The second wave of Covid-19 appears to be underway. Infection rates are rising in numerous countries that had achieved impressive control of the pandemic. France and Spain are experiencing rapid growth, with around 7,000 new cases being identified each day. The UK is more akin to Italy at the moment, with a less steep rise – although on 6 September it reported nearly 3,000 confirmed infections, the first time daily positive tests had exceeded 2,000 since the decline of the first wave in May.
Yet things also seem different this time around. Hospitalisation and death rates are beginning to nudge up in France, but nothing like what one might expect, and in the UK there has, as yet, been no impact on admissions or mortality. The explanation is both simple and complex. The simple part is that the demographics of those infected is very different. According to Tim Spector of King’s College London, at the height of the peak in early April, 60 per cent of proven cases were in people over 60. Today that higher-risk age group accounts for only 12 per cent of patients; the clear majority are under 40 years old. The complex bit is why the demographics are so different.
To get a Covid-19 test in April you had to be in hospital, so only the most severely unwell were being identified. Nowadays, anyone with grounds to suspect they’re infected can access testing, so the national figures are capturing large numbers of individuals with milder disease who went undetected before. One possibility is that, because of this entirely different testing environment, we are merely picking up the early stages of what will prove to be a comparably substantial wave. It is likely that if there had been this level of community testing in February, the rates and patterns of infection would have been similar to what we’re seeing today.
Most of the nationwide seeding that went unnoticed then will have been from families returning from half-term holidays, and working-age people travelling from regions not considered a risk. When these folk became unwell it was typically with mild symptoms, and transmission to peers will have gone unchecked. Even in those who got much sicker, there was no “relevant” travel or contact history, so Covid-19 didn’t enter anyone’s mind. The spread of coronavirus into sufficient numbers of higher risk individuals to make the problem apparent probably took well over a month.
Another explanation for the current demographics might lie in different lessons certain subsets of the population have drawn about Covid-19. Younger people generally perceive themselves to be at low risk, and many have become bored of, and cavalier about, observing social distancing. At the same time, older people remain – in my experience – highly wary of the risk. I have many patients over 70 who are continuing fairly stringent self-isolation; some are effectively continuing to shield. And care homes, now routinely resourced with PPE, remain hyper-vigilant in their infection control measures. Although the virus is spreading ever more swiftly among the young and middle-aged, many of those at highest risk are staying out of harm’s way, which was not the case in February.
This scenario – where coronavirus moves through the younger, healthier majority, while the aged and those with co-morbidities remain sequestered – recalls the controversial herd immunity strategy. This suggests that once enough of the low-risk population has been infected, and has in theory acquired immunity, society becomes a far safer place for at-risk people to rejoin, as the ranks of low-risk people who are no longer susceptible act as firebreaks to obstruct the virus’s progress.
If that approach ever did have a place in the population management of this pandemic, it certainly should not now. If the neglect of care homes was the scandal of the first wave, the second wave scandal may prove to be the concept of “low-risk” people. We now possess a much deeper understanding of Covid-19 as a disease. In the first wave, it was thought to be a respiratory infection from which most patients recovered fairly swiftly, while a small minority would succumb or require intensive care to pull through.
We now know that for anywhere between 5 and 10 per cent of patients, Covid-19 becomes a chronic disease, relapsing and remitting for months on end. There are ongoing respiratory and gastrointestinal symptoms, and profound fatigue, heart rhythm disturbances, life-threatening blood clot formation, and debilitating abnormalities of the nervous system. While some “long Covid” patients do recover, many have not as yet. Most are frightened about the future, and enervated by being a “medical mystery” for whom no one can give definitive explanations, advice or prognosis.
The demographics of “long Covid” are very different from those for hospitalisation and mortality; if anything, younger people appear disproportionately affected. And instances of relapsing-remitting disease are independent of severity – the majority of sufferers were never unwell enough to be admitted to hospital at any stage.
Research into this variant is in its infancy – trying to define how many people develop it, to understand what factors make the illness chronic, and to discover effective treatments. Nonetheless, long Covid is now an accepted phenomenon. The puzzle is why government pronouncements and statistics continue to suggest that death rates are the only meaningful outcome.
It is uncertain how much a communications strategy raising awareness of long Covid might modify risky behaviour among the young. But we had no idea about it in the first wave. The second-wave of coronavirus patients who develop this disease may legitimately ask why no one warned them this might come.
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