A trial of a new vaccine that appears to train the immune system to fight coronavirus has begun in the UK. Early tests showed the jab, developed by US biotechnology company Novavax, leads to high levels of virus-fighting antibodies being produced. The trial on 10,000 people will now see if the vaccine can prevent people getting ill. The UK government has already ordered 60 million doses in case it proves successful.

The Novavax jab is only the second to enter large scale trials in the UK; the other has been developed by the University of Oxford.

Some of the vaccines being developed for Covid-19 use either completely new or barely proven technologies. Novavax are using traditional methods - proteins from the coronavirus that cannot replicate in the body and a chemical, called an adjuvant, to boost the immune response.