.@ClareCraigPath has been getting a hard time for questioning whether an asymptomatic infection can be a disease. She has a better grasp of the philosophical issue than her critics, which tells us something interesting about the difference between medicine and biology. (1/7)
LS King was a wise US physician "Biological science does not try to distinguish between health and disease. Biology is concerned with the interaction between living organisms and their environment. What we call health or disease is quite irrelevant." (2/7) jstor.org/stable/185276
Medicine, and related sciences, are ways to control the world in the interests of - some or all - humans. Biology seeks to understand it. The idea of an asymptomatic infection does not make sense in biology (3/7)
A biologist might describe a virus that inhabits the human body with no obvious deleterious effects - like the many bacteria that live in our gut - with words like mutualism, parasitism or commensality but these have none of the moral force of 'infection'. (4/7)
Many geneticists think that quite a lot of human DNA derives from ancient viruses that took up residence and modified their host in ways that were either neutral or advantageous. (5/7)
One of the things we need to sort out with Covid-19 is the proper description for a virus whose effects are not necessarily visible. Should we think of it as similar to gut flora, which we ignore unless something happens to disturb them? (6/7)
The UK does not have a big tradition in the philosophy of medicine and biology - but this pandemic might remind us why it matters if we are going to avoid errors in policy and practice. (7/7)
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I am very concerned about the implicit ageism in a lot of the debate around Christmas - and more generally around Coivd-19 policy. Some highlights from @age_uk valuable overview of the lives of people over 65 (1/5) ageuk.org.uk/globalassets/a…
There are just under 12 million people in the UK aged over 65 - only 400,000 live in care homes. 93.5% of those aged 60-9 are not considered frail by official definitions. Even among the 90+group, 35% are not defined as frail (2/5)
24% of those over 50 in England report feeling lonely some of the time: 7% feel this often. Loneliness, social isolation, and living alone have all been associated with an increased risk of premature death. They are also thought to bring a 40% increase in risk of dementia (3/5)
There is currently a great deal of fear-mongering about Christmas visits in the UK. In order to assess the risk associated with a family or social visit within the rules, it is useful to consider some facts. The science is not exact but the orders of magnitude are secure (1/8)
Around 20%, possibly up to 30%, of infections are asymptomatic - the person will not know they have been infected. Around 80% of symptomatic infections are mild or moderate. They do not require a hospital admission (2/8)
The risks of serious illness and death increase with age - but most people recover. Estimates from the First Wave, published in Nature, suggest 30 deaths in 1000 infections (970 survivors) among 65-74 year olds and 116 (884 survivors) in 75+ year olds (3/8)
As a public health scientist, I think it is irresponsible to continue promoting fear and anxiety about the Covid-19 risks of Christmas when we cannot know the circumstances of every individual's life. (1/4)
I am 70 with no known co-morbidities. Several of my likely family visitors have already had Covid and recovered. They will still be largely immune from reinfection - risk is 1 in several million. I shall hug them freely. (2/4)
I have four grandchildren under 6. Children of this age represent a minimal risk. I shall hug them as freely as I have done all along because I think the value to each party exceeds the risk. (3/4)