August 15 launch for Covaxin
August 15 launch for Covaxin
1. CONTEXT OF THE NEWS
Recently the head of the Indian Council of Medical Research (ICMR) wrote to all the 12 trials for the Covid-19 vaccine candidate, Covaxin, asking to complete all the clinical trials by August 15, which is the date set for the public launch of Covaxin.
This editorial discusses various aspects of the development of a vaccine.
2. ABOUT COVAXIN
2.1 What is Covaxin?
- Covixin is a potential candidate for the COVID-19 vaccine. It has been developed by the company Bharat Biotech India (BBIL) in collaboration with ICMR’s National Institute of Virology (NIV).
- It is an “inactivated” vaccine, which means it is made up of particles of killed Covid-19 virus rendering them unable to infect or replicate.
- When a specific dose of these particles is injected in a person, it stimulates the body to produce antibodies against the deadly virus thereby building immunity against the virus.
2.2 Details regarding Launch of Covaxin
- The ICMR aims to make Covaxin available for public use by August 15.
- For achieving this, the ICMR Head has written to the 12 trial sites to make sure that 'all' clinical trials are completed within time.
- For achieving this, the ICMR head has directed BBIL to complete enrolment of trial participants a week before BBIL had initially planned.
2.3 Is the August 15 launch achievable?
- Generally, a vaccine goes through three phases of human trials.
- Until now the approvals have been given only for phase I and II trials by the Central Drugs Standard Control Organisation.
- It its application submitted to Clinical Trials Registry of India (CTRI), BBIL had estimated phase I and II trials to take fifteen months including at least a month for phase I alone.
- Experts have raised doubts over the successful completion of all three phases within a month and a half.
- Even most ambitious companies that are already in advanced stages of development of the COVID-19 vaccine have a longer timeframe.
- Bioethics experts are deeply concerned that the development of vaccines should not be done at the cost of efficacy and safety.
3. OTHER TYPE OF VACCINE CANDIDATES FOR COVID-19
3.1 Non-replicating viral vector
- Some viruses as the SARS-CoV-2 (Severe Acute Respiratory Syndrome coronavirus 2) has a spike on its surface called the ‘spike protein’, which the virus uses to enter and infect cells and multiply.
- In a non-replicating viral vector vaccine, the Covid-19 spike protein is modified so that it does not replicate and is then delivered in the human body using a weakened version of a different virus.
- The body sees the spike protein as an antigen and builds immunity against it so that it can attack the real virus if it tries to infect the body.
- An antigen is any foreign object (mostly toxins) that stimulates an immune response in the body most importantly the production of antibodies.
- Antibodies are used by the immune system to neutralize the antigens.
- A COVID-19 vaccine candidate of this type being tested by the University of Oxford in collaboration with AstraZeneca.
- The vaccine uses the ChAdOx1 virus (a weakened version of a common cold virus infecting chimpanzees).
- The Vaccine is already in phase III and on the earliest will only be available towards the end of this year.
3.2 RNA vaccine
- This type of vaccine uses messenger RNA (mRNA) molecules that direct the cells to build specific types of protein.
- For the COVID-19 vaccine, the messenger RNA (mRNA) molecule is coded to direct the cells to build the molecular structure present on the surface of SARS-Cov-2.
- The immune system will recognize this as an antigen and build antibodies against it, thereby building immunity.
- Moderna has developed an mRNA vaccine in collaboration with the US National Institute of Allergy and Infectious Diseases. The phase III trials of this vaccine are expected to start this month.
- Pfizer (in collaboration with Germany’s BioNTech) has been giving patients its experimental RNA vaccine at low- and mid-level doses and a launch could be made by the end of the year.
3.3 DNA vaccine
- This type of vaccine uses genetically engineered DNA molecules coded with an antigen.
- The body recognizes this antigen and develops an immune response against it producing antibodies developing immunity.
- Inovio Pharmaceuticals is developing a DNA vaccine named INO-4800 in collaboration with the International Vaccine Institute which has shown positive results in phase I trials.
4. DEVELOPMENT OF A VACCINE
4.1 Time required to develop a vaccine
- There is no fixed time period for the development process of a vaccine but the process could take decades and still yield no result.
- An important case being the vaccine for HIV, which is still in phase III of clinical trials even after thirty years of research.
- One of the fastest developed vaccines was for mumps, which got approval within four years after beginning the trials in 1963.
- In March this year, Antony Fauci, Director of the US National Institute of Allergy and Infectious Diseases, told the Senate Committee that it was not possible to develop a vaccine for COVID-19 before a year or a year and a half and even this ambitious target would require emergency authorization by regulators.
5. STATES OF DEVELOPMENT OF A VACCINE
Generally, a vaccine is developed and tested over a number of stages which have been fast-tracked in various ways for the development of the Covid-19 vaccine.
The stages are:
Stage I: Research and Development
- This stage generally takes 2 - 4 years but for Covid-19 this stage has progressed very fast due to two reasons.
- One, Chinese researchers shared the genetic sequence of the coronavirus in January itself, and there are a large number of candidates based on the virus's genetic code instead of its protein.
- Second, the use of new technologies like m-RNA technology, which injects genetic instructions to human cells directing them to create proteins to fight the virus. However, the technology is still unproven.
Stage II: Pre-clinical Trials
- This stage generally takes 2 - 3 years.
- In this stage, scientists test the vaccine on cell cultures and animals. This stage is done before testing the vaccine on humans.
- In Pre-clinical Trials first, the virus is inactivated and parts of its genetic sequence are pulled out and checked if they stimulate any immune response.
- This is intended to check if the vaccine candidate continues to harm the cell.
- In the absence of an immune response or if the vaccine candidate harms the animals, researchers return to phase I.
- By performing various sub-stages simultaneously, this stage has been shortened for Covid-19.
- However, the majority of vaccine candidates for COVID-19 are still in the pre-clinical stage.
Stage III: Clinical trials
- Regulators permit for human testing based on data submitted from the pre-clinical trials.
- Only a few candidates enter this stage. This stage consists of three phases and usually takes more than 90 months.
- PHASE I: The vaccine is delivered to a small group of people and antibodies in their blood are measure. This takes about three months.
- PHASE II: If phase I is successful, scientists move to phase II. In this phase, the vaccine is delivered to several hundred people and three aspects are evaluated.
- reactogenicity (ability to produce common, adverse reactions)
- immunogenicity (ability to provoke an immune response) and
- To compare the working of the vaccine under different variables a control is also used.
- For Covid-19 vaccine development, this stage has been shortened like Moderna, which took just 63 days to reach clinical trials.
- PHASE III: In the last phase of clinical trials, the vaccine is delivered to thousands of people.
- This usually takes 6-8 months.
- This phase assesses the working of the vaccine in larger populations.
Stage IV: Regulatory review
- The manufacturer submits the data of the clinical trials to receive a licence. This stage is usually fast-tracked during emergencies.
Stage V: Manufacturing
- Manufacturing of vaccines requires immense resources like funds to the tune of millions of dollars, infrastructure, raw material, and scientific expertise.
Stage VI: Quality control
- In this stage, both the regulator and the manufacturer monitor the safety of the vaccine.
This development of Covaxin is indeed a necessity to fight the COVID-19 pandemic. Given the high cost of medical services, a nationally developed vaccine will be a huge relief.
While the intention of ICMR to develop the vaccine in record time is laudable, at the same time, the concerns of bioethics experts about crunching all the three phases of clinical trials within a month when human trials are yet to begin is equally important.
Efficacy and safety issues should not be ignored in any case.
Source: Indian Express