COVID-19 vaccine trial stalled

Final clinical trials for a coronavirus vaccine, developed by Astrazeneca and Oxford University, have been put on hold after a participant had an adverse reaction in the UK.

Astrazeneca described it as a routine pause in the case of an unexplained illness.

The outcome of vaccine trials is being closely watched around the world.

The Astrazeneca-Oxford University vaccine is seen as a strong contender among dozens being developed globally.

Hopes have been high that the vaccine might be one of the first to come on the market, following successful phase 1 and 2 testing.

Its move to phase 3 testing in recent weeks has involved some 30,000 participants in the US as well as in the UK, Brazil and South Africa.

Phase 3 trials in vaccines often involve thousands of participants and can last several years.