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NB: (a) The original title of this article is 'Largest COVID-19 contact tracing study to date finds children key to spread, evidence of superspreaders' -- I ed

NB: (a) The original title of this article is 'Largest COVID-19 contact tracing study to date finds children key to spread, evidence of superspreaders' -- I edited it to fit within the HN character limit (b) The actual article is published in Science: https://science.sciencemag.org/content/early/2020/09/29/science.abd7672 https://science.sciencemag.org/content/early/2020/09/29/scie... (c) This is a large study on 500k people in India. The researchers found that 71% of infected individuals did not infect any of their contacts, while a mere 8% of infected individuals accounted for 60% of new infections -- providing evidence for so-called 'superspreaders'. Regarding children, the researchers found that 'These patterns of enhanced transmission risk in similar-age pairs were strongest among children ages 0-14 years and among adults ages ≥65 years', and that they 'identif[ied] high prevalence of infection among children who were contacts of cases around their own age' -- something that was also true in adults. The overall case-to-fatality ratio was between 0.05% at ages 5-17 years to 16.6% at ages ≥85 years.

lbeltrame 6y ago
The paper says that children are more efficient in transmitting to people of their same age range, so perhaps the title as you edited it can be misleading. Some key limitations to keep in mind from the study: > The contact tracing data analyzed included only 20% of all reported cases as index cases and represented only 19% of all contacts traced So the observations, while important, are probably just part of a more complex picture. > Another limitation was the lack of data on timing of exposure and symptoms onset in relation to testing dates; this necessitated assumptions about identification of true index cases. This is important: some cases may not be "true positives" in the sense that the PCR test alone does not tell if you have the disease, or had the disease if you did not develop symptoms. Given the size of the population tested, admittedly doing that is difficult. > Finally, while comorbidities data collected as part of COVID-19 mortality surveillance revealed clinical and epidemiological attributes of fatal cases, the fact that such data were not collected for all diagnosed cases prevented inference of the contribution of comorbidities to fatal outcomes.

lbeltrame 6y ago

The paper says that children are more efficient in transmitting to people of their same age range, so perhaps the title as you edited it can be misleading. Some key limitations to keep in mind from the study: > The contact tracing data analyzed included only 20% of all reported cases as index cases and represented only 19% of all contacts traced So the observations, while important, are probably just part of a more complex picture. > Another limitation was the lack of data on timing of exposure and symptoms onset in relation to testing dates; this necessitated assumptions about identification of true index cases. This is important: some cases may not be "true positives" in the sense that the PCR test alone does not tell if you have the disease, or had the disease if you did not develop symptoms. Given the size of the population tested, admittedly doing that is difficult. > Finally, while comorbidities data collected as part of COVID-19 mortality surveillance revealed clinical and epidemiological attributes of fatal cases, the fact that such data were not collected for all diagnosed cases prevented inference of the contribution of comorbidities to fatal outcomes.