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Effectiveness of Non-Adjuvanted Pandemic Influenza A Vaccines for Preventing Pandemic Influenza Acute Respiratory Illness Visits in 4 U.S. Communities  [PDF]
Marie R. Griffin, Arnold S. Monto, Edward A. Belongia, John J. Treanor, Qingxia Chen, Jufu Chen, H. Keipp Talbot, Suzanne E. Ohmit, Laura A. Coleman, Gerry Lofthus, Joshua G. Petrie, Jennifer K. Meece, Caroline Breese Hall, John V. Williams, Paul Gargiullo, LaShondra Berman, David K. Shay, for the U.S. Flu-VE Network
PLOS ONE , 2011, DOI: 10.1371/journal.pone.0023085
Abstract: We estimated the effectiveness of four monovalent pandemic influenza A (H1N1) vaccines (three unadjuvanted inactivated, one live attenuated) available in the U.S. during the pandemic. Patients with acute respiratory illness presenting to inpatient and outpatient facilities affiliated with four collaborating institutions were prospectively recruited, consented, and tested for influenza. Analyses were restricted to October 2009 through April 2010, when pandemic vaccine was available. Patients testing positive for pandemic influenza by real-time RT-PCR were cases; those testing negative were controls. Vaccine effectiveness was estimated in logistic regression models adjusted for study community, patient age, timing of illness, insurance status, enrollment site, and presence of high-risk medical conditions. Pandemic virus was detected in 1,011 (15%) of 6,757 enrolled patients. Fifteen (1%) of 1,011 influenza positive cases and 1,042 (18%) of 5,746 test-negative controls had record-verified pandemic vaccination >14 days prior to illness onset. Adjusted effectiveness (95% confidence interval) for pandemic vaccines combined was 56% (23%, 75%). Adjusted effectiveness for inactivated vaccines alone (79% of total) was 62% (25%, 81%) overall and 32% (?92%, 76%), 89% (15%, 99%), and ?6% (?231%, 66%) in those aged 0.5 to 9, 10 to 49, and 50+ years, respectively. Effectiveness for the live attenuated vaccine in those aged 2 to 49 years was only demonstrated if vaccination >7 rather than >14 days prior to illness onset was considered (61%: 12%, 82%). Inactivated non-adjuvanted pandemic vaccines offered significant protection against confirmed pandemic influenza-associated medical care visits in young adults.
Adverse Events Following Pandemic A (H1N1) 2009 Monovalent Vaccines in Pregnant Women — Taiwan, November 2009–August 2010  [PDF]
Wan-Ting Huang,Wan-Chin Chen,Hwa-Jen Teng,Wei-I Huang,Yu-Wen Huang,Chien-Wen Hsu,Jen-Hsiang Chuang
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0023049
Abstract: During the 2009 H1N1 pandemic, pregnant women were prioritized to receive the unadjuvanted or MF59?-adjuvanted pandemic A (H1N1) 2009 monovalent vaccines (“2009 H1N1 vaccines”) in Taiwan regardless of stage of pregnancy. Monitoring adverse events following 2009 H1N1 vaccination in pregnant women was a priority for the mass immunization campaign beginning November 2009.
Pandemic Influenza Vaccines – The Challenges  [PDF]
Lars R. Haaheim,Abdullah S. Madhun,Rebecca Cox
Viruses , 2009, DOI: 10.3390/v1031089
Abstract: Recent years’ enzootic spread of highly pathogenic H5N1 virus among poultry and the many lethal zoonoses in its wake has stimulated basic and applied pandemic vaccine research. The quest for an efficacious, affordable and timely accessible pandemic vaccine has been high on the agenda. When a variant H1N1 strain of swine origin emerged as a pandemic virus, it surprised many, as this subtype is well-known to man as a seasonal virus. This review will cover some difficult vaccine questions, such as the immunological challenges, the new production platforms, and the limited supply and global equity issues.
Comparing the Immunogenicity of AS03-Adjuvanted 2009 Pandemic H1N1 Vaccine with Clinical Protection in Priority Risk Groups in England  [PDF]
Chee-Fu Yung, Nick Andrews, Katja Hoschler, Elizabeth Miller
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0056844
Abstract: In England, during pandemic 2009 H1N1, vaccine efficacy and immunogenicity population studies in priority groups were rolled out in parallel to evaluate the pandemic vaccination programme. This provided a unique opportunity to compare immunogenicity and clinical protection in the same population and thus provide insights into the correlates of protection for the pandemic H1N1 2009 vaccine in risk groups. While clinical protection from AS03-adjuvanted pandemic 2009 H1N1 vaccine was high in those aged <25 years and pregnant women, effectiveness in older adults with chronic conditions has been found to be surprisingly poor. Here we present results from the immunogenicity study derived from the same population. Individuals from priority groups eligible for pandemic vaccination attending participating general practices were recruited. Pre and post-vaccination blood samples were collected and HI antibody testing to assess immune response to vaccination performed. The final cohort consisted of 610 individuals: 60 healthy children aged <5 years; 32 healthy pregnant women; 518 individuals from risk groups. Seroconversion rate in healthy children aged <5 years (87%, 95% CI: 75% to 94%) was higher than that of risk groups combined (65%, 95% CI: 61% to 69%) (p<0.001). Multivariable analysis of risk groups showed that the size of response in those who did seroconvert was lower in those who received the 2009/10 seasonal TIV (Fold effect: 0.52, 0.35 to 0.78). Predicted immunological boosting from higher pre-vaccine titres after 2009 pandemic H1N1 vaccination only occurred in children (seroconversion rate = 92%) and not in individuals aged 10 to 39 from risk groups (seroconversion rate = 74%). The lack of clinical protection identified in the same population in older adults from risk groups could be attributed to these lower seroresponses. Current immunogenicity licensing criteria for pandemic influenza vaccine may not correlate with clinical protection in individuals with chronic disease or immunocompromised.
Meta-Analysis of the Immunogenicity and Tolerability of Pandemic Influenza A 2009 (H1N1) Vaccines  [PDF]
Lamberto Manzoli, Corrado De Vito, Georgia Salanti, Maddalena D'Addario, Paolo Villari, John P.A. Ioannidis
PLOS ONE , 2011, DOI: 10.1371/journal.pone.0024384
Abstract: Background Although the 2009 (H1N1) influenza pandemic officially ended in August 2010, the virus will probably circulate in future years. Several types of H1N1 vaccines have been tested including various dosages and adjuvants, and meta-analysis is needed to identify the best formulation. Methods We searched MEDLINE, EMBASE, and nine clinical trial registries to April 2011, in any language for randomized clinical trials (RCTs) on healthy children, adolescents, adults and the elderly. Primary outcome was the seroconversion rate according to hemagglutinination-inhibition (HI); secondary outcomes were adverse events. For the primary outcome, we used head-to-head meta-analysis and multiple-treatments meta-analysis. Results Eighteen RCTs could be included in all primary analyses, for a total of 76 arms (16,725 subjects). After 2 doses, all 2009 H1N1 split/subunit inactivated vaccines were highly immunogenic and overcome CPMP seroconversion criteria. After 1 dose only, all split/subunit vaccines induced a satisfactory immunogenicity (> = 70%) in adults and adolescents, while only some formulations showed acceptable results for children and elderly (non-adjuvanted at high-doses and oil-in-water adjuvanted vaccines). Vaccines with oil-in-water adjuvants were more immunogenic than both nonadjuvanted and aluminum-adjuvanted vaccines at equal doses and their immunogenicity at doses < = 6 μg (even with as little as 1.875 μg of hemagglutinin antigen) was not significantly lower than that achieved after higher doses. Finally, the rate of serious vaccine-related adverse events was low for all 2009 H1N1 vaccines (3 cases, resolved in 10 days, out of 22826 vaccinated subjects). However, mild to moderate adverse reactions were more (and very) frequent for oil-in-water adjuvanted vaccines. Conclusions Several one-dose formulations might be valid for future vaccines, but 2 doses may be needed for children, especially if a low-dose non-adjuvanted vaccine is used. Given that 15 RCTs were sponsored by vaccine manufacturers, future trials sponsored by non-industry agencies and comparing vaccines using different types of adjuvants are needed.
Immunogenicity and Tolerability after Two Doses of Non-Adjuvanted, Whole-Virion Pandemic Influenza A (H1N1) Vaccine in HIV-Infected Individuals  [PDF]
Heimo Lagler, Katharina Grabmeier-Pfistershammer, Veronique Touzeau-R?mer, Selma Tobudic, Michael Ramharter, Judith Wenisch, Guido Andrés Gualdoni, Monika Redlberger-Fritz, Theresia Popow-Kraupp, Armin Rieger, Heinz Burgmann
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0036773
Abstract: Background During the influenza pandemic of 2009/10, the whole-virion, Vero-cell-derived, inactivated, pandemic influenza A (H1N1) vaccine Celvapan? (Baxter) was used in Austria. Celvapan? is adjuvant-free and was the only such vaccine at that time in Europe. The objective of this observational, non-interventional, prospective single-center study was to evaluate the immunogenicity and tolerability of two intramuscular doses of this novel vaccine in HIV-positive individuals. Methods and Findings A standard hemagglutination inhibition (HAI) assay was used for evaluation of the seroconversion rate and seroprotection against the pandemic H1N1 strain. In addition, H1N1-specific IgG antibodies were measured using a recently developed ELISA and compared with the HAI results. Tolerability of vaccination was evaluated up to one month after the second dose. A total of 79 HIV-infected adults with an indication for H1N1 vaccination were evaluated. At baseline, 55 of the 79 participants had an HAI titer ≥1:40 and two patients showed a positive IgG ELISA. The seroconversion rate was 31% after the first vaccination, increasing to 41% after the second; the corresponding seroprotection rates were 92% and 83% respectively. ELISA IgG levels were positive in 25% after the first vaccination and in 37% after the second. Among the participants with baseline HAI titers <1:40, 63% seroconverted. Young age was clearly associated with lower HAI titers at baseline and with higher seroconversion rates, whereas none of the seven patients >60 years of age had a baseline HAI titer <1:40 or seroconverted after vaccination. The vaccine was well tolerated. Conclusion The non-adjuvanted pandemic influenza A (H1N1) vaccine was well tolerated and induced a measurable immune response in a sample of HIV-infected individuals.
Long-term follow-up in patients with HIV vaccinated with pandemic influenza A(H1N1)/09 AS03-adjuvanted split virion vaccine and seasonal trivalent influenza split virion vaccine
Karlis Pauksens
Infection Ecology & Epidemiology , 2013, DOI: 10.3402/iee.v3i0.20766
Abstract: Introduction: In Sweden in 2009, two doses of the pandemic influenza A(H1N1)/09 AS03-adjuvanted split virion vaccine were recommended for those with HIV infection along with one dose of seasonal trivalent influenza vaccine (TIV). At that time, no data for HIV patients and their response to the adjuvanted vaccine were available. Methods: Forty-two HIV-infected individuals were vaccinated with the pandemic vaccine on study days 0 and 28. Twenty-one of them received TIV on day 56 and 21 did not. Serum samples were taken at these time points, and also on day 86 and after 1 year for serologic analyses. Results: Before vaccination, none of the 42 patients had putatively protective levels of antibodies (haemagglutination inhibition [HI] titres ≥1:40) to the pandemic-like strain A/California/7/2009 H1N1. After dose 1, the seroprotection rate (SPR) and seroconversion rate (SCR) were both 69% (29 of 42). After dose 2, the SPR and SCR were 89 and 86%, respectively. At 1 year, 10 (34%) of 29 had protective antibodies and 16 (62%) of 26 who had had protective antibody levels had lost them. There was a retained factor increase of the geometric mean titre (GMT) of 3.9.Serological analyses could be performed in 19 subjects who were vaccinated with TIV and in 21 who were not. Protective antibodies to the three strains before vaccination were 20–37%. The SCR was 26% to A/Brisbane/59/2007 H1N1, 47% to A/Uruguay/10/2007/ H3N2 and 42% to B/Brisbane/60/2008. At 1 year, the factor increase of GMT was 1.8 to the two influenza A strains. Conclusion: Two doses of adjuvanted influenza vaccine improved the SCR and the SPR among HIV-infected subjects. Long-term follow-up indicates revaccination in the next influenza season whether they received an adjuvanted or non-adjuvanted influenza vaccine.
Developing Vaccines to Combat Pandemic Influenza  [PDF]
James S. Robertson,Othmar G. Engelhardt
Viruses , 2010, DOI: 10.3390/v2020532
Abstract: Influenza vaccine manufacturers require antigenically relevant vaccine viruses that have good manufacturing properties and are safe to use. In developing pandemic vaccine viruses, reverse genetics has been employed as a rational approach that can also be used effectively to attenuate the highly virulent H5N1 virus and at the same time place the H5 HA and N1 NA on a background of PR8, a virus that has been used over many decades to provide high yielding vaccine viruses. Reverse genetics has also been used successfully alongside classical reassorting techniques in the development of (swine flu) pandemic A(H1N1)v vaccine viruses.
Safety of Pandemic (H1N1) 2009 Monovalent Vaccines in Taiwan: A Self-Controlled Case Series Study  [PDF]
Wan-Ting Huang, Hsu-Wen Yang, Tzu-Lin Liao, Wan-Jen Wu, Shu-Er Yang, Yi-Chien Chih, Jen-Hsiang Chuang
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0058827
Abstract: In Taiwan, new H1N1 monovalent vaccines without adjuvant and with MF59? adjuvant were used in the nationwide vaccination campaign beginning on November 1, 2009. From November 2009 through February 2010, the authors identified recipients of H1N1 vaccines who were diagnosed with adverse events of special interest (AESIs) in a large-linked safety database, and used the self-controlled case series (SCCS) method to examine the risk of each AESI in the 0–42 days after H1N1 vaccination. Of the 3.5 million doses of H1N1 vaccines administered and captured in the linked database, the SCCS analysis of Guillain-Barré syndrome (GBS) found an incidence rate ratio of 3.81 (95% confidence interval 0.43–33.85) within 0–42 days after nonadjuvanted H1N1 vaccination and no cases after MF59?-adjuvanted H1N1 vaccination. The risks of other AESIs were, in general, not increased in any of the predefined postvaccination risk periods and age groups. The databases and infrastructure created for H1N1 vaccine safety evaluation may serve as a model for safety, effectiveness and coverage studies of licensed vaccines in Taiwan.
Effect of Vaccines and Antivirals during the Major 2009 A(H1N1) Pandemic Wave in Norway – And the Influence of Vaccination Timing  [PDF]
Birgitte Freiesleben de Blasio, Bj?rn G. Iversen, Gianpaolo Scalia Tomba
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0030018
Abstract: To evaluate the impact of mass vaccination with adjuvanted vaccines (eventually 40% population coverage) and antivirals during the 2009 influenza pandemic in Norway, we fitted an age-structured SEIR model using data on vaccinations and sales of antivirals in 2009/10 in Norway to Norwegian ILI surveillance data from 5 October 2009 to 4 January 2010. We estimate a clinical attack rate of approximately 30% (28.7–29.8%), with highest disease rates among children 0–14 years (43–44%). Vaccination started in week 43 and came too late to have a strong influence on the pandemic in Norway. Our results indicate that the countermeasures prevented approximately 11–12% of potential cases relative to an unmitigated pandemic. Vaccination was found responsible for roughly 3 in 4 of the avoided infections. An estimated 50% reduction in the clinical attack rate would have resulted from vaccination alone, had the campaign started 6 weeks earlier. Had vaccination been prioritized for children first, the intervention should have commenced approximately 5 weeks earlier in order to achieve the same 50% reduction. In comparison, we estimate that a non-adjuvanted vaccination program should have started 8 weeks earlier to lower the clinical attack rate by 50%. In conclusion, vaccination timing was a critical factor in relation to the spread of the 2009 A(H1N1) influenza. Our results also corroborate the central role of children for the transmission of A(H1N1) pandemic influenza.
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