government's advice was the strongest predictor for intention. Furthermore, women expressed concern over lack of sufficient knowledge about vaccine safety.

Conclusions

A considerable number of pregnant women in the Netherlands reported to be vaccinated against 2009 influenza A (H1N1). The challenge for the government in the future will be to provide pregnant women and health care professionals with sufficient and clear information about disease severity and the benefits and safety of vaccination.     

Determinants of 2009 A/H1N1 Influenza Vaccination Among Pregnant Women in Hong Kong

During the 2009–2010 A/H1N1 influenza pandemic, pregnant women infected with the virus experienced excess morbidity and mortality when compared with other groups. Once a vaccine was available, pregnant women were a priority group for vaccination. Only a few studies have reported on the uptake of 2009 A/H1N1 influenza vaccine among pregnant women during the pandemic and none were from Asia. The purpose of this study was to examine factors associated with 2009 A/H1N1 influenza vaccine uptake among pregnant women in Hong Kong. Using a multi-center, cross-sectional design, we recruited 549 postpartum women from four post-natal wards in Hong Kong over a 4-month period during the second wave of the A/H1N1 influenza pandemic in the winter and spring of 2010. Only 6.2% (n = 34) of participants had received the 2009 A/H1N1 influenza vaccine and 4.9% (n = 27) had received the seasonal influenza vaccine. The most common reasons for not receiving the 2009 A/H1N1 vaccine were fear of causing harm to themselves or their fetus. A high knowledge level (OR = 19.06; 95% CI 5.55, 65.48), more positive attitudes (OR = 3.52; 95% CI 1.37, 9.07), and having a family member who had the 2009 A/H1N1 influenza vaccine (OR = 7.69; 95% CI 2.92, 20.19) were independently and positively associated with vaccination. Study results show an unacceptably low uptake of the pandemic A/H1N1 influenza vaccine among pregnant women in Hong Kong. Interventions to increase influenza vaccine knowledge and uptake among this group should be a priority for future pandemic planning and seasonal vaccination campaigns.     

Immunogenicity of inactivated 2009 H1N1 influenza vaccine in pediatric liver transplant recipients

To assess the safety and immunogenicity of 2009 H1N1 influenza vaccination, 13 pediatric liver transplant recipients and 31 immunocompetent controls received inactivated influenza vaccine without adjuvant according to Japanese guidelines. Serious adverse events and acute allograft rejections were not observed in participants. Seroprotection rates (hemagglutinin-inhibition (HI) antibody titer ≥ 1:40) were 53.8% among recipients and 58.1% among controls (p = 0.797). Seroconversion rates (4-fold or more HI antibody rise) were 46.2% for the recipient group and 51.6% for the control group (p = 0.741). Geometric mean titers were elevated after vaccination in both groups. In comparison with the seasonal influenza vaccination, the seroconversion rate for 2009 H1N1 appeared to be higher than that for seasonal influenza antigens, and the seroprotection rate for 2009 H1N1 clearly increased after vaccination. These findings suggest that pediatric liver transplant patients may respond safely to inactivated 2009 H1N1 influenza vaccines in a manner similar to immunocompetent children.     

Central European Vaccination Advisory Group (CEVAG) guidance statement on recommendations for 2009 pandemic influenza A(H1N1) vaccination

The 2009 influenza A(H1N1) pandemic is markedly different from seasonal influenza with the disease affecting the younger population and a larger than expected number of severe or fatal cases has been seen in pregnant women, obese people and in people who were otherwise healthy. In Europe, influenza activity caused by the 2009 influenza A(H1N1) virus has passed the winter peak with nearly all countries now reporting lower influenza activity. However, although the rate of 2009 pandemic influenza A(H1N1) is declining, fatal cases continue to be reported and the future is hard to predict. The most effective protection against influenza is vaccination and increasing vaccine coverage is the only way to eliminate uncertainties regarding possible future waves of 2009 pandemic influenza A(H1N1). Recommendations have been developed for several central European countries but there is no clear or uniform definition with respect to priority groups or age groups who should receive vaccination. This paper contains the Central European Vaccination Advisory Group (CEVAG) guidance statement on recommendations for the vaccination of adults and children against 2009 pandemic influenza A(H1N1). CEVAG recommends vaccination of all health-care workers, pregnant women, children ≥6 months and <2 years of age and people with chronic medical conditions as a first priority.     

Nurses' vaccination against pandemic H1N1 influenza and their knowledge and other factors

This study aimed to estimate the vaccination coverage against the pandemic H1N1 influenza in a group of nurses and determine the factors associated with their vaccination behaviours. An anonymous, self-administered questionnaire was distributed to a convenience sample of nurses who were enrolled on continuing professional education courses in a university in London. The survey response rate was 77.7% (n=522). A total of 172 (35.2%) nurses reported receiving the pandemic H1N1 vaccine in the 2009-2010 influenza season and only 22.3% of them had the intent to accept the vaccine in the next season. Compared to nurses with low knowledge scores, those with high knowledge scores were more likely to receive the pandemic H1N1 vaccine (p=0.017), recommend the vaccine to their patients (p=0.003), and have the willingness to recommend vaccination to patients in the future (p=0.009). There was a higher vaccination rate among nurses with higher risk perception scores than with lower scores (p=0.001). A small, positive correlation between H1N1 knowledge and risk perception scores was identified (p<0.001) indicating that a high knowledge level was associated with high levels of risk perception. More male nurses received the H1N1 vaccine than females (p<0.001) and there were a significant differences in the uptake among nurses from different clinical specialty groups (p<0.001). About half of the vaccinated nurses reported the intent to be vaccinated again but only 8.1% of the unvaccinated nurses had the intent to receive the vaccine in the next season (p<0.001). The pandemic H1N1 2009 influenza vaccination coverage among this nurse sample was sub-optional. Lack of knowledge and risk perception were predictors associated with the nurses' vaccination behaviours. The identified knowledge items should be addressed in future vaccination campaigns. The hindrances associated with continuing vaccination decision-making and factors contributing to the different vaccination coverage among clinical specialty groups require further exploration.     

云南保山市甲型H1N1流感病毒裂解疫苗应急接种效果分析

目的 了解保山市2009～2010年甲型H1N1流感病例的分布特征及疫苗控制效果,为甲型H1N1流感防控及疫苗的科学使用提供依据.方法 回顾性分析接种疫苗前后保山市甲型H1N1流感发病人群的分布特征,并比较接种前后甲型H1N1流感发生情况.结果 该市总人口接种率为6.26％,其中学生接种率最高为73.44％.甲型H1...     

An elastase-dependent attenuated heterologous swine influenza virus protects against pandemic H1N1 2009 influenza challenge in swine

Influenza virus infections continue to cause production losses in the agricultural industry in addition to being a human public health concern. The primary method to control influenza is through vaccination. However, currently used killed influenza virus vaccines must be closely matched to the challenge virus. The ability of an elastase-dependent live attenuated influenza A virus was evaluated to protect pigs against the pandemic H1N1 2009 influenza virus. Pigs vaccinated intranasally or intratracheally with the elastase-dependent swine influenza virus (SIV) vaccine had significantly reduced macroscopic and microscopic lung lesions and lower viral loads in the lung and in nasal swabs. Thus, elastase-dependent SIV mutants can be used as live-virus vaccines against swine influenza in pigs. In addition, low levels of cross-neutralizing antibodies to H1N1 2009 were elicited prior to challenge by the swine adapted H1N1 avian strain vaccine.