Egg-based Production Research Articles

Isolation of an Egg-Adapted Influenza A(H3N2) Virus without Amino Acid Substitutions at the Antigenic Sites of Its Hemagglutinin.

Antigenic changes in the hemagglutinin protein of recent A(H3N2) viruses often arise when these viruses adapt to their egg host. By serial egg passages of a cell-propagated virus, we successfully isolated an egg-adapted influenza A(H3N2) virus, A/Saitama/103/2014, without amino acid substitutions at the antigenic sites of its hemagglutinin protein but with multiple substitutions in its neuraminidase protein. Antigenic analysis of this egg-adapted A/Saitama/103/2014 virus indicated that its antigenicity did not differ from that of the World Health Organization prototype cell-propagated vaccine virus: A/Hong Kong/4801/2014. Our results suggest that this strategy may facilitate egg-based vaccine production without antigenic alterations in hemagglutinin by egg adaptation.

A structural explanation for the low effectiveness of the seasonal influenza H3N2 vaccine.

The effectiveness of the annual influenza vaccine has declined in recent years, especially for the H3N2 component, and is a concern for global public health. A major cause for this lack in effectiveness has been attributed to the egg-based vaccine production process. Substitutions on the hemagglutinin glycoprotein (HA) often arise during virus passaging that change its antigenicity and hence vaccine effectiveness. Here, we characterize the effect of a prevalent substitution, L194P, in egg-passaged H3N2 viruses. X-ray structural analysis reveals that this substitution surprisingly increases the mobility of the 190-helix and neighboring regions in antigenic site B, which forms one side of the receptor binding site (RBS) and is immunodominant in recent human H3N2 viruses. Importantly, the L194P substitution decreases binding and neutralization by an RBS-targeted broadly neutralizing antibody by three orders of magnitude and significantly changes the HA antigenicity as measured by binding of human serum antibodies. The receptor binding mode and specificity are also altered to adapt to avian receptors during egg passaging. Overall, these findings help explain the low effectiveness of the seasonal vaccine against H3N2 viruses, and suggest that alternative approaches should be accelerated for producing influenza vaccines as well as isolating clinical isolates.

Egg-Independent Influenza Vaccines and Vaccine Candidates.

Vaccination remains the principal way to control seasonal infections and is the most effective method of reducing influenza-associated morbidity and mortality. Since the 1940s, the main method of producing influenza vaccines has been an egg-based production process. However, in the event of a pandemic, this method has a significant limitation, as the time lag from strain isolation to final dose formulation and validation is six months. Indeed, production in eggs is a relatively slow process and production yields are both unpredictable and highly variable from strain to strain. In particular, if the next influenza pandemic were to arise from an avian influenza virus, and thus reduce the egg-laying hen population, there would be a shortage of embryonated eggs available for vaccine manufacturing. Although the production of egg-derived vaccines will continue, new technological developments have generated a cell-culture-based influenza vaccine and other more recent platforms, such as synthetic influenza vaccines.

Accelerated mass production of influenza virus seed stocks in HEK-293 suspension cell cultures by reverse genetics

Despite major advances in developing capacities and alternative technologies to egg-based production of influenza vaccines, responsiveness to an influenza pandemic threat is limited by the time it takes to generate a Candidate Vaccine Virus (CVV) as reported by the 2015 WHO Informal Consultation report titled “Influenza Vaccine Response during the Start of a Pandemic”.In previous work, we have shown that HEK-293 cell culture in suspension and serum free medium is an efficient production platform for cell culture manufacturing of influenza candidate vaccines. This report, took advantage of, recombinant DNA technology using Reverse Genetics of influenza strains, and advances in the large-scale transfection of suspension cultured HEK-293 cells. We demonstrate the efficient generation of H1N1 with the PR8 backbone reassortant under controlled bioreactor conditions in two sequential steps (transfection/rescue and infection/production). This approach could deliver a CVV for influenza vaccine manufacturing within two-weeks, starting from HA and NA pandemic sequences. Furthermore, the scalability of the transfection technology combined with the HEK-293 platform has been extensively demonstrated at >100L scale for several biologics, including recombinant viruses.Thus, this innovative approach is better suited to rationally engineer and mass produce influenza CVV within significantly shorter timelines to enable an effective global response in pandemic situations.

Manipulation of neuraminidase packaging signals and hemagglutinin residues improves the growth of A/Anhui/1/2013 (H7N9) influenza vaccine virus yield in eggs

In 2013, a novel avian-origin H7N9 influenza A virus causing severe lower respiratory tract disease in humans emerged in China, with continued sporadic cases. An effective vaccine is needed for this virus in case it acquires transmissibility among humans; however, PR8-based A/Anhui/1/2013 (Anhui/1, H7N9), a WHO-recommended H7N9 candidate vaccine virus (CVV) for vaccine production, does not replicate well in chicken eggs, posing an obstacle to egg-based vaccine production. To address this issue, we explored the possibility that PR8’s hemagglutinin (HA) and neuraminidase (NA) packaging signals mediate improvement of Anhui/1 CVV yield in eggs. We constructed chimeric HA and NA genes having the coding region of Anhui/1 HA and NA flanked by the 5′ and 3′ packaging signals of PR8’s HA and NA, respectively. The growth of CVVs containing the chimeric HA was not affected, but that of those containing the chimeric NA gene grew in embryonated chicken eggs with a more than 2-fold higher titer than that of WT CVV. Upon 6 passages in eggs further yield increase was achieved although this was not associated with any changes in the chimeric NA gene. The HA of the passaged CVV, did, however, exhibit egg-adaptive mutations and one of them (HA-G218E) improved CVV growth in eggs without significantly changing antigenicity. The HA-G218E substitution and a chimeric NA, thus, combine to provide an Anhui/1 CVV with properties more favorable for vaccine manufacture.

Cell-cultured, live attenuated, X-31ca-based H5N1 pre-pandemic influenza vaccine

The manufacture of influenza vaccines has traditionally depended upon a method using embryonated hen's eggs. However, concerns regarding the potential shortage of the influenza substrate in the event of a pandemic has led to the development of cell culture-derived vaccines, which offers shorter lead-in times and greater production flexibility. We examined optimal conditions for the production of reassortant X-31ca-based H5N1 cold-adapted live attenuated influenza vaccine (rH5N1ca) cultured in mammalian cell lines. During ten passages in MDCK cells, the rH5N1ca vaccine maintained cold-adapted and temperature-sensitive phenotypes, and no mutations occurred in the hemagglutinin and neuraminidase surface antigens, demonstrating genetic and phenotypic stability. Single immunization in mice with the rH5N1ca induced robust antibody responses and protected the mice against lethal challenge. Stable maintenance of attenuation phenotypes and immunogenicity of the rH5N1ca from cell-culture suggest that they can be produced as a stockpile for pandemic preparedness as an alternative to current egg-based production.

Recombinant Hemagglutinin Protein Vaccine: a new Option in Immunization Against Influenza

Influenza continues to be a major cause of morbidity and mortality worldwide. Vaccination is the most effective strategy to prevent influenza complications. Traditional influenza vaccines rely on an egg-based production system that has several limitations like dependence on egg supply, long production time and contraindication in people with severe egg allergy. Alternative vaccine production systems are then necessary. The insect cell-baculovirus-based production technology has shown the ability to overcome these limitations. A recombinant trivalent hemagglutinin vaccine (RIV3 – Flublok®) produced using this system is available and licensed in the USA since 2013 for use in adults. This is the first vaccine to contain recombinant influenza virus proteins, with a hemagglutinin concentration that is three-times the one found in inactivated influenza vaccine. Different studies have shown that RIV3 is well tolerated, immunogenic and efficacious, thus proving it to be an additional option for immunization against influenza in adults.

Generation of Live Attenuated Influenza Virus by Using Codon Usage Bias.

Seasonal influenza epidemics and occasional pandemics threaten public health worldwide. New alternative strategies for generating recombinant viruses with vaccine potential are needed. Interestingly, influenza viruses circulating in different hosts have been found to have distinct codon usage patterns, which may reflect host adaptation. We therefore hypothesized that it is possible to make a human seasonal influenza virus that is specifically attenuated in human cells but not in eggs by converting its codon usage so that it is similar to that observed from avian influenza viruses. This approach might help to generate human live attenuated viruses without affecting their yield in eggs. To test this hypothesis, over 300 silent mutations were introduced into the genome of a seasonal H1N1 influenza virus. The resultant mutant was significantly attenuated in mammalian cells and mice, yet it grew well in embryonated eggs. A single dose of intranasal vaccination induced potent innate, humoral, and cellular immune responses, and the mutant could protect mice against homologous and heterologous viral challenges. The attenuated mutant could also be used as a vaccine master donor strain by introducing hemagglutinin and neuraminidase genes derived from other strains. Thus, our approach is a successful strategy to generate attenuated viruses for future application as vaccines. Vaccination has been one of the best protective measures in combating influenza virus infection. Current licensed influenza vaccines and their production have various limitations. Our virus attenuation strategy makes use of the codon usage biases of human and avian influenza viruses to generate a human-derived influenza virus that is attenuated in mammalian hosts. This method, however, does not affect virus replication in eggs. This makes the resultant mutants highly compatible with existing egg-based vaccine production pipelines. The viral proteins generated from the codon bias mutants are identical to the wild-type viral proteins. In addition, our massive genome-wide mutational approach further minimizes the concern over reverse mutations. The potential use of this kind of codon bias mutant as a master donor strain to generate other live attenuated viruses is also demonstrated. These findings put forward a promising live attenuated influenza vaccine generation strategy to control influenza.

Egg-adaptive mutations in H3N2v vaccine virus enhance egg-based production without loss of antigenicity or immunogenicity

The recently detected zoonotic H3N2 variant influenza A (H3N2v) viruses have caused 343 documented cases of human infection linked to contact with swine. An effective vaccine is needed for these viruses, which may acquire transmissibility among humans. However, viruses isolated from human cases do not replicate well in embryonated chicken eggs, posing an obstacle to egg-based vaccine production. To address this issue, we sought to identify egg-adaptive mutations in surface proteins that increase the yield of candidate vaccine viruses (CVVs) in eggs while preserving their immunizing effectiveness. After serial passage of a representative H3N2v isolate (A/Indiana/08/2011), we identified several egg-adaptive combinations of HA mutations and assessed the egg-based replication, antigenicity, and immunogenicity of A/Puerto Rico/8/34 (H1N1, PR8)-based 6+2 reverse genetics CVVs carrying these mutations. Here we demonstrate that the respective combined HA substitutions G1861V+N2461K, N1651K+G1861V, T1281N+N1651K+R762G, and T1281N+N1651K+I102M, all identified after egg passage, enhanced the replication of the CVVs in eggs without substantially affecting their antigenicity or immunogenicity. The mutations were stable, and the mutant viruses acquired no additional substitutions during six subsequent egg passages. We found two crucial mutations, G186V, which was previously defined, and N246K, which in combination improved virus yield in eggs without significantly impacting antigenicity or immunogenicity. This combination of egg-adaptive mutations appears to most effectively generate high egg-based yields of influenza A/Indiana/08/2011-like CVVs.

Critical assessment of influenza VLP production in Sf9 and HEK293 expression systems.

BackgroundEach year, influenza is responsible for hundreds of thousand cases of illness and deaths worldwide. Due to the virus’ fast mutation rate, the World Health Organization (WHO) is constantly on alert to rapidly respond to emerging pandemic strains. Although anti-viral therapies exist, the most proficient way to stop the spread of disease is through vaccination. The majority of influenza vaccines on the market are produced in embryonic hen’s eggs and are composed of purified viral antigens from inactivated whole virus. This manufacturing system, however, is limited in its production capacity. Cell culture produced vaccines have been proposed for their potential to overcome the problems associated with egg-based production. Virus-like particles (VLPs) of influenza virus are promising candidate vaccines under consideration by both academic and industry researchers.MethodsIn this study, VLPs were produced in HEK293 suspension cells using the Bacmam transduction system and Sf9 cells using the baculovirus infection system. The proposed systems were assessed for their ability to produce influenza VLPs composed of Hemagglutinin (HA), Neuraminidase (NA) and Matrix Protein (M1) and compared through the lens of bioprocessing by highlighting baseline production yields and bioactivity. VLPs from both systems were characterized using available influenza quantification techniques, such as single radial immunodiffusion assay (SRID), HA assay, western blot and negative staining transmission electron microscopy (NSTEM) to quantify total particles.ResultsFor the HEK293 production system, VLPs were found to be associated with the cell pellet in addition to those released in the supernatant. Sf9 cells produced 35 times more VLPs than HEK293 cells. Sf9-VLPs had higher total HA activity and were generally more homogeneous in morphology and size. However, Sf9 VLP samples contained 20 times more baculovirus than VLPs, whereas 293 VLPs were produced along with vesicles.ConclusionsThis study highlights key production hurdles that must be overcome in both expression platforms, namely the presence of contaminants and the ensuing quantification challenges, and brings up the question of what truly constitutes an influenza VLP candidate vaccine.Electronic supplementary materialThe online version of this article (doi:10.1186/s12896-015-0152-x) contains supplementary material, which is available to authorized users.

Safety and immunogenicity of influenza whole inactivated virus vaccines: A phase I randomized clinical trial

BACKGROUND: Influenza vaccine production capacity is still insufficient to meet global demand in case of a pandemic. To expand worldwide influenza vaccine production capacity, a solid and transferable egg-based influenza vaccine production process was established that is suitable for upscaling and technology transfer to vaccine manufacturers in low- and middle-income countries. As a proof-of-concept, the safety and immunogenicity of a pandemic whole inactivated virus (WIV) vaccine (H5N1) and a monovalent seasonal WIV vaccine (H3N2) were evaluated in a phase I clinical trial in adults. METHODS: Subjects were vaccinated with 2 doses of pandemic WIV vaccine (pWIV), or one dose of either seasonal WIV vaccine (sWIV) or a commercially available trivalent comparator vaccine followed by a placebo dose. Haemagglutination inhibiting antibody titres against the influenza strains were determined before and 21 d after each vaccination. RESULTS: The frequency and severity of adverse reactions were comparable between groups. No serious adverse events were reported. After a single dose of sWIV the seroconversion rate was 91% (Committee for Proprietary Medicinal Products (CPMP) criterion >40%), the seroprotection rate was 100% (CPMP criterion >70%), and the mean geometric mean titre (GMT) increase was 24.9 (CPMP criterion >2.5). After two doses of pWIV, seroconversion rate and seroprotection rate were both 71%, and the mean GMT increase was 7.8. CONCLUSIONS: Both pWIV and sWIV were equally well-tolerated as the comparator vaccine, and both vaccines complied with all 3 CPMP criteria. EudraCT 2011-000159-17. Netherlands National Trial Register 2695.

Rapid production of a H₉ N₂ influenza vaccine from MDCK cells for protecting chicken against influenza virus infection.

H9N2 subtype avian influenza viruses are widespread in domestic poultry, and vaccination remains the most effective way to protect the chicken population from avian influenza pandemics. Currently, egg-based H9N2 influenza vaccine production has several disadvantages and mammalian MDCK cells are being investigated as candidates for influenza vaccine production. However, little research has been conducted on low pathogenic avian influenza viruses (LPAIV) such as H9N2 replicating in mammalian cells using microcarrier beads in a bioreactor. In this study, we present a systematic analysis of a safe H9N2 influenza vaccine derived from MDCK cells for protecting chickens against influenza virus infection. In 2008, we isolated two novel H9N2 influenza viruses from chickens raised in southern China, and these H9N2 viruses were adapted to MDCK cells. The H9N2 virus was produced in MDCK cells in a scalable bioreactor, purified, inactivated, and investigated for use as a vaccine. The MDCK-derived H9N2 vaccine was able to induce high titers of neutralizing antibodies in chickens of different ages. Histopathological examination, direct immunofluorescence, HI assay, CD4(+)/CD8(+) ratio test, and cytokine evaluation indicated that the MDCK-derived H9N2 vaccine evoked a rapid and effective immune response to protect chickens from influenza infection. High titers of H9N2-specific antibodies were maintained in chickens for 5months, and the MDCK-derived H9N2 vaccine had no effects on chicken growth. The use of MDCK cells in bioreactors for LPAIV vaccine production is an attractive option to prevent outbreaks of LPAIV in poultry.

Current and emerging cell culture manufacturing technologies for influenza vaccines.

Annually, influenza virus infects millions of people worldwide. Vaccination programs against seasonal influenza infections require the production of hundreds of million doses within a very short period of time. The influenza vaccine is currently produced using a technology developed in the 1940s that relies on replicating the virus in embryonated hens' eggs. The monovalent viral preparation is inactivated and purified before being formulated in trivalent or tetravalent influenza vaccines. The production process has depended on a continuous supply of eggs. In the case of pandemic outbreaks, this mode of production might be problematic because of a possible drastic reduction in the egg supply and the low flexibility of the manufacturing process resulting in a lack of supply of the required vaccine doses in a timely fashion. Novel production systems using mammalian or insect cell cultures have emerged to overcome the limitations of the egg-based production system. These industrially well-established production systems have been primarily selected for a faster and more flexible response to pandemic threats. Here, we review the most important cell culture manufacturing processes that have been developed in recent years for mass production of influenza vaccines.

Hydrophobin fusion of an influenza virus hemagglutinin allows high transient expression in Nicotiana benthamiana, easy purification and immune response with neutralizing activity.

The expression of recombinant hemagglutinin in plants is a promising alternative to the current egg-based production system for the influenza vaccines. Protein-stabilizing fusion partners have been developed to overcome the low production yields and the high downstream process costs associated with the plant expression system. In this context, we tested the fusion of hydrophobin I to the hemagglutinin ectodomain of the influenza A (H1N1)pdm09 virus controlled by the hybrid En2PMA4 transcriptional promoter to rapidly produce high levels of recombinant antigen by transient expression in agro-infiltrated Nicotiana benthamiana leaves. The fusion increased the expression level by a factor of ∼2.5 compared to the unfused protein allowing a high accumulation level of 8.6% of the total soluble proteins. Hemagglutinin was located in ER-derived protein bodies and was successfully purified by combining an aqueous-two phase partition system and a salting out step. Hydrophobin interactions allowed the formation of high molecular weight hemagglutinin structures, while unfused proteins were produced as monomers. Purified protein was shown to be biologically active and to induce neutralizing antibodies after mice immunization. Hydrophobin fusion to influenza hemagglutinin might therefore be a promising approach for rapid, easy, and low cost production of seasonal or pandemic influenza vaccines in plants.

Characterization and immunogenicity in mice of recombinant influenza haemagglutinins produced in Leishmania tarentolae

The membrane displayed antigen haemagglutinin (HA) from several influenza strains were expressed in the Leishmania tarentolae system. This non-conventional expression system based on a parasite of lizards, can be readily propagated to high cell density (>108cells/mL) in a simple incubator at 26°C. The genes encoding HA proteins were cloned from six influenza strains, among these being a 2009 A/H1N1 pandemic strain from swine origin, namely A/California/07/09(H1N1). Soluble HA proteins were secreted into the cell culture medium and were easily and successfully purified via a His-Tag domain fused to the proteins. The overall process could be conducted in less than 3 months and resulted in a yield of approximately 1.5–5mg of HA per liter of biofermenter culture after purification. The recombinant HA proteins expressed by L. tarentolae were characterized by dynamic light scattering and were observed to be mostly monomeric. The L. tarentolae recombinant HA proteins were immunogenic in mice at a dose of 10μg when administered twice with an oil-in-water emulsion-based adjuvant. These results suggest that the L. tarentolae expression system may be an alternative to the current egg-based vaccine production.

Optimization of Microcarrier-based MDCK-SIAT1 Culture System for Influenza Virus Propagation

The preparation of seasonal influenza virus vaccines and especially its large-scale production requirement after the emergence or reemergence of a pandemic will need an alternative host cell system due to current suboptimal methods and the insufficiency of embryonated chicken eggs needed for producing them. In response to the vital and increasing demand for alternative means for influenza vaccine production, a cell line culture on microcarriers could be a potential alternative to the egg-based production. Methods: Influenza A/PR/8/1934 H1N1 was purified and quantified by plaque assay. The purified virus with 0.01 multiplicity of infection (MOI) was inoculated on Madin-Darby canine kidney-Siat1 (MDCK-SIAT1) cell line. Cytodex-1 microcarrier beads (2 g/l and 2.0×10 5 cells/ml) were used in a spinner flask to culture MDCK-SIAT1cells .The culture medium was harvested and clarified and the virus yield was quantified by 50% cell culture infective dose ( CCID 50 ) and hemagglutination assays. Next, the virus was concentrated and purified by ultra-filtration and ul- tra-centrifugation, respectively. Results: MDCK-SIAT1cells attached to the microcarriers and the cell numbers were increased efficiently. The cellular yield from the microcarrier culture was 2×10 6 cells/ml after 4-5 days. The yield of the virus titer measured by CCID 50 and hemagglutination assays after the clarification was 108 CCID 50 / ml and 40960 HA unit/ml, respectively. Conclusion: MDCK-SIAT1cells may be considered as a new substrate for the production of influenza vaccines. Using Cytodex-1 microcarrier beads can be an appropriate strategy to improve the viral yield and to lower the cost of influenza vaccine production. Vac Res, 2014, 1 (1): 35-38

Efficient chromatographic reduction of ovalbumin for egg-based influenza virus purification

Vaccination is the most effective prevention strategy to avoid influenza infection and for protection of large populations. The vast majority of influenza vaccines are still produced with allantoic fluid from fertilized chicken eggs. The presence of ovalbumin, which can constitute over 60% of the total protein content in allantoic fluid, can result in severe allergies. Consequently, efficient reduction of ovalbumin is critical during egg based vaccine manufacturing. Here we present Capto Core 700, a novel core bead chromatographic flow through mode resin for removal of ovalbumin and compare it to sucrose zonal gradient ultracentrifugation, which is the industry standard for egg-based vaccine production. The results demonstrate that core bead chromatography is fully comparable to zonal centrifugation in removing ovalbumin to meet regulatory requirements. Furthermore, the scalability and the shorter process times of this method have the potential to significantly improve the productivity and economy for industrial production compared to zonal centrifugation.

An H5N1 influenza DNA vaccine for South Africa

The highly pathogenic avian influenza virus H5N1 is a potent pandemic threat because of its frequent transmission from birds to humans and the increasing possibility of human to human transmission. During the 2009 H1N1 pandemic it was clear that rapid influenza vaccine production is a problem worldwide. Additionally, developing countries like South Africa generally cannot produce their own influenza vaccines because the traditional egg-based vaccine production method currently employed is too lengthy and too difficult to establish. As part of an exercise aimed at exploring the feasibility of producing emergency response influenza vaccines, we investigated an experimental DNA vaccine to the H5N1 influenza virus. We focused on the virion haemagglutinin, because it elicits the primary neutralising immune response following infection. Accordingly, we developed an H5N1 DNA vaccine with full-length and truncated versions of the haemagglutinin gene, to match previously developed protein candidates. Vaccinated mice developed a strong antibody response to the haemagglutinin protein. In addition, the full-length H5 gene elicited high haemagglutination inhibition titres in mice, indicating that it has potential as a candidate pandemic vaccine for South Africa.

Vaccination against Influenza with Recombinant Hemagglutinin Expressed by Schizochytrium sp. Confers Protective Immunity

For the rapid production of influenza vaccine antigens in unlimited quantities, a transition from conventional egg-based production to cell-based and recombinant systems is required. The need for higher-yield, lower-cost, and faster production processes is critical to provide adequate supplies of influenza vaccine to counter global pandemic threats. In this study, recombinant hemagglutinin proteins of influenza virus were expressed in the microalga Schizochytrium sp., an established, fermentable organism grown in large scale for the manufacture of polyunsaturated fatty acids for animal and human health applications. Schizochytrium was capable of exporting the full-length membrane-bound proteins in a secreted form suitable for vaccine formulation. One recombinant hemagglutinin (rHA) protein derived from A/Puerto Rico/8/34 (H1N1) influenza virus was evaluated as a vaccine in a murine challenge model. Protective immunity from lethal challenge with homologous virus was elicited by a single dose of 1.7, 5 or 15 µg rHA with or without adjuvant at survival rates between 80–100%. Full protection (100%) was established at all dose levels with or without adjuvant when mice were given a second vaccination. These data demonstrate the potential of Schizochytrium sp. as a platform for the production of recombinant antigens useful for vaccination against influenza.

Influenza Vaccine Progress

I have devoted several Hospital Pharmacy editorials1-4 to the safety and ethical concerns of vaccine use. I reported on a rigorous analysis5 that raised questions regarding the evidence for effectiveness of the present generation of influenza vaccines in the elderly and those at risk for medical complications. The editorial conclusion reported that current influenza vaccines do provide a moderate level of protection and the evidence still supports their use but that a partnership between industry and government may be required to guarantee the prospects for much better flu vaccines. I am pleased to report this has happened. A pandemic influenza would seriously threaten the global economy; there is currently optimism in the scientific community that better vaccines are within reach if we have the will to do it.6 Novartis, in partnership with US Department of Human Services – Biomedical and Advanced Research Authority (HHS BARDA), received approval on November 20, 2012 for Flucelvax (influenza virus vaccine). It is the first cell culture–derived vaccine available for patients 18 years of age and older. Flucelvax utilizes full-scale cell culture manufacturing technology instead of traditional egg-based production. Novartis has chosen to use a mammalian cell line rather than the current, slower process involving chicken embryos. It does not contain preservatives and allows for rapid response to an urgent public health need, such as a pandemic, within weeks. Patients have also expressed ethical concern about the use of fetal cell lines purchased by several other pharmaceutical companies. These lines have been used in production for vaccines for measles, mumps and rubella, hepatitis, polio, rabies, chickenpox, and smallpox. Bioethical issues have been raised as to the use of these vaccines for some patients.7 If the health of a child is at risk, parents, who otherwise would not use vaccines developed with fetal cell lines, may use these vaccines. Some parents may choose not to have vaccines administered to their children for ethical or religious reasons, which puts their children and, potentially, the population as a whole at increased risk of disease transmission. Those who object to these types of vaccines should make their concerns known and ask their health care system to make other types of vaccines available. This cell culture technique for vaccine production obviates these ethical concerns. Prior editorials concluded that it is incumbent on us to do what is possible to make available alternative vaccines, to encourage the pharmaceutical industry to do so as well, and to petition the US Food and Drug Administration to process any such application expeditiously. My congratulations go to Novartis and HHS BARDA. This method of cell culture technology may lead the way for further vaccine development and ensure the availability of seasonal influenza vaccines and those of a potential pandemic.