Early days but fall in Covid cases is reason to be cautiously optimistic

There is something unexplained going on in the data. Tim Spector’s symptom tracker app appeared to have picked up a turning point a couple of weeks ago, but that was considered to be a sampling blip. His app still indicates widespread infections in the South West, see below, and no fall nationally. – Owl

Tom Whipple, Science editor www.thetimes.co.uk 

It is great news that cases are falling. It is also slightly mysterious. In only a few days we have gone from rapid increases to rapid decreases. The graph of UK cases looks like a spiky Matterhorn.

What is confusing is that if this change was a result of infections and vaccinations only we would expect the rounded dome of a Mont Blanc-style summit, as we slowly edge up to and then pass herd immunity.

So what is happening?

The first thing to note is that we have yet to see most of the effects of England’s July 19 reopening percolate through. Neither, though, have we seen the (hopefully) opposite effect of schools closing for summer.

What is happening now, which cannot be explained by falling test numbers, largely represents trends that came before.

It may be partly the consequences of the Euros ending. We know that football affected case numbers because for the first time we could see a gender split. There was a divergence between men, who watch a lot of football, and women, who not only watch it less but are less likely to do so while congregating in crowds with flares up their bottoms.

The fall may also be the effect of better weather — for both fire safety and infection control reasons it is greatly preferable to have such celebrations, and more staid gatherings, outdoors.

Vaccines have had a huge effect, yet it still remains the case that every thousand fewer infections translates into about one fewer death.

But if behaviour rather than immunity is the most plausible explanation, there is also still some reason for wariness. After all, behaviour, not to mention lifted restrictions and worsening weather, can take cases in both directions.

Both Blackburn and Bolton had early outbreaks of the Delta variant and became the Petri dish for the nation’s third wave. In May their peaks declined, which led some to suggest they had reached herd immunity, but they are rising again.

Even so, this is a good day. Many thought reported cases would keep rising until we hit 100,000 a day. Many looked at the trajectory and thought 200,000 a day — a figure that could threaten the NHS — would not be unreasonable.

Today, with due caveats and uncertainty, it is plausible to believe that we have peaked at 50,000 and are on our way down. All of which means there is reason to be cautiously hopeful.

From Zoe Covid Symptom Tracker