A Covid-19 treatment derived from the immune cells of virus survivors gives better protection than vaccines after six months and could last for a year, a trial has found.
Experts hope that the injection, produced by AstraZeneca, could mark a breakthrough in treatment of the virus, particularly for the elderly and other vulnerable groups.
What did the trial find?
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AstraZeneca said that its antibody injection, known as AZD7442, reduces the risk of symptomatic Covid by 83% six months after a single dose and that one injection could offer protection for a year.
In contrast, explained The Telegraph, vaccine protection can “wane substantially” in the months following an injection even after two doses, with the AstraZeneca vaccine falling to around 40% effectiveness and Pfizer about 60%.
A separate trial found the new drug also reduces the risk of severe symptoms and death by 88% when given within three days of the onset of symptoms.
How does it work?
The Guardian said the “antibody cocktail” consists of two lab-made antibodies – tixagevimab and cilgavimab – which bind to the spike protein of the virus, stopping it from entering the body’s cells and causing an infection.
The respective antibodies attach to different parts of the protein. It is hoped this means they will offer protection against future variants, since the virus would have to mutate in more than one way to escape both antibodies’ actions.
The injected treatment provides antibodies directly to the body via two intra-muscular injections administered consecutively. Therefore, it differs from vaccines, which simply train the body’s immune system to respond to the virus if a person becomes infected in the future.
However, compared with vaccines, AZD7442 takes longer to administer, is more expensive and needs to be given by a trained doctor or nurse. Also, patients may need to be monitored for longer afterwards than the 15 minutes required for a vaccine. As a result, experts told The Guardian that the treatment is not suitable for a widespread, fast rollout.
Who will benefit?
AstraZeneca said around 2% of the world’s population is thought to be at risk of not responding well to Covid-19 vaccines. Elderly and immunocompromised people who cannot mount an adequate immune response to the virus even after vaccination are expected to be helped by the breakthrough.
The Telegraph said potential beneficiaries include cancer victims being treated with chemotherapy, patients on dialysis, or those taking medication to suppress their immune systems such as those undergoing organ transplants, or with arthritis or multiple sclerosis.
What are the experts saying?
Hugh Montgomery, professor of intensive care medicine at University College London and principal investigator in the trials, told CNBC that the “compelling results” give him 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”.
Mene Pangalos, executive vice president of biopharmaceuticals research and development at AstraZeneca, said the latest trial’s findings “add to the growing body of evidence supporting AZD7442’s potential to make a significant difference in the prevention and treatment of Covid-19”.
When will it be available?
AstraZeneca has submitted the findings to regulators, who must decide whether to grant approval to the new treatment before it can be rolled out anywhere.
The pharmaceutical giant has already agreed to supply the US with 700,000 doses, subject to being granted authorisation, and has agreements to supply to other countries.
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