Healthy workers as young as 45 at greater Covid risk than workers deemed clinically vulnerable

A study just published in Nature reveals the following: even for someone with no underlying health conditions, the increased risk associated with being 45 years of age, rather than 30, is greater than the increased risk associated with various health conditions the NHS deems sufficient to render a person clinically vulnerable to serious illness from Covid-19.

I. Quantifying the risks to the clinically vulnerable

“Coronavirus (COVID-19) can make anyone seriously ill. But for some people, the risk is higher”, according to an NHS webpage entitled “Who’s at higher risk from coronavirus”. The NHS lists the following people as at “moderate risk (clinically vulnerable)”:

“Who’s at higher risk from coronavirus”

The aforementioned study in Nature — which is entitled “OpenSAFELY: factors associated with COVID-19 death in 17 million patients” — quantifies the risks associated with most of the above health conditions. It finds that, when one adjusts to control for age, gender, level of income deprivation, and other health conditions, the listed NHS conditions are associated with increases in one’s risk of death from Covid-19 by the following factors (see righthand column of Table 2 on p. 10):

  • Those who have asthma which requires oral corticosteroids are at 1.13 times greater risk of death than those without asthma
  • Those who have chronic respiratory diseases other than asthma, including COPD, emphysema, or bronchitis, are at 1.63 times greater risk of death than those without respiratory diseases
  • Those who have chronic heart disease are at 1.17 times greater risk of death than those without heart disease
  • Those who have uncontrolled diabetes are at 1.95 times greater risk of death than those without diabetes
  • Those who have kidney disease (GFR <30) are at 2.52 times greater risk of death than those without kidney disease
  • Those who have liver disease are at 1.75 times greater risk of death than those without liver disease
  • Those who have neurological conditions such as Parkinson’s, motor neurone disease, multiple sclerosis, or cerebral palsy are at 2.58 times greater risk of death than those without these conditions
  • Those who have auto-immune diseases such as rheumatoid arthritis, lupus, or psoriasis are at 1.19 times greater risk of death than those without these conditions
  • Those who are very obese (BMI of 40 or above) are at 1.92 times greater risk of death than those who are not obese

Whatever one’s age — and therefore even if one is as young as 30 — having any of the above conditions is sufficient for classification as clinically vulnerable to serious illness from Covid-19. The increased risks associated with these conditions range from 1.13 to 2.58 times the risks to those who lack these, as well as any other, health conditions.

From Table 2, we can infer strikingly dramatically increasing risks associated with advancing age, even among those who are “healthy” insofar as they lack all of the above, as well as any other, health conditions. Compared with a healthy 30 year old:

  • a healthy 45 year old is at 5.00 times greater risk of death
  • a healthy 55 year old is at 16.67 times greater risk of death
  • a healthy 65 year old is at 40.00 times greater risk of death
  • a healthy 75 year old is at 101.33 times greater risk of death

II. Why are those who are older at such increasing risk?

The “OpenSAFELY” study does not address this question. Elsewhere, the hypothesis that Covid-19 involves impairment of the immune system has been offered as an explanation for why increasing age appears to be such a great risk factor:

Many T cells apparently die, and so the body’s reserves are depleted — particularly in those over age 40, in whom the thymus gland, the organ that generates new T cells, has become less efficient.

…The new research may help answer another pressing question: Why is it so rare for a child to get sick from the coronavirus?

Children have highly active thymus glands, the source of new T cells. That may allow them to stay ahead of the virus, making new T cells faster than the virus can destroy them. In older adults, [as mentioned above] the thymus does not function as well.

Among the health conditions analysed in the “OpenSAFELY” study, those associated with the greatest increase of risk — organ transplant (3.55 times the risk of those without a transplant) and haematological cancer (2.82 times greater risk if diagnosed within the last year, versus those without such cancer) — involve serious compromise of the immune system. These two conditions are also among those which place one on the NHS’s list of people at “high risk (clinically extremely vulnerable)” , who had been advised to shield. By contrast, none of the other health conditions in the “OpenSAFELY” study is associated with more than 2.60 times greater risk.

III. Health Secretary declares those above age 50 at increased risk

In light of findings of the “OpenSAFELY” study, it is unsurprising that the Health Secretary Matt Hancock has recently declared that “those at increased risk of serious disease and death from coronavirus” include “adults over the age of 50” as well as, for example, “those with heart and kidney disease”. Hancock noted that, in coming to this conclusion, he was “guided by the clinical science, prioritising those in most need”. Specifically, he was guided by a report of the Joint Committee on Vaccination and Immunisation, according to which:

Currently available data from the UK indicate that those at greatest risk of severe illness and mortality from COVID-19 includes:

— adults over the age of 50, with the risk increasing with age

— those with underlying co-morbidities including chronic heart disease, chronic kidney disease, chronic pulmonary disease, malignancy, obesity and dementia

UPDATE: The above report has been superseded by the following linked report dated 25 September, which states the following:

Currently available data from the UK indicates that those at greatest risk of severe illness and mortality from COVID-19 are adults over the age of 50 years, with the risk increasing markedly over the age of 70 years.

Certain underlying health conditions may result in a higher risk of serious disease and mortality. Such conditions may include:

— solid organ transplant recipients
— haematological cancers
— certain neurological conditions
— chronic kidney disease
— immunosuppression
— dementia
— stroke
— poorly controlled diabetes
— chronic pulmonary disease
— obesity (BMI greater than 40)
— malignancy
— liver disease

Written by

Professor, Dept. of Philosophy, Logic & Scientific Method, LSE

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