Covid cases have fallen by a third in a week but Boris Johnson warned they would rise again if people did not remain cautious.
The prime minister braced the country for a further increase resulting from the end of restrictions as he cautioned against drawing “premature conclusions” that the threat of the pandemic had passed.
The sustained reduction has taken ministers and scientists by surprise, with the government concluding that much of it is likely to be real, but they are concerned that it will reverse if people react to the good news by becoming less cautious.
Cases have fallen most among those in their late teens and early twenties, according to analysis of internal government data. Some scientists believe this reflects less testing as schools break up for the summer, while another theory being taken seriously in Whitehall is that a big part of the reduction is because people are avoiding tests in case their summer holiday plans are ruined.
After a seventh consecutive day of falling numbers, when reported cases usually rise on a Tuesday because of post-weekend testing, there is increasing optimism in government that cases truly are falling. The seven-day average of cases in the UK has fallen 31 per cent in the past week while the equivalent figure for testing has fallen only 14 per cent. Less than 3 per cent of tests are positive, compared with more than 4 per cent a week ago.
The end of a rise linked to England’s progress in the Euro 2020 football tournament and a spell of hotter weather have been suggested as possible reasons for a true fall in cases.
Ministers are playing down its significance, with science advisers wanting to see another week of data before they are convinced the trend is meaningful. They want to prepare people for rises in the next week as the full impact of unlocking is felt, and for when schools, universities and offices return to normal in September.
During a visit to Surrey yesterday, Johnson said: “I’ve noticed, obviously, that we are six days in to some better figures. But it is very, very important that we don’t allow ourselves to run away with premature conclusions about this.”
The impact of more people mixing after the reopening has yet to be fully felt. Johnson said: “Step 4 of the opening up only took place a few days ago, people have got to remain very cautious and that remains the approach of the government.”
Analysis of internal Public Health England data by Alastair Grant, of the University of East Anglia, suggests that cases have almost halved in a week in people aged 17-26, and are down by a third in 15 and 16-year-olds. There has been a small increase in cases in the over-80s. Grant said that “reduced testing will be a contributing factor to the reduction in cases”, but argued that “there has to be a substantial real reduction in numbers too”.
There were 131 deaths reported in the UK yesterday, the first day in three figures for four months. Yvonne Doyle, the medical director of Public Health England, said this was “in part due to the high number of cases recorded in recent weeks” and that the third wave had not passed. She insisted that “rates are still high and the pandemic is not over yet”, urging people to meet outdoors, limit contacts and stay at home if unwell.
Professor Neil Ferguson, of Imperial College London, said that it appeared cases had plateaued, but warned that further rises were possible because people still had “relatively low contact rates” compared with before the pandemic. He said he was “positive that by late September, October time we will be looking back at most of the pandemic”, but insisted: “we need to remain cautious, there is the potential of quite a substantial increase in contact rates again, particularly if the weather becomes less fine, as schools reopen in September, so we’re not completely out of the woods”.
Marc Baguelin, of Imperial College London, who sits on the Spi-M panel of pandemic modellers, said that it was difficult to explain “such a sharp fall in the number of new cases and so synchronised among all English regions”.
He suspects, as many of the government’s scientific advisers do, that several factors have combined to quell the virus, including a large number of people self-isolating, the end of the football tournament and a heatwave that encouraged people to spend more time outdoors. Baguelin said he expected case numbers to remain relatively low, at least until schools returned. “I think we will have a wave in September, especially as the school-aged population is almost entirely not vaccinated . . . But I think we can be optimistic, that we are likely to be in the lower end of the predictions,” he said.