- James Gallagher
- Health and science correspondent
—
Image source, Getty Images
—
–
In the past two weeks, Pfizer and BioNTech and Moderna have announced the successful trial of the Covid-19 vaccine.
–
Another vaccine is in the development stage, while trials of a third vaccine – from a Belgian company called Janssen – are underway in the UK.
–
Why do we need a vaccine?
If you want your life back to normal, then you need a vaccine.
–
Especially now, when most people are still vulnerable to exposure to corona virus infection.
–
Only restrictive measures in our lives prevent more people from dying.
–
But a vaccine can teach our bodies to fight viral infections thereby preventing us from being exposed to viruses, or at least making them less lethal.
–
Getting a vaccine, along with better care, is the exit strategy for the pandemic.
–
Image source, Getty Images
—
–
Which vaccine is expected to work?
Pfizer and BioNtech are the first companies to announce the news about the final stages of their vaccine trials.
–
Company data shows the vaccine protects 90% of a person from Covid-19.
–
About 43,000 people have been vaccinated, and to date there have been no safety concerns.
–
Meanwhile, US company Moderna is running vaccine trials on 30,000 people in the US, half of whom are given a vacuum injection.
–
Image source, Getty Images
—
–
The company says the vaccine protects 94.5% of the people who are given the vaccine, after only five of the 95 trial participants who received the vaccine developed symptoms of Covid-19 later.
–
Trial results will also be released in the next few weeks on a vaccine being developed by British drugmaker AstraZeneca and scientists at the University of Oxford.
–
Meanwhile, convincing data regarding the Sputnik V vaccine made in Russia have also been released.
–
Referring to preliminary data from the third trial phase, the same stage achieved by the Pfizer vaccine, Russian researchers report that its vaccine is 92% effective.
–
What other vaccines are being developed?
The results of trials from other vaccine research teams are expected in the coming weeks or months.
–
The Janssen trial has started by recruiting 6,000 volunteers across the UK. Other countries will join in bringing the total number of participants to 30,000.
–
The company has already conducted large-scale trials of the vaccine, during which volunteers receive a single dose. This trial will see if the two vaccines provide stronger and longer-lasting immunity.
–
A number of other vaccines are in the final stages of trials, including those developed by the Wuhan Institute of Biological Products and Sinopharm du China, as well as those developed by the Gamaleya Research Institute in Russia.
–
However, trials in Brazil for a drug developed by Chinese company Sinovac have been suspended after what was described as a “serious adverse incident” – believed to be the death of a volunteer.
–
—
–
How different are the vaccines being developed?
The essence of a vaccine is to expose parts of the virus to the immune system, which then recognizes it as an invader and learns how to fight it.
–
There are many ways to do this.
–
Pfizer / BioNtech (and Moderna) developed what it calls an RNA vaccine using an experimental approach, which includes injecting the body’s genetic code for the coronavirus, to train the immune system.
–
Image source, Science Photo Library
—
–
The Janssen vaccine instead uses the common cold virus that has been genetically modified to make it harmless and looks more like a corona virus at the molecular level.
–
This vaccine trains the immune system to recognize and fight the coronavirus.
–
Similarly, the Oxford and Russian vaccines use a harmless virus that infects chimpanzees, and genetically modify it to resemble the coronavirus, to try to elicit a response.
–
Two of the major vaccines made in China use the original virus but are defective, so they cannot cause infection.
–
It is very important to understand which method produces the best results. The challenge of testing, where people are intentionally infected, can help answer this question.
–
—
–
When will the vaccine be available?
Pfizer believes the company can supply 50 million doses worldwide by the end of this year, and about 1.3 billion doses by the end of 2021.
–
There will be 10 million UK-made vaccines available by the end of 2020, with 30 million doses already ordered.
–
Meanwhile, Astra Zeneca / Oxford agreed to supply 100 million doses of vaccine in the UK and possibly 2 billion doses globally if trials prove successful.
–
Image source, Getty Images
—
–
Who will get the vaccine first?
This depends on where Covid spreads when a vaccine is available and which group is most effective.
–
Nursing home residents and nursing home staff top the list of priorities in the UK, followed by healthcare workers such as hospital staff, and those over their 80s.
–
Age is by far the biggest risk factor for Covid.
–
What remains to be done now?
- Trials must show that the vaccine is safe
- Clinical trials must show that vaccines prevent people from being exposed to the virus or at least reduce the number of people dying
- Large-scale development needs to be done for billions of potential doses
- Regulators must approve a vaccine before it is given to the public
—
It is estimated that 60-70% of the global population must be immune to easily stop the spread of the virus (known as herd immunity) – that means billions of people, even if the vaccine works perfectly.
–
Image source, Getty Images
—
–
Will the vaccine protect everyone?
People respond differently to vaccinations.
–
History shows vaccines can be ineffective in the elderly because the aging immune system does not respond well.
–
Additional doses may work against this, such as giving them along with chemicals (called adjuvants) that boost the immune system.
—
