The government adviser who warned that daily Covid cases would almost inevitably hit 100,000 has warned of a “resurgence” in the virus in the coming weeks, following six days of falling numbers.
Imperial College London professor Neil Ferguson said it would be “several weeks” before the full impact of the removal of lockdown restrictions on 19 July was felt in terms of rising cases, hospitalisations and deaths.
But he said that the vaccination campaign had “fundamentally changed” the course of the outbreak, leaving him “positive” that by late September or October, the bulk of the pandemic in the UK will be “behind us”.
Prof Ferguson said earlier this month that the current wave of Delta variant cases could top 200,000 before beginning a slow decline into the autumn.
But he today said he would be “happy to be proved wrong” after a steady decline in cases from 54,674 on 17 July to 24,950 on Monday.
The “unexpected” fall in cases in recent days may be linked to the end of the Euro 2020 football tournament on 11 July and the arrival of heatwave weather, both of which have led to a reduction in people gathering indoors, he said.
But he cautioned that this did not mean the latest wave of coronavirus is over.
“I think it’s too early to tell,” the epidemiologist told BBC Radio 4’s Today programme. “The reductions we’re seeing at the moment occurred before the unlocking took place and we won’t see for several more weeks what the effect of the unlocking is.
“I’m happy to be proved wrong if it’s wrong in the right direction. If case numbers stay low that will be really good news.
“But I think we do have to be slightly cautious. I think probably infections in the community are plateauing, but we’ll see that later this week with the latest Office of National Statistics infection survey.
“Positivity – the proportion of cases which test positive – only started going down very, very slightly on 21 July.
“We have to monitor quite a lot of different indicators to see what’s going on, but it will probably take several more weeks for us to see the effect of unlocking.”
Prof Ferguson said that the crucial rate of transmission – known as R – would be as high as three or four if it were not for the high rate of vaccination in the UK, but is currently probably around one thanks to widespread immunity.
“The key issue is what effect will 19 July have had,” he said. “School closure and holidays reduce transmission generally, but the relaxation will increase it.
“At the moment, we can’t judge exactly how those things are going to balance out and we haven’t seen the effect of those in any of the data so far.”
Prof Ferguson rejected suggestions that the apparent fall in cases was purely down to a reduction in testing following the closure of schools, or to people dodging tests in the hope of being able to go away on holidays in the coming weeks.
He said he expects a “clear plateau” in positive cases to emerge this week, following the unexpected fall of the past few days.
“The real issue is, will that turn into a long-term decline – which we of course all hope it will – or will we see a resurgence of … hospitalisations and deaths as we go late into the summer and into the autumn,” he said.
By the autumn, Prof Ferguson suggested that the pandemic could effectively be over in the UK.
“We’ll be able to tell really later this week and then next week whether we see hospitalisations – which are still rising at the moment – start to decline,” he said. “That would give us more confidence that we really have seen a peak – maybe not the peak, but a peak – at the moment.
“We need to remain cautious. There is the potential of quite a substantial increase in contact rates again, particularly if the weather remains less fine and schools reopen in September.
“We’re not completely out of the woods but the equation has fundamentally changed. The effect of vaccines has been huge in reducing the risk of hospitalisation and death.
“I think I’m positive that by late September, October time we will be looking back at most of the pandemic. We’ll still have Covid with us, we’ll still have people dying from Covid, but we will have the bulk of the pandemic behind us.
“The higher we can get vaccination coverage the better – that will protect people and reduce transmission. But there is going to be remaining uncertainty until the autumn.”
