Quantitation of residual valproic acid in flu vaccine drug substance.

Quantitative measurement of process-related impurities is a critical safety requirement for the production of drug substances of vaccine and therapeutic biologics. A simple and sensitive HPLC method has been developed for separation and quantitation of residual valproic acid (VPA) used in the cell transfection procedure for the manufacturing of an influenza vaccine. The method is comprised of a modified Dole liquid phase extraction followed by a quick pre-column derivatization using 2-bromoacetophenone. Nonanoic acid (NNA) is used as the internal standard (IS) and the quantification is performed by reversed-phase liquid chromatography. This new method can accurately measure as low as 6.8 µg/mL (LOQ) residual VPA in the vaccine drug substance.

Assessing the Low Influenza Vaccination Coverage Rate Among Healthcare Personnel in India: A Review of Obstacles, Beliefs, and Strategies.

BACKGROUND: Most countries recommend that their healthcare personnel be vaccinated against influenza in order to protect themselves as well as their patients. However despite the strong scientific rationale, recommendations and advocacy from health organizations, influenza vaccination coverage among healthcare personnel remains low. This has been attributed to various obstacles and a range of strategies have been implemented to increase uptake with varying levels of success. OBJECTIVES: To highlight the vaccination coverage, beliefs, and obstacles among healthcare personnel in India and to discuss strategies that can be implemented to improve influenza vaccination coverage. CONCLUSIONS: Various barriers are responsible for the low influenza vaccination coverage among Indian healthcare personnel. Many interventions are being practiced, but they need to be multidimensional keeping in mind that healthcare personnel value their autonomy in making decisions about vaccinations.

Universal influenza virus vaccines and therapeutic antibodies.

BACKGROUND: Current influenza virus vaccines are effective when well matched to the circulating strains. Unfortunately, antigenic drift and the high diversity of potential emerging zoonotic and pandemic viruses make it difficult to select the right strains for vaccine production. This problem causes vaccine mismatches, which lead to sharp drops in vaccine effectiveness and long response times to manufacture matched vaccines in case of novel pandemic viruses. AIMS: To provide an overview of universal influenza virus vaccines and therapeutic antibodies in preclinical and clinical development. SOURCES: PubMed and clinicaltrials.gov were used as sources for this review. CONTENT: Universal influenza virus vaccines that target conserved regions of the influenza virus including the haemagglutinin stalk domain, the ectodomain of the M2 ion channel or the internal matrix and nucleoproteins are in late preclinical and clinical development. These vaccines could confer broad protection against all influenza A and B viruses including drift variants and thereby abolish the need for annual re-formulation and re-administration of influenza virus vaccines. In addition, these novel vaccines would enhance preparedness against emerging influenza virus pandemics. Finally, novel therapeutic antibodies against the same conserved targets are in clinical development and could become valuable tools in the fight against influenza virus infection. IMPLICATIONS: Both universal influenza virus vaccines and therapeutic antibodies are potential future options for the control of human influenza infections.

A novel approach for preparation of the antisera reagent for potency determination of inactivated H7N9 influenza vaccines.

BACKGROUND: The potency of inactivated influenza vaccines is determined using a single-radial immunodiffusion (SRID) assay and requires standardized reagents consisting of a Reference Antigen and an influenza strain-specific antiserum. Timely availability of reagents is a critical step in influenza vaccine production, and the need for backup approaches for reagent preparation is an important component of pandemic preparedness. OBJECTIVES: When novel H7N9 viruses emerged in China in 2013, candidate inactivated H7N9 influenza vaccines were developed for evaluation in clinical trials, and reagents were needed to measure vaccine potency. METHODS: We previously described an alternative approach for generating strain-specific potency antisera, utilizing modified vaccinia virus Ankara vectors to produce influenza hemagglutinin (HA)-containing virus-like particles (VLPs) for immunization. Vector-produced HA antigen is not dependent upon the success of the traditional bromelain-digestion and HA purification. RESULTS: Antiserum for H7N9 vaccines, produced after immunization of sheep with preparations of bromelain-HA (br-HA), was not optimal for the SRID assay, and the supply of antiserum was limited. However, antiserum obtained from sheep boosted with VLPs containing H7 HA greatly improved the ring quality in the SRID assay. Importantly, this antiserum worked well with both egg- and cell-derived antigen and was distributed to vaccine manufacturers. CONCLUSIONS: Utilizing a previously developed approach for preparing vaccine potency antiserum, we have addressed a major bottleneck encountered in preparation of H7N9 vaccine reagents. The combination of br-HA and mammalian VLPs for sequential immunization represents the first use of an alternative approach for producing an influenza vaccine potency antiserum.

Expanding the recommendations for annual influenza vaccination to school-age children in the United States.

BACKGROUND: Despite long-standing recommendations to vaccinate children who have underlying chronic medical conditions or who are contacts of high-risk persons, vaccination coverage among school-age children remains low. Community studies have indicated that school-age children have the highest incidence of influenza and are an important source of amplifying and sustaining community transmission that affects all age groups. METHODS: A consultation to discuss the advantages and disadvantages of a universal recommendation for annual influenza vaccination of all children age ≥6 months was held in Atlanta, Georgia, in September 2007. Consultants provided summaries of current data on vaccine effectiveness, safety, supply, successful program implementation, and economics studies and discussed challenges associated with continuing a risk- and contact-based vaccination strategy compared with a universal vaccination recommendation. RESULTS: Consultants noted that school-age children had a substantial illness burden caused by influenza, that vaccine was safe and effective for children aged 6 months through 18 years, and that evidence suggested that vaccinating school-age children would provide benefits to both the vaccinated children and their unvaccinated household and community contacts. However, implementation of an annual recommendation for all school-age children would pose major challenges to parents, medical providers and health care systems. Alternative vaccination venues were needed, and of these school-located vaccination programs might offer the most promise as an alternative vaccination site for school-age children. CONCLUSIONS: Expansion of recommendations to include all school-age children will require additional development of an infrastructure to support implementation and methods to adequately evaluate impact.

Safety and long-term humoral immune response in adults after vaccination with an H1N1 2009 pandemic influenza vaccine with or without AS03 adjuvant.

BACKGROUND: In this study (NCT00985088) we evaluated different formulations of an H1N1 2009 pandemic influenza vaccine that deliver various viral hemagglutinin (HA) doses with or without AS03 (a tocopherol-based oil-in-water adjuvant system). METHODS: A total of 1340 healthy subjects aged ≥18 years were randomized to receive 1 or 2 doses of an adjuvanted (3.75-µg HA/AS03(A) or 1.9-µg HA/AS03(B)) or nonadjuvanted vaccine formulation. Safety and immunogenicity (by hemagglutination-inhibition [HI] assay) after each dose and 6 months after dose 1 are reported here. RESULTS: A single dose of AS03(A)-adjuvanted 3.75-µg HA H1N1 2009 induced the strongest immune responses in subjects aged 18-64 years (seroprotection rate [SPR], 97.2%; seroconversion rate [SCR], 90.1%) as well as in subjects aged >64 years (SPR, 91.1%; SCR, 78.2%) 21 days after vaccination. Six months after dose 1, subjects who received 2 doses of either the adjuvanted formulation or 1 dose of the adjuvanted 3.75-µg HA formulation continued to meet all Center for Biologics Evaluation and Research and Committee for Medicinal Products for Human Use criteria. All formulations had clinically acceptable safety profiles. CONCLUSION: A single dose of the 3.75-µg HA AS03(A)-adjuvanted H1N1 2009 influenza vaccine was highly immunogenic in both age strata (18-64 and >64 years), inducing long-term persistence of the immune response until at least 6 months after dose 1.

Adverse events associated with 2010 CSL and other inactivated influenza vaccines.

The 2010 trivalent influenza vaccine (TIV) manufactured by CSL Biotherapies (CSL) was associated with increased febrile reactions, including febrile convulsions, among Australian children. CSL is one of the few manufacturers that use deoxycholate as the virus-splitting agent in the manufacture of TIV. Clusters of adverse events following immunisation (AEFI) have been previously linked to other deoxycholate-split TIV formulations in Europe and Canada. We hypothesise that suboptimal virus splitting or other mechanisms related to the use of deoxycholate may have played a role in adverse events linked to the 2010 CSL TIV. This hypothesis garners support from a recent United States Food and Drug Administration warning letter indicating that CSL failed to determine optimal splitting conditions for new virus strains and that assays to assess virus splitting had not been validated. While there may be other causes, the use of deoxycholate should be further explored. Comprehensive and timely investigations of AEFI, especially those involving children, are necessary to prevent their recurrence and to maintain public confidence in vaccination programs.

Open-label, randomised, parallel-group, multicentre study to evaluate the safety, tolerability and immunogenicity of an AS03(B)/oil-in-water emulsion-adjuvanted (AS03(B)) split-virion versus non-adjuvanted whole-virion H1N1 influenza vaccine in UK children 6 months to 12 years of age.

OBJECTIVE: To evaluate the safety, tolerability and immunogenicity of an AS03(B)/oil-in-water emulsion-adjuvanted (AS03(B)) split-virion versus non-adjuvanted whole-virion H1N1 influenza vaccine in UK children aged 6 months to 12 years. DESIGN: Multicentre, randomised, head-to-head, open-label trial. SETTING: Five UK sites (Oxford, Bristol, Southampton, Exeter and London). PARTICIPANTS: Children aged 6 months to < 13 years, for whom a parent or guardian had provided written informed consent and who were able to comply with study procedures, were eligible for inclusion. INTERVENTIONS: A tocopherol/oil-in-water emulsion-adjuvanted (AS03(B)) egg culture-derived split-virion H1N1 vaccine and a non-adjuvanted cell culture-derived whole-virion vaccine, given as a two-dose schedule, 21 days apart, were compared. Participants were grouped into those aged 6 months to < 3 years (younger group) and 3 years to < 13 years of age (older group) and were randomised by study investigators (1 : 1 ratio) to receive one of the two vaccines. Vaccines were administered by intramuscular injection (deltoid or anterior-lateral thigh, depending on age and muscle bulk). Local reactions and systemic symptoms were collected for 1 week post immunisation, and serum was collected at baseline and after the second dose. To assess safety and tolerability, parents or guardians recorded the following information in diary cards from days 0-7 post vaccination: axillary temperature, injection site reactions, solicited and unsolicited systemic symptoms, and medications. MAIN OUTCOME MEASURE: Comparison between vaccines of the percentage of participants demonstrating seroconversion by microneutralisation assay. RESULTS: Among 937 children receiving vaccine, per-protocol seroconversion rates were higher after the AS03(B)-adjuvanted vaccine than after the whole-virion vaccine (98.2% vs 80.1% in children < 3 years, 99.1% vs 95.9% among those aged 3-12 years), as were severe local reactions (3.6% vs 0.0% in those under 5 years, 7.8% vs 1.1% in those aged 5-12 years), irritability in children < 5 years (46.7% vs 32.0%), and muscle pain in older children (28.9% vs 13.2%). The second dose of the adjuvanted vaccine was more reactogenic than the first, especially for fever > 38.0°C in those under 5 years of age (8.9% vs 22.4%). CONCLUSION: The adjuvanted vaccine, although reactogenic, was more immunogenic, especially in younger children, indicating the potential for improved immunogenicity of influenza vaccines in this age group. TRIAL REGISTRATION NUMBER: ISRCTN89141709.

Influenza vaccine powder formulation development: spray-freeze-drying and stability evaluation.

The purpose of this study was to develop a spray-freeze-drying (SFD) process for preparing an influenza vaccine dry powder formulation suitable for epidermal powder immunization. After preformulation of two types of flu vaccines, their dry-powder formulations were prepared by SFD. Powder properties and physical stability were determined using particle size analysis, tap density measurement, scanning electron microscopy, optical microscopy, and moisture content analysis. Chemical and biochemical stability of vaccine antigens was determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, single radial immunodiffusion assay, and in vivo immunogenicity in a mouse model. We demonstrated that SFD could produce high-density particles-a critical parameter for effective skin penetration. From the stability perspective, the stress posed by SFD was mild because the antigen in the dry powder retained its stability, potency, and immunogenicity. Among several formulations screened, we noted that formulation composition has a significant role in the powder's long-term physical and biochemical stability. One formulation, in particular, containing sub-unit vaccine (45 microg of antigen in 1 mg of powder) with a tertiary mixture of trehalose, mannitol, and dextran, exhibited excellent overall stability, including acceptable biochemical stability after being exposed to a highly humid environment. After all, we have not only demonstrated the suitability of SFD to prepare powders for epidermal powder immunization but also developed a systematic formulation development strategy that allowed the optimization of an influenza vaccine dry powder formulation. More important, this study led to the selection of a formulation system that had been successfully tested in a human clinical study.

The role of sodium bisulfite in the 1996-1997 USA influenza vaccine recall.

During the 1996-1997 influenza season, all the lots of influenza vaccine manufactured by Parke-Davis were recalled. This voluntary recall by the manufacturer was prompted by the finding of decreasing potency of the A/Nanchang/933/95 (H3N2) component of the vaccine. The primary cause of this lowered potency has been identified as primarily due to the presence of sodium bisulfite which was used to neutralize residual formaldehyde which in turn is used to inactivate the live influenza vaccine strains. This paper reviews these events and what we have learned.

Emergence and possible transmission of amantadine-resistant viruses during nursing home outbreaks of influenza A (H3N2).

Outbreaks of influenza A (H3N2, A/Shanghai/11/87-like) occurred in two partially (60% and 79%) vaccinated nursing home populations in January 1988. A retrospective cohort study using chart review was designed to assess the effectiveness of influenza vaccination and amantadine prophylaxis (100 mg per day) in controlling the outbreaks and to determine the amantadine susceptibility of influenza viruses isolated from case-patients. The point estimate of vaccine efficacy in preventing influenza-like illness was -33% (95% confidence interval -115% to 18%). However, 9% of vaccinated case-patients died within 14 days after onset of influenza-like illness compared with 26% of unvaccinated case-patients (relative risk = 0.4, 95% confidence interval 0.1-1.0). There was no significant difference in illness severity among case-patients who became ill before amantadine prophylaxis was started (n = 84) compared with those who became ill while taking amantadine (n = 34). Four virus isolates obtained before amantadine prophylaxis was started demonstrated 52-68% inhibition by 1 microgram/ml of amantadine; by comparison, six isolates (resistant viruses) obtained from residents who became ill while taking amantadine demonstrated 1-18% inhibition. The resistant viruses had four different RNA sequences in the gene coding for the M2 protein transmembrane region. Three resistant viruses with identical RNA sequences were isolated from residents living in contiguous rooms who had onset of signs and symptoms during a 6-day interval. Further studies are needed to determine how frequently and under what circumstances resistant viruses occur when antiviral agents are used to control institutional influenza A outbreaks. Strategies for antiviral agent administration that limit the emergence and transmission of resistant virus strains may be needed.

[Epidemiological effect of influenza vaccination (author's transl)]. / Epidemiologische Wirkung der Influenza-Impfung.

No influenza-A virus epidemic occurred in the Federal Republic of Germany during 1971-1975. The neighbouring countries, however, reported up to three such epidemics. The vaccines used had differences: contrary to neighbouring countries, in the FRG largely those were used which had mineral adjuvants, and they more frequently had viral subgroups. Comparison between the USA and FRG with respect to influenza death-rates over 20 years revealed a strict correlation from 1956 up to 1965. But since 1966 the death-rate has decreased progressively in the FRG while it has remained unchanged in the USA. Immunisation methods in the two countries have differed since 1966 in that the Public Health Authorities of the two countries have recommended immunisation of different population groups: in the USA it has been only for patients at risk, while in the FRG the rest of the population has also been urged to be immunised. As a result, immunisation rates differ markedly between the two countries. Absence of an influenza epidemic, accompanied by a reduction in death-rate due to influenza, strongly suggests that the two phenomena are the result of a break in the infection chain. This seems to be more successful when both part of the total population and the risk groups are immunised.