Keith Dawson has written up a great summary of a paper by Dr. Zoë Hyde:
The general perception and belief for the last year has been that children are less likely than adults to be infected with SARS-CoV-2. A new paper in the journal Clinical Infectious Diseases casts serious doubt on this assumption. The author of that paper, Zoë Hyde of the University of Western Australia, argues that there are two principal reasons why the myth of a lower attack rate in children developed: we don’t test kids much, and they may only be infectious for a very short window of time. The CDC’s stance on kids and Covid seems to be overly sanguine. The metric used in their paper is hospitalization rate. It is true that hospitalization rates for teenagers and younger people are extremely low, but that may not be strongly indicative of infection rate. Kids’ infections are more likely to result in a mild or even asymptomatic case of Covid-19 — about twice as likely as for adults, according to Hyde. Combine this fact with the US bias towards testing only once symptoms appear, and you can see how this could contribute to an undercount of childhood cases. Compounding the dearth of testing is the (fairly robust) finding that, when infected, children may be shedding virus for a shorter time than adults: only two days on average, compared to five days for adults. So kids are more than twice as likely to show up PCR-negative even in the rare instances in which they are tested. Looking at seroprevalence surveys, Hyde cites studies from Italy and Brazil pointing to similar levels of children and adults who have antibodies indicating they have recovered from the disease. (In the Italian study from last year, children’s seroprevalence was even higher than that of the oldest adults, the result of what Hyde calls “survivorship bias” — i.e., the older people who got Covid-19 mostly died.) The hosts on This Week in Virology went over Hyde’s paper in last week’s podcast, TWiV #731. If you can spare the time, listen to 11 minutes’ worth of their discussion beginning at 23:33. One compelling point the TWiV team brought out: children are not immune from long Covid. A UK study found that 12.9% of kids had symptoms weeks after clearing the disease, compared with 22% of adults. The belief that children don’t get infected much should no longer be used as an argument for why schools ought to be reopened.
Turns out they accidentally released some charts back in Feb, modelling vaccination/reopening scenarios — these were probably used in private briefings to the cabinet, and not intended for public consumption (via Andrew Flood)