Coronavirus arrived like a stone thrown into a still pond. Out from this impact surged a first wave, a tsunami of infections that subsumed countries as it spread. Behind it, as many had predicted, has come the second wave, almost exactly six months later.
Tom Whipple, Science Editor www.thetimes.co.uk
But just as with a stone in a pond, this ripple does not match up to the first. Of all the statistical comparisons between the waves, two from hospitals exemplify the trends that matter. One is a graph going up, and the other a graph going down.
The first, the graph that is going up, shows how fast hospital beds are filling. Between March 1 and April 1, the number of covid patients entering hospital went from 0 a day to 3,500 a day. Between September 1 and October 1, the number went from 100 to 500.
Ours is not the naive, socially undistanced, office-working world of spring 2020. Today, the virus can still spread — we are very far from herd immunity — but with the connections between people and groups cut or fractured it finds its task a lot harder.
Back in March, the number of new infections doubled every three to four days. Today, at the speediest end of estimates, it managed seven to eight days. Probably, it took longer still. This tells us that we have longer to respond, and have to do less to bring outbreaks under control.
However, ours is also a society where there is less that we can do. The easiest social restrictions are already in place. Some, such as school closures, will never be enacted again. This leaves us with just a few tools with which to bring that graph of new hospital cases down.
So far, the levers we have available have not worked so well — as the same graph shows us. The first wave may have been more dramatic, but it also faded faster. After a month, back in spring, new admissions to hospital started to fall. Six weeks into the second wave, and they are still continuing their slow and steady upwards path. If anything, in fact, they are accelerating.
Partly, the trajectory is a sign there has been a shift in who is being infected. This is not a disease that strikes all sections of society equally. When the second wave started, some hoped it would stay where it began, in the young.
Was it inevitable that teenagers and students, tired of a virus that did not affect them but still demanded so much of them, would pass it to their grandparents?
Heat maps of its spread among society show that it seems it was indeed inevitable: the idea we could somehow seal off one section of society appears to be misplaced.
Despite our efforts, an infection of the young is rapidly becoming one of the old yet again. Or as one expert memorably put it, trying to have an infection-free demographic in a pandemic is like trying to have a urine-free lane in a swimming pool.
How worrying is this? With deaths lagged from infections by around a month, it is too soon into the second wave to judge how deadly the virus will be this time.
It is, in fact, hard to even judge how deadly it was the first time. Calculating fatality rates depends on who is counted as a Covid-19 case when they die and who is spotted as a Covid-19 case when they don’t. In April, when testing levels were a 20th of what they are now, scientists estimate that we missed 90-95 per cent of all cases.
We don’t tend to miss ICU cases though. When assessing what has changed, statistics of critical care beds provide a reasonably solid anchor in a shifting sea of data.
This is where the second graph, the one going down, becomes useful. It is a measure of how likely it is that those who go into intensive care, almost entirely the late middle-aged and elderly, will go on to leave it alive.
The graph shows that in the first wave for every ten Covid-19 patients who entered critical care, four never left. So far in the second wave things look marginally more promising. A month after entering ICU, more than seven in ten patients are still alive.
This should not be surprising. Unlike in the spring, the most severe cases today have a drug that works — dexamethasone. They also have protocols that have been refined and improved. In March and April, 60 per cent of those entering ICU were put on ventilators in the first 24 hours.
Today, with better understanding of what helps and what hinders, the proportion is less than half that. Paradoxically, the rise in cases gives us hope this might improve further. As more patients end up in hospital, we have more people to test new drugs on.
By Christmas it is very likely the world’s doctors will be given another proven drug, to complement dexamethasone. Even so, there is no disguising that winter looks likely to be long, depressing and, for many, lonely.
We will not be buoyed by the weather of April. Nor — perhaps — will we be carried along by the cohesion of a country that met its neighbours every Thursday to clap the NHS. But, with a grim determination and a lot of hard-won knowledge, the statistics show that we can still keep our heads above water as the second wave passes.