COVID-19 Some Basic Biology

COVID-19 is a new virus to humans. Researchers are busy trying to answer some of the basic questions. Today I offer two links that provide such basic information. The first link is a two part Twitter thread. (I didn’t even know you could do this on Twitter, but a lot of people actually get their information there.) It was written by Professor Palli Thordarson of the School of Chemistry of the University of New South Wales in Sydney, Australia. I think he was surprised at the popularity of what he had written. Here’s the link:

The German government and health system, unlike our own, were better funded and better led. They got ahead of the curve on the COVID-19 pandemic, chasing down contacts as early as the end of December. I do not have the numbers at my fingertips, but Germany has, so far, done better containment and has a lower death rate than other developed nations. The following article provides some detail on the transmission of SARS-CoV-2 in the form of a case study of nine people with known exposure whose virus shedding was intensively monitored during their course of Covid-19. (technically, SARS-CoV-2 is the virus, Corvid-19 is the disease the virus produces.) Here’s the link to the story:

Here’s the link to the original research paper:

This study is just one of many that will need to be done before this virus and it’s associated disease is better understood. Several take-home points (not hard and fast conclusions, but good information):

1) Patients with clinically very mild disease can shed lot of virus early on when they might have only mild upper respiratory tract symptoms (a “cold”). Hence the rapid spread with severely ill patients popping up unexpectedly.

2) Generally, severely ill patients shed even more virus.

3) All nine patients developed antibodies to SARS-CoV-2 within about a week of the appearance of the first mild symptoms, antibodies that neutralized (i.e. destroyed) the infectivity of the virus particles the patients bodies continued to shed. That’s an important point, because testing for virus particles with the common method, something called PCR (polymerase chain reaction) detects bits of viral RNA, but that RNA may be “dead” from the standpoint of disease spreading capability. It suggests that the current recommendation for isolating an exposed patient for fourteen days may actually be time enough for them to become non-infectious. Moreover, the development of functioning antibodies raises some hope that most patients after mild illness will be immune to this virus for some period of time (as yet to be determined). [In this study infectivity was assessed by “cell culture,” a more expensive and time-consuming method than the PCR method.]

Below I repeat the rational for social distancing–Flatten the Curve–that I shared last Friday. We are all in this boat together.

By the time this is over most of us will have been infected by Covid-19. Some of us will become very ill–and some of us will die (people from almost age groups, but more so among the elderly and among those with pre-existing medical problems). For those who experience severe pneumonia medical help for our breathing will be life-saving. The idea of all this pre-emptive closing of events is to “flatten the curve.” Here that is in graphic form:

I also offered the link below in last Friday’s email.  It is a great animated illustration of COVID-19 epidemiology.

Keep to the high ground–and I’ll be back Monday week, i.e. March 23,