Science

Can typhoid be an illness of the past?

Lab technicians testing for the presence of bacteria. (Representational image)   | Photo Credit: REUTERS

The world is rid of smallpox. Globe-wide vaccination against it made this possible. We are close to getting rid of polio as well, and hoping that it too may no longer afflict us. Now, with a new vaccine against typhoid, made by an Indian vaccine manufactorer, Bharat Biotech of Hyderabad, that has been approved by WHO, typhoid, too, may soon be a thing of the past. The journal Nature Medicine called this one of the “Treatments that made headlines in 2018.” The journal writes: And it is here that we read with pride that “The WHO has approved a vaccine against typhoid fever, called Typbar TCV, short for typhoid conjugate vaccine. It is the only vaccine deemed safe enough for use in infants starting at 6 months of age. This vaccine is the first conjugate vaccine — a vaccine in which a weak antigen (of the typhoid germ) is attached to a strong antigen (from the tetanus germ) to elicit antibody responses — against a bacterial disease (typhoid) that “affects up to 20 million people annually” (quote from Nature Medicine December 24, 2018, pp. 1780).

This vaccine Typbar TCV, whose creation and trial was first published by Bharat Biotech in 2013 (Mohan et al., Clinical Infectious Diseases 2015; 61(3):393-402; DOI: 10.1093/cid/civ295). This vaccine was tried in a unique human challenge model by an Oxford University group, and found to be superior to other competitive vaccines (made by e.g., Sanofi Pasteur, France). Based on this, the vaccine has been cleared for introduction in the National Immunization Programmes in Africa and Asia.

Vaccines for the world

Many people across even India do not realise that over one-third of the world’s vaccines are made in our country today by just a handful of biotech firms and distributed across the Indian continent, Africa and Asia. All this has happened during the last 30 years or so. Until then, we imported vaccines made abroad and manufactured them here using the same process, on license. It is only when biotech firms forayed into the discovery of local strains of bacteria and viruses that indigenous creation of vaccines using modern biological methods began happening. Dr. Chandrakant Lahariya has published an informative, brief history of vaccines and vaccination in India (Indian Journal of Medical Research 2014 April; 139 (4):491- 511: online accessible at PMID: 24927336).

Until recently, vaccine against typhoid was made by injecting live, but grossly weakened typhoid germs into the human body, provoking the body to mount immunochemicals called antibodies. Later, scientists found that it was not good to use live germs, since there are unwanted side-effects. Hence, they started using an important molecular component (the polymer that coats or covers the surface of the germ) which can elicit the same antibody from the injected ‘host’. However, the treatment was not as effective or strong as we want. If only one can boost the immunological strength of the host! This was also tried using what are called carrier proteins added to the capsular polymer of typhoid germ. Several such carrier protein-based vaccines have also been tried and are in the market, even in India. A current paper by S. Sahastrabuddhe and T. Saluja which overviews the Typhoid Conjugate Vaccine Pipeline (Clinical Infectious Diseases, 2019; 68(S1):S22-26; doi: 10.1093/cid/ciy884) points out that Typbar-TCV has superior results on clinical trials, and is thus awarded WHO’s pre-qualification and stipulations that allow for purchase by UNICEF.

Team science model

It is instructive in this connection to note what a Canadian group had written about the Indian vaccine industry (Chakma et al., Case Study: India’s Billion Dollar Biotech. Nature Biotechnology 2010; 28(8):783.doi:10.1038/nbt0810-783; and also in Globalization and Health, 2011, https://globalizationandhealth.biomedcentral.com/articles/10.1186/1744-8603-7-9). (The group discussed how another creative vaccine manufacturer in Hyderabad, Shantha Biotechnics, successfully introduced Hepatitis B vaccine across the world at affordable costs). The four important points that they pointed out for such success were: identify the therapeutic area and the scale of demand, investment and partnership, innovation through collaboration with scientists and clinics, and connect with national and global agencies- plus a current Good manufacturing Practice (cGMP) setup.

And Bharat Biotech has done all these in good measure. In fact, their successful introduction of the Rotavirus vaccine is an early example of what has been called the ‘Team Science Model’ involving clinicians, scientists, national and global support groups, and the national government (see Bhan et al., Team science and the creation of a novel rotavirus vaccine in India: a new framework for vaccine development. Lancet 2014; 383 (9935): 2180-3. doi.10.1016/S0140-6736 (14)60191-4). Another such team science effort was their vaccine JenVac against Japanese Encephalitis (Singh A et al., Journal of Infectious Diseases 2015 Sep 1;212(5):715-25. doi: 10.1093/infdis/jiv023. Epub 2015 Jan 18).

And a fifth point: the role played by the India government, through its “Process Patent Law” of 1970, which led to the booming of private drug firms manufacturing global quality drugs at affordable costs across the world (for example, the Gandhian steps by Dr Yusuf Hamied of CIPLA in offering anti-HIV drugs at affordable costs to Africa, and Kiran Majumdar Shaw of Biocon offering insulin at Rs 7 per day’s need), and through recognition, grants and loans from the Department of Science and Technology and the Department of Biotechnology, Government of India, through research grants (including Biotechnology Industry Research Assistance Council, BIRAC), has been catalytic and praiseworthy. These have led to our vaccine companies offer quality vaccines for the entire world at globally affordable costs.

dbala@lvpei.org

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Printable version | Jan 18, 2021 2:37:10 AM | https://www.thehindu.com/sci-tech/science/can-typhoid-be-an-illness-of-the-past/article29667473.ece

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