Since coronavirus emerged in January almost 200 vaccine candidates have been put into development, with at least 15 in human trials.
Vaccines being developed by Oxford University and in Germany are the most likely candidates to be ready this year, experts have said, but there are also candidates being tested in the US, Russia and China. There are also some signs that China is pulling ahead in the race.
However, a major new study has 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.
“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.”
Here’s everything you need to know about what vaccines are being developed, the latest news, and when a jab might be ready.
What’s the latest news in the hunt for a vaccine?
The latest data in the Oxford trials shows that the vaccine produces a “strong” immune response among the elderly. Analysis of the Phase II stage of the trial process reportedly found similar responses across all age groups, in findings that have been hailed as a “milestone” in the fight against the pandemic.
As well as several phase 3 trials taking place on vaccine candidates around the world, the UK is starting some “human challenge trials”, where volunteers are exposed to the virus as part of testing the vaccines.
The Imperial human challenge trial is being run by hVivo, a spin-off company from Queen Mary University of London. Already roughly 2,000 people have signed up to take part in challenge studies in Britain through the group 1Day Sooner.
Those testing the vaccine will be given the jab and will then wait a month for antibodies to build. The volunteers will then be exposed to the virus.
Currently, vaccines are tested at population level, so scientists look to see whether a smaller percentage of people are infected than would be expected in the vaccine arm of the trial compared to a control group.
However worldwide lockdowns have meant that virus in the community has been very low in recent months, and scientists have struggled to get enough data to know whether their vaccines are working.
Oxford University has been forced to move some of its vaccine testing to South America and South Africa, although it is expecting results back soon.
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.
Having to satisfy the safety criteria in each of these stages is why developing a vaccine is such a long and complicated process.