2020-11-15 18:55:18 | How close is a Covid-19 vaccine after the Pfizer breakthrough


Story by: Annelies Gartner The Telegraph

What about the Imperial College vaccine?

Researchers at Imperial have developed a candidate which, when injected, will deliver the genetic instructions to muscle cells to make the SARS-CoV-2 spike surface protein. This should provoke an immune response and create immunity to the virus.

Rather than giving people a weakened form of the illness, the Imperial vaccine instead uses synthetic strands of genetic code based on the virus’ genetic material. 

Another vaccine candidate is being developed by the University of Cambridge which hopes to start clinical trials in the autumn after it received £1.9 million in funding from the British government.

The Cambridge candidate, DIOS-CoVax2, is DNA based. Computer-generated antigen structures are encoded by synthetic genes, which can then re-programme the body’s immune system to produce antibodies against coronavirus.

How long will these vaccines last?

Despite the upbeat news, a major new study found that immunity to coronavirus may only last a matter of a months –  which could hinder the rollout of a successful vaccine.

A study by Imperial College London, which involved 365,000 people, showed that antibodies in the population fell by more than a quarter in just three months.

Scientists said the findings suggested a “rapid” decline in immunity – which could mean that even if a successful vaccine is found, it might have to be administered twice a year.

It comes after the head of the UK’s vaccine taskforce has warned that any jab is likely to be only 50 per cent effective. Kate Bingham said any vaccine capable of immunising against the coronavirus will likely only be as effective as the flu vaccine. 

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“The vaccines we have for flu are about 50 per cent effective, and they are annual shots, based on the strain that emerges each summer which we then get vaccinated for the winter,” Ms Bingham said. “So, I think it would be fair to say, we shouldn’t assume it’s going to be for the moment, better than a flu vaccine.”

Ugur Sahin, chief executive of BioNTech, told the BBC’s Andrew Marr Show on November 15, that vaccines could be combined if someone no longer has an immune response.

When asked if the coronavirus jab could be used in combination with other vaccines, such as the one being developed by AstraZeneca, he said: “At the beginning, it does not make sense to combine vaccines, as every vaccine has been clinically evaluated as a prime boost.

“So that means most vaccines are based on a first injection, and after three weeks, or after four weeks, a second injection. And I wouldn’t mix that, because this has not been evaluated for safety.”

He added: “But if after one year, for example, if someone who has received an AstraZeneca vaccine, who does not any more have an immune response, then it could be combined with the BioNTech/Pfizer vaccine, or vice versa.”

Mr Sahin said it was not known how long immunity lasts after a second dose of the vaccine, adding: “The antibody response might decline over time, and we expect it will decline over time, but what is not known, how fast it will decline?

“We are collecting this information and we will see it and if the antibody response, for example, after one year appeared to be too low, we can do a booster immunisation, which should not be too complicated.”

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Mr Sahin added that more data needed to be generated to find out if immunisation against coronavirus was required each year.

How do vaccines work, how long do they take to make, and why?

A vaccine stimulates your body’s immune system to produce antibodies and fight off a disease. It does this by introducing into your body the germs that cause disease. Your immune system then fights off these germs, developing the antibodies that then make you immune. Vaccines, therefore, can be potent weapons in preventing disease.

However, developing a vaccine is complicated. While researchers are confident that a vaccine could be ready by the summer of 2021, that would be the fastest humans have ever gone from seeing a brand new pathogen to developing a vaccine against it.

Here’s the journey a vaccine takes, from initial development to approval:

  • Before clinical testing: At this stage, scientists test the vaccine on cells and then give the virus to animals. If the vaccine produces an immune response – ie if antibodies are produced – it can move to the next stage
  • Phase 1 testing: In these tests, also known as safety trials, the vaccine is tested on a small number of people. It is in this stage that scientists work out the dosage and if the jab produces an immune response in humans
  • Phase 2: Now the vaccine is tested on a lot more people, with hundreds of participants split into groups, often by age. Sometimes, to speed up the process, phases 1 and 2 can be combined.
  • Phase 3: In the third phase of testing, the vaccine is delivered to thousands of people. The vaccine runs alongside a placebo. This phase is extremely important because it simulates mass adoption of the vaccine; the larger sample size of participants means that the trial can find out rare potential side effects of the vaccine that might not be present in smaller groups. The Oxford and Imperial vaccines are currently at this stage.
  • Approval: If the vaccine passes through these stages, it can be approved by national and international regulators. Then it can be distributed. Scientists would continue to monitor people who receive the vaccine, in case it is not safe. However, researchers have expressed concern that approval could be rushed without adequate scrutiny – as with China and Russia’s vaccines – or that emergency authorisation of a coronavirus vaccine could be dangerous. Approval is also subject to political pressures, such as President Trump’s hope to get a vaccine distributed to Americans before he faces the polls on November 3 – which is looking increasingly unlikely. 
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Having to satisfy the safety criteria in each of these stages is why developing a vaccine is such a long and complicated process.


Story continues…

Source References: The Telegraph

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