People, as they should, pay attention to information coming from the CDC. Two recent studies deal with transmission in a day care setting and one with transmission among people who dare to actually go eat in a restaurant. Let’s address those naughty diners first. (CDC Study) In this study the researchers attempted to match people who reported symptoms and had a positive PCR test result for CV-19 and those who reported symptoms and had a negative test result, and then ascertain participation in certain activities and behaviors, like mask wearing. They were unable to do the study as a matched control design for lack of participation and other issues, so they used a less rigorous design. They ended up with 154 people with a positive test, and 160 with a negative test. The only meaningful difference between the two groups in activities or behaviors was going to a restaurant. The people with CV-19 were far more likely to report contact with another person known to have CV-19, 42% to 14%, so that really explains any difference in cases. A sub-group analysis restricted to both positive and negative cases with no known contact with a CV-19 patient, however, purported to show that the positive cases were more likely to have gone to a restaurant or bar. Fairly weak evidence, and we continue to not get any firm contact tracing evidence that restaurants are a major source of transmission. One interesting side note from looking at the data, mask wearing often or always made absolutely no difference in whether or not the person had a positive result.
Now on to the naughty children in the day care settings. (CDC Study) In this study, three day cares in Utah were followed as a result of cases arising among children and staff. Just want to note at the start that day cares have been widely followed and have remarkably low rates of cases among either children or staff, so an unusual circumstance was picked for the study. The researchers attempted to track transmission patterns. 184 persons with a link to one of the three facilities was studied. 110 were children. 83 were contacts who didn’t attend or work at the facilities. There were 31 confirmed cases (As usual, no description of the nature of the test results, so I am highly suspicious of how infectious the children actually were. Researchers have to start giving us cycle numbers or culture results or something, or you can’t trust conclusions based on PCR tests.) among this group, and 13 occurred in children, or 42% of the cases, so children were under-represented according to their proportion of the study population. All these children had no or mild symptoms. 12 got CV-19 in the day care facility. A staff member was the index case in all three of the centers. So an adult got CV-19 and infected the children. Children were said to be responsible for spreading the virus to 12 people outside the facilities. I am dubious about the quality of the alleged contact tracing described here, particularly because the numbers are not presented in a clear way and the tables and the text don’t appear consistent. It also appears that among non-facility contacts, only about half the cases could be confirmed as attributable to the day care center cases. The authors do not rule out that the household contacts of the children who were allegedly infected by those children could have picked up the virus elsewhere. I am sure the teachers’ unions and the school panic brigade will try to make hay out of this study, but it has some pretty big holes and is an outlier compared to other research on transmission outside of day cares.
Like this study, in regard to day cares in Rhode Island. (CDC Study) Day care had ridiculously been closed in the state for three months and re-opened on June 1. Between then and July 31, the state had a rigorous program to inspect day cares for compliance with infection prevention rules and was checking on all possible CV-19 cases. During this time, 101 possible cases were linked to day care programs. 33 ended up being positive and 19 were probable cases. 30 of those were among children and 20 among staff and 2 parents. Out of 29 child care programs with cases, 20 had no secondary transmission. One child aged 2 went to day care for 6 days while probably infectious and symptomatic, but no secondary cases were reported. The study was unclear whether any secondary transmission occurred in other day cares that were closed; if it did, it is not reported in the study.