The idea that Covid variants can be stopped from entering the country is “not realistic”, and Covid will eventually have to be managed in a similar manner to serious seasonal viruses such as flu, Prof Chris Whitty has said.
Speaking at a Royal Society of Medicine webinar, England’s chief medical adviser said the relaxation of Covid restrictions was likely to result in the R number rising above 1 and the risk of variants gaining a foothold and spreading increasing.
The more cases that have been imported, the quicker that will happen. As a result, Whitty said, border policies are focused on countries with more cases, or more cases of particular variants, than the UK.
“The UK is a net exporter of [the Kent] B117 variant, so other countries are understandably putting their border measures up against us to slow that down. We are a net importer of other variants that are a bit more of a worry from the vaccine point of view. That’s really what drives a lot of the policy, when it is being rational, excepting that border policy isn’t always fully rational,” he said.
Q&A
What does the ‘R’ number of coronavirus mean?
R, or the ‘effective reproduction number’, is a way of rating a disease’s ability to spread. It’s the average number of people on to whom one infected person will pass the virus. For an R of anything above 1, an epidemic will grow exponentially. Anything below 1 and an outbreak will fizzle out – eventually.
At the start of the coronavirus pandemic, the estimated R for coronavirus was between 2 and 3 – higher than the value for seasonal flu, but lower than for measles. That means each person would pass it on to between two and three people on average, before either recovering or dying, and each of those people would pass it on to a further two to three others, causing the total number of cases to snowball over time.
The reproduction number is not fixed, though. It depends on the biology of the virus; people’s behaviour, such as social distancing; and a population’s immunity. A country may see regional variations in its R number, depending on local factors like population density and transport patterns.
Hannah Devlin Science correspondent
Whitty said the majority of experts believed Covid was not going to go away and it would eventually have to be managed in a similar manner to flu. In a bad year, flu can kill 20,000 to 25,000 people. “It is not flu, it is a completely different disease, but the point I am making is, here is a seasonal, very dangerous disease that kills thousands of people every year and society has chosen a particular way around it,” he said.
While Whitty noted that factors such as variants and population density were important, he cautioned against trying to explain how Covid had affected different countries by focusing on just one or two factors, noting that Germany was now facing a difficult situation despite its previous success in tackling Covid largely being put down to its diagnostic capabilities.
“It is actually usually a large combination of factors, some of which are under our control, many of which are not. And more of it is chance than I think people are prepared to accept,” he said.
Whitty said new vaccine technologies meant it had become easier and quicker to tweak vaccines, which will be important for tackling new Covid variants, and he said that two years from now it was likely there would be a wide portfolio of vaccines available.
He said at present the main effort of companies was to boost vaccine supplies and there was less capacity to respond to new variants, while it was unclear whether current vaccines offer a “fair degree” of protection against severe disease and death even if they do not generate high levels of neutralising antibodies.
“What we have got to do is work out some balance which actually keeps [Covid] at a low level, minimises deaths as best we can but in a way that the population tolerates and do as much of the heavy lifting as we can by medical countermeasures,” he said.
