The number of people testing positive for new cases of Covid-19 has now fallen for seven days in a row, prompting thoughts that the UK may be through the worst of the third wave of the pandemic. But are they justified?
A seven day stretch of falling case rates last happened in summer last year, when the government had just introduced mass testing and began recording comparable figures.
In November, the UK came close with six consecutive days of falling cases after the second lockdown restrictions were introduced across the country.
This time round, the UK has next to no restrictions in place after the 19 July “Freedom Day” easing, and cases have dropped sharply from above 50,000 on 17 July to 24,000 on 27 July, according to the latest government data.
The good news prompted Boris Johnson to urge people not to get complacent or jump to premature conclusions on Tuesday, as he warned that the effects of Freedom Day had not yet fed through to the data.
But his warning came as Imperial College epidemiologist Neil Ferguson – whose analysis has been among the most influential scientific advice to the government during the pandemic – said that the end of Covid in the UK could be just months away, thanks to the vaccination rollout.
So do the figures equate to the end of the third wave in the UK?
At the heart of the matter is the question surrounding why cases are falling so quickly. With each day that passes, more people are fully vaccinated against the virus, giving greater protection against infection and transmission. The recent spell of warm weather will have led to more mixing outdoors, where the virus is less likely to spread.
It is possible that the Euro 2020 football tournament helped drive spike in cases in the weeks leading up to Freedom Day, thanks to people gathering in large groups to watch the matches. The tournament finished on July 11 – long enough for a change in people’s behaviour to start to affect the daily figures.
The steady rise in cases during June and early July might have prompted people to start acting in a more cautious way – for example, limiting the amount of meeting indoors – and this is helping to drive down the numbers. The summer term has finished, which means there is no longer regular testing of staff and pupils at secondary schools, which in turn means fewer cases are being found.
And there is a small chance that some are choosing not to record their symptoms or take regular tests, to avoid disrupting work or holiday plans and the so-called “pingdemic”.
“A great many people have been asked to self-isolate recently and this could have a direct impact upon transmission,” says Dr Stephen Griffin, of Leeds University School of Medicine.
“People might actively avoid being put forward for testing as a result of messaging that minimises the dangers of infection, or that vaccinated individuals with mild symptoms might not realise they are infected. While they are likely to represent a relatively small proportion of cases, this could still result in transmission given the current absence of restrictions.”
Shortly after replacing Matt Hancock as health secretary, Sajid Javid warned that the daily positive case rate could reach 100,000 at some point during the summer – but this was not a prediction or a forecast.
Rather it was a projection of how high the number could rise in a scenario where the virus is spreading rapidly through the population and people are taking few or no precautions in terms of mixing and socialising.
Freedom Day impact day still to come
But in reality, we won’t know whether the UK is through the worst of the third wave for a few weeks at the beginning of August when, as the PM suggested, the full impact of lifting restrictions on July 19 will feed through to daily case numbers.
Before then, we will get a better idea of the national picture on Friday when the Office for National Statistics (ONS) publishes its latest weekly infection survey.
This will contain estimates of the number of people who had coronavirus in the UK in the week ending July 24 – not simply the number of new cases – and show whether this is higher or lower than previous weeks.
Another key date, according to Oxford University professor James Naismith, will be the survey on Friday August 21, as this is when “we will know for sure the effect of the end of the lockdown”.
He adds: “Many scientists, myself included, expect the end of lockdown to see a rise in cases. However, we have been wrong before and we will be wrong in the future. This is a new disease and we are learning more every day.”
A potentially long winter
Even if this wave of coronavirus peters out during the summer, there is still the chance of another spike in the autumn and winter, once schools have returned and the weather encourages more mixing indoors.
Professor Karl Friston, of University College London, said a “key question” is “how do we prepare effectively for a winter resurgence”, especially as attention shifts from “mortality to morbidity, such as long Covid and post-Covid syndrome, and the secondary effects on healthcare beyond Covid-19”.
Neil Ferguson echoed this sentiment, and told the BBC, “We won’t see for several more weeks what the effect of the unlocking is.”
“We need to remain cautious, especially with the potential increase in contact rates again as the weather becomes less fine and schools return.”
But Ferguson said the vaccine rollout had weakened the crucial link between case rates and deaths and hospitalisations.
“We’re not completely out of the woods but the equation has fundamentally changed,” he said.