For months, we’ve been told once a vaccine arrives, we might be able to get back to some semblance of normal. So, where are we at with a due date?
In the UK, there are two key vaccine contenders we’ve been keeping an eye out for.
The first is the University of Oxford and Astrazeneca vaccine, which goes by two catchy names: ChAdOx1 or AZD1222. The trial for this was recently halted to allow a review of safety data by an independent committee, but has since been resumed.
The vaccine harnesses an adenovirus (common cold virus) from chimpanzees, which has been genetically modified so it can’t replicate in our body’s cells. This virus is used as it contains the genetic material of the SARS-CoV-2 virus spike protein (a protein that lives on the surface of the coronavirus).
When the vaccine enters cells inside the body, it uses this genetic code to produce the surface spike protein of the coronavirus, priming the immune system to attack the SARS-CoV-2 virus if it later infects the body.
It’s in the last phase of trials, which means tens of thousands of people globally are being vaccinated. The point of this trial is to see how the vaccine works in a large body of adults. Does it prevent people from becoming infected and unwell with Covid-19? That’s the question researchers hope to answer.
If the answer is yes, we could have a vaccine ready for early to mid-2021. It’s worth noting the World Health Organisation has said it doesn’t expect vaccines to be available to the masses until the middle of next year, due to checks for efficacy and safety.
Early trials of the Oxford vaccine have shown promise, with people displaying a “robust immune response” against the virus. A single dose of the vaccine resulted in a four-fold increase in antibodies to the virus spike protein in most (95% of) participants one month after injection.
A T-cell response was also induced in all participants, which is good news as T-cells are another important factor in fending off the virus once it enters the body.
More recently, two sources familiar with the ongoing trials told the Financial Times the vaccine has produced a robust immune response in elderly people.
The second contender for a workable vaccine in the UK comes from Imperial College London. The team behind the vaccine – dubbed saRNA – is now conducting trials in humans.
Its vaccine uses genetic code called ‘self-amplifying RNA’, rather than bits of the virus. This code has been made in a lab, so there’s no need for animal cells or human stem cells.
Once injected into the body, it should produce copies of the spike protein found on the outside of the coronavirus – it’s kind of like you’re injecting an instruction manual to build some flat-pack furniture, but rather than furniture, you’re building the spike protein – and that trains the immune system to respond to it in future.
Professor Robin Shattock, who is leading the vaccine research, said trials are showing promising results and human volunteers are “responding well”. All being well, he believes they could have a vaccine ready by mid-2021.
There are three typical trial phrases when testing a vaccine, but it’s been reported there will also be “challenge trials” – where volunteers are deliberately infected with coronavirus – conducted to help researchers establish which vaccines are most likely to succeed.
Imperial College London; the Department for Business, Energy and Industrial Strategy (BEIS); hVIVO, a leading clinical company with expertise in viral human challenge models; and the Royal Free London NHS Foundation Trust have teamed up to initiate challenge trials, which are expected to take place in January next year.
The first stage of the project will explore the feasibility of exposing healthy volunteers to the SARS-CoV-2 coronavirus. The study would recruit volunteers between the ages of 18 and 30 with no previous history or symptoms of Covid-19, no underlying health conditions and no known adverse risk factors for Covid-19, such as heart disease, diabetes or obesity.
The aim will be to discover the smallest amount of virus it takes to cause a person to develop Covid-19. This is known as a virus characterisation study.
Once this first phase is completed, clinical researchers aim to use this human challenge model to study how vaccines work in the body to stop or prevent Covid-19, to look at potential treatments and study the immune response.
Dr Claire Waddington, clinical lecturer in infectious diseases at the University of Cambridge, says such trials have the advantage of allowing us to know exactly when people are exposed to the pathogen of interest, “so the response to infection and the protection of any vaccine used in the model can be directly and accurately investigated”.
That said, safety is an important factor when you’re exposing someone to a live virus. “As we gain more understanding of Covid-19, we are increasingly in a position to identify those people for who Covid-19 infection is a mild illness, and these people could safely participate in a controlled human infection study after a thorough medical assessment and consent process,” she says.
Worldwide, there are no Covid-19 vaccines currently approved for widespread use. Some are approved for limited use. One of China’s vaccine candidates, for example, has been approved for use in the military.
A vaccine was approved for widespread use in Russia, however this happened before the vaccine had even reached phase III trials, which are deemed the most important part for determining safety and effectiveness. Experts in the UK didn’t think it was a particularly sensible idea. Reports in the New York Times suggest the vaccine has been rolled out slowly in Russia and phase III trials are now underway in Moscow.
There have already been some success stories in phase 3 trials outside of the UK. A vaccine being trialled by Pfizer and Germany’s BioNTech has been found to be more than 90% effective in preventing Covid-19 and No.10 Downing Street said the UK has procured 40m doses of the vaccine, with 10m set to be manufactured by the end of the year if the jab is approved by regulators.
A government spokesperson said that while they are “optimistic of a breakthrough” it’s important to remember that there are no guarantees.
“We will know whether the vaccine meets our robust standards of safety and effectiveness once their safety data has been published, and only then can the medicines regulator consider whether it can be made available to the public,” they said.
“Once approved, the NHS stands ready to begin a vaccination programme for those most at risk, as currently recommended by the independent JCVI, before being rolled out more widely.”
Interim guidance published in September on the UK government’s website suggested that care home residents and workers could be prioritised for the vaccine if and when it’s ready.
Hopes are high. Discussing the Pfizer news, Professor Sir John Bell, Regius professor of medicine at Oxford University, told BBC Radio 4′s World at One he believed life in the UK could return to normal by spring 2021 with a vaccine on the cards.
“I am really delighted with this result,” he said. “It shows you can make a vaccine against this little critter.
“I can’t see any reason now why you shouldn’t have a handful of good vaccines available for this disease.”