I am just doing a couple of papers here, because they are both fairly important, one because it has been extensively misrepresented in the press, including by the New York Times, and the other because it again suggests little benefit from the lockdowns.
The NY Times, desperate to keep the coronavirus panic up and to hinder school reopenings at the behest of teachers’ unions, took this study of contact tracing in South Korea and completely mis-represented it. The paper was published in a Centers for Disease Control journal. (CDC Paper) There are a number of interesting pieces of information in the paper. The researchers tested 59,073 contacts of 5,706 index patients. Of about 10,600 contacts in the same household as an index case, 11.8% had coronavirus. Out of the remaining 48,500 non-household contacts, 1.9% had CV. So about a 6 times greater risk in a household, so again, we see how smart those stay-at-home orders are, because you are really safe there.
Note very importantly, that they explicitly say they could not determine direction of transmission, so in the case of children and adults, they could not and did not say that children transmitted to adults. Other contact tracing studies have shown basically zero transmission from children to adults, even in the same household. Index patients were grouped in ten year age buckets. The largest percent were 20-29 year-olds, with around 32% of the total. 50 to 59 year-olds were 19%, 40 to 49 year-olds were 16.5%. The index patients 19 and under represented only 2.7% of the total, although they are over 15% of the South Korean population. So they are far less likely to be infected and be an apparent index patient than their proportion of the population would suggest. They also had far fewer contacts traced than did other age groups. In the zero to 9 age group only 5.3% of household contacts of an index patient tested positive, which is the lowest % among all age groups. In the 10 to 19 age group 18.6% of household contacts tested positive, which was the highest rate, but just slightly, so something seems odd, particularly since schools were not open during much of the study period. Again, transmission could not be directly tracked so where there were multiple positives in a household it could be adults transmitting to each other after the index case. In any event, the total numbers were quite low and I wonder if they accurately identified the index case, since children are so often asymptomatic. Among non-household contacts these age groups had very low transmission rates compared to adults.
People are going to be arguing about whether the lockdowns made a difference for years. These researchers took a variety of country demographic factors, health care system characteristics and responses to the epidemic to see if there was any correlation with disease outcomes among the top 50 countries in terms of cases. One strong limitation of the analysis was that it only went up to May 1. A lot has happened since then in many countries. (Lancet Paper) The outcomes assessed included death, new cases recovered cases and critical cases. Many response measures were included such as travel bans, stay-at-home orders, etc. Obesity and and longer number of days to border closure were associated with more cases. A longer time to implementing a lockdown was associated with fewer cases. A full lockdown and a less secure health system were associated with an increased number of recovered cases. More critical cases were associated with a higher unemployment rate and per capita GDP. More smoking and less income inequality were associated with fewer critical cases. In terms of mortality, increased rates were linked to obesity and higher GDP. Reduced income inequality, more smoking and more nurses per population led to lower mortality per capita. Lockdowns, border closures and high rates of testing were not associated with lower mortality. So much for the value of those.