UK's Johnson confident vaccines prevent deaths

"We think that both the vaccines that we're currently using are effective in, as I say, in stopping serious disease and death," Johnson told reporters.

"We also think in particular in the case of the Oxford AstraZeneca vaccine that there's good evidence that it is stopping transmission, as well, I think 67% reduction in transmission."

"They remain a massive benefit to our country and the population," he said when asked about AstraZeneca's vaccine.

"I've no doubt that vaccines generally are going to offer a way out. And with every day that goes by, you can see that medicine is slowly getting the upper hand over the disease."