|Year : 2015 | Volume
| Issue : 2 | Page : 203-204
The narrow road to the indigenous rotavirus vaccine
Department of Microbiology, All India Institute of Medical Sciences, New Delhi, India
|Date of Submission||22-Mar-2015|
|Date of Acceptance||25-Mar-2015|
|Date of Web Publication||10-Apr-2015|
B K Das
Department of Microbiology, All India Institute of Medical Sciences, New Delhi
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Das B K. The narrow road to the indigenous rotavirus vaccine. Indian J Med Microbiol 2015;33:203-4
The recent launch of an indigenous rotavirus vaccine resonated well with the "Make in India" theme. As India rapidly progresses to an economic super power, manufacturing an Indian rotavirus vaccine based on a strain isolated from a newborn at All India Institute of Medical Sciences (AIIMS), heralds a new era in Indian healthcare. Indian pharmaceutical industries have been exporting millions of doses of affordable vaccines and essential drugs to other countries providing the much needed relief. The development of an indigenous vaccine, the journey as inspiring as India's Mangalayan mission to Mars, will motivate new generations of Indian researchers to dream big. The realization of this dream started way back in the 1990s, with the chance meeting of two like-minded individuals. Dr. Roger I Glass, working on his PhD in Bangladesh, understood the immense burden of rotavirus diarrhea in the developing world. Dr. MK Bhan, a pediatrician at AIIMS had recognized the possibility of prevention of this disease through vaccine. The common dream of fighting this disease led to a joint venture under INDO-US Vaccine Action Program (VAP) of Department of Biotechnology (DBT), Ministry of Science and Technology, Government of India and Centers for Disease Control and Prevention (CDC), Atlanta, GA, USA. The pursuit of this goal, from the drawing board to the battle ground was long and arduous. It began with Dr Jon R Genstch, a molecular virologist, working at CDC, Atlanta, GA leading the basic research and I was fortunate to be a part of this group. The initial characterization of the asymptomatic neonatal rotavirus virus 116E as a vaccine candidate resulted in a successful US patent. Active collaboration of basic researchers, clinicians, and epidemiologist during initial phase of development; and close coordination between governmental, nongovernmental, and funding organizations and manufacturing industry; in the later part, was crucial for scaling up the vaccine for clinical efficacy trials.
The rotavirus vaccine strain 116E, an asymptomatic human-animal hybrid virus,  perhaps emerged in the immunologically less hostile neonatal gut through random event of a mixed infection. Natural attenuation of this virus may have taken place as a result of its ability to persist and survive in the niche of a neonatal mucosa despite presence of large quantities of maternal antibodies crossing over from placenta or from ingestion of colostrum in the breast milk. The recombinant nature of the genome possibly helped the virus to adapt to humans well, an ideal situation for developing a vaccine using Jennerian approach. Existence of circulating viruses with similar genetic make up  diminishes the probability of a vaccine -wild type hybrid virus with higher virulence; the spread of the vaccine virus in the community, in reality, may enhance the herd immunity. Administration of this live, naturally-attenuated, oral vaccine early in infancy, as a part of the developing gut microbiota, may help constitute a robust mucosal immune response through probiotic like effect despite maternal antibodies. Vaccine efficacy of 116E was shown to be comparable to RotaTeq and Rotarix vaccines, in its ability to prevent severe dehydration in the 1st year of life. 116E vaccine had also demonstrated heterotypic immunity across diverse rotavirus genotypes.  Identification of the cross protective epitopes present either on VP7, VP4, or other undefined locations will be essential to understand which components of the innate or the adaptive immune systems are involved in heterotypic protection. Additionally, the ability of 116E to induce heterotypic cross protection may reduce the fear of vaccine like virus replacement among circulating rotavirus strains in the community, as was observed for example in Hib vaccine after effect (homotypic protection). 116E as a combination vaccine, rather than its monovalent avatar, is more appealing as it may offer better protection across divergent genotypes. Developing countries of the world may have a lot to look forward, as this indigenously developed vaccine from India becomes part of an affordable vaccine package. On the flip side, this will greatly boost the home-grown vaccine manufacturing industries in India. Furthering this discussion, it is important to understand that a major proportion of the diarrheal diseases in developing countries are primarily due to bacterial causes, especially the diarrheagenic Escherichia More Details coli species. The issue gets a little murkier as there are no assays currently available for identification of these agents in a routine diagnostic laboratory. Hopefully, with more emphasis on innovation and cutting edge research, a pentavalent vaccine for bacterial diarrhea may not be an impossible dream! Any takers?
| ~ References|| |
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