When a novel virus infects a population unhindered, it will spread exponentially, some will die, most will recover and develop immunity and as herd immunity increases, viral spread diminishes and the epidemic resolves. During its course, the consequences may be catastrophic, as in 1918. Thus, governments stepped in with population lockdown to reduce the spread and ensure the health services can cope. This, however, prolongs the natural history of the epidemic rather than changing the outcomes: there is less of a peak of infected cases, but herd immunity is still a prerequisite to resolution. Vaccination can artificially induce herd immunity but there is no certainty that a vaccine will become available or when. Certainly, a vaccine will not rescue the population from lockdown.
How do we assess our progress?
Simply, when people stop getting infected, the epidemic is over. But how do we know who is infected or who has been infected and is immune? Viral tests tell you if you are infected and become negative when you recover. Even if we test 100,000 a day it would take two years to test everyone for an infection which only lasts a fortnight. Antibody tests, which are currently not widely available in a reliable form, tell if you have been infected but you may not be immune. Again, these are good for cohort studies but not practical for the population.
Our best guess of how we are doing is to look at the number of new infections over time and wait for the numbers to fall to nothing. But how do we identify those new infections? Some will get sick, be identified and tested for the infection: confirmed diagnosis. Some will get ill, then better without testing: presumed diagnosis or not diagnosed and others who are ill will be wrongly diagnosed in the absence of testing and be falsely diagnosed. Also, reported statistics usually show the total number infected so far in the country. This is unhelpful and should better be expressed as the number infected per number of population over time. e.g. 100 per 1,000,000 per week. This allows comparison both over time and between countries. The problem is that these figures will inevitably include confirmed cases, presumed cases and false positives. The same applies to deaths resulting from the virus.
A further complication with these data is that people die all the time from other causes and this will inevitably inflate the false positive data: many presumed deaths from COVID19 in care homes have not been examined by a doctor. A more accurate way is therefore to look at the excess mortality during the epidemic which unfortunately identifies a further cause of death during the epidemic. Thus, there are those who die from COVID19, there are those who die with Covid19 but not of it and there are whose who die without the virus but in addition to the normal death rate.
Who will die from the COVID19 epidemic and lockdown?
So, to return to the question in the title there are three separate groups at risk of dying during this epidemic. Firstly, some patients will become infected, develop severe symptoms and die despite medical support. This can happen to any infected patient but there are groups who seem particularly at increased risk of infection and death. The largest group is men: they are more susceptible than women. Then there are the BAME communities who are over-represented in the mortality statistics. This may be due to ethnic or cultural susceptibilities. Overweight or obese people are at increased risk of death presumably as a result of immune susceptibility of reduced respiratory reserve. Lastly, medically compromised patients, those with heart or lung disease, diabetes, or immunocompromising diseases, are more at risk. More than 90% of patients dying from COVID19 are medically compromised or overweight.
Secondly, there is a cohort of patients who die with COVID19 but not from it. They should not legitimately be included in the statistics but serve to make the numbers less robust. The contribution of COVID19 to their deaths will be variable.
The third and potentially largest group comprises those people who have died, or will die, as a result of the epidemic but not from the viral infection. Some will be victims of increased domestic abuse resulting from lockdown. Others will commit suicide and yet others as a result of medical neglect. Since the start of the epidemic, the NHS has hugely expanded its capacity to cope with COVID19 patients. This has been achieved often at the expense of existing healthcare provision: in Scotland, breast screening, bowel screening and cervical screening have all been suspended. Routine surgery has been suspended across the UK and most importantly patients with cancer have seen their care compromised.
This last cancer group comprises two cohorts: those with existing, known cancer and those with undiagnosed disease. The group with existing known cancer include those who have had a tumour diagnosis or excision and who are awaiting chemotherapy or radiotherapy. Such therapy may be curative or palliative but without it cancer patients will die prematurely or unnecessarily. Continued neglect of this group will lead to an increasing peak of excess mortality.
Patients with undiagnosed symptoms or signs of cancer are delaying diagnosis by having appointments delayed or cancelled or through fear of attending an overstretched NHS despite daily evidence of masked NHS staff dancing in the ward corridors in tik tok videos. Cancer diagnoses in England is currently 25,000 cases per month below pre-epidemic figures.
The strategies for exit from lockdown are still to emerge and develop but it should be clear to the decision makers that procrastination and caution will come with a human cost.