Boris Johnson insisted the vaccination programme had “severed” the link between rising coronavirus cases and deaths, despite his chief scientific adviser stating the relationship had merely been weakened.
The Government is braced for a surge in coronavirus cases, possibly around 100,000 a day, as restrictions are lifted, but the Prime Minister said the success of the vaccination programme meant the link between infections and deaths had been broken.
In the Commons he told MPs it was “certainly true” there was a “wave of cases because of the Delta variant” of the virus.
“But scientists are also absolutely clear that we have severed the link between infection and serious disease and death,” he said.
“Currently there are only a 30th of the deaths that we were seeing at an equivalent position in previous waves of this pandemic.”
His comments came just two days after Sir Patrick Vallance, at a press conference alongside the Prime Minister, said the link had been weakened but not broken.
On Monday, Sir Patrick, the Government’s chief scientific adviser, said there had been an increase in the number of people in hospital, but the rise was not as steep as it had been in January.
“The doubling time is slower than for cases so it’s not rising as fast, but the hospitalisations are rising and are rising quite steeply in some places, and we would expect them to continue,” he told the briefing.
“So essentially what this shows is that the vaccines have weakened the link between cases and hospitalisation, but it’s a weakened link, not a completely broken link, and we will still see increases in hospitalisation.”
At Prime Minister’s Questions Sir Keir Starmer told Mr Johnson: “We know that the link between infection rates and deaths has been weakened, but it hasn’t been broken.”
The word 'severed' doesn’t really have a scientific definition so it’s not helpful terminology
Dr Alexander Edwards
Dr Alexander Edwards, associate professor in biomedical technology at the University of Reading, said Mr Johnson’s choice of word was “not helpful terminology”.
He told the PA news agency: “Right now, we are only just starting to gather enough data to know how different the link between deaths/hospitalisation and overall cases is than before the vaccine rollout.
“It has become clear in the last weeks that the link has changed, with far fewer deaths/hospitalisation than previous waves, for the same number of cases.
“The difficulty is that deaths/hospitalisation numbers lag behind reported cases by around two weeks. So although case rates have risen dramatically, it’s too soon to know precisely how this translates to deaths/hospitalisation now.”
He added: “The word ‘severed’ doesn’t really have a scientific definition, so it’s not helpful terminology.”
Professor Christl Donnelly, professor of applied statistics at the University of Oxford and professor of statistical epidemiology at Imperial College London, said: “The link between cases and deaths has not disappeared.
“There is still a positive correlation because some proportion (thankfully quite small) of the current cases will still be serious enough to result in hospitalisation and death.”