Scientists are developing a new Covid drug from antibodies of those who previously had coronavirus – and the results are highly promising.
The drug, an antibody injection created by AstraZeneca, who co-developed the first Covid vaccine to be approved in the UK in 2020, reduces the risk of symptomatic Covid by 83% six months after a single dose.
In comparison, vaccine protection can wane significantly – with the original AstraZeneca jab to 40% after six months while Pfizer reduces to 60%.
This new antibody cocktail, called AZD7442, could provide additional protection to the population, particularly those who haven’t responded well to the vaccine, such as cancer patients.
The artificial antibodies used in the injection last longer than the vaccine, said AstraZeneca, and could offer protection for a year.
And while the drug wasn’t tested on large populations, it was tested when the Delta variant was rampant, showing possible protection from harmful variants.
Hugh Montgomery, professor of intensive care medicine at University College London and the AZD7442 principal investigator, said: “These compelling results give me confidence that this long-acting antibody combination can provide my vulnerable patients with the long-lasting protection they urgently need to finally return to their everyday lives.
“Importantly, six months of protection was maintained despite the surge of the elta variant among these high-risk participants who may not respond adequately to vaccination.”
A separate trial also showed the drug reduces the risk of severe Covid and death by 88% when given within three days of experiencing symptoms.
How does the injection work?
The injection, which only requires one dose, combines two antibodies taken from immune B-cells donated by those who have recovered from coronavirus. These antibodies then bind to sites on the spike protein which the virus uses to enter cells.
Like the vaccine, it is taken in the arm.
How is it different from the current vaccines?
Antibodies are created as memory of an immune response. So if you get Covid and recover, your body creates antibodies. This new drug mimics antibodies, instead of the virus – as with the vaccine – to offer protection.
In traditional vaccines, mRNA – that is messenger RNA, a strain to mimic the virus – is administered into the body so the immune response kicks in.
The mRNA vaccines do not contain any live virus. Instead, they work by teaching our cells to make a harmless piece of a “spike protein,” which is found on the surface of the virus that causes Covid-19.
After making the protein piece, cells display it on their surface. Our immune system then recognises that it does not belong there and responds to get rid of it. When an immune response begins, antibodies are produced, creating the same response that happens in a natural infection.
Will we be getting this in the future?
AZD7442 is expensive to manufacture and administer so would only be used to booster the most vulnerable members of society.
While the vaccine costs roughly £22.50 per dose to create, so £45 per person for two shots, the AZD7442 drug costs approximately $1000 (£744) per dose.
So it will need to be used sparingly for those who truly need it.
The results of both of its trials are set to be published within the next few weeks with more details and clearer answers.