With a new coronavirus variant circulating London and its surrounding areas, concerns have been raised as to what this may mean for vaccines.
An effective immunisation programme has long been hailed as a route back to life as we knew it.
While hundreds of vaccine candidates are under development worldwide, only the Pfizer-BioNTech jab is approved in the UK, with limited doses being prioritised for the most vulnerable individuals.
Scientists and government officials have repeatedly stressed there is no evidence the new variant will be immune to the Pfizer-BioNtech vaccine or others in a late stage of development, with many optimistic the jabs will still be effective.
The risk cannot be ruled out, however, prompting an official team to urgently investigate the issue, with results expected in the coming weeks.
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How will vaccines be tested against the new variant?
Public Health England scientists at the Porton Down laboratory in Wiltshire are investigating whether vaccines are effective against the variant. The pharmaceutical firms behind the jabs are also said to be running their own tests.
When asked how these experiments will be carried out, Professor Adam Finn, from the University of Bristol, said: “You can propagate [multiply] viruses in the lab.”
Cell lines – animal cells that can be propagated repeatedly, sometimes indefinitely, in the laboratory – can then be infected with these viruses.
“They have to be cells the virus is capable of infecting,” said Prof Finn.
“For COVID [the disease caused by the coronavirus], they need to express ACE2”.
ACE2 is the receptor the coronavirus uses to invade cells.
“[Next] put the virus in with these cells and see if the virus has infected the cell,” said Prof Finn.
Scientists can then introduce antibodies from the blood of someone who has survived the coronavirus or had a vaccine.
Antibodies are immune-fighting proteins released in response to an infection. Once the infection has been overcome, memory antibodies circulate at low levels. These are ramped up if the infection is encountered again, helping to prevent it taking hold for a second time.
Ordinarily, antibodies should bind to the coronavirus via its spike protein, “which interferes with its ability to infect cells”.
The spike protein – the target of many coronavirus vaccines, including the Pfizer/BioNTech jab – binds to a cell’s ACE2 receptor.
The experiment is repeated with both the coronavirus variant in question and a more established variant that was circulating earlier in the pandemic.
“You can see a difference in the capability of the antibodies to prevent the virus infecting the cell,” said Professor Finn.
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Will vaccines work against the new coronavirus variant?
Scientists are largely optimistic coronavirus vaccines will be effective against the new variant.
“The vaccines induce neutralising antibodies to several parts of spike and most of these would be unchanged by the mutations; so the vaccines will still work,” said Professor Daniel Altmann, from Imperial College London.
Dr Michael Head, from the University of Southampton, agreed, adding: “The vaccines should still be as effective [at] reducing the risk of severe disease [and] death in people vaccinated.”
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Evidence so far points to the new variant being up to 70% more transmissible. There is nothing to say it causes more severe disease.
An increase in transmissibility may mean more people need to be immunised to achieve herd immunity, which occurs when a sufficient number are protected to prevent the infection taking hold in the community.
“The increased transmissibility does mean even with some benefit from vaccine on reducing transmissibility, the vaccination programme is even less likely to protect those people who choose not to be vaccinated,” said Dr Head.
Professor Ravindra Gupta, from the University of Cambridge, pointed out that as well as antibodies, vaccines also induce other aspects of immunity, like T-cells.
So-called helper T-cells stimulate antibody production and assist in the development of “killer cells”. Killer T-cells directly destroy body cells that have already been infected by a virus.
T-cells also send out messages that instruct the rest of the immune system to ramp up its response.
“The new variant is very unlikely to evade vaccines,” added Prof Gupta.
If the vaccines do need to be tweaked, Prof Finn reassured “it’s a lot easier than [creating a jab] the first time around”.
“In the same way we reformulate the flu vaccine, you can make a new vaccine without having to go through the exhaustive process,” he said.
“[It is] not [available] immediately, but quite quickly.”
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