scholarly journals Quantifying the mortality caused by the H1N1 influenza virus during the 2009 pandemic in Mexico

2014 ◽  
Vol 8 (06) ◽  
pp. 742-748 ◽  
Author(s):  
Eusebio Perez-Flores ◽  
Juan Carlos Izquierdo-Puente ◽  
Jose Juan Castillo-Perez ◽  
Gustavo Ramírez-Rosales ◽  
Israel Grijalva-Otero ◽  
...  
Keyword(s):  
Influenza Virus ◽  
Cause Of Death ◽  
Influenza A ◽  
H1n1 Influenza ◽  
The United States ◽  
Study Data ◽  
Death Certificates ◽  
Influenza A H1n1 ◽  
Uniform Probability Distribution ◽  
Source Of Error

Introduction: The frequency and mortality of the pandemic caused by influenza A(H1N1)pdm09 might have been underestimated, especially in developing countries. This study was designed to quantify the possible underestimation of pandemic influenza mortality and evaluate the concordance between the data reported for A(H1N1)pdm09 mortality and the causes of death reported during the pandemic period of April 2009 to February 2010. Methodology: The death certificates of 754 confirmed cases of A(H1N1)pdm09 infection were included in the study. Data was analyzed using the United States Centers for Disease Control and Prevention’s statistical model accounts for the variability in the proportion at each step using the Monte Carlo probabilistic model sampled from a uniform probability distribution. Results: A total of 1,969 deaths were estimated, with an estimated lethality of 5.53 per 100,000 (range, 3.5-8.76 per 100,000) in contrast with the 754 deaths and a lethality of 1.98 per 100,000 infected patients officially reported. In 631 of 754 (83.7%) death certificates from A(H1N1)pdm09 influenza-positive patients, influenza was not mentioned as a cause of death. Conclusions: It is possible that the mortality of the pandemic was three times higher than officially reported in Mexico. One source of error that could explain this underestimation is in the completion of death certificates, because in > 80% of confirmed cases of infection with influenza virus, it was not reported as the cause of death.

scholarly journals Contemporary Seasonal Influenza A (H1N1) Virus Infection Primes for a More Robust Response To Split Inactivated Pandemic Influenza A (H1N1) Virus Vaccination in Ferrets

2010 ◽  
Vol 17 (12) ◽  
pp. 1998-2006 ◽  
Author(s):  
Ali H. Ellebedy ◽  
Thomas P. Fabrizio ◽  
Ghazi Kayali ◽  
Thomas H. Oguin ◽  
Scott A. Brown ◽  
...  
Keyword(s):  
Influenza Virus ◽  
Pandemic Influenza ◽  
Influenza A ◽  
Seasonal Influenza ◽  
H1n1 Virus ◽  
H1n1 Influenza ◽  
Influenza Viruses ◽  
Inactivated Vaccine ◽  
H1n1 Influenza Virus ◽  
Influenza A H1n1

ABSTRACT 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.

scholarly journals A comparison of live and inactivated influenza A (H1N1) virus vaccines: Short-term immunity

1983 ◽  
Vol 90 (3) ◽  
pp. 351-359 ◽  
Author(s):  
A. Clark ◽  
C. W. Potter ◽  
R. Jennings ◽  
J. P. Nicholl ◽  
A. F. Langrick ◽  
...  
Keyword(s):  
Influenza Virus ◽  
Antibody Response ◽  
Surface Antigen ◽  
Influenza A ◽  
Serum Antibody ◽  
H1n1 Influenza ◽  
Live Attenuated Vaccine ◽  
Challenge Virus ◽  
Influenza A H1n1 ◽  
Aqueous Surface

SUMMARYGroups of volunteers were immunized subcutaneously with one of three inacti vated influenza virus A/USSR/77 (HlNl) vaccine preparations; a whole virus vaccine, a surface-antigen subunit adsorbed vaccine, or an aqueous surface-antigen subunit vaccine. The reactions to immunization were recorded, and the antibody response was measured 1 month later. A fourth group of volunteers were inoculated intranasally with live attentuated A/USSR/77 (H1N1) influenza virus; the reactions and antibody response of these volunteers were also measured. One month after immunization, the incidence of infection by challenge with homologous live attentuated virus was determined for all groups of volunteers. The results showed that all four vaccines used were relatively non-reactogenic, and that inactivated vaccines induced higher titres of serum antibody than the live attenuated vaccine. All the vaccines induced significant protection against challenge virus infection which was directly related to the level of serum HI antibody response.

scholarly journals The Modified JiuWei QiangHuo Decoction Alleviated Severe Lung Injury Induced by H1N1 Influenza Virus by Regulating the NF-κB Pathway in Mice

2015 ◽  
Vol 2015 ◽  
pp. 1-12 ◽  
Author(s):  
Lijuan Chen ◽  
Xin Yan ◽  
Qianlin Yan ◽  
Jiajun Fan ◽  
Hai Huang ◽  
...  
Keyword(s):  
Influenza Virus ◽  
Lung Injury ◽  
Influenza A ◽  
H1n1 Virus ◽  
Alternative Therapy ◽  
Severe Pneumonia ◽  
H1n1 Influenza ◽  
Influenza A H1n1 ◽  
Lung Injuries ◽  
Severe Lung

A new approach to treat infections of highly pathogenic influenza virus is to inhibit excessive innate immune response. JiuWei QiangHuo decoction has been used for centuries for the treatment of pulmonary disorders in China. In this study, we evaluated the anti-inflammatory activities of the modified JiuWei QiangHuo (MJWQH) decoction in the treatment of influenza A (H1N1) virus-induced severe pneumonia in mice. The results showed that MJWQH significantly increased the survival rate of H1N1-infected mice and suppressed the production of TNF-α, IL-1, IL-6, MCP-1, RANTES, and IFN-αon day 4 after infection. Moreover, oral administration of MJWQH efficiently inhibited virus replication and alleviated the severity of lung injuries. The results also showed that MJWQH may have potential therapeutic effect on severe lung injury induced by H1N1 virus by regulating the NF-κB pathway. Our study suggested that MJWQH might be an alternative therapy for the treatment of viral pneumonia.

scholarly journals Pandemic H1N1 influenza: predicting the course of a pandemic and assessing the efficacy of the planned vaccination programme in the United States

2009 ◽  
Vol 14 (41) ◽  
Author(s):  
S Towers ◽  
Z Feng
Keyword(s):  
United States ◽  
Influenza A ◽  
Influenza Pandemic ◽  
Vaccination Campaign ◽  
H1n1 Influenza ◽  
The United States ◽  
Pandemic H1n1 ◽  
Pandemic H1n1 Influenza ◽  
Influenza A H1n1 ◽  
Control And Prevention

We use data on confirmed cases of pandemic influenza A(H1N1), disseminated by the United States Centers for Disease Control and Prevention(US CDC), to fit the parameters of a seasonally forced Susceptible, Infective, Recovered (SIR) model. We use the resulting model to predict the course of the H1N1 influenza pandemic in autumn 2009, and we assess the efficacy of the planned CDC H1N1 vaccination campaign. The model predicts that there will be a significant wave in autumn, with 63% of the population being infected, and that this wave will peak so early that the planned CDC vaccination campaign will likely not have a large effect on the total number of people ultimately infected by the pandemic H1N1 influenza virus.

scholarly journals A Single-Dose Influenza A (H5N1) Vaccine Safe and Immunogenic in Adult and Elderly Patients: an Approach to Pandemic Vaccine Development

2009 ◽  
Vol 84 (3) ◽  
pp. 1237-1242 ◽  
Author(s):  
Zoltan Vajo ◽  
John Wood ◽  
Lajos Kosa ◽  
Istvan Szilvasy ◽  
Gyorgy Paragh ◽  
...  
Keyword(s):  
Influenza A ◽  
Vaccine Development ◽  
H1n1 Influenza ◽  
The United States ◽  
Dose Finding ◽  
Elderly Subjects ◽  
Serum Samples ◽  
Influenza A H1n1 ◽  
Pandemic Vaccine ◽  
H5n1 Vaccine

ABSTRACT With the ongoing pandemic of influenza A (H1N1) virus infection and the threat of high fatality rates for recent human cases of infection with highly pathogenic H5N1 strains, there has been considerable interest in developing pandemic vaccines. Here we report a randomized multicenter dose-finding clinical trial of a whole-virion, inactivated, adjuvanted H5N1 vaccine in adult and elderly volunteers. Four hundred eighty patients were randomly assigned to receive one or two doses of 3.5 μg of the vaccine or one dose of 6 or 12 μg. The subjects were monitored for safety analysis, and serum samples were obtained to assess immunogenicity by hemagglutination inhibition and microneutralization tests. The subjects developed antibody responses against the influenza A (H5N1) virus. Single doses of ≥6 μg fulfilled EU and U.S. licensing criteria for interpandemic and pandemic influenza vaccines. Except for occasional injection site pain, malaise, and fever, no adverse events were observed. We found that the present vaccine is safe and immunogenic in healthy adult and elderly subjects and requires low doses and, unlike any other H5N1 vaccines, only one injection to trigger immune responses which comply with licensing criteria. A vaccine using the same methods as those described in this report, but based on a wild-type swine-origin 2009 (H1N1) influenza A virus isolate from the United States (supplied by the CDC), has been developed and is currently being tested by our group.

scholarly journals Pathogenesis of Pandemic Influenza A (H1N1) and Triple-Reassortant Swine Influenza A (H1) Viruses in Mice

2010 ◽  
Vol 84 (9) ◽  
pp. 4194-4203 ◽  
Author(s):  
Jessica A. Belser ◽  
Debra A. Wadford ◽  
Claudia Pappas ◽  
Kortney M. Gustin ◽  
Taronna R. Maines ◽  
...  
Keyword(s):  
Influenza Virus ◽  
Influenza A ◽  
H1n1 Virus ◽  
Swine Influenza Virus ◽  
Swine Influenza ◽  
The United States ◽  
Chemokine Production ◽  
Highly Pathogenic ◽  
Influenza A H1n1 ◽  
2009 H1n1

ABSTRACT The pandemic H1N1 virus of 2009 (2009 H1N1) continues to cause illness worldwide, primarily in younger age groups. To better understand the pathogenesis of these viruses in mammals, we used a mouse model to evaluate the relative virulence of selected 2009 H1N1 viruses and compared them to a representative human triple-reassortant swine influenza virus that has circulated in pigs in the United States for over a decade preceding the current pandemic. Additional comparisons were made with the reconstructed 1918 virus, a 1976 H1N1 swine influenza virus, and a highly pathogenic H5N1 virus. Mice were inoculated intranasally with each virus and monitored for morbidity, mortality, viral replication, hemostatic parameters, cytokine production, and lung histology. All 2009 H1N1 viruses replicated efficiently in the lungs of mice and possessed a high degree of infectivity but did not cause lethal disease or exhibit extrapulmonary virus spread. Transient weight loss, lymphopenia, and proinflammatory cytokine and chemokine production were present following 2009 H1N1 virus infection, but these levels were generally muted compared with a triple-reassortant swine virus and the 1918 virus. 2009 H1N1 viruses isolated from fatal cases did not demonstrate enhanced virulence in this model compared with isolates from mild human cases. Histologically, infection with the 2009 viruses resulted in lesions in the lung varying from mild to moderate bronchiolitis with occasional necrosis of bronchiolar epithelium and mild to moderate peribronchiolar alveolitis. Taken together, these studies demonstrate that the 2009 H1N1 viruses exhibited mild to moderate virulence in mice compared with highly pathogenic viruses.

scholarly journals Hospitalizations associated with 2009 influenza A (H1N1) and seasonal influenza in Saurashtra region, India

2010 ◽  
Vol 4 (12) ◽  
pp. 834-841 ◽  
Author(s):  
Rajesh K Chudasama ◽  
Umed V Patel ◽  
Pramod B Verma
Keyword(s):  
Influenza Virus ◽  
Median Time ◽  
Influenza A ◽  
Seasonal Influenza ◽  
H1n1 Influenza ◽  
Pandemic H1n1 ◽  
H1n1 Influenza Virus ◽  
Pandemic H1n1 Influenza ◽  
Influenza A H1n1 ◽  
Epidemiological Characteristics

Introduction: This study investigated the clinico-epidemiological characteristics of patients who were hospitalized with 2009 pandemic H1N1 influenza virus infection and seasonal influenza in the Saurashtra region of India. Methodology: From September 2009 to February 2010, a total of 773 patients with influenza virus attending different hospitals in Rajkot city were studied. Real-time reverse-transcriptase-polymerase-chain-reaction (RT-PCR) testing was used to confirm infection; the clinico-epidemiological features of the disease were closely monitored. Results: Of the 733 patients, 35.4% (274/773) were cases of 2009 pandemic H1N1 influenza and 64.6% (499/773) were cases of seasonal influenza. Of the 274 patients with 2009 pandemic H1N1 influenza, the median age was 29.5 years, and 51.5% were males. Only 1.1% positive patients had recent travel history to an infected region. A median time of five days was observed from onset of illness to influenza A (H1N1) diagnosis, and a median time of six days was reported for hospital stay. All admitted influenza A (H1N1) patients received Oseltamivir drug, but only 16.1% received it within two days of onset of illness. One fourth of the admitted positive patients died. The most common symptoms were cough, fever, sore throat, and shortness of breath. The coexisting conditions were diabetes mellitus, hypertension, chronic pulmonary diseases, and pregnancy (p = 0.001). Chest radiography revealed 93% of the positive patients had pneumonia. Conclusion: The clinical course and outcomes of the 2009 pandemic (H1N1) influenza virus are comparable to those of the currently circulating seasonal influenza, with high mortality in influenza A (H1N1) patients.

scholarly journals mRNA Vaccines Encoding the HA Protein of Influenza A H1N1 Virus Delivered by Cationic Lipid Nanoparticles Induce Protective Immune Responses in Mice

Vaccines ◽  
2020 ◽  
Vol 8 (1) ◽  
pp. 123 ◽  
Author(s):  
Xinyu Zhuang ◽  
Yanxin Qi ◽  
Maopeng Wang ◽  
Ning Yu ◽  
Fulong Nan ◽  
...  
Keyword(s):  
Influenza Virus ◽  
Immune Responses ◽  
Influenza A ◽  
Cationic Lipid ◽  
H1n1 Influenza ◽  
Translation Efficiency ◽  
H1n1 Influenza Virus ◽  
Influenza A H1n1 ◽  
Better Than

The design of the mRNA vaccine involves the selection of in vitro transcription (IVT) systems and nonviral delivery vectors. This study aimed to verify the effect of 5’ and 3’ untranslated region (UTR) sequences on the translation efficiency of mRNA. Three modes of IVT-mRNA systems (IVT-mRNA-n1/n2/n3) with diverse UTRs were constructed, and EGFP (enhanced green fluorescent protein) and HA (hemagglutinin) gene of H3N2 influenza virus were introduced into each of them. The results showed that the mode of 5’ and 3’ UTRs originating from human β-globulin was better than the mode of UTRs from human α-globulin, and the n3 mode was the best. mEGFP-n3, mH3HA-n3, and mLuciferease-n3 were prepared to compare the effect of cationic lipid nanoparticle (LNP) with that of mannose-conjugated LNP (LNP-Man) on the efficiency of gene delivery. The results showed that the effect of LNP-Man was better than that of LNP both in vitro and in vivo. Choosing appropriate ligands might help in vaccine design. After selecting the IVT-mRNA-n3 system and delivery vectors, mRNA vaccines were constructed against the H1N1 influenza virus, and C57BL/6 mice were immunized through intranasal administration. The results showed that mRNA vaccines could elicit both humoral and cellular immune responses and completely protect mice from the tenfold LD50 H1N1 influenza virus challenge.

scholarly journals Comparable Disease Severity by Influenza Virus Subtype in the Acute Respiratory Infection Consortium Natural History Study

2020 ◽  
Vol 185 (7-8) ◽  
pp. e1008-e1015
Author(s):  
Christina Schofield ◽  
Rhonda E Colombo ◽  
Stephanie A Richard ◽  
Wei-Ju Chen ◽  
Mary P Fairchok ◽  
...  
Keyword(s):  
Influenza Virus ◽  
Disease Severity ◽  
Department Of Defense ◽  
Symptom Severity ◽  
Influenza A ◽  
H1n1 Influenza ◽  
Influenza B ◽  
Prevention Measures ◽  
Severity Scores ◽  
Influenza A H1n1

Abstract Introduction Since the influenza A/H1N1 pandemic of 2009 to 2010, numerous studies have described the clinical course and outcome of the different subtypes of influenza (A/H1N1, A/H3N2, and B). A recent systematic literature review concluded that there were no appreciable differences in either clinical presentation or disease severity among these subtypes, but study parameters limit the applicability of these results to military populations. We sought to evaluate differences in disease severity among influenza subtypes in a cohort of healthy, primarily outpatient adult U.S. Department of Defense beneficiaries. Materials and Methods From 2009 to 2014, we enrolled otherwise healthy adults age 18 to 65 years with influenza-like illness in an observational cohort study based in 5 U.S. military medical centers. Serial nasopharyngeal swabs were collected for determination of etiology and viral shedding by polymerase chain reaction. The presence and severity of symptoms was assessed by interview and patient diary. Results Over a 5-year period, a total of 157 adults with laboratory-confirmed influenza and influenza subtype were enrolled. Of these, 69 (44%) were positive for influenza A(H1N1), 69 (44%) for influenza A(H3N2), and 19 (12%) for influenza B. About 61% were male, 64% were active duty military personnel, and 72% had received influenza vaccine in the past 8 months. Almost 10% were hospitalized with influenza. Seasonal influenza virus distribution among enrollees mirrored that of nationwide trends each year of study. Individuals with A/H1N1 had upper respiratory composite scores that were lower than those with A/H3N2. Multivariate models indicated that individuals with A(H1N1) and B had increased lower respiratory symptom scores when compared to influenza A(H3N2) (A[H1N1]: 1.51 [95% CI 0.47, 2.55]; B: 1.46 [95% CI 0.09, 2.83]), whereas no other differences in symptom severity scores among influenza A(H1N1), influenza A(H3N2), and influenza B infection were observed. Overall, influenza season (maximum in 2012–2013 season) and female sex of the participant were found to be associated with increased influenza symptom severity. Conclusions Our study of influenza in a cohort of otherwise healthy, outpatient adult Department of Defense beneficiaries over 5 influenza seasons revealed few differences between influenza A(H1N1), influenza A(H3N2), and influenza B infection with respect to self-reported disease severity or clinical outcomes. This study highlights the importance of routine, active, and laboratory-based surveillance to monitor ongoing trends and severity of influenza in various populations to inform prevention measures.

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