The global impact of the novel coronavirus 2019 (2019-nCoV) pandemic has been massive. Schools have been closed. Elite and recreational sport has been stopped. Conferences, medical and otherwise have been delayed or cancelled (including a coronavirus conference). Countries have closed their borders. Global economies have all but collapsed. This pandemic has left its mark on China and is now settling in the current epicentre: Europe, though this is likely transient, and it may soon move to America. Today the number of confirmed cases has passed 1 million.
The ever-changing numbers
Epidemiological patterns that have previously been described in China are replicable in many other countries. This follows what is called exponential growth. This means that the number of new cases increases by a given factor every day (Fig. 1). In most countries, the first 100 confirmed cases of corona virus disease 2019 (COVID-19) are often sporadic and take some time to spread to large numbers of individuals. However, once the first 100 cases are confirmed in each country, the subsequent growth is remarkably predictable (Fig. 2). For example, the time it takes a country to get from 100 to 1000 confirmed cases is fairly consistently between 6–9 days. The next 1000 cases occur in the subsequent 3–4 days. By 14 days, most countries can expect to have had their first 6000 patients with COVID-19.
In Italy and Iran, the exponential growth continued, and each reached more than 12,000 cases exactly 17 days after they hit 100. Today, the numbers in Italy and the USA are higher than those reported from China. However, the South Koreans managed to slow their spread much earlier than the Italians for example by implementing aggressive testing and isolation measures, a highly effective public information and social isolation campaign, early treatment of those that require it, and rigorous decontamination policies. This provides an opportunity for other nations to strongly consider some of these effective (albeit obvious) measures to be implemented early. The intermediate and longer-term impact of these policies are unclear.
The attack rate (the proportion of the population that will be affected by the virus), is likely to be anywhere between 30-80% of individuals. Thus, the importance of effective public health measures is less about limiting the total number of affected individuals, but more about spreading that number over a longer period of time to enable the health service to cope with the demands. Put another way, if a restaurant has capacity for 25 people and 100 people turn up for dinner on one night, the restaurant will be unable to accommodate them physically or with food. If those same 100 individuals attend over four days or more, the restaurant may still be busy, but still able to cope.
Variations in mortality
The case fatality rate (number of deaths/number of confirmed cases) continues to rise. Whilst in China, this rate is approximately 3.9%, in Italy it is just above 10%, and this figure will only increase. Mortality is age-sensitive, and the Italian population is on average older than that of China. Latest analyses suggests that the global case fatality rate may be closer to 5.4%, and the infection fatality rate (number of deaths/number of infections) could be as high as 0.9%. The daily increase in deaths per capita is also an important consideration, with both Spain and the UK showing worse trajectories than Italy and the USA (Table 1).
As devastating as these figures might be, they only tell one part of the story.
All of the victims
Beyond the number of individuals who contract COVID-19 and those that succumb to it, there is a population of people who become critically ill with it. It is estimated that 1.5% of all infected patients need to be admitted to the intensive care unit (ICU), which could be somewhere in the hundreds of thousands in the UK.
Accepting that non-clinicians may be reading this: being admitted to the ICU is a traumatic experience. It often involves being anaesthetised and placing a tracheal tube with ventilation delivered by an increasingly scarce resource. Cannulas and catheters are placed into arteries and veins, the nose, and the bladder. Patients are given analgesia, vasopressors, antibiotics, fluids, neuromuscular blocking drugs and various other drugs. They are unable to move for themselves so must be turned regularly, including being nursed in the prone position for much of the time. If there is evidence of renal failure, their blood must be filtered with another limited resource: haemofilters. In their unconscious state they are unable to communicate with their families, but because of the contagious nature of the virus, no visitors are allowed anyway. This resource-intensive treatment is often initiated very quickly, but in patients with COVID-19, generally lasts for approximately 10 days. Some patients, particularly young patients who do not respond to treatment immediately, may remain in ICU for far longer. Around half of patients will survive their stay in ICU. For these the road to recovery is long. Patients will be weak, may have ongoing respiratory problems, and perhaps most importantly, the long-term psychosocial impact could be traumatic.
Even during an epidemic, the patients with COVID-19 are only part of the responsibilities the health service has. Whilst the resources invested in COVID-19 are already, and will continue to be unprecedented, there is no doubt there will be a major impact on other services that each form part of an effective healthcare system: cancer treatment; cardiac surgery; orthopaedic surgery; psychiatric services; and much more. As resources are stretched to breaking point, those patients who would normally have received prompt and effective treatment may have this care delayed to the detriment of their short- or long-term health. The idea of a waiting list is effectively gone, and patients previously waiting for care could see that wait prolonged to the point of being suspended in an uncertain limbo. The health of some of these patients will deteriorate: they may have pain they might otherwise not have had. Some will die earlier than otherwise. The national mortality rate from disease unrelated to COVID-19 will increase for some time to come.
The impact on healthcare workers cannot be underestimated. Frontline staff who place themselves in direct contact with patients with COVID-19 are at a greater risk of acquiring the disease. In Italy, nearly 1 in 10 new diagnoses have been in healthcare workers. Anaesthetists and intensive care physicians in particular are at high risk due to exposure to a high viral load during procedures performed close to the airway: called aerosol-generating procedures. So too are ear, nose and throat and eye surgeons, as well as dentists. The data remain unclear as to whether mortality rates are greater in healthcare workers or not, and studies are being undertaken to determine this, but it is clear that access to appropriate personal protective equipment (PPE) is of the highest priorities but the lack of access is perhaps one of the biggest threats. Moreover, there remains debate about what appropriate PPE is for different settings. Surgeons have suggested that everyone in an operating theatre setting should don full PPE for all patients, while this disagrees with other recommendations suggesting that full PPE should only be used when there is a significant risk of aerosolisation. These areas of contention leave healthcare workers confused and may compound the high levels of anxieties in healthcare workers. Healthcare workers may also be concerned about taking the infection home to their family and some are even making the decision to remain isolated from their families in order to reduce risk.
To add to this burden, capacity and resource may simply not be enough to match demand. Frontline staff will shoulder a tremendous responsibility for difficult clinical decision-making, and ultimately in some cases for selecting who is given the best chance of survival and who cannot be saved. The NHS is currently commissioning, planning and constructing at great pace a network of Nightingale hospitals in exhibition centres and empty universities. The aim is to provide much needed additional capacity and to provide a safety valve for current hospitals. It is ambitious and to an extent a gamble to spread the resource and staff even further, but one we all hope will succeed. We will soon know.
Despite the devastating numbers of diagnoses and deaths due to COVID-19, the reduction in R0 in China is reassuring, with the number of new cases falling dramatically and locally spread cases being almost zero. In Italy, their daily rate of new cases has plateaued at around 6000, and may have peaked. The world’s largest democracy, India, has locked down with fewer than 500 cases at that time. And the public health measures implemented in Switzerland mean that their rate of increase has also plateaued. All the evidence is that this will pass.
In the UK, individual hospitals have spent the last few weeks preparing for the worst, and at an institutional level, preparation is probably as good as it could be given the circumstances. The availability of PPE and diagnostic testing for frontline staff is increasing. And the public have never been as well-informed about a health crisis as they currently are.
We encourage all readers to heed public health advice, healthcare professionals to continue to train and prepare for the management of patients with COVID-19, and for institutions to continue to be agile and responsive to the rapidly changing demands on healthcare resources.
Dr Kariem El-Boghdadly and Professor Tim Cook