While everyone celebrated this month’s news that not one but two experimental vaccines against Covid-19 have proved at least 90% effective at preventing disease in late-stage clinical trials, research into understanding how the Sars-CoV-2 virus, which causes Covid-19, interacts with the human immune system never paused.
There are plenty of questions still to answer about the Pfizer/BioNTech and Moderna vaccines: how well will they protect the elderly, for example, and how long for? Which aspects of the immune response that they elicit are protective and which aren’t? Can even better results be achieved, with vaccines that target different parts of the immune system?
We are likely to need several Covid-19 vaccines to cover everyone and as a contingency, in case the virus mutates and “escapes” the ability of one vaccine to neutralise it, a real possibility in light of the discovery of an altered form of Sars-CoV-2 infecting European mink. But we also need better methods of diagnosing and treating the disease. The recent suspension of two major vaccine trials due to serious adverse events is a salutary reminder that there’s much still to learn and a pandemic, while no one would wish for one, provides scientists with a golden opportunity for learning.
Like most Covid-19 vaccine candidates, the Pfizer and Moderna vaccines are injected into the muscle, from where they enter the bloodstream and stimulate the production of antibodies to Sars-CoV-2 (specifically to the protein that forms the spikes covering its surface).…