Quantitation of novel pentavalent meningococcal polysaccharide conjugate vaccine (Men A-TT, Men C-CRM, Men Y-CRM, Men W-CRM, Men X-TT) using sandwich ELISA.

Meningococcal vaccines have been developed over the years, to control outbreaks of meningitis. There are 12 immunologically distinct serogroups of which, A, B, C, W, Y and X are predominant and invasive in nature. Meningococcal vaccines can be sorted out as, polysaccharide vaccines, polysaccharide protein conjugate vaccines or protein based (independent of polysaccharides) vaccines. Stringent quality control analysis as per the regulatory guidelines is a requirement for any vaccine manufacturer for commercial release of vaccines. Quantitation becomes challenging when it comes to analysis of multivalent vaccines. We describe the quantitation of novel pentavalent meningococcal polysaccharide conjugate vaccine manufactured at Serum Institute of India Pvt Ltd (SIIPL). Briefly, sandwich ELISA assay was developed to quantitate five different serogroups (Men A-TT, Men C-CRM, Men Y-CRM, Men W-CRM, Men X-TT) in pentavalent meningococcal polysaccharide conjugate vaccine containing two different carrier proteins (TT and CRM). ELISA reported herein showed significant reproducibility and repeatability over a range of developed standard curve with acceptable coefficient of variation (<15%) for both intra and inter assay. Furthermore analysis showed that, polysaccharide conjugate (PC) contents were within the accepted range (±30%) of the stated label claim. The immunoassay was verified for its sensitivity, accuracy and precision. Based on the relevant experimental data; it is proposed that, reported sandwich ELISA is well suited for quantitation of individual polysaccharide conjugate from pentavalent formulation. Furthermore, the ELISA was explored for forced degradation and polysaccharide spiking studies. This leads to open up an area of research for sandwich ELISA as a tool to assess the integrity of vaccine as well as for lot to lot consistency monitoring.

Developmental strategy for a new Group A meningococcal conjugate vaccine (MenAfriVacR).

Until recently, periodic Group A meningococcal meningitis outbreaks were a major public health problem in the sub-Saharan Africa. In 2001, the Meningitis Vaccine Project (MVP), a partnership between the World Health Organization (WHO) and PATH, a Seattle-based NGO, and the Serum Institute of India Pvt Ltd (SIIPL) initiated discussions aimed at establishing a collaboration to develop a Group A meningococcal conjugate vaccine for this unmet medical need. Over the next 8 years the partnership made countless strategic decisions about product characteristics, raw materials, potential target populations, geographic prioritization and affordability of the vaccine to name a few. These decisions evolved into detailed plans for preclinical development, extensive field trials in Africa and India and a focused regulatory strategy specific for the Men A conjugate vaccine. Important characteristics of the process included, flexibility, transparency andeffective partnerships that included public agencies as well as private companies in Africa, Europe, the United States and India.

Regulatory Pathways That Facilitated Timely Registration of a New Group A Meningococcal Conjugate Vaccine for Africa's Meningitis Belt Countries.

BACKGROUND: Through its normative and public health leadership roles, the World Health Organization (WHO) plays a key role in the availability of vaccine products in low-and middle-income countries. The recent introduction of a new group A meningococcal conjugate vaccine, PsA-TT (MenAfriVac), in Africa exemplifies this process. WHO requires that any new vaccine to be introduced in countries for public health reasons and supplied through United Nations centralized mechanisms be licensed by the national regulatory agency (NRA) in the producing country, then prequalified and given a marketing authorization in the user countries. METHODS: PsA-TT was manufactured by the Serum Institute of India, Ltd (SIIL), which submitted a license application in April 2009 to the Drug Controller General of India (DCGI), the Indian NRA responsible for licensing vaccines. WHO encouraged the DCGI to establish a collaboration with Health Canada's Centre for Vaccine Evaluation for the review. Through this collaborative effort, registration was facilitated and in December 2009 an export license was granted to SIIL, which subsequently submitted an application for WHO prequalification. RESULTS: Given the importance of the vaccine, WHO "fast tracked" the prequalification review, and after a detailed review and site visit, WHO prequalification was granted to PsA-TT in June 2010. Country use of the new vaccine could not occur until the vaccine was a registered product in each country seeking its use. WHO facilitated country reviews by conducting regulatory training exercises (in French and English) for country NRA staff, which used the PsA-TT registration as a case study. CONCLUSIONS: PsA-TT was gradually registered in African countries as vaccine introduction proceeded. The regulatory pathway for this new group A meningococcal conjugate vaccine proved to be a useful training opportunity both in India and Africa, because the availability of the vaccine was a high African public health priority, as well as for WHO as a case study to facilitate registration of vaccines based on reliance on other regulatory bodies.

Challenges and Opportunities While Developing a Group A Meningococcal Conjugate Vaccine Within a Product Development Partnership: A Manufacturer's Perspective From the Serum Institute of India.

BACKGROUND: In 2002, the Meningitis Vaccine Project (MVP) chose the Serum Institute of India, Ltd (SIIL), as its manufacturing partner to establish a product development partnership (PDP) with the Meningitis Vaccine Project (MVP). MVP was a collaboration between PATH and the World Health Organization (WHO) to develop meningococcal conjugate vaccines for sub-Saharan Africa. METHOD: From the outset, SIIL recognized that a partnership with MVP carried some risk but also offered important opportunities for accessing new conjugate vaccine technology and know-how. Over 3 years, SIIL successfully accepted technology transfer for the group A meningococcal polysaccharide from SynCo Bio Partners and a conjugation method from the US Food and Drug Administration. RESULTS: SIIL successfully scaled up production of a group A meningococcal conjugate vaccine that used SIIL tetanus toxoid as the carrier protein. Phase 1 studies began in India in 2005, followed by phase 2/3 studies in Africa and India. A regulatory dossier was submitted to the Indian authorities in April 2009 and WHO in September 2009. Export license was granted in December 2009, and WHO prequalification was obtained in June 2010. Vaccine was introduced at public scale in Burkina Faso that December. The group A meningococcal conjugate vaccine was named MenAfriVac, and is the first internationally qualified vaccine developed outside of big pharma. CONCLUSIONS: The project proved to be a sound investment for SIIL and is a concrete example of the potential for PDPs to provide needed products for resource-poor countries.

Omega-3-fatty acid adds to the protective effect of flax lignan concentrate in pressure overload-induced myocardial hypertrophy in rats via modulation of oxidative stress and apoptosis.

Objective of the present investigation was to study the effect of the flax lignan concentrate (FLC) and Omega-3-fatty acid (O-3-FA) on myocardial apoptosis, left ventricular (LV) contractile dysfunction and electrocardiographic abnormalities in pressure overload-induced cardiac hypertrophy. The rats were divided into five groups such as sham, aortic stenosis (AS), AS+FLC, AS+O-3-FA and AS+FLC+O-3-FA. Cardiac hypertrophy was produced in rats by abdominal aortic constriction. The rats were treated with FLC (400mg/kg, p.o.), O-3-FA (400mg/kg, p.o.) and FLC+O-3-FA orally per day for four weeks. The LV function, myocardial apoptosis, and oxidative stress were quantified. FLC+O-3-FA treatment significantly reduced hemodynamic changes, improved LV contractile dysfunction, reduced cardiomyocyte apoptosis and cellular oxidative stress. Moreover, it significantly up-regulated the VEGF expression and decreased TNF-alpha level in serum. The histological analysis also revealed that FLC+O-3-FA treatment markedly preserved the cardiac structure and inhibited interstitial fibrosis. In conclusion, FLC+O-3-FA treatment improved LV dysfunction, inhibited cardiomyocyte apoptosis, improved myocardial angiogenesis, conserved activities of membrane-bound phosphatase enzymes and suppressed inflammation through reduced oxidative stress in an additive manner than FLC alone and O-3-FA alone treatment in pressure overload-induced cardiac hypertrophy.

Structure function attributes of gold nanoparticle vaccine association: effect of particle size and association temperature.

Many biotherapeutic applications of gold nanoparticles make use of conjugated or adsorbed protein moieties. Physical parameters of association such as particle size, morphology, surface chemistry and temperature influences the protein-nanoparticle association and thereby their interaction with the biological environment. In present study, effect of size of chitosan reduced gold nanoparticles (CsAuNPs) and association temperature on structure and function of tetanus toxoid (TT) vaccine has been investigated. CsAuNPs were synthesized in the sizes of 20±3, 40±5 and 80±7 nm followed by loading of TT. Binding process of CsAuNPs with TT was investigated at their predetermined micro molar concentrations. Upon binding of TT onto CsAuNPs, particle surface was characterized using X-ray photoelectron spectroscopy. CD spectroscopic evaluation of TT bound 20 nm CsAuNPs led to 75% reduction in secondary structure of TT and thereby compromised immune function. Binding of TT with 40 and 80 nm sized CsAuNPs did not cause significant modifications in secondary structure or function of TT. Thermodynamic studies using temperature dependent fluorescence spectroscopy revealed an increase in association constants with the temperature. Based on thermodynamic data three phases in CsAuNPs and TT association process were traced. Samples from these distinct phases were also investigated for immunological recognition. Ex-vivo interaction of TT-CsAuNPs with TT positive and negative sera followed by relative change in particle size and zeta potential was studied. The findings here suggests prominent role of particle size and association temperature on adsorbed TT structure and function. Such studies may help in engineering functional nanotherapeutics.

An evaluation of the emerging vaccines against influenza in children.

BACKGROUND: Influenza is an under-appreciated cause of acute lower respiratory infections (ALRI) in children. It is estimated to cause approximately 20 million new episodes of ALRI in children annually, 97% of these occurring in developing countries. It is also estimated to result in 28000 to 112000 deaths annually in young children. Apart from hospitalisations and deaths, influenza has significant economic consequences. The current egg-based inactivated influenza vaccines have several limitations: annual vaccination, high production costs, and cannot respond adequately to meet the demand during pandemics. METHODS: We used a modified CHNRI methodology for setting priorities in health research investments. This was done in two stages. In Stage I, we systematically reviewed the literature related to emerging cross-protective vaccines against influenza relevant to several criteria of interest: answerability; cost of development, production and implementation; efficacy and effectiveness; deliverability, affordability and sustainability; maximum potential impact on disease burden reduction; acceptability to the end users and health workers; and effect on equity. In Stage II, we conducted an expert opinion exercise by inviting 20 experts (leading basic scientists, international public health researchers, international policy makers and representatives of pharmaceutical companies). They answered questions from the CHNRI framework and their "collective optimism" towards each criterion was documented on a scale from 0 to 100%. RESULTS: The experts expressed very high level of optimism for deliverability, impact on equity, and acceptability to health workers and end users. However, they expressed concerns over the criteria of answerability, low development cost, low product cost, low implementation cost, affordability and, to a lesser extent sustainability. In addition they felt that the vaccine would have higher efficacy and impact on disease burden reduction on overall influenza-associated disease rather than specifically influenza-associated pneumonia. CONCLUSION: Although the landscape of emerging influenza vaccines shows several promising candidates, it is unlikely that the advancements in the newer vaccine technologies will be able to progress through to large scale production in the near future. The combined effects of continued investments in researching new vaccines and improvements of available vaccines will hopefully shorten the time needed to the development of an effective seasonal and pandemic influenza vaccine suitable for large scale production.

Trigonelline ameliorates diabetic hypertensive nephropathy by suppression of oxidative stress in kidney and reduction in renal cell apoptosis and fibrosis in streptozotocin induced neonatal diabetic (nSTZ) rats.

Oxidative stress and apoptotic cell death in kidney have been suggested as contributing factors in the development and complication of diabetes especially in diabetic nephropathy (DN). This study investigated the effects of trigonelline (TG) on the renal functional, morphological changes and renal apoptosis in neonatal diabetic rats, a model of non-insulin-dependent diabetes mellitus. Diabetes mellitus was induced in one day old neonatal Wistar rat pups by an intraperitoneal (i.p.) injection of streptozotocin (STZ) (50mg/kg) and monitored for 16 weeks thereafter. The diabetic rats were divided as follows: the nSTZ diabetic group, the TG (50mg/kg) treated diabetic group, and the TG (100mg/kg) treated diabetic group. The age matched nondiabetic group received an injection of citrate buffer (0.1M, pH4.5). At the end kidney samples were taken for light microscopic examinations. The levels of serum creatinine and BUN were significantly low in TG (100mg/kg) treated diabetic rats. Glomerular filtration rate was improved in TG treated rats. The activities of antioxidant enzyme and membrane bound enzyme were decreased and the levels of tumor necrotic factor (TNF-α) and hydroxyproline content were increased in renal tissues of the diabetic group. TG (100mg/kg/day) treatment for a period of 4 weeks showed significant ameliorative effects on all the biochemical parameters studied. Biochemical findings were supported by histological studies. The degenerative changes in kidney tissue and fibrosis were alleviated in the TG treated groups. These results suggested that TG might have a significant role in alleviating kidney damage in nSTZ-diabetic rats.

Assessment of safety and immunogenicity of two different lots of diphtheria, tetanus, pertussis, hepatitis B and Haemophilus influenzae type b vaccine manufactured using small and large scale manufacturing process.

BACKGROUND: Hib vaccine can be easily incorporated in EPI vaccination schedule as the immunization schedule of Hib is similar to that of DTP vaccine. To meet the global demand of Hib vaccine, SIIL scaled up the Hib conjugate manufacturing process. This study was conducted in Indian infants to assess and compare the immunogenicity and safety of DTwP-HB+Hib (Pentavac(®)) vaccine of SIIL manufactured at large scale with the 'same vaccine' manufactured at a smaller scale. METHODS: 720 infants aged 6-8 weeks were randomized (2:1 ratio) to receive 0.5 ml of Pentavac(®) vaccine from two different lots one produced at scaled up process and the other at a small scale process. Serum samples obtained before and at one month after the 3rd dose of vaccine from both the groups were tested for IgG antibody response by ELISA and compared to assess non-inferiority. RESULTS: Neither immunological interference nor increased reactogenicity was observed in either of the vaccine groups. All infants developed protective antibody titres to diphtheria, tetanus and Hib disease. For hepatitis B antigen, one child from each group remained sero-negative. The response to pertussis was 88% in large scale group vis-à-vis 87% in small scale group. Non-inferiority was concluded for all five components of the vaccine. No serious adverse event was reported in the study. CONCLUSIONS: The scale up vaccine achieved comparable response in terms of the safety and immunogenicity to small scale vaccine and therefore can be easily incorporated in the routine childhood vaccination programme.

Seroprevalence of rubella and immunogenicity following rubella vaccination in adolescent girls in India.

INTRODUCTION: Serologic surveys conducted in different countries indicate that rubella is a worldwide infection. Several such sero surveys conducted in India have also confirmed that 6-47% of women are susceptible to rubella infection. The current study was conducted on 1,329 female adolescents in 12 districts of Maharashtra, India, to assess their serological status in terms of rubella exposure. METHODOLOGY: After enrollment, a pre-vaccination blood sample was collected from the participants followed by rubella vaccination (R-vac). Adverse events were monitored for the next 6-8 weeks, at which time a post-vaccination sample was collected. RESULTS: Pre-vaccination rubella immunity was higher in the urban (80.2%) population compared to the rural (73.1%) population. Following R-vac vaccination, out of 1,159 participants who completed the study, all (100%) in the urban and 99.5% of participants in the rural area developed antibodies against rubella. CONCLUSION: Substantial numbers of women reach childbearing age without immunity against rubella and thus are at a risk of passing the infection to their fetuses, who can then develop subsequent congenital defects leading to congenital rubella syndrome (CRS). An immunization policy recommending vaccination with rubella or rubella containing vaccine is highly desirable to prevent rubella and CRS. 

An evaluation of respiratory administration of measles vaccine for prevention of acute lower respiratory infections in children.

BACKGROUND: Measles was responsible for an estimated 100,000 deaths worldwide in 2008. Despite being a vaccine-preventable disease, measles remains a major cause of morbidity and mortality in young children. Although a safe and effective injectable measles vaccine has been available for over 50 years it has not been possible to achieve the uniformly high levels of coverage (required to achieve measles eradication) in most parts of the developing world. Aerosolised measles vaccines are now under development with the hope of challenging the delivery factors currently limiting the coverage of the existing vaccine. METHODS: We used a modified CHNRI methodology for setting priorities in health research investments to assess the strengths and weaknesses of this emerging intervention to decrease the burden of childhood pneumonia. This was done in two stages. In Stage I, we systematically reviewed the literature related to emerging aerosol vaccines against measles relevant to several criteria of interest. Although there are a number of different aerosol vaccine approaches under development, for the purpose of this exercise, all were considered as one intervention. The criteria of interest were: answerability; cost of development, production and implementation; efficacy and effectiveness; deliverability, affordability and sustainability; maximum potential impact on disease burden reduction; acceptability to the end users and health workers; and effect on equity. In Stage II, we conducted an expert opinion exercise by inviting 20 experts (leading basic scientists, international public health researchers, international policy makers and representatives of pharmaceutical companies). The policy makers and industry representatives accepted our invitation on the condition of anonymity, due to the sensitive nature of their involvement in such exercises. They answered questions from the CHNRI framework and their "collective optimism" towards each criterion was documented on a scale from 0 to 100%. RESULTS: The panel of experts expressed mixed feelings about an aerosol measles vaccine. The group expressed low levels of optimism regarding the criteria of likelihood of efficacy and low cost of development (scores around 50%); moderate levels of optimism regarding answerability, low cost of production, low cost of implementation and affordability (score around 60%); and high levels of optimism regarding deliverability, impact on equity and acceptability to health workers and end-users (scores over 80%). Finally, the experts felt that this intervention will have a modest but nevertheless important impact on reduction of burden of disease due to childhood pneumonia (median: 5%, interquartile range 1-15%, minimum 0%, maximum 45%). CONCLUSION: Aerosol measles vaccine is at an advanced stage of development, with evidence of good immunogenicity. This new intervention will be presented as a feasible candidate strategy in the campaign for global elimination of measles. It also presents an unique opportunity to decrease the overall burden of disease due to severe pneumonia in young children.

Immunogenicity and safety of an indigenously manufactured reconstituted pentavalent (DTwP-HBV+Hib) vaccine in comparison with a foreign competitor following primary and booster immunization in Indian children.

OBJECTIVE: An open label, controlled clinical study was conducted in Indian infants aged 6-14 weeks to compare the immunogenicity and safety of a reconstituted pentavalent vaccine (DTwP-HBV+Hib) of Serum Institute of India Ltd (SIIL) with TritanrixHB+Hiberix vaccine of Glaxo Smithkline (GSK). METHODS: Eligible infants were randomized to receive three doses of the study / comparator vaccine. The vaccines were reconstituted prior to administration, by mixing DTwP-HBV (liquid) with the Hib (lyophilized) vaccine. IgG antibody titres were assessed by ELISA at baseline and after one month following the 3-dose primary immunization schedule. Safety was evaluated after each dose. Further, safety and immunogenicity was also evaluated following a booster dose in the same cohort of children (aged between 15-24 months). SETTING: Tertiary-care hospitals in India Important outcome measures: Immunogenicity and safety following a 3-dose primary vaccination series and a booster vaccination. RESULTS: Post-primary immunization, 100% seroprotection was noted for Diphtheria, Tetanus, Hepatitis B and PRP-Hib components in both the vaccine groups. For pertussis, response was 96.1% in SIIL and 95.4% in GSK group. The overall safety profile as well as persistence of antibodies against all vaccine components up to the time of booster immunization was comparable between the SIIL and GSK groups. A marked rise of all antibody concentrations indicated effective priming. The booster dose was safe, well tolerated with a significant increase in antibody concentrations of all the vaccine antigens in both the groups. CONCLUSION: DTwP-HBV+Hib vaccine of SIIL was found to be safe and immunogenic. This Indian vaccine compared well with the licensed vaccine and is a cost-effective alternative for incorporating into the immunization schedule of various countries so as to control worldwide Hepatitis B and Hib infections.

Renoprotective effect of Linum usitatissimum seeds through haemodynamic changes and conservation of antioxidant enzymes in renal ischaemia-reperfusion injury in rats.

OBJECTIVE: To evaluate an ethanolic extract of seeds of Linum usitatissimum (Linn.) (EELU) for its renoprotective role in rats through its antihypertensive effect and conservation of biological oxidation enzymes. MATERIALS AND METHODS: Male Wistar rats (200-250 g) underwent uninephrectomy on day 0; after 2 weeks of recovery, the nephrectomised rats were divided into four groups of eight each: (I) sham (II); renal ischaemia reperfusion (RIR); (III) RIR + EELU 200 mg/kg; and (IV) RIR + EELU 400 mg/kg. In group II, III and IV the renal artery was occluded for 45 min and reperfused for 4 weeks; the sham group did not undergo RIR. RESULTS: EELU (400 mg/kg) significantly decreased the haemodynamic changes after 4 weeks of RIR injury. EELU treatment significantly restored the levels of renal endogenous antioxidant enzymes and membrane-bound enzymes. EELU 400 mg/kg restored the levels of blood urea nitrogen and serum creatinine. EELU also decreased the levels of tumour necrosis factor-α and myeloperoxidase activity. A flow-cytometric study confirmed a significant decrease in cellular necrosis and increase in viability after RIR in EELU-treated rats. The anti-apoptotic role of EELU was evident from the decrease in DNA fragmentation. Renal tissue damage as assessed by histopathology was decreased in groups III and IV (200 and 400 mg/kg EELU). CONCLUSION: We conclude that EELU protected the kidney against RIR-induced renal injury, probably by inhibiting reactive oxygen species that have a causal role in such cases. It also inhibits apoptotic cell death and inflammation, and improves haemodynamic changes.

Diphtheria, tetanus, and pertussis immunity in Indian adults and immunogenicity of td vaccine.

Rise of diphtheria cases in adults is a cause of concern worldwide. Pertussis is also now affecting adults. We assessed serum levels of tetanus, diphtheria and pertussis antibodies in 62 adults in Pune, India, who had missed their primary immunization. All adults were then given three doses of tetanus-diphtheria (Td) vaccine at 0, 1, and 6 months. All adults were immune to tetanus but 78% had long-term protection. For diphtheria, 88% were protected but only 9% had long term immunity. Only 60% were immune to pertussis. After three doses of the vaccine, long term immunity to both tetanus and diphtheria increased to 87% and 97%, respectively (P < 0.05). Geometric mean titres (GMT) of both antibodies also increased significantly. The vaccine caused minor local reactions and mild fever in a few subjects. There is need of three doses of Td vaccination in those Indian adults, who missed their primary immunization. Susceptibility to pertussis also needs to be further explored.

Stability testing of vaccines: Developing Countries Vaccine Manufacturers' Network (DCVMN) perspective.

Stability testing is an integral part of the vaccine manufacturing process and is crucial for the success of immunization programs. WHO (World Health Organization) has recently published guidelines on the stability testing of vaccines. These guidelines enlist scientific basis and principles for stability testing at various stages like development, pre-clinical, clinical, licensing, lot release and post-licensure monitoring. DCVMN (Developing Countries Vaccine Manufacturers' Network) is an international body of developing countries vaccine manufacturers and has viewpoints on technical and administrative issues in stability testing of vaccines. We here highlight viewpoints, possible roles and global expectations of DCVMN in the area of stability testing of vaccines.

Emerging markets & emerging needs: developing countries vaccine manufacturers' perspective & its current status.

The success of vaccination has remained an important contribution towards public health in both industrialised and developing countries. However, there are still unmet public health needs in vaccine preventable diseases owing to issues related to affordability, supply, public awareness, research and development, intellectual property, skilled human resource, etc. Various global initiatives are being taken to tackle such issues. DCVMN, Developing Country Vaccine Manufacturers' Network, is one of such novel initiatives by developing countries, and is playing an important role in facilitating cheaper and quality vaccines to children of the world. DCVMN has become an international body for emerging vaccine manufacturers from the developing world. This manuscript provides an overview of DCVMN with respect to its origin, objectives, achievements, limitations and expectations.

Immunogenicity of two modern tissue culture rabies vaccines in pre-exposure prophylaxis.

Pre-exposure prophylaxis was given to employees supposed to be involved in rabies vaccine production in India. Prior to availability of the manufacturer's own human diploid cell (HDC) vaccine (Rabivax), immunization was executed with a chick embryo cell (CEC) vaccine (Rabipur). This constellation gave an opportunity to compare retrospectively immunogenicity of these two vaccines. The data was collected by retrospective analysis over more than three years at the clinic of Serum Institute of India Ltd. As per the standard protocol, persons with negative rabies vaccination history receive a dose of 1 ml of rabies vaccine intramuscularly on day 0, 7 and 28, and the virus anti-glycoprotein antibodies are measured one month after the third dose. The antibody levels > or =0.5 IU/ml are considered protective. The CEC and HDC vaccines were used during the analysis period. In all, 43 individuals received the CEC vaccine, 106 the HDC vaccine. The mean age of recipients was 33 years five months (Rabipur) and 30 years three months (Rabivax). All subjects in both groups were males. Five commercial batches of the CEC vaccine (129 doses) and seven batches of the HDC vaccine (318 doses) were used. Ninety-nine percent of the HDC and 93% of the CEC vaccine recipients were protected after the standard three dose schedule. Geometric mean titre was significantly greater for the HDC than CEC vaccine, being 5.05 IU/ml and 2.90 IU/ml, respectively (p = 0.0002). The HDC vaccine showed a good lot-to-lot consistency with respect to GMT both by ANOVA test and Nonparametric ANOVA test. On the other hand, the CEC vaccine demonstrated a variation in titres, when the lots were compared. Three out of four low-responders accepted a booster vaccination, and regardless of whether Rabipur or Rabivax was used, all three responded well one month after the booster. The Indian HDC vaccine compares well with the CEC vaccine in terms of immunogenicity. With HDC vaccines, cost has been an issue. However, since the new HDC vaccine has a comparable cost to the CEC vaccine, it may be possible to use it in large-scale vaccinations.

Mumps outbreaks in Canada and the United States: time for new thinking on mumps vaccines.

Mumps epidemics in Canada and the United States prompted us to review evidence for the effectiveness of 5 different vaccine strains. Early trials with the Jeryl Lynn vaccine strain demonstrated an efficacy of approximately 95%, but in epidemic conditions, the effectiveness has been as low as 62%; this is still considerably better than the effectiveness of another safe strain, Rubini (which has an effectiveness of close to 0% in epidemic conditions). The Urabe vaccine strain has an effectiveness of 54%-87% but is prone to cause aseptic meningitis. Little epidemiological information is available for other vaccines. The Leningrad-Zagreb vaccine strain, which is widely used in developing countries and costs a fraction of what vaccines cost in the developed world, seems to have encouraging results; in 1 study, the effectiveness of this vaccine exceeded 95%. Aseptic meningitis has also been reported in association with this vaccine, but the benign nature of the associated meningitis was shown recently in Croatia. Also, the Leningrad-3 strain seems to be effective but causes less-benign meningitis. No mumps vaccine equals the best vaccines in quality, but the virtually complete safety of some strains may not offset their low effectiveness. Epidemiological data are pivotal in mumps, because serological testing is subject to many interpretation problems.