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expert comment on age, COVID-19 infection and the role of social distancing

There have been questions from journalists about why it is important for young people to practise social distancing.


Dr Stephen Griffin, Associate Professor, University of Leeds and Chair of the Virus Division, Microbiology Society, said:

“We are at the beginning of our understanding of this virus and how it causes disease. Thousands of clinical cases from China, Italy and elsewhere have been, and continue to be, collated to generate the summary average characteristics relating to death or severe disease. These are then stratified according to, e.g. age, underlying conditions, gender etc. However, it is important to keep in mind that individual cases will likely vary in terms of their disease course, as well as potentially the healthcare environment in which they might be treated and other factors. Furthermore, multiple aspects interact on a case by case basis for individual SARS-CoV2 infections.

“Thus, the summary data presented via WHO and elsewhere apply to the vast majority of cases. During the early stages of the pandemic, these were naturally some of the key facts shared with the public via governments and the media. However, averages are just that, so outlier events will be more likely to occur as cases increase. When you start applying small percentage chances to hundreds of thousands of events the actual real life numbers involved become considerable. When you reach hundreds of thousands of infected individuals, even a small percentage chance of an event occurring can translate into an enormous public health issue. Sadly, this means that as the COVID19 epidemic continues to worsen in the UK and elsewhere, we will see more and more cases of severe disease within groups of the population that were perhaps previously considered less likely to be affected.

“It appears that the urgent, decent and humane need to protect those most vulnerable within our society from SARS-CoV2 infection is not sufficient to convince some amongst our population of the importance of social distancing. This virus does not discriminate amongst who it infects. Perhaps the realisation that severe disease is not, in fact, limited to a vulnerable minority might help re-educate those who consider this pandemic to be nothing more than a trivial disruption to their daily routine.”


Dr James Gill, Honorary Clinical Lecturer, Warwick Medical School, said:

“Social isolation is advised to protect everyone. Not just you who feels well. Not just you with diabetes. Everyone.

“Public health messages are often difficult to get through. As a result, they frequently rely on broad brush strokes for advice and there are always caveats to any statement, or recommendations. However, at the moment simple is safe.

“Originally, we thought that 1% people were asymptomatic however, a study looking at the Diamond Princess suggested that the asymptomatic patient portion was 17.9% (95%CrI: 15.5–20.2%)*. More worryingly a study looking at Japanese evacuees from Wuhan places that number at a shocking 33% (95% confidence interval: 8.3–58.3%). This suggests that some members of the public could be feeling completely fine but may still be infected with the virus and might be able to infect others, therefore everyone should be following the government recommendations – even if they feel well.

“Ultimately, as with many things about COVID19. We don’t yet know for sure the proportion of those infected with COVID-19 who are asymptomatic, or how many of these will be able to pass on the virus without showing symptoms. We have educated guesses and strongly suspected hypotheses, but very little concrete facts.”

*The referenced study is here 


Professor Alan McNally, Professor in Microbial Evolutionary Genomics at the University of Birmingham, says:

“I think the message on who COVID-19 can infect and cause serious infection in has been misrepresented in general. It is absolutely true that risk of serious infection increases significantly with age, and in particular in those over 70. However, infection has been widely reported in adults of all ages in all affected countries, and adults of all ages have been hospitalised with COVID-19. Anyone with an underlying condition that puts them in the significant risk category, such as transplant recipients or other conditions listed by the CMO, should stay at home, regardless of age.

“The message is clear. If you are a young healthy adult you have a moral and social obligation to act responsibly and practice adequate social distancing. Do not go out unless you need to. At the minimum you will interrupt or prevent a transmission chain that would otherwise lead to thousands of new infections and a number of deaths. You may also save yourself from a significant bout of illness and prevent doctors from having to make a choice on who is a priority for treatment. Don’t be selfish.”


All our previous output on this subject can be seen at this weblink:


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