At what stage are under-trial vaccine candidates in India?

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• Various companies across the world have signed agreements to make Covid-19 vaccines or have started conducting human trials of their vaccines in India, over the last few months.

 

Following is the status of different vaccines in various stages of development.

‘Covishield’ by University of Oxford-AstraZeneca:

• Covishield works on a mechanism that uses a weakened version of a common cold virus that infects chimpanzees.
• The body’s immune system is expected to recognise this as a threat and develop antibodies, so that it will be ready in case the real virus tries to infect it.
• This vaccine, is in late stage phase III tests, with over 10,000 human participants across countries like the UK, Brazil and South Africa. It has started phase II human trials in India.
• According to Clinical Trials Registry – India (CTRI), phase II/III trials in India are expected to take around seven months–potentially until March 2021.
• Serum Institute of India will be manufacturing a billion doses of the vaccine for low- and middle-income countries by the end of 2021.

ZyCov-D’ by ZydusCadila

• ZyCov-D’ developed by ZydusCadilla, is indigenously developed in India.
• It uses a genetically engineered DNA molecule coded with the DNA sequence of the SARS-CoV-2 virus, against which the immune response is expected to be developed.
• Phase I trials of the candidate showed that the vaccine was “safe and well tolerated”, which allowed it to move to the second phase of human trials on August 6.
• As per CTRI, trials to be conducted on over 1,000 participants, are expected to take around a year to complete.
• The firm is planning to build a capacity to produce 100 million doses if phase II trials are successful.

‘Covaxin’ by Bharat Biotech

• Covaxin developed by Bharat Biotech, is also indigenously developed in India.
• This vaccine works by injecting SARS-CoV-2 virus that has been killed in the lab. It aims to use this dead virus, to induce (generate) an immune response by the body.
• It is currently expected to enter phase II human trials in India, this week.
• Bharat Biotech is looking to develop a capacity of around 300 million doses of the vaccine.

RBD protein vaccine by Baylor College of Medicine-Biological E:

• RBD protein vaccine is developed by using the traditional technique used to make vaccines against Hepatitis B.
• This makes it easier to produce, as most companies already possess the technical understanding to develop it.
• Biological E, which entered into an agreement with Baylor College of Medicine (BCM) last month, is expected to conduct human trials for this vaccine candidate in India.
• These trials are likely to begin this month or next, depending on when the company applies for and receives permission to begin the testing.
• Biological E has indicated that it has the annual capacity to make up to a billion doses of this vaccine.

 

 

About: Clinical trials for vaccines in general

• On the basis of data submitted from the pre-clinical phase (in which the vaccine is tested on cell cultures and animals), regulators allow testing in humans.
• Cell culture is the process by which cells are grown under controlled conditions, generally outside their natural environment.
• The clinical trial stage consists of three phases and usually takes more than 90 months.

Phase I:

• The vaccine is given to a small group of people and scientists measure antibodies in their blood.
• It involves studying the safety of the vaccine in a healthy individual and helps in deciding the right dosage that will be effective against the virus. This phase generally takes around three months.

Phase II:

• If found safe in Phase I, the trial moves to the next phase, where it is given to several hundred people and can take around 6-8 months to complete.
• The following three aspects are assessed in this phase:
  • Reactogenicity - ability to produce common, adverse (harmful) reactions
  • Immunogenicity - ability to produce an immune response and
  • Safety

Phase III:

• Since certain side effects of the vaccine may not have come up in the smaller groups of humans tested in earlier phases, the vaccine candidate is given to thousands of people in this stage.
• This phase can take around 6-8 months and assesses how the vaccine works in larger populations.

Approval of the vaccine:

• After Phase III trials, the vaccine developer submits a license application to the regulatory authority in their respective country. The regulator then inspects the factory where the vaccine will be made and approves its labelling.
• During a pandemic, a vaccine may receive emergency use authorisation before a formal approval.

 

About: Clinical Trials Registry – India (CTRI)

• CTRI is the government of India's official clinical trial registry. It is a free and online public record system for registration of clinical trials conducted in India.
• It was established by Indian Council of Medical Research in 2007.
• In 2009, Drug Controller General of India made it compulsory for everyone conducting clinical trials in India, to register in the CTRI, before enrolling any research participants.
• Registration of trials ensures transparency, accountability, and accessibility of clinical trials.