I am going to make a COVID-19 prediction, a rather reckless idea in this turbulent world, granted. Considering that almost every prediction I have made, and some of those from experts, on COVID–19 have been eventually rendered inaccurate, I am curious to see if this one pans out. Yes, I am playing around here, I admit.
My prediction is this: that COVID-19 has evolved into a newer highly infectious disease, though one which is far less severe than the one that burned through the world in the first wave in the first months of this year, and most likely much earlier. Although caseloads in Europe are beginning to surge once again, I feel we will not see anywhere near the levels of fatalities that we have experienced in the first wave. However, the high infectivity levels, and the high levels of asymptomatic patients, strongly indicate to me at least that this new guy on the block will be around for a very long time, vaccine notwithstanding. We are going to have to live with it for ever, probably.
I must admit, I am not picking this idea out of the ether here; it is not even a prediction. There is in fact a growing wealth of publications describing the emerging (and indeed fast establishing) COVID-19 strain G614 and its structural, behavioural, and epidemiological characteristics (see here).
The current picture of the so called second wave welling up across the world is that of a lower age profile among the infected. According to the WHO, it is being driven by those aged between 20 and 40 (link). The numbers of cases are increasing across Europe, but interestingly, large numbers of hospitalisations due to severe illness have not really followed, unlike the earlier wave in March and April. Now, lets drill down into that.
April 2020 pretty much stands as the peak of the epidemic in Europe and Asia, so far. At that stage, over 1000 people were dying each day in countries such as Italy, UK, and Spain. The rest of Europe was losing significant numbers also, but not quite as high. In the American continent, north and south the virus was starting to exact a devastating toll. The world death count on 18th August 2020 stands at 784,785, and many of the European deaths occurred between March and June. All this information can be gleaned from here, with some tweaking (link). Not so in the Americas, where surging caseloads and death rates are currently double the numbers for April and May (there are a variety of reason why the Americas have failed to supress the virus). The majority of deaths were among the older demographic, 65 and above, and among those with underlying conditions, both young and old. Some deaths occurred among younger patients, for a variety of reasons, some unknown. The one common theme within a healthcare context in every country in April was of overload. Healthcare systems were on the brink of collapse, even in so called advanced economic regions, such as Europe and the USA.
Numbers are rising again, and although they started to rise about a month ago in Europe, they have not translated into an over whelming surge in hospital demand, and the death rates appear to be lower overall. Again, the numbers of deaths verses total cases can be retrieved from here (link).
Now there could be a number of reasons for this:
- The epidemiology of SARS-CoV-2 may be such that infection waves are driven initially by the more social, and often reckless (smiley face here), younger population, who tend not to be so ill, or even remain asymptomatic. This portion of the demographic would then enable the movement of infections into the older generations on contact (parents, grandparents etc of the infected younger family members). These older generations then begin to register as a rising tide of patients that exhibit the more severe form of the illness. This would take time to show up, probably a couple of weeks. It could have been what happened at the beginning of the first wave; the virus first surged through the younger generation before it reached the vast swathes of our populations that are more vulnerable. Certainly, there is evidence that the disease was present in Europe long before February (link). Add to that, that we did not know what to look for owing that we did not know that SARS-CoV-2 existed, it could well turn out to be the case that young people enabled the fire, the older people then burned, as it were. However, although possible, this scenario should have started to present increased numbers of severely ill patients and a rising death rate by now, considering we are a month into this new surge. It has not (link). At least not yet.
- It is possible too that vastly improved healthcare has cut death rates down, as well as the emergence of “COVID-experienced” healthcare staff. There are now several treatments available that reduce the severity of the disease in some of those afflicted. These treatments are not universally successful and there exists no widely used therapy. It still is a case of making skilled and educated guesses on a case by case basis. However, to find oneself within the setting of a COVID ward receiving a cocktail of experimental drugs, one must be sick enough to end up there in the first place. These patients have not presented in increased numbers yet.
- Increased awareness of social distancing has prevented the virus from transmitting to the more vulnerable sectors of society in large numbers. Is it a case that asymptomatic young people are running around, and the older generation are simply avoiding them as much as they can? Everyone the world over now knows about social distancing and what to do about it. We know that elder care homes and hospitals are particularly prone to severe outbreaks and the nature of their operations has been radically altered to prevent infections from getting a hold in these settings. Add to that, in the west, the older generations (grandparents and the like) generally do not live with the younger generations, making socially distancing far easier. Older generations are now (unlike in February and prior when the virus was circulating unbeknownst to us) unlikely to spend so much time in the presence of their younger grandchildren, however tragically sad that may seem to be. Particularly when a younger member has been tested as positive. Other countries, where many generations live in the same household, might not be so lucky with this advantage and further research on this aspect will be interesting to see. Are those factors playing a role in the current lethal surges in South America, South Africa and other places? Widespread mask wearing, and copious hand washing, sanitising, and vastly improved widely employed respiratory etiquette could all play a role too. In a nutshell, the young have run amok and have disregarded the rules, thus are starting to catch COVID in increasing numbers once again. But the rest of us, and the young when not in a bar or caught up in high energy interactions with their friends, are observing the wealth of measures we have implemented to limit the spread of the disease. If that is the case, I find that very heartening. What we are doing is working.
- A new strain has emerged which is less lethal, but even more infectious than the strain (or strains) that took hold the first time around. Certainly, selection pressures will naturally choose any strain that emerges that allows the virus to reproduce as much as possible. That means it is in the interests of the virus to kill as few of their hosts as possible, at least until they can transmit to new hosts. After all, if you are an infective agent, the thing you do not want to happen is to kill your host before they can mingle within a large number of other hosts that you can subsequently infect. If you infect, immobilise, and kill your host quickly it’s pretty much a limited sum game. Maybe you will infect some of those in nurturing roles as they care for you, but it is not as effective causing an asymptomatic infection and spreading your particles far and wide from a largely healthy and mobile host. The earlier strain already had a good biological strategy of course; a greater number of infected patients survived than died. But it is not without the bounds of possibility for an even more efficient strain to emerge. One that is not so severe when causing symptoms, but which can shed easily from the hosts and survive long enough to invade a new host and evade the immune system. The SARS-CoV-2 virus invades the upper respiratory tract and attaches to and fuses with the cells lining it by use of the now famous spike protein (S). The S protein subunits act in tandem to interact with the angiotensin converting enzyme 2 (ACE2) of epithelial host cells, allowing to enter the cell and gain access to the nucleus. The new strain that has been detected (dubbed G614) emerged from a single nucleotide mutation (adenosine to guanidine [A to G]) at position 23,403 in the genome in the original “Wuhan” strain (dubbed D614) (link). This resulted in an amino acid change in the spike protein (a change dubbed D614G) which in turn resulted in a strain which can infect with greater efficiency then the “wild type” strain, the Wuhan strain. What’s more, patients infected with this strain appear to exhibit far higher viral loads in the upper respiratory tract, a characteristic that would enable elevated viral shedding (see the paper describing all this here). So successful is this strain that it has supplanted the original strain as the most common strain in circulation worldwide with some most recent estimates sitting at 97% global prevalence (link). Currently, there is little evidence that this new strain causes a more severe form of the disease, according to scientists. However, as in all things science, there is widespread disagreement as to the significance of this, as there is also a lack of evidence that it causes a less severe form. If the latter is the case, we could be looking at the first stages of the beginning of the end of the pandemic in certain aspects.
- All of the above.
It could well be that we are slowly learning to live with this little annoying parasite already. Improved healthcare, improved social hygiene and a new state of mind that could be called “viral awareness”, together with a viral strain that causes a less severe form of the illness, could be all coming together slowly and eventually render the virus a far less threat than it was originally. Certainly, that holy grail of disease medicine, herd immunity, would be achieved far less painfully if this was the case. Here is hoping. The next month or so of new data coming through may give a better picture of what is happening.
A surge in hospitalisations and deaths by September will firmly put paid to my theory.