COVID

Estimating SARS-CoV-2 transmission in educational settings: A retrospective cohort study 

This comprehensive contact tracing study shows clearly that children in schools are a major source of transmission among students and that household spread is a major amplifier of infection.

 

Noteworthy Preprints

Lack of correlation between school mask mandates and paediatric Covid-19 cases in a large cohort

This is a deeply flawed study on masking in schools purporting to show that a similar CDC study was misleading. The authors add new data without considering the ways in which those data might introduce bias and confounding. Despite that, their data still suggest a protective effect of masking.

As one commenter noted: If you can't see the forest for the trees, you don't get to call a tree a forest. Yet the authors, finding case rates equal in masked vs. unmasked communities during week 6 of their study, forgets weeks 1-5 and claims masks make no difference at all.

Risk of death following SARS-CoV-2 infection or COVID-19 vaccination in young people in England: a self-controlled case series study

This is a carefully designed self-controlled case series study that follows the basic rules of this design. It is particularly useful in that it directly compares the effect of the vaccine to the effect of the disease.

Exploring the relationship between all-cause and cardiac-related mortality following COVID-19 vaccination or infection in Florida residents:

Proper study design demands a clear prior justification for the duration of the study and calls for a short time frame to limit the impact on underlying trends in death rates. They offer no justification of a 25 week time frame, especially given that the risk period is four weeks long.