In Search Of Vaccine

There are around 100 vaccines being developed against Covid-19 by research teams in companies and universities across the world

Prof Upendra Kaul

VACCINATION is a simple, safe, and effective way of protecting people against harmful diseases, before they come into contact with them. We now have vaccines to prevent more than 20 life-threatening diseases, helping people of all ages live longer, healthier lives. Immunization currently prevents 2-3 million deaths worldwide every year from diseases like diphtheria, tetanus, whooping cough pertussis, influenza and measles etc. It makes the body’s systems immune to get infections against which vaccination has been done.

The term vaccine  is related to Edward Jenner to denote cowpox ,Variolae vaccinae (smallpox of the cow), which he discovered in 1798 and used for small pox prevention. In 1881, to honour Jenner, Louis Pasteur proposed that the term should be extended to cover the new protective inoculations then being developed and the term thus stayed.

All these vaccine development programs are complex and have several stages; Exploratory stage, Pre-clinical stage, Clinical development, Regulatory review and approval, Manufacturing and Quality control. Clinical development is a three-phase process. During Phase I, small groups of people receive the trial vaccine. In Phase II, the clinical study is expanded and vaccine is given to people who have characteristics (such as age and physical health) similar to those for whom the new vaccine is intended. In Phase III, the vaccine is given to thousands of people and tested for efficacy and safety. Many vaccines undergo Phase IV formal, ongoing studies after the vaccine is approved and licensed.

Testing the vaccine safety is of paramount importance in addition to its efficacy in the development of immunity and protection from the said disease. An Investigational New Drug application, Pre-licensure vaccine clinical trials, A Biologics License Application (BLA), Inspection of the manufacturing facility, Presentation of findings to the controller from the controlling authorities and finally the usability testing of product labelling.

What about COVID 19? There are around 100 vaccines being developed against SARS-CoV-2 by research teams in companies and universities across the world. Researchers are trying different technologies, some of which haven’t been used in a licensed vaccine before. At least six groups have already begun injecting formulations into volunteers in safety trials; others have started testing in animals.

All vaccines aim to expose the body to an antigen that won’t cause disease, but will provoke an immune response that can block or kill the virus if a person becomes infected. There are at least eight types being tried against the coronavirus, and they rely on different viruses or viral parts. The four groups – with each having 2 sub-groups are:1.  Virus- Inactivated or weakened, 2. Viral Vector- replicating and Non-Replicating. 3. Nucleic Acid based- DNA or RNA. 4.Protein based- Protein subunit and Virus like particles.

Just to give an update of some recent reports in prestigious international Journals. New England journal of medicine carried an original article based upon a mRNA vaccine on July 14th this year, in a phase 1, dose-escalation, open-label trial including 45 healthy adults, who received two vaccinations, 28 days apart, with mRNA-1273 in 3 different escalating doses in 15 participants each. The vaccine mRNA- induced anti–SARS-CoV-2 immune responses in all participants, and no trial-limiting safety concerns were identified. These findings support further development of this vaccine. The financial support of this ambitious program is from National Institute of Allergy and Infectious Diseases and others sources of US federal government.

The other very talked about vaccine is the Oxford vaccine the preliminary report of its Phase 1 and 2 came in on  July 20 last month, in the LANCET. It showed an acceptable safety profile, and homologous boosting increased antibody responses. The vaccine was the chimpanzee adenovirus-vectored vaccine (ChAdOx1 nCoV-19). These results, together with the induction of both humoral and cellular immune responses, support a large-scale evaluation of this candidate vaccine in an ongoing phase 3 program, which is a time-consuming program involving several thousand subjects assessing safety and efficacy.

On the other hand we also hear about a Russian vaccine from Moscow’s Gamaleya Institute which according to their health minister has completed clinical trials, and ‘paperwork’ for its ‘registration’ with the country’s regulatory body was underway. He also announced that a mass vaccination programme, presumably using this vaccine, would be launched in Russia in October and that doctors and teachers would be among the first groups to be vaccinated. A news report by Russia’s Tass news agency in the second week of July had said that this candidate vaccine had entered phase 2 of clinical trials on July 13. A phase in which the vaccine is tested for its ability to trigger immune response in human beings, usually takes a few months to be completed.

Although the vaccine programs for COVID are being fast tracked but jumping phase 3 is a dangerous gamble which most scientific authorities do not agree to. Only a very small number of vaccines that are developed actually get the approval to be used. In the case of the Russian Coronavirus vaccine, however, a regulatory approval is being taken almost for granted. Because of these reasons, there is some amount of scepticism with regard to the Russian vaccine. This scepticism was expressed by top infectious disease experts internationally. Same concerns are being raised against the Chinese Vaccine which is also according to Chinese news reports around the corner.

Zydus Cadila of India is working with 2 COVID vaccines, one using DNA and the other using Replicating Viral Vector. Both are in very early stages. The Serum Institute of India vaccine based upon live attenuated virus is also in early stages. They are partnering with Codagenix vaccine which is in pre-clinical trials and their, Novavax candidate is only a few months behind the Astra-Zenica Oxford vaccine. They plan to announce its availability possibly by the end of 2021.

With the total number of cases in India of COVID-19, mounting TO around two million with about 40,000 deaths the situation has assumed alarming proportions. The situation in Kashmir valley is also very scary. We really need an early breakthrough in the form of an effective and safe vaccine and not just a political rhetoric. We are experts in the field of deriving political mileage from premature and unscientific jargons.

  • Author is a Cardiologist, recipient of Padmashiri and Dr B C Roy Award . The author can be contacted at [email protected]

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