I have used Sweden and New Zealand as contrasts before in how to approach the pandemic. This article gives a different perspective on how New Zealand handled the epidemic than you will read in most of the media. Sooner or later New Zealand is going to have a lot of coronavirus cases, even if there is a vaccine. The cost of these extreme lockdowns is much greater than any supposed benefit. (NZ Article) And right on time, New Zealand’s largest city, Aukland is going back into lockdown because it had four new cases. This just shows the absurdity of thinking you can actually stop a virus. (NZ story)
The surest way to ascertain who infects who, in terms of both demographic factors and place of infection, is by contact tracing coupled with genomic sequencing of the specific virus in each case, which gets a little expensive. The contact tracing is more common than sequencing. This study from Greece looks at some cases in families with children. (Greece Study) The researchers studied 23 families with 109 members. An adult was the first case in 21 of the families and a child in 2. They did not identify any cases of either child to adult transmission or child to child. Children had a much higher likelihood of asymptomatic or mild illness. Children were slightly more likely than adults to have a high viral load, and much more likely to have a low viral load, when loads were classified as high, moderate or low.
How about transmission in schools in France. (French Paper) The setting was primary schools in one area in the country. The most relevant finding is that 3 students attended school while positive and there was no evidence of any onward transmission. Most children were asymptomatic. The findings were different from those for a secondary school in the same area, where a greater likelihood of child involvement in transmission was found.
And here is a report on the contact tracing for the first 30 cases in South Korea. (SK Paper) Out of all those contacts, 12 became infected. There were 119 household contacts, and 9 of those became infected, so household transmission was by far the largest source of transmission. Only one person under the age of 19 became infected.
And another study from South Korea, looking at pediatric index cases. This is a more detailed examination, compared to an earlier report, which I summarized a week or so ago, and which was interpreted by the media as indicating a significant role for children in transmission, which wasn’t what the data actually showed. (SK Paper) The authors examined every case age 18 and under from January 20 to April 6, when the epidemic was most noticeable in South Korea. The median age of these cases was 15, meaning that it was heavily weighted to older children. Out of 107 cases, with 248 household members, while 41 of the household members had coronavirus, there was only one case of the child transmitting to a household member and that was a 16 year old child transmitting to a 14 year old.
Finally, here is an interesting article on a town in Oregon that at one point apparently had an active infection rate of around 17% of residents. (Oregon Article) 80% had no symptoms and apparently a very low rate of serious illness or deaths.