Explained: Oxford Trials & What They Mean for Vaccine Development

Experts remain cautiously optimistic, even as phase 3 human trials are underway in the UK, Brazil and South Africa.

Updated
Explainers
3 min read
Preliminary data from phase 1/2 of human trials has shown that the vaccine produces immune response, and it may be safe for human use.
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Oxford University’s Jenner Institute has been working on a vaccine for the novel coronavirus, often referred to as the ‘most exciting’ of the 160 odd vaccine candidates in the works.

At one stage, the scientists had predicted the vaccine will be ready for a roll out by September itself. That’s changed. Now, preliminary data from phase 1/2 of human trials has shown that the vaccine produces immune response, and it may be safe for human use.

What does all this mean for vaccine development? Are we still making predictions of by when we’ll have the vaccine and how effective it will be?

Explained: Oxford Trials & What They Mean for Vaccine Development

  1. 1. What Do the Preliminary Results Indicate?

    Phase 1/2 human trial of ChAdOx1 nCoV-19 was launched in April. 1077 healthy candidates in the age group of 18 to 55 with no history of laboratory-confirmed COVID-19 were recruited for the trials carried across five sites in the UK.

    This was a single-blind randomised controlled trial where half of the candidates were given the coronavirus vaccine and the other half were given meningitis vaccine. 10 candidates were given an additional booster shot 28 days later.

    Side-effects including pain, feeling feverish, chills, muscle ache, headache, were treated with paracetamol and no adverse events were observed.

    The success of the vaccine was measured on the basis of how many antibodies and T Cells were produced in the blood of the volunteers. The results are preliminary. These results are seen to evaluate safety, but don't necessarily indicate if the vaccine really protects against the virus, and for how long.

    The volunteers were monitored for eight weeks. Dr Adrian Hill, director of the Jenner Institute, said, “We are seeing good immune response in almost everybody. What this vaccine does particularly well is trigger both arms of the immune system.”

    The vaccine seems to have produced comparable levels of neutralising antibodies as those who have recovered from the infection. Scientists hope T Cell response will provide additional protection. However, they don't yet know how long will the immune response last.

    “We just don’t know what level is needed if you meet this virus in the wild, to provide protection, so we need to do the clinical trials and to work that out,” said Prof Andrew Pollard.

    Expand
  2. 2. What is a Viral Vector Vaccine?

    ChAdOx1 nCoV-19 is a viral vector vaccine. It has been made from a genetically engineered virus that causes the common cold in chimpanzees.

    It underwent heavy modifications to ensure it doesn't cause infection and to imitate the coronavirus. This was achieved when scientists transferred genetic instructions from the spike protein of the coronavirus to the vaccine. Coronavirus uses this spike protein to invade human cells.

    How it works is by building the body's immune response against the spike protein of the coronavirus.

    This is an experimental vaccine. The Oxford team has previously used ChAdOx1 vaccine technology to produce candidate vaccines against flu, Zika and Middle East Respiratory Syndrome (MERS).

    Expand
  3. 3. What's Next?

    Larger Phase 3 trials evaluating the effectiveness of the vaccine involves 10,000 people in the UK, and in South Africa and Brazil. These trials are still underway. A trial with 30,000 candidates will also start in the US soon.

    Here in India, Serum Institute in Pune has filed for carrying out stage 3 trials on 10,000 people.

    While the Jenner Institute is not saying when the vaccine will be ready, if the data shows efficacy, immunisation of some high-risk groups in Britain could begin in December.

    Oxford has partnered with pharma major AstraZeneca to produce their vaccine globally. They have committed two billion doses, but these also may not be enough to meet global needs.

    Countries like Germany, France, the Netherlands, Italy, US and the UK have all signed deals to receive the first doses of these vaccines. The vaccine is yet to be licensed and the deliveries are scheduled for fall next year.

    Expand
  4. 4. Will We Get it in India?

    India has prioritised its own vaccine for production. Bharat Biotech and Indian Institute of Medical Research (ICMR) was ready with early pre-clinical trials of its vaccine candidate by end June, called Covaxin. Currently phase 1 human trials are on across various sites in India.

    India's name doesn't feature in the list of countries in talks with Oxford and AstraZeneca to source the vaccine. But Serum Institute of India in Pune has tied up with Jenner Institute to produce the vaccine here and they've applied to carry out human trials in India. They've said that they can manufacture and produce millions of doses in a short span of time.

    (The article was first published in FIT and has been republished with permission.)

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    Expand

What Do the Preliminary Results Indicate?

Phase 1/2 human trial of ChAdOx1 nCoV-19 was launched in April. 1077 healthy candidates in the age group of 18 to 55 with no history of laboratory-confirmed COVID-19 were recruited for the trials carried across five sites in the UK.

This was a single-blind randomised controlled trial where half of the candidates were given the coronavirus vaccine and the other half were given meningitis vaccine. 10 candidates were given an additional booster shot 28 days later.

Side-effects including pain, feeling feverish, chills, muscle ache, headache, were treated with paracetamol and no adverse events were observed.

The success of the vaccine was measured on the basis of how many antibodies and T Cells were produced in the blood of the volunteers. The results are preliminary. These results are seen to evaluate safety, but don't necessarily indicate if the vaccine really protects against the virus, and for how long.

The volunteers were monitored for eight weeks. Dr Adrian Hill, director of the Jenner Institute, said, “We are seeing good immune response in almost everybody. What this vaccine does particularly well is trigger both arms of the immune system.”

The vaccine seems to have produced comparable levels of neutralising antibodies as those who have recovered from the infection. Scientists hope T Cell response will provide additional protection. However, they don't yet know how long will the immune response last.

“We just don’t know what level is needed if you meet this virus in the wild, to provide protection, so we need to do the clinical trials and to work that out,” said Prof Andrew Pollard.

What is a Viral Vector Vaccine?

ChAdOx1 nCoV-19 is a viral vector vaccine. It has been made from a genetically engineered virus that causes the common cold in chimpanzees.

It underwent heavy modifications to ensure it doesn't cause infection and to imitate the coronavirus. This was achieved when scientists transferred genetic instructions from the spike protein of the coronavirus to the vaccine. Coronavirus uses this spike protein to invade human cells.

How it works is by building the body's immune response against the spike protein of the coronavirus.

This is an experimental vaccine. The Oxford team has previously used ChAdOx1 vaccine technology to produce candidate vaccines against flu, Zika and Middle East Respiratory Syndrome (MERS).

What's Next?

Larger Phase 3 trials evaluating the effectiveness of the vaccine involves 10,000 people in the UK, and in South Africa and Brazil. These trials are still underway. A trial with 30,000 candidates will also start in the US soon.

Here in India, Serum Institute in Pune has filed for carrying out stage 3 trials on 10,000 people.

While the Jenner Institute is not saying when the vaccine will be ready, if the data shows efficacy, immunisation of some high-risk groups in Britain could begin in December.

Oxford has partnered with pharma major AstraZeneca to produce their vaccine globally. They have committed two billion doses, but these also may not be enough to meet global needs.

Countries like Germany, France, the Netherlands, Italy, US and the UK have all signed deals to receive the first doses of these vaccines. The vaccine is yet to be licensed and the deliveries are scheduled for fall next year.

Will We Get it in India?

India has prioritised its own vaccine for production. Bharat Biotech and Indian Institute of Medical Research (ICMR) was ready with early pre-clinical trials of its vaccine candidate by end June, called Covaxin. Currently phase 1 human trials are on across various sites in India.

India's name doesn't feature in the list of countries in talks with Oxford and AstraZeneca to source the vaccine. But Serum Institute of India in Pune has tied up with Jenner Institute to produce the vaccine here and they've applied to carry out human trials in India. They've said that they can manufacture and produce millions of doses in a short span of time.

(The article was first published in FIT and has been republished with permission.)

Liked this story? We'll send you more. Subscribe to The Quint's newsletter and get selected stories delivered to your inbox every day. Click to get started.

The Quint is available on Telegram & WhatsApp too, click to join.

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