The Covid infection rate has been waxing and waning since the late summer in what experts interpret as a sign that the end of the epidemic in Britain is in sight.
As this fascinating graph shows, rates have been swinging like a pendulum this autumn, with a few weeks of rise in the figures being typically followed by a few weeks of contraction.
When a bar in the graph is above the line, it shows that daily Covid cases are growing. When it dips below the line, daily cases are reducing.
As this fascinating graph shows, rates have been swinging like a pendulum this autumn, with a few weeks of rise in the figures being typically followed by a few weeks of contraction
Government adviser Paul Hunter, an expert on infectious diseases at the University of East Anglia, says such swinging to and fro indicates that Covid is starting to become ‘endemic’ in Britain.
Reaching the endemic state is generally regarded as good news, as it means the most dangerous ‘epidemic’ stage is over.
Prof Hunter said: ‘We would not be seeing this pattern of rises and falls if the infection was not getting close to what’s called the endemic equilibrium.’
He explained: ‘Early on in an epidemic, there are lots of people susceptible [to the new virus], so you have to do something pretty dramatic – like lockdown – to get cases to start falling.’
But once most of the population has a defence against the invading pathogen – either thanks to natural infection or vaccination – he says it becomes harder for it to spread.
New outbreaks do occur, for example among those who haven’t been infected or in those who have lost total immunity.
Recently, that has been happening in children and teenagers, and to a lesser extent in older people whose vaccine-induced immunity has begun to fade.
However, because most people have protection, the number of those vulnerable to infection ‘drops rapidly’ as the new outbreaks attempt to spread, says Prof Hunter.
As a result, new cases fall and the outbreaks falter.
After a time, fresh outbreaks are triggered by further waning of immunity, and the cycle repeats itself.
Reaching the endemic state, which government adviser Paul Hunter says Britain is starting to become, is generally regarded as good news, as it means the most dangerous ‘epidemic’ stage is over
But – crucially – these fresh outbreaks increasingly involve people with some in-built protection, meaning they become less seriously ill than during the epidemic stage.
However, there is an alternative explanation: that recent ups and downs have largely been driven by changes in people’s behaviour, such as children going back to school and the recent half-term.
When viruses become endemic, the waves of growth and contraction tend to last for months rather than weeks, said Prof Hunter.
Leading epidemiologist Professor Sunetra Gupta, of Oxford University, believes the changing level of population immunity to Covid is now ‘the major driving force’ behind rising and falling waves of infection.
‘I said a long time ago that I thought we were headed towards an endemic state in summer 2020,’ she said. ‘I think a large part of that journey was accomplished before then.’
The professors’ views that the epidemic is probably nearing its end in Britain comes after the Deputy Chief Medical Officer, Professor Jonathan Van-Tam, said he thought Britain was at ‘half- time of extra time’, and he hoped the ‘final whistle’ would blow in spring.
But, he warned, between now and then there were ‘hard months to come in winter’.
Source: Daily Mail UK