The World Health Organization is urging people to be cautious following yesterday's news about a vaccine for COVID-19.

Pfizer confirmed its experimental vaccine to be 90% effective following trials, something WHO Director-General David Nabarro agreed was positive news.

However, Nabarro warned people not to get complacent and to continue to follow safety guidelines, particularly as it is not currently known how long protection lasts after vaccination.

Priscilla Lynch, clinical editor of the Medical Independent, told us more.