Responses to pandemic AS03-adjuvanted A/California/07/09 H1N1 influenza vaccine in human immunodeficiency virus-infected individuals

ABSTRACT: BACKGROUND: Influenza infection may be more serious in human immunodeficiency virus (HIV)-infected individuals, therefore, vaccination against seasonal and pandemic strains is highly advised. Seasonal influenza vaccines have had no significant negative effects in well controlled HIV infection, but the impact of adjuvanted pandemic A/California/07/2009 H1N1 influenza hemaglutinin (HA) vaccine, which was used for the first time in the Canadian population as an authorized vaccine in autumn 2009, has not been extensively studied. OBJECTIVE: Assess vaccine-related effects on CD4+ T cell counts and humoral responses to the vaccine in individuals attending the Newfoundland and Labrador Provincial HIV clinic. METHODS: A single dose of ArepanrixTM split vaccine including 3.75 mug A/California/07/2009 H1N1 HA antigen and ASO3 adjuvant was administered to 81 HIV-infected individuals by intramuscular injection. Plasma samples from shortly before, and 1--5 months after vaccination were collected from 80/81 individuals to assess humoral anti-H1N1 HA responses using a sensitive microbead-based array assay. Data on CD4+ T cell counts, plasma viral load, antiretroviral therapy and patient age were collected from clinical records of 81 individuals. RESULTS: Overall, 36/80 responded to vaccination either by seroconversion to H1N1 HA or with a clear increase in anti-H1N1 HA antibody levels. Approximately 1/3 (28/80) had pre-existing anti-H1N1 HA antibodies and were more likely to respond to vaccination (22/28). Responders had higher baseline CD4+ T cell counts and responders without pre-existing antibodies against H1N1 HA were younger than either non-responders or responders with pre-existing antibodies. Compared to changes in their CD4+ T cell counts observed over a similar time period one year later, vaccine recipients displayed a minor, transient fall in CD4+ T cell numbers, which was greater amongst responders. CONCLUSIONS: We observed low response rates to the 2009 pandemic influenza vaccine among HIV-infected individuals without pre-existing antibodies against H1N1 HA and a minor transient fall in CD4+ T cell numbers, which was accentuated in responders. A single injection of the ArepanrixTM pandemic A/California/07/2009 H1N1 HA split vaccine may be insufficient to induce protective immunity in HIV-infected individuals without pre-existing anti-H1N1 HA responses.     

Contemporary seasonal influenza A (H1N1) virus infection primes for a more robust response to split inactivated pandemic influenza A (H1N1) Virus vaccination in ferrets

Human influenza pandemics occur when influenza viruses to which the population has little or no immunity emerge and acquire the ability to achieve human-to-human transmission. In April 2009, cases of a novel H1N1 influenza virus in children in the southwestern United States were reported. It was retrospectively shown that these cases represented the spread of this virus from an ongoing outbreak in Mexico. The emergence of the pandemic led to a number of national vaccination programs. Surprisingly, early human clinical trial data have shown that a single dose of nonadjuvanted pandemic influenza A (H1N1) 2009 monovalent inactivated vaccine (pMIV) has led to a seroprotective response in a majority of individuals, despite earlier studies showing a lack of cross-reactivity between seasonal and pandemic H1N1 viruses. Here we show that previous exposure to a contemporary seasonal H1N1 influenza virus and to a lesser degree a seasonal influenza virus trivalent inactivated vaccine is able to prime for a higher antibody response after a subsequent dose of pMIV in ferrets. The more protective response was partially dependent on the presence of CD8(+) cells. Two doses of pMIV were also able to induce a detectable antibody response that provided protection from subsequent challenge. These data show that previous infection with seasonal H1N1 influenza viruses likely explains the requirement for only a single dose of pMIV in adults and that vaccination campaigns with the current pandemic influenza vaccines should reduce viral burden and disease severity in humans.     

Immunogenicity and safety of the influenza A/H1N1 2009 inactivated split-virus vaccine in young and older adults: MF59-adjuvanted vaccine versus nonadjuvanted vaccine

Since initial reports in April 2009, the pandemic influenza A (H1N1) virus has spread globally. Influenza vaccines are the primary method for the control of influenza and its complications. We conducted a multicenter clinical trial to evaluate the immunogenicity and safety of H1N1 vaccine (Green Cross Co.) in young adults (18 to 64 years) and the elderly (≥ 65 years) using a two-dose regimen, with the doses administered 21 days apart. Three different regimens of hemagglutinin antigen were comparatively analyzed: 3.75 μg (MF59 adjuvanted) versus 7.5 μg (MF59 adjuvanted) versus 15 μg (nonadjuvanted) in young adults and 3.75 μg (MF59 adjuvanted) versus 7.5 μg (MF59 adjuvanted) in the elderly. In young adults, all three vaccine regimens met the European Agency for the Evaluation of Medicinal Products (EMA) criteria after the first dose. In the elderly, on day 21 after the first dose, the rates of seroprotection and seroconversion were significantly higher for the 7.5-μg dose of MF59 adjuvanted vaccine than for the 3.75-μg dose (58.0% versus 44.3% [P = 0.03] and 53.7% versus 37.2% [P < 0.01], respectively). After the second dose, the geometric mean titer (GMT) increment was blunted with a 15-μg dose of nonadjuvanted vaccine, whereas the GMT increased about 2-fold with MF59 adjuvanted vaccines. In conclusion, a single 7.5-μg dose of MF59 adjuvanted vaccine would have a practical advantage over a two-dose, 3.75-μg, MF59 adjuvanted vaccine priming schedule. Following a two-dose priming schedule, the increase in hemagglutinin inhibition titers was higher with MF59 adjuvanted vaccine than with nonadjuvanted vaccine.     

A pandemic H1N1 influenza virus-like particle vaccine induces cross-protection in mice

Influenza virus-like particles (VLPs) represent promising alternative vaccines. However, it is necessary to demonstrate that influenza VLPs confer cross-protection against antigenically distinct viruses. In this study, a VLP vaccine comprising hemagglutinin (HA) and M1 from the A/California/04/2009 (H1N1) were used and its ability to induce cross-protective efficacy against heterologous viruses A/PR/8/34 (H1N1) and A/New Caledonia/20/99 (H1N1) in mice was assessed. Vaccination with 2009 H1 VLPs induced significantly higher levels of IgG cross-reactive with these heterologous viruses after the second boost compared to after the prime or first boost. Lung virus titers also decreased significantly and the lung cross-reactive IgG response after lethal virus challenge was significantly greater in immunized mice compared to naïve mice. Vaccinated mice showed 100% protection against A/PR/8/34 and A/Caledonia/20/99 viruses with only moderate body weight loss and induction of cross-reactive recall, IgG antibody-secreting cell responses. The variations in HA amino acid sequences and antigenic sites were determined and correlated with induction of cross-protective immunity. These results indicate that VLPs can be used as an effective vaccine that confers cross-protection against antigenically distinct viruses.     

Aprotinin-induced inhibition of pandemic influenza virus A(H1N1) reproduction

Infectivity of pandemic influenza virus A(H1N1) infectivity is shown to be activated through proteolytic cleavage of hemagglutinin HA0 --> HA1 + HA2 during virus propagation in the human intestinal cell line Caco-2 and chicken embryonated eggs. Injection of aprotinin, a natural serine protease inhibitor, into the liquid culture or allantoic cavity of chicken embryos inhibited the proteolysis of the viral HA0 and suppressed the proteolytic activation of the synthesized virus and its multicycle replication. These data allow aprotinin to be recommended as an antiviral drug for the treatment of swine influenza in humans.     

中国甲型H1N1流感疫苗质量分析

目的 通过对甲型H1N1流感疫苗批签发中的检测数据进行分析和比较,了解我国甲型H1N1流感疫苗的总体质量状况.方法 按照各企业注册标准对甲型H1N1流感疫苗进行资料审查和全项检定,对关键项目检测结果进行分析和比较.结果 甲型H1N1流感疫苗批签发总体合格率为99.8%,有效成分血凝素含量在标示量的90%～103%范围内,甲醛、卵清蛋白和内毒素含量等安全性指标均符合规定.结论 我国甲型H1N1流感疫苗各项检测总体情况良好,能充分保证疫苗的安全性和有效性,中国食品药品检定研究院的独立检验和批签发对保证上市疫苗的质量发挥了重要作用.

Abstract：

Objective To analyze the laboratory testing data of 2009 pandemic influenza A (H1N1) vaccines during lot release procedure, thus to know the overall quality status of this vaccines.Methods National Institutes for Food and Drug Control(NIFDC) carried out the laboratory test according to the specifications of each manufacture, and the results was analyzed and compared between manufacturer and NIFDC. Results 99.8% of vaccines batches were released by NIFDC, haemagglutinin contents were between 90% to 103 % of labeled values, and testing results slightly differ between manufactures and NIFDC,other items related to safety were all meet specifications. Conclusion The quality of H1N1 vaccines in China were satisfying, the lot release and independent test by NIFDC play important roles to ensure the vaccines' quality.     

In vitro assessment of the allergenicity of novel MF59-adjuvanted pandemic H1N1 influenza vaccine produced in dog kidney cells

A licensed inactivated MF59-adjuvanted seasonal influenza vaccine (Optaflu) produced in canine kidney cells (MDCK 33016-PF) contained no egg proteins and did not trigger degranulation in rat basophilic leukemia (RBL) cells passively sensitized with human anti-dog IgE, supporting its safe use in dog-allergic individuals. The cell-derived pandemic H1N1 influenza vaccine was also adjuvanted with the emulsion adjuvant MF59, and support for its similar safe use was sought. We sought to evaluate in vitro allergenicity of the MF59-adjuvanted cell-derived pandemic H1N1 influenza vaccine in subjects with dog allergy, with a mediator release assay. RBL-2H3 cells transfected with human Fcε receptor type 1 were sensitized with sera from adult dog-allergic subjects and stimulated with serial dilutions of pandemic H1N1 influenza vaccine and dog dander extract. β-N-hexosaminidase release (NHR) was used as a marker of RBL degranulation.. Median dog dander-specific IgE in 30 dog-allergic subjects was 27.7 kUA/L (range 10.1; > 100); and in 5 dog non-allergic subjects was < 0.35 kUA/L (UniCAP system). Median (range) maximum NHR in dog-allergic subjects was: pandemic H1N1 influenza vaccine 1.1% (0; 4.4) and dog dander 6.9% (0.7; 37.3), P < 0.001. In conclusion, MF59-adjuvanted pandemic H1N1 influenza vaccine produced in continuous canine kidney cells did not trigger degranulation in RBL cells passively sensitized with human anti-dog IgE, supporting its safe use in dog-allergic individuals.     

Superior protection provided by a single dose of MF59-adjuvanted whole inactivated H5N1 influenza vaccine in type 1 diabetic mice

Vaccination is the preferred strategy for the prevention of influenza virus infection. Both H5N1 subunit and split vaccines have shown poor immunogenicity in clinical trials thus far. Therefore, it is urgent to develop more immunogenic and antigen-sparing H5N1 influenza vaccines as well as safe and effective adjuvants for humans, especially for immunocompromised people such as patients with diabetes mellitus. In this study, the protective effect of an MF59-adjuvanted inactivated whole-virion H5N1 vaccine was investigated in a type 1 diabetic mouse model. Mice (both healthy and diabetic) were immunized with a single dose of the inactivated vaccine, alone or adjuvanted with MF59 or Al(OH)₃. After four weeks, mice were challenged with a lethal dose of H5N1 virus. Antibody responses, survival rates, lung virus titers and body weight changes were tested. The results showed that addition of MF59 or Al(OH)₃ to the vaccine enhanced the antibody responses in both healthy mice and diabetic mice, but the MF59-adjuvanted groups showed higher antibody responses than the Al(OH)₃-adjuvanted groups. The addition of MF59 or Al(OH)₃ to the vaccine led to a conversion of the immune response from a Th1-biased response to an enhanced mixed Th1/Th2 profile. The MF59-adjuvanted inactivated whole-virion H5N1 vaccine provided superior protection in type 1 diabetic mice to either the vaccine alone or the vaccine adjuvanted with Al(OH)₃.     

Fatal cases of 2009 pandemic influenza A (H1N1) in Korea

The aim of this study was to describe the features of deaths associated with the 2009 pandemic influenza A (H1N1) by 26 November 2009 in Korea. We collected standardized case reports on 115 confirmed deaths through a nationwide enhanced influenza surveillance system. The median age was 61 yr (interquartile range [IQR], 0.2-97 yr) and 58 (50.4%) were females. The case fatality rate was estimated as 16 per 100,000 cases. The age-related mortality rate had a J-shaped curve. Eighty-three patients (72.2%) had at least 1 underlying medical disease. Bacterial co-infections were detected in the blood or sputum specimens from 34 patients. Of the 63 patients who were hospitalized in the intensive care unit (ICU), the median time from symptom onset to hospital admission was 2 days (IQR, 0-22 days), and the median time from hospitalization to ICU admission was 1 day (IQR, 0-17 days). Neuraminidase inhibitors were administered to 100 patients (87.0%), 36% of whom began treatment within 2 days. In conclusion, fatal cases from the 2009 influenza A (H1N1) infection in Korea are mainly aged individuals with underlying disease, and associated with pneumonia, bacterial co-infections, and multi-organ failure.     

Pandemic influenza A (H1N1) 2009 vaccine: an update

The world witnessed a the first influenza pandemic in this century and fourth overall since first flu pandemic was reported during the World War I. The past experiences with influenza viruses and this pandemic of H1N1 place a consider-able strain on health services and resulted in serious illnesses and a large number of deaths. Develop-ing countries were declared more likely to be at risk from the pandemic effects, as they faced the dual problem of highly vulnerable populations and limited resources to respond H1N1. The public health experts agreed that vaccination is the most effective ways to mitigate the negative effects of the pandemic. The vaccines for H1N1 virus have been used in over 40 countries and administered to over 200 million people helped in a great way and on August 10, 2010, World Health Organization (WHO) announced H1N1 to be in postpandemic period. But based on knowledge about past pandemics, the H1N1 (2009) virus is expected to continue to circulate as a seasonal virus and may undergo some agenic-variation. As WHO strongly recommends vaccination, vigilance for regular updating of the composition of influenza vaccines, based on an assessment of the future impact of circulating viruses along with safety surveillance of the vaccines is necessary. This review has been done to take a stock of the currently available H1N1 vaccines and their possible use as public health intervention in the postpandemic period.     

Reduced antibody responses to the pandemic (H1N1) 2009 vaccine after recent seasonal influenza vaccination

The vaccination program against the 2009 pandemic H1N1 influenza virus (2009 H1N1) provided a unique opportunity to determine if immune responses to the 2009 H1N1 vaccine were affected by a recent, prior vaccination against seasonal influenza virus. In the present study, we studied the immune responses to the 2009 H1N1 vaccine in subjects who either received the seasonal influenza virus vaccination within the prior 3 months or did not. Following 2009 H1N1 vaccination, subjects previously given a seasonal influenza virus vaccination exhibited significantly lower antibody responses, as determined by hemagglutination inhibition assay, than subjects who had not received the seasonal influenza virus vaccination. This result is compatible with the phenomenon of "original antigenic sin," by which previous influenza virus vaccination hampers induction of immunity against a new variant. Our finding should be taken into account for future vaccination programs against pandemic influenza virus outbreaks.     

A novel intranasal virus-like particle (VLP) vaccine designed to protect against the pandemic 1918 influenza A virus (H1N1)

We have prepared a virus-like particle (VLP) vaccine bearing the surface glycoproteins HA and NA of the 1918 influenza A virus by infecting Sf9 cells with a quadruple recombinant baculovirus that expresses the four influenza proteins (HA, NA, M1, and M2) required for the assembly and budding of the VLPs. The presence of HA and M1 in the purified VLPs was confirmed by Western blot, and that of NA by a neuraminidase enzymatic assay. For in vivo studies, the 1918 VLP vaccine was formulated with or without an oligonucleotide containing two CpG motifs and administered in two doses 2 wk apart via the intranasal route. The antibody titers in mice immunized with VLP vaccines were higher than in mice vaccinated with an inactivated swine virus (H1N1) control, when CHO cells expressing 1918 HA were used as antigen. The opposite result was obtained when disrupted swine virus was the antigen for the ELISA test. Vaccine efficacy was evaluated by challenging immunized mice with the 1918 antigenically related influenza virus A/swine/Iowa/15/30 (H1N1) and measuring viral titers in the upper and lower respiratory tract. Mice immunized with VLP vaccine plus CpG demonstrated significantly lower viral titers in the nose and lungs than did the control on days 2 and 4 postchallenge and completely cleared the virus by day 6. Furthermore, they did not show symptoms of disease although there was a minor decrease in body weight. Mice vaccinated with VLP alone also demonstrated significantly lower viral titers in the nose and lungs than did the placebo group as well as the inactivated virus group on days 4 and 6 postchallenge. These results suggest that it is feasible to make a safe and immunogenic vaccine to protect against the extremely virulent 1918 virus, using a novel and safe cell-based technology.     

rapidSTRIPE H1N1 test for detection of the pandemic swine origin influenza A (H1N1) virus

The rapidSTRIPE H1N1 test, based on a nucleic acid lateral-flow assay, has been developed for diagnosis of a swine-origin influenza A (H1N1) virus. This test is simple and cost-effective and allows specific detection of the S-OIV A (H1N1) virus from swab sampling to final detection on a lateral-flow stripe within 2 to 3 h.     

Pathologic study of pandemic influenza A (H1N1) 2009 cases from India

The pandemic influenza A (H1N1) 2009 originated in Mexico and rapidly spread to the United States and many other countries. India reported the first pandemic influenza case in May 2009. Autopsy studies describing the pathology of pandemic influenza infection in humans have appeared in the literature and most of these were from Western countries. We present the clinicopathologic features in 46 fatal cases with confirmed pandemic influenza A (H1N1) 2009 virus infection during August 2009 to October 2010. Postmortem needle biopsy tissues were examined for histopathological changes and distribution of virus antigen by immunohistochemistry. The results are comparable with previous autopsy studies. Diffuse alveolar damage was the consistent finding in the lung tissues. However, underlying medical conditions were not noted in the cases from present study. Consistent presence of viral antigen was noted in the bronchiolar epithelium without any reference to the duration of illness. This study also emphasizes the use of the postmortem needle biopsy technique whenever an autopsy is not possible.     

2009甲型H1N1流感大流行期间北京儿童的流感监测

目的 了解2009年甲型H1N1流感大流行期间北京地区儿童中流感流行的情况.方法 采用WHO推荐的实时荧光定量RT-PCR和国家流感中心推荐的分型方法,对2009年甲型H1N1流感大流行期间因流感样症状来首都儿科研究所附属儿童医院就诊患儿的咽拭子标本进行流感病毒核酸检测.结果 2009年6月1日至2010年2月28日期间共检测了4363份咽拭子标本,其中623例为甲型H1N1阳性,阳性率为14.3%,657例为其他甲型流感病毒阳性(15.1%),所有甲型流感病毒的总阳性率为29.3%.623例中有23例为危重症病例(占阳性患者的3.7%),其中5例死亡.618例信息完整的甲型H1N1病例中,患儿年龄为14天～16岁,性别比例为男比女为1.3:1.1～3岁儿童占25.2%,3～6岁学龄前儿童和6～12岁学龄儿童所占比例相近,各约占30%.在监测期间,仅呈现了一个甲型H1N1的流行波.2009年11月达到最高峰,随后减弱,2010年2月快速下降至2.7%.对监测期间每周20～30份临床标本同时进行季节性流感的监测显示,季节性H3N2、甲型H1N1和乙型流感交替流行.呼吸道合胞病毒(RSV)在甲型H1N1流行趋势减缓后逐渐流行成为流行优势株.结论 2009年6月至2010年2月北京地区儿童中出现甲型H1N1的流行,主要累及学龄前和学龄儿童.季节性流感和RSV与甲型H1N1交替流行.