On another note.
Some research.
They mass tested in one Italian town called Vo to try and get an idea of how the disease spreads and whether lockdown is effective.
Eric Topol @erictopol
The Vo, Italy experience/data is indeed impressive.
43% of all infections across 2 surveys were asymptomatic
The viral load was the same, irrespective of symptoms
Caitlin Rivers PhD @cmyeaton
A small town in Italy tested most of their residents twice. The preprint describing their findings is full of interesting results. What impresses me most though is the full line list data is available for download.
www.medrxiv.org/content/10.1101/2020.04.17.20053157v1
We collected information on the demography, clinical presentation, hospitalization, contact network and presence of SARS-CoV-2 infection in nasopharyngeal swabs for 85.9% and 71.5% of the population of Vo at two consecutive time points. On the first survey, which was conducted around the time the town lockdown started, we found a prevalence of infection of 2.6% (95% confidence interval (CI) 2.1-3.3%). On the second survey, which was conducted at the end of the lockdown, we found a prevalence of 1.2% (95% CI 0.8-1.8%). Notably, 43.2% (95% CI 32.2-54.7%) of the confirmed SARS-CoV-2 infections detected across the two surveys were asymptomatic.
And
Contact tracing of the newly infected cases and transmission chain reconstruction revealed that most new infections in the second survey were infected in the community before the lockdown or from asymptomatic infections living in the same household. This study sheds new light on the frequency of asymptomatic SARS-CoV-2 infection and their infectivity (as measured by the viral load) and provides new insights into its transmission dynamics, the duration of viral load detectability and the efficacy of the implemented control measures.
Interestingly it says:
No infections were detected in either survey in 234 tested children ranging from 0 to 10 years, despite some of them living in the same household as infected people (Table S3).
It says later in the document thst
This is particularly intriguing in the light of the very high observed odd ratio for adults to become infected when living together with SARS-CoV-2 positive family members. However, this result does not mean that children cannot be infected by SARS-CoV-2
7 day quarantine just not enough...
^A substantial fraction of infected individuals (67.7%; 95% CI 54.9%-78.8%, symptomatic and asymptomatic combined over all ages) cleared the infection between the first and second surveys
(Table S2). The time to viral clearance (time from the earliest positive sample for the subjects with more than one sample in the first survey and a negative sample in the second survey) ranged from 8
to 13 days and was on average 9.3 days^
And
These results suggest that asymptomatic infections may play a key role in the transmission of SARS-CoV-2. We also found evidence that transmission can occur before the onset of symptoms, as detailed hereafter for a family cluster.
So that makes isolating after you have symptoms limited in its effectiveness as you could have passed it on to multiple people before you show any signs of having it, and that's before you account for asymptomatic cases.
Big cavet - still small numbers in this study and not yet peer reviewed but interesting and the under 10s stuff is consistent with research from Iceland too.
Another big of research published in the Lancet is also interesting. It questions whether covid-19 is a respiratory disease alone.
The Lancet @thelancet
^NEW—Endothelial cell infection and endotheliitis in #COVID19. Correspondence from Z Varga, A Flammer, P Steiger, et al
"Here we demonstrate endothelial cell involvement across vascular beds of different organs in a series of patients with COVID-19"^
t.co/KTLQvHH6ZH
This I find intriguing. We know that young people can suddenly have heart attacks for example - particularly those who do a lot of sport. And it turns out to be an undetected underlying heart problem. What if many of these youngerpeople with no known medical issues, do have something underlying we don't know about?
<a class="break-all" href="https://www.nytimes.com/2020/04/16/health/coronavirus-asthma-risk.html#click=t.co/tUCq2WklgX" rel="nofollow noindex" target="_blank">www.nytimes.com/2020/04/16/health/coronavirus-asthma-risk.html#click=t.co/tUCq2WklgX
Asthma Is Absent Among Top Covid-19 Risk Factors, Early Data Shows
Despite warnings that asthmatics were at higher risk for severe illness from the coronavirus, asthma is showing up in only about five percent of New York State’s fatal Covid cases.
The research at this early stage is minimal and not always consistent, as one would expect. A recent commentary published in Lancet by a group of European researchers called it “striking” that asthma appeared “to be underrepresented in the comorbidities reported for patients with Covid-19” — comorbidity being the term for a secondary health problem. A small study of 24 critically ill patients in Washington State noted that three had asthma.
“We’re not seeing a lot of patients with asthma,” said Dr. Bushra Mina, a pulmonary and critical care physician at Lenox Hill Hospital in New York City, which has treated more than 800 Covid cases. The more common risk factors, he added, are “morbid obesity, diabetes and chronic heart disease.”
The top Covid-19 comorbidities listed by New York, in order, are hypertension, diabetes, high cholesterol, coronary artery disease, dementia and atrial fibrillation, a heart condition. Chronic obstructive pulmonary disease, another respiratory ailment, but one with an older demographic than asthma, ranks seventh. Renal disease, cancer and congestive heart failure round out the list.
I note here, they seem a lot more vascular related than respiratory as co-morbidities...