Induction of cross-neutralizing antibody against H5N1 virus after vaccination with seasonal influenza vaccine in COPD patients

Patient-Reported Consequences of Community-Acquired Pneumonia in Patients with Chronic Obstructive Pulmonary Disease

Community acquired pneumonia (CAP) carries high morbidity, mortality, and economic burden, which is even higher in adults diagnosed with chronic obstructive pulmonary disease (COPD). While several studies have assessed the clinical burden and mortality risk of CAP and COPD, very few studies focus on CAP burden from a COPD patient perspective. Individuals recently diagnosed with CAP and with pre-existing COPD were recruited through the COPD Foundation. The CAP Burden of Illness Questionnaire (CAP-BIQ), a content validated questionnaire assessing CAP symptomatology, duration of symptoms and CAP impact on work, activities and family, was administered at baseline and at 30-days follow-up. Of the 490 participants recruited, 481 had data sufficient for analysis. The prevalence of respiratory-related symptoms was very high (>90%) at the time of diagnosis with other generalized symptoms such as fatigue, trouble sleeping, headaches and confusion present in more than 60% of participants. Mean duration of symptoms varied from approximately 2 weeks for headaches and fever to more than a month for fatigue, wheezing, dyspnea, and cough. Employed participants missed an average of 21 days of work and those not employed missed 36 days of usual activities. Over 84% required help from family, friends or care givers. CAP is a serious and burdensome condition for people with COPD, a condition that can impair activities for weeks, frequently requires care from family or friends, and includes lingering symptoms. The patient-reported impact of CAP reported in this study underscores the need for prevention strategies in this population.

Seasonal influenza vaccination in patients with COPD: a systematic literature review

BACKGROUND

Influenza is a frequent cause of exacerbations of chronic obstructive pulmonary disease (COPD). Exacerbations are associated with worsening of the airflow obstruction, hospitalisation, reduced quality of life, disease progression, death, and ultimately, substantial healthcare-related costs. Despite longstanding recommendations to vaccinate vulnerable high-risk groups against seasonal influenza, including patients with COPD, vaccination rates remain sub-optimal in this population.

METHODS

We conducted a systematic review to summarise current evidence from randomised controlled trials (RCTs) and observational studies on the immunogenicity, safety, efficacy, and effectiveness of seasonal influenza vaccination in patients with COPD. The selection of relevant articles was based on a three-step selection procedure according to predefined inclusion and exclusion criteria. The search yielded 650 unique hits of which 48 eligible articles were screened in full-text.

RESULTS

Seventeen articles describing 13 different studies were found to be pertinent to this review. Results of four RCTs and one observational study demonstrate that seasonal influenza vaccination is immunogenic in patients with COPD. Two studies assessed the occurrence of COPD exacerbations 14 days after influenza vaccination and found no evidence of an increased risk of exacerbation. Three RCTs showed no significant difference in the occurrence of systemic effects between groups receiving influenza vaccine or placebo. Six out of seven studies on vaccine efficacy or effectiveness indicated long-term benefits of seasonal influenza vaccination, such as reduced number of exacerbations, reduced hospitalisations and outpatient visits, and decreased all-cause and respiratory mortality.

CONCLUSIONS

Additional large and well-designed observational studies would contribute to understanding the impact of disease severity and patient characteristics on the response to influenza vaccination. Overall, the evidence supports a positive benefit-risk ratio for seasonal influenza vaccination in patients with COPD, and supports current vaccination recommendations in this population.

The immunogenicity of the intradermal injection of seasonal trivalent influenza vaccine containing influenza A(H1N1)pdm09 in COPD patients soon after a pandemic

The antibody responses of a reduced-dose intradermal seasonal influenza vaccination have never been studied in COPD patients soon after a pandemic. A total of 149 COPD patients (60 y of age or older) were randomized to receive trivalent influenza vaccine (Sanofi-Pasteur, France) either 9 µg of hemagglutinin (HA) per strain split into 2-site intradermal (ID) injections via the Mantoux technique or one intramuscular (IM) injection of 15 µg of HA per strain. The geometric mean titers, seroconversion factors, seroconversion rates and seroprotection rates for influenza A(H3N2) and B administered through the ID injection (n = 75) were similar to those obtained with the IM injection (n = 74) 4 weeks post-vaccination. The antibody responses for influenza A(H1N1)pdm09 administered through the ID injection were lower than those obtained with the IM injection, but all of these responses met the 3 criteria proposed by the Committee for Proprietary Medicinal Products (CPMP) for annual re-licensure. The seroprotection rates 4 weeks post-vaccination for influenza A(H1N1)pdm09 were 64.0% (95%CI 52.7-74.0%) in the ID group vs. 78.4% (95% CI 67.6-86.3%) in the IM group (p = 0.053). Influenza-related acute respiratory illness (ARI), diagnosed as a 4-fold rise in HI titers with a convalescent titer > 1:40, and/or the RT-PCR between the ID group (5.3%) and the IM group (8.1%) were not significantly different. The reduced-dose intradermal influenza vaccine may expand vaccine coverage in cases of vaccine shortage.

Homosubtypic and heterosubtypic antibodies against highly pathogenic avian influenza H5N1 recombinant proteins in H5N1 survivors and non-H5N1 subjects

Six recombinant vaccinia viruses containing HA, NA, NP, M or NS gene insert derived from a highly pathogenic avian influenza H5N1 virus, and the recombinant vaccinia virus harboring plasmid backbone as the virus control were constructed. The recombinant proteins were characterized for their expression and subcellular locations in TK(-) cells. Antibodies to the five recombinant proteins were detected in all 13 sequential serum samples collected from four H5N1 survivors during four years of follow-up; and those directed to rVac-H5 HA and rVac-NA proteins were found in higher titers than those directed to the internal proteins as revealed by indirect immunofluorescence assay. Although all 28 non-H5N1 subjects had no neutralizing antibodies against H5N1 virus, they did have cross-reactive antibodies to those five recombinant proteins. A significant increase in cross-reactive antibody titer to rVac-H5 HA and rVac-NA was found in paired blood samples from patients infected with the 2009 pandemic virus.

Kinetics of the antibody response to seasonal influenza vaccination among the elderly

Influenza vaccination, which has been targeted to the elderly and those at serious risk of complications, is recommended. The purpose of this study was to determine antibody responses after influenza vaccination among Thai elderly persons living in the community. A total of 591 subjects consisting of 308 vaccinees and 283 non-vaccinees were enrolled in the study. Antibodies to H1N1, H3N2, and B viruses were detected by hemagglutination inhibition (HI) testing. The numbers of subjects who had protective antibody titers ≥40 and geometric mean titers (GMTs) of antibodies against A(H1N1), A(H3N2), and B viruses prior to vaccination were similar for the vaccine and placebo groups. The seroprotection rates and GMTs for influenza virus A(H1N1), A(H3N2), and B strains after influenza vaccination at 1, 5, and 12 mo in the vaccine group were significantly higher than those in the placebo group. The seroprotection rates for the A(H1N1) and A(H3N2) strains, but not the B strain, met Committee for Proprietary Medicinal Products (CPMP) criteria (>60%). GMTs and seroprotection rates against influenza B strain in the vaccinees at all time points were <40% and <60%, respectively, and significant differences between the vaccinees and the placebo controls were observed. The GMTs and seroprotection rates for influenza strains in those with pre-existing antibody titers ≥40 were significantly higher than those in the group with pre-existing antibody titers <40. These findings demonstrated that the elderly living in the community developed adequate antibody responses with sustainable titers throughout the 12-month study period after influenza vaccine immunization. Moreover, the presence of pre-existing antibody at a titer ≥40 prior to vaccination strongly affected the antibody response to influenza vaccination.

The influence of virus infections on the course of COPD

Chronic obstructive pulmonary disease (COPD) is extensively influenced by viral infections. The mechanisms of how viral agents affect the pathogenesis and prognosis of COPD are numerous. In general, patients with infectious exacerbations are characterized by longer hospitalization periods and greater impairment of several lung function parameters than those with non-infectious exacerbations. Prodromal, clinical, and outcome parameters fail to distinguish virally from non-virally induced illnesses in cases of exacerbations. The importance of infections with respiratory and non-respiratory viral agents for pathogenesis and course of COPD is detailed. Human adenovirus, non-respiratory viruses including human immunodeficiency virus, human metapneumovirus, influenza virus, human rhinovirus, and respiratory syncytial virus are especially stressed.

Heterosubtypic antibody response elicited with seasonal influenza vaccine correlates partial protection against highly pathogenic H5N1 virus

Background

The spread of highly pathogenic avian influenza (HPAI) H5N1 virus in human remains a global health concern. Heterosubtypic antibody response between seasonal influenza vaccine and potential pandemic influenza virus has important implications for public health. Previous studies by Corti et al. and by Gioia et al. demonstrate that heterosubtypic neutralizing antibodies against the highly pathogenic H5N1 virus can be elicited with a seasonal influenza vaccine in humans. However, whether such response offers immune protection against highly pathogenic H5N1 virus remained to be determined.

Methodology/Principal Findings

In this study, using a sensitive influenza HA (hemagglutinin) and NA (neuraminidase) pseudotype-based neutralization (PN) assay we first confirmed that low levels of heterosubtypic neutralizing antibody response against H5N1 virus were indeed elicited with seasonal influenza vaccine in humans. We then immunized mice with the seasonal influenza vaccine and challenged them with lethal doses of highly pathogenic H5N1 virus. As controls, we immunized mice with homosubtypic H5N1 virus like particles (VLP) or PBS and challenged them with the same H5N1 virus. Here we show that low levels of heterosubtypic neutralizing antibody response were elicited with seasonal influenza vaccine in mice, which were significantly higher than those in PBS control. Among them 2 out of 27 whose immune sera exhibited similar levels of neutralizing antibody response as VLP controls actually survived from highly pathogenic H5N1 virus challenge.

Conclusions/Significance

Therefore, we conclude that low levels of heterosubtypic neutralizing antibody response are indeed elicited with seasonal influenza vaccine in humans and mice and at certain levels such response offers immune protection against severity of H5N1 virus infection.

Serological response to the 2009 pandemic influenza A (H1N1) virus for disease diagnosis and estimating the infection rate in Thai population

Background

Individuals infected with the 2009 pandemic virus A(H1N1) developed serological response which can be measured by hemagglutination-inhibition (HI) and microneutralization (microNT) assays.

Methodology/Principal Findings

MicroNT and HI assays for specific antibody to the 2009 pandemic virus were conducted in serum samples collected at the end of the first epidemic wave from various groups of Thai people: laboratory confirmed cases, blood donors and health care workers (HCW) in Bangkok and neighboring province, general population in the North and the South, as well as archival sera collected at pre- and post-vaccination from vaccinees who received influenza vaccine of the 2006 season. This study demonstrated that goose erythrocytes yielded comparable HI antibody titer as compared to turkey erythrocytes. In contrast to the standard protocol, our investigation found out the necessity to eliminate nonspecific inhibitor present in the test sera by receptor destroying enzyme (RDE) prior to performing microNT assay. The investigation in pre-pandemic serum samples showed that HI antibody was more specific to the 2009 pandemic virus than NT antibody. Based on data from pre-pandemic sera together with those from the laboratory confirmed cases, HI antibody titers ≥40 for adults and ≥20 for children could be used as the cut-off level to differentiate between the individuals with or without past infection by the 2009 pandemic virus.

Conclusions/Significance

Based on the cut-off criteria, the infection rates of 7 and 12.8% were estimated in blood donors and HCW, respectively after the first wave of the 2009 influenza pandemic. Among general population, the infection rate of 58.6% was found in children versus 3.1% in adults.