June 16, 2020

expert reaction to new paper looking at age and COVID-19 susceptibility and severity

A study, published in Nature Medicine, has looked at the relationship between age, COVID-19 susceptibility, and severity, in various global countries including Italy and China. 

This Roundup accompanied an SMC Briefing.

Prof Mark Woolhouse, Professor of Infectious Disease Epidemiology, University of Edinburgh, said:

“The paper by Davies et al. reports a model-based analysis of data on COVID-19 epidemics in six different countries. They find evidence that children and teenagers are both less susceptible to infection and less likely to show symptoms once infected than are adults.

“Their analysis uses data on reported cases but relies on indirect estimates of unreported cases to quantify the fraction of cases which show clinical symptoms. They do not use mortality data though this shows an even more marked relationship with age.

“Davies et al. were not able to determine whether young people are also less infectious, though this could be the case if infectiousness is linked to the severity of symptoms. This makes it difficult to precisely assess the impact of school closures on the wider spread of COVID-19.

“The study highlights the differences between the epidemiology of COVID-19 and that of influenza-like illnesses, particularly in how they affect children. Using a mathematical model the authors show that even under the most pessimistic assumption that young people are fully infectious then school closures could still have substantially less impact on the epidemic than they would for influenza-like infections.

“This evidence suggests interventions aimed at children, such as school closures, might have a relatively small impact on reducing transmission of SARS-CoV-2.”

‘Age-dependent effects in the transmission and control of COVID-19 epidemics’ by Nicholas G. Davies et al. was published in Nature Medicine on Tuesday 16 June 2020.

DOI: 10.1038/s41591-020-0962-9

Declared interests

None received.