Covid-19 – Why Does the Fatality Rate Appear to Be Falling Off?

It seems to have become an article of faith to those who, for whatever strange reason, feel an obligation to underplay the seriousness of the Covid-19 pandemic, that notwithstanding the apparent resurgence of the virus it is somehow less threatening or less deadly this time around. Whilst case numbers are increasing, they argue, any corresponding increase in the number of fatalities has thus far been negligible.

On the surface of it there would appear to be some evidence to support these claims. At the height of the first wave of infections the United States saw 34,196 new cases in a single day and a pinnacle of 2,804 deaths. The second time around saw daily cases peak at 78.009, yet “only” 1,504 deaths were recorded on the darkest day.

Tests ramped up massively

To begin with these figures need to be treated with some caution. Almost everywhere testing has been ramped up massively since the first wave of infections prompted lockdowns across the western world. The figures we have only represent confirmed positive cases, and it is all but certain that the virus was substantially more prevalent in the US in April than it was in July. In most western economies the start of the pandemic saw testing only being undertaken in hospitals, whilst the much larger number of infected people who either were asymptomatic or who endured symptoms mild enough not to require hospital treatment were left to guess. As such the ratio of deaths to infections has not altered as starkly as the statistics would appear to suggest.

All the same, it is notable that at a time when thousands of people are still testing positive for the virus the number of fatalities has dropped to a surprisingly low point, especially perhaps in Europe. For most of June and July daily deaths in Spain were in single figures, and here in the United Kingdom fatality numbers remain similarly low describe a tangible recent increase in transmission.

A more cavalier attitude

The received wisdom has it that infections this time around seem to be most predominant amongst younger people, particularly in the 20-29 age group. This would seem to make sense bearing in mind that younger people tend to interact more with one another, and also that very few people within this age group become seriously ill with the virus and therefore a more cavalier attitude can be expected. But we have precious little to compare it with. As only people admitted to hospital were being tested back in March and April, we probably had very little idea of just how many people were carrying the virus, particularly amongst the young.

The recent evidence from France and Spain is that a contagion which begins by doing the rounds amongst the young does inevitably find its way into older society after a while, and then hospital admissions and sadly deaths do indeed follow. Whilst fatalities are thankfully nowhere near the levels that we saw back in the spring, these two countries have seen significant increases in both, and the first stories of intensive care units being close to saturation have begun to emerge from Marseilles. In the United Kingdom, which seems always to be a few weeks behind continental Europe in these matters, an uptick in the number of hospital admissions and ventilator use has been noted over the past few days.

Low survival rate

Undoubtedly as the pandemic has progressed hospital staff have become more knowledgeable about how the virus works, and more adept at treating sufferers. It is quite likely that the hideous process of intubation was used too enthusiastically during the earlier months, and the introduction of CPAP technology has allowed many to avoid having to undergo this experience which had an unappealingly low survival rate. The successful use of remdesivir (largely in the United States) and dexamethasone have had a positive impact in terms of lessening the duration of the illness and, in the latter case, preventing a significant number of deaths. These factors alone ensure that, provided that health services are not overwhelmed when and if future spikes occur, fatality rates should be statistically lower than they were in the spring.

Of course, life-saving treatments given to seriously ill patients only benefit those who are receiving hospital care. Their increased use has no relevance to the question of whether fewer people with Covid-19 are actually bring admitted to hospital in the first place. If this is indeed the case (and we are too early into the latest phase to determine whether it is with any certainty), it may be at least partly down to the fact that the National Health Service has become better at assessing which patients need to be hospitalised after becoming ill.

Is the virus becoming less lethal?

All this brings us to the final question, which is has there been any significant change in the nature of the virus which may have made it less deadly? On this matter the jury is still out. There have been some tentative suggestions that a mutation has taken place which has produced a more contagious but less lethal strain of the virus. Paul Tambyah, a senior consultant at the National University Hospital in Singapore and president-elect of the International Society of Infectious Diseases, has argued that the emergence and proliferation of what has been called the D614G mutation in certain parts of the world has coincided with a reduction in fatalities.

It is certainly true that most viruses tend to become less virulent as they mutate. This helps them to survive and to move between hosts, a thing that ceases to be possible once a fatality has occurred. Nevertheless, rising deaths figures in Spain and France do seem to indicate that Covid-19 retains at least a good part of its deadly potential.

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