COVID-19 – do the numbers tell us anything?
In January when coronavirus first made the headlines, we heard that the disease was fatal in 3 to 4% of cases – also that the mortality rate was higher among those over seventy or with an underlying health condition. ‘Not that much worse than regular flu’ and ‘…not going to be as bad as the 1918-19 Spanish influenza pandemic’ many of us thought. Yet, more and more of us around the world now find ourselves in lock down . Why? And, how dangerous is this disease really? The rising death toll makes for depressing reading – but understanding the story behind the numbers is important.
The 3 to 4% figure
At the time of writing (the morning of the 26th of March 2020), statistics site Worldometers https://www.worldometers.info/coronavirus/ reports more than 472,529 cases of which 336,484 are currently active with 21,305 deaths (4.5%). This figure needs to be treated with caution because it reports cases that are yet to conclude – not outcomes. Outcomes for the 336,484 sufferers won’t be known until they have either died or recovered. Furthermore, the Worldometers data is sourced from national health agencies around the world who count cases using methods that differ from each other, so beware:
- Since the outbreak began in Wuhan, the PRC has
reportedly changed its method of counting ‘confirmed’ cases no less than five
times (The Daily Telegraph – 29th
Feb). During some periods, patients with regular influenza or pneumonia
would have made it into the Chinese coronavirus numbers.
- Many countries are short of test kits. In the UK this means that only those patients admitted to hospital – the most serious cases – get tested. Anyone suspected of suffering from the disease is advised by the NHS to self-isolate unless their life is actually ebbing away. Do these phone-in cases – obviously unconfirmed – make it into the UK statistics?
This figure almost certainly under-reports the extent of the outbreak because those with very mild symptoms, or showing no symptoms at all, are unlikely to find their way into the count. There is speculation that as many as half of us may have had the infection anyway without even noticing it.
The 44% (and rising) number
To get an idea of how dangerous the pandemic really is the number to watch is the closed cases. Only these – rather than the active cases – give the figure for final outcomes. Comprised of confirmed recoveries and doctor’s certificates quoting cause of death, more of these cases are likely to have had the benefit of a proper test, making it more reliable than the one for active cases. The figure for closed cases this morning stands at 136,045 of whom 114,740 recovered and 21,305 died – a rather more worrying mortality rate of 16%. This doesn’t mean that 16% of us will die or even that 16% of those who catch Covd-19 will die. What it does tell us is that (a) if you catch the disease and (b) have a serious enough case to be admitted to one of the hard-pressed hospitals then your chances of pulling through are below 84%.
What is most worrying about the mortality rate, based on closed cases, is that it has risen by 1% every single day for the past few days – what was 10% a week ago is 16% today. How can that be? If you remove China’s improving numbers from the statistics the mortality rate appears even worse. One possible explanation is that the PRC and Iran, where the bulk of the figures came from in the early weeks of the outbreak, have been under-reporting. Certainly, neither state enjoys a reputation for transparency.
As the (presumably more open) democracies of the EU and North America have begun to be affected more reliable figures for case outcomes have started to find their way onto the global total. This might explain the rising rate of deaths – but why would the PRC wilfully falsify its figures? After peaking on the 12th February, the number of cases China that has been reporting has been in decline. Perhaps the PRC wishes to show the world how ‘effectively’ it has managed its crisis? If the figures are to be believed – and let’s pray they are – then the declining number of cases in China shows that the social distancing and quarantine measures employed there and now everywhere else have been increasingly effective at curtailing the spread of the virus.
Getting Covid-19 under control
Governments around the world are pinning their hopes onsocial distancing to the curtail the spread of the disease. The costs of the measures (ultimately to tax-payers of course) are horrendous. Businesses will have their profits wiped out, others will fail altogether, unemployment and national debts will go through the roof, government tax takes will be down. Yet, social distancing is considered a worthwhile strategy because of the benefits. So what are they?
The most obvious one is that it should preserve the effectiveness of health services. If peaks in the numbers of severe cases can be softened and the curves smoothed then health services will be able to cope. If not, the hospitals and medical staff will be inundated and become incapable of helping sufferers – exacerbating rather than helping the mortality rate.
There are two further benefits – both around ‘initial viral load’. The human immune system can deal with many viruses, Covid-19 included, provided the attack is a light one rather than a swarm. If you made a journey on the London Underground and inhaled as someone who had the virus walked past you to take a seat at the other end of the carriage the viral load challenging your immune system would be a light one – one it should be able to cope with. On the other hand, if the carriage was packed with fellow commuters who were all infectious, half of them coughing over you, your immune system would in all likelihood be overwhelmed by such a high initial load. People caring for family members who are sick with Covid-19 are advised to put each patient into separate rooms while they are ill – again in order to minimise the patient’s exposure to additional viral load from fellow sufferers. Incidentally, it is because of viral load that highly promiscuous individuals or individuals with accompanying STD infections contracted AIDS during the nineties epidemic more often than those who were mildly promiscuous and free of other STDs. In a similar way the elderly, and people on immune-suppressant medication, are more vulnerable through having immune systems less able to deal with a high initial viral load.
Social distancing exposes people to fewer carriers and to a lower viral load when they do cross paths with one. If you’re prevented from taking the Underground to work then that is one less place you might cross paths with an infectious person. It is also one less place you might touch a surface on which the virus is sitting. If one of your colleagues is an asymptomatic spreader, you won’t find yourself sitting next to them over prolonged periods in the office in the usual way. Furthermore, initial exposure to the virus in a limited way increases the chances of you developing some immunity to Covid-19. Thousands have already had the infection and made a full recovery. In one of the earliest cases in the UK a family was put into quarantine in York and one of their children – who exhibited no symptoms at all – tested positively for the infection. The child had had exposure to the Covid-19 virus, but not in sufficient volume to overwhelm his immune system. This is how people go through the disease as ‘mild’ cases. Reducing initial viral load through social distancing is seen as the way to achieve the Holy Grail of the pandemic: herd immunity.
I while ago I was chatting with a London friend who works in the rag trade. He had recently been on a business trip to Milan, and described an extraordinary scene. He was taken to a business park in one of the surrounding villages where he saw poor Chinese families living, sleeping and working 24*7 in warehouses. These people spent their days operating sewing machines, ‘finishing off’ garments that arrived by the container load from China. The ‘finishing off’ consisted of attaching ‘Made in Italy’ labels – presumably because a garment labelled ‘Armani’ or ‘Gucci’ with such a label commands a higher price than one that should more truthfully read ‘Made in Wubei Province, the PRC’. This questionable practice probably explains why Italy has the largest Chinese population in Europe (said to number 300,000), many of whom would have returned home for the New Year celebrations that started on the 25th January. It cannot be coincidence that Covid-19 infections were first recorded in Italy in the first week of February with the first death occurring on the 21st February. Italy quickly became Europe’s ‘ground zero’ for the disease with new cases spreading across the continent from there and rising exponentially over the following weeks. Italy is reporting twice as many deaths today as China (7,530 versus 3,287).
The Italian curve matters to all of us because it is the best ‘canary in the cage’ for the rest of us. Social distancing was introduced, first to certain small towns and villages south of Milan, then to all of Italy north of Pisa on the 8th of March, and finally to the whole of Italy on the 11th of March. All eyes are now upon the Italian figures to see when they will start to fall i.e. when (and if) social Distancing will start to bite. On Saturday the 21st of March they appeared to peak at 6,557 new cases. On Sunday and Monday this week the number fell for two consecutive days, suggesting that the rise was finally being reversed. Disappointingly they ticked up again on Tuesday from 4,789 to 5,249 and added 5,210 again yesterday (Wednesday). With all our hopes relying on the social distancing strategy, we will still have to wait a few more days to see if and how long it will be before the strategy proves effective in Italy. Today Italy is reporting 16,865 closed cases of which 7,503 ended in death – a staggering mortality rate of 44%