This study comes from Ireland and deals with asymptomatic cases among residents and staff in Irish nursing homes. (Medrxiv Paper) 28 nursing homes were included in the study and 21 had outbreaks. About 44% of residents got the disease and 27% of these were asymptomatic (it is impressive that so many fragile, presumably elderly, residents still did not get any signs of the disease). 27.6% of those infected died, so again we see the very high case fatality rate among such residents. 675 staff members also were infected with 27.5% being asymptomatic. There was a strong correlation between symptomatic staff and the extent of an outbreak.
The next study involved the potential for pre-symptomatic individuals to cause transmission. (Path. Paper) the authors provided an extensive critique of a paper supposedly identifying significant asymptomatic or pre-symptomatic transmission. In addition, they analyzed other studies and found that the most methodologically sound research found a very limited role for such transmission. They suggested improvements in techniques to assure good results from studies on how transmission occurs.
More research on what an incredibly low risk children and young adults face from coronavirus disease. (Medium Article) Looking at data from England and Wales, 5 children out of 10.7 million died from coronavirus disease, a rate thousands of times lower than that occurring among people 70 and over. These young people have hundreds of times greater risk of dying from many other causes. And of course, almost all of the younger people who died, as well as the older ones, had contributing pre-existing conditions.
This Wall Street Journal article summarizes some of the research we have been reporting on regarding pre-existing immunity to coronavirus disease. (WSJ Article)
This paper examines what variables may relate to death risk. (Medrxiv Paper) The authors collected data from a variety of sources on 28 factors that might be related to such risk. Note that some of the data used may not be that reliable. The number one factor was population density, along with retail spending, average annual precipitation, and annual spring precipitation. Together these factors supposedly explained 97% of variation in deaths. Applying some further statistical techniques, they determined that weighted population density, average spring temperature and precipitation, retail spending and grocery mobility were most associated with variation in deaths. And as they continued with ever more complex techniques, weighted population density continued to be an explanatory factor, but now race and retail mobility also had a substantial role, and retail mobility appeared most explanatory. Not sure that we learned anything. Denser populations are obviously likely to have more cases, and more social distancing probably means that as well. Race tends to be a proxy for differences in rates of pre-existing chronic disease.
Next up is a systematic review of asymptomatic and pre-symptomatic transmission. (Medrxiv Paper) Again, this is not original research but a review of existing studies to see what they might tell us in totality. These authors also note numerous issues with the quality of the research and the difficulty in drawing conclusions. They also propose the need for further, better studies.
And finally, what would a day be without something relating to antibodies and immunity. (Medrxiv Paper) The study comes from China and the researchers were looking for neutralizing antibodies, those that prevent a virus particle from infecting a new cell. They found that 96% of recovered patients had these antibodies. Those with severe disease had more of them than those patients with mild disease. And a large percent of patients had antibodies that were cross-reactive against the original SARS and MERS.