One of the first questions asked when an infectious disease pandemic is looming is: "Is there a vaccine for this?" The short answer is "no". But the longer answer is that the world has never been more geared up to develop vaccines against emerging infectious diseases than it is today.
However, Covid-19 has mutated into two strains, one which appears to be far more aggressive, scientists have said, in a discovery which could hinder attempts to develop a vaccine.
The virus has evolved into two major lineages - dubbed ‘L’ and ‘S’ types. The older ‘S-type’ appears to be milder and less infectious, while the ‘L-type’ which emerged later, spreads quickly and currently accounts for around 70 per cent of cases.
In addition, genetic analysis of a man in the US who tested positive on January 21 also showed it is possible to be infected with both types.
Health experts have warned that the virus could hit Britain in "multiple waves", and led to fears that some vaccines might not work on mutated strains.
That said, work to develop a vaccine is accelerating.
The rapid genetic sequencing and open publication of the virus by Chinese researchers has been a boon for researchers who have been working against the clock to produce a preventive jab or pill, as well as treatments and diagnostics.
Human trials on a vaccine against coronavirus are due to start in April, with British scientists competing with dozens of laboratories around the world to be the first to develop a drug.
Several labs now have prototype vaccines which they are trialling in animals, with many confident that they will move to human testing next month.
If proven safe and effective, larger "live situation" trials will be carried out to see whether inoculation works in a natural infection scenario. If successful, a vaccine could be widely available by early next year.
Professor Robin Shattock and his team at the Department of Infectious Disease at Imperial College London had developed a candidate vaccine within 14 days of getting the sequence from China. They have been testing it on animals since February 10 and hope to move to clinical trials in the summer if they can secure funding.
Other than creating a traditional antibody jab, the Imperial drug works by effectively injecting new genetic code into a muscle, instructing it to make a protein found on the surface of coronavirus, which triggers a protective immune response.
"We have the kind of technology to be able to generate a vaccine with a speed that's never been realised before," said Prof Shattock. "Most vaccines are five years in the discovery phase, and at least one or two years to manufacture and get into trials.
"We may not be the first, but it only requires one group to get there. We're only one party and at some point we might say: 'Somebody else is ahead, we should stop working'. While we want to go the whole way, we're also prepared to stand down."
One crucial advance aiding vaccine research is the development of an organisation called Cepi, set up in response to the lack of scientific progress when Ebola ripped through West Africa in 2014 to 2016.
Cepi's mission is to rapidly respond to epidemics by providing the money to researchers to develop vaccines.
It harnesses the power of so-called "rapid response platforms" which use what its chief executive, Dr Richard Hatchett, describes as a "common backbone" that can be adapted quickly for different pathogens by inserting new genetic or protein sequences.
It is already working on the development of a vaccine against another coronavirus - Middle East respiratory syndrome (Mers) - and in January, Cepi announced that a vaccine for Covid-19 would be ready for testing by the end of May.
Such rapid progress is a remarkable turnaround. But having a vaccine ready for testing is only the beginning of the journey.
The vaccine will have to be tested on animals first, and then humans. After that it will have to go through regulatory approval, a long process but one that can be accelerated, as was done for the Ebola vaccine first used in the Democratic Republic of Congo two years ago.
The biggest hurdle is manufacturing the vaccine at scale and then distributing it. Even the most optimistic pharmaceutical salesperson would be inclined to suggest the vaccine would only be ready by the end of this year - by which time this outbreak may well have run its course.
And if it were ready before the end of the outbreak it would probably be given to what public health experts call "key populations" first - health workers, vulnerable groups and the contacts of affected patients - before any nationwide mass vaccination programme took place.
But what doctors are pinning their hopes on - more than vaccines - are drugs for diseases, such as HIV and malaria, that they are repurposing to treat coronavirus patients.
The most promising of these is a drug called remdesivir, a broad-spectrum antiviral treatment developed by drug firm Gilead that began testing earlier this week.
The drug was developed for Ebola and was used to treat the Scottish nurse Pauline Cafferkey when she suffered a relapse 18 months after being cleared of the disease which she contracted while volunteering in Sierra Leone.
Doctors in the United States first used the drug in January on a patient who was not responding to other treatment - within 24 hours, he showed improvements, eventually making a full recovery.
HIV antiviral drugs have also been flagged as potential options, and there are at least two studies ongoing in China looking at a combination of lopinavir and ritonavir, both of which work to lower the levels of HIV in the bloodstream.
Earlier this month doctors in Thailand claimed that, 48 hours after taking a cocktail of these HIV drugs alongside a flu treatment, a patient tested negative for the coronavirus.
Sir Jeremy Farrar, director of the UK biomedical research charity Wellcome, said using existing drugs makes sense because all the safety and efficacy testing has already been carried out.
But before we can start hailing any miracle cures, proper clinical trials must be conducted.
"Do the drugs work?" Sir Jeremy asks.
"We just don't know, but we won't know unless we look."
What about a vaccine for a mutated virus?
Experts suggest that while Covid-19's mutation makes it more difficult to develop a vaccine, a vaccine is still possible.
Dr Stephen Griffin, of the Leeds Institute of Medical Research and chair of the virus division at the Microbiology Society, said that two of the changes between the ‘S’ and ‘L’ lineages were in crucial protein called ‘spike’, which plays a key role in the infection process and is a target for vaccines.
Dr Griffin said developers would need to test whether their prototype vaccines would still neutralise viruses with the changes, but added that the variations were "fairly limited" and may not be a "huge hurdle."
“It is usually the case that when RNA viruses first cross species barriers into humans they aren’t particularly well adapted to their new host - us!” said Dr Griffin.
“Thus, they usually undergo some changes allowing them to adapt and become better able to replicate within, and spread from human-to-human.”
Virologist Professor Jonathan Ball also warned that mutations could affect vaccine production, but said that the Chinese results needed replication with a larger study.
“At the moment we don't have hard evidence that the virus has changes with regards to disease severity or infectivity so we need to be cautious when interpreting these kinds of computer-based studies, interesting as they might be,” he added.
New mutations were also discovered in the case of a 61-year-old man from Brazil, although Professor David Heymann of the London School of Hygiene and Tropical Medicine said a vaccine should still work on the emerging strain.
“Nothing has occurred that is major and this virus appears to be stable,” he said.
“Small mutations are normal, especially with RNA viruses. We look for the parts of the virus that are most sustained.”
By Anne Gulland and Sarah Knapton,
SCIENCE EDITOR
https://www.telegraph.co.uk
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