Even on the holiday weekend the papers just keep rolling in.
What would the day be without an antibody study. This one looks at mucus antibodies. (Medrxiv Paper) The authors looked at the development of systemic and mucosal antibodies during the course of mild and severe illness. The authors note that coronavirus disease appears to be mild in about 80% of symptomatic patients and severe in 15% and critical in 5%. I am not sure the numbers support that assertion, since they are Chinese numbers. Why not use US numbers when they are available. In any event, the researchers examined 56 confirmed patients with mild to severe illness, and 109 health care workers who were exposed to coronavirus patients, some with positive tests and some with negative ones. They tracked development of antibodies to the spike protein, but longitudinally in only two mild case patients. 36 of the health care workers volunteered to have serum, nasal, saliva and tear antibody tests. Severe cases in the patient cohort appeared to have higher levels of antibodies. The most intriguing finding, however, is that among some health care workers who were negative for antibodies in blood, there were coronavirus specific antibodies in their nasal mucus. There appeared to be more mucosal antibodies in younger workers. As the authors note, this could be consistent with so few children and young people getting infected, or appearing not to get infected; they already have immune reactions in their upper airway to coronavirus.
Next up, another homeless shelter prevalence study. (Medrxiv Paper) People 18 years of age or older were studied in Rhode Island shelters. Of about 300 tested individuals, 11.7% were positive by infection testing, but the rates varied from 0% at three shelters to 35% and 21% at others. Only 20% of positive test persons had any symptoms and prevalence of coronavirus disease symptoms did not vary among those who tested positive or negative. Not one had fever. This is one explanation for why so many infection tests are negative, the symptoms are consistent with a lot of other causes. The study again expresses concern about asymptomatic spread, but everyone now acknowledges much lower infectiousness of asymptomatic persons. And as usual, the authors ignore the fact that all these positive tested persons were asymptomatic or had mild illness. This is truly remarkable in a shelter population.
So here is another study on the infectivity of asymptomatic persons. (NIH Paper) The study is from China and examined contacts by one infected person being treated at a hospital with 35 patients, 196 family members and 224 medical staff. Okay, so out of all these contacts with uninfected persons, not one became infected. The researchers concluded that transmission by asymptomatic persons might be “weak”. How about non-existent.
Next up, another meta-review of asymptomatic proportion of infections and more bad research work. (Medrxiv Paper) This group of ding-dongs only looked at supposedly asymptomatic percent as a portion of confirmed positive test results. They found 11%. As have others, they noted that many asymptomatic person who test positive may just be pre-symptomatic, but so what when you have a limited testing strategy. They also noted inconsistent or non-definition of “symptoms” in the study. What good is this kind of research; it tells you nothing about actual prevalence of infections and given that it doesn’t adjust for testing variation, all it really tells you is that if you only test people who think they have a symptom or their known contacts, you aren’t going to get many asymptomatic persons.
This paper purports to be a systematic review of studies on the susceptibility to and transmission of infection in children and adolescents. (Medrixiv Paper) The paper found a total of 18 studies, 9 contact tracing and 9 population screening. Children had less than half the odds of an adult of being infected by an infected contact in contact tracing studies with one population-based one finding basically zero transmission by children. They also were only 10% of likely causes for transmission in a household clusters study. The authors strangely concluded that there was only weak preliminary evidence that children played a lesser role in both transmission and in being infected.
The next study looked at age patterns of case incidence over time, using Washington state as the test bed. (Medrxiv Paper) From March 1 to April 19, the incidence in persons over 60 dropped 10% and that in persons under age 39 rose 20%. Can you say more testing. Apparently the authors couldn’t. And they said nothing about the nature of the cases, but did note a significant decline in hospitalizations even as positive test result percents rose. The authors bizarrely concluded that coronavirus posed a significant morbidity and mortality risk to young people. Really, taken a look at the CDC stats, or how about the ones in your own state, or how about just look at your own study results. They also referred to this group as being at highest risk for spreading the virus. Uhhh, not what the prior reported meta-analysis says or any other study I am aware of. This is an example of a poorly researched and analyzed paper that just enrages me and leads to poor public policy.