An ongoing dialogue on HIV/AIDS, infectious diseases,
February 2nd, 2020
A Coronavirus ID Link-o-Rama, Because I’m Not Watching the Super Bowl
With so much of the ID-related news out there dominated by the novel coronavirus (2019-nCoV, hard to type) outbreak, it seems appropriate to collect some of the more interesting or useful findings in this busy past week.
Think of it as an ID Link-o-Rama — Special Novel Coronavirus Edition.
As with last week’s post, an important caveat — the outbreak continues to evolve rapidly, and data quickly become out of date. All are encouraged to check in with the excellent guidance and information on the CDC, WHO, and IDSA sites (among others), all of which are updated regularly.
On to the links:
- The mean incubation period of novel coronavirus disease after contact with an active case is around 5 days. The 95% confidence interval around that estimate is 4.1 to 7.0 days. Importantly, the onset of symptoms 2 weeks or more after exposure appears very unlikely. These data should dispel circulating rumors that this virus has a much longer incubation period than other coronaviruses — in fact, it appears quite similar (Figure 3).
- This case cluster demonstrates coronavirus can spread before the onset of symptoms. However, as in most infectious diseases, symptomatic cases are probably more contagious — usually because people with symptoms have a higher viral burden. While the findings in this report are of concern, the true contribution of asymptomatic spread of the virus in the present outbreak remains unknown. [Update: The “asymptomatic” person may have had symptoms after all. Additional details summarized here.]
- The New York Times has posted a widely cited figure comparing mortality and contagiousness of coronavirus with other infectious diseases. Current estimates are 3% mortality and transmission number (R0) between 1.5 and 3.5. It’s an impressive graphic (modeled on this one) that puts the infection into perspective. Importantly, note the log scale of the vertical axis in the Times figure, which prompted this revision:
This is one of those “please don’t judge me for making this horror” graphs that I’ve just thrown together with possibly the least reliable underlying data (hence extensive caveats in caption). All available on github, please scrutinise and send improvements pic.twitter.com/vtU3bUFDzH
— Isaac Florence (@IsaacATFlorence) January 31, 2020
- Here’s a clear explanation why the estimated mortality will likely change — for the better — as we gain greater understanding of the disease. Severe cases tend to dominate reports early in an outbreak; only later, when diagnostic tests and surveillance improves, will we understand how many mild (and even asymptomatic) cases occur. Remember when West Nile virus first appeared in North America? It was initially terrifying — yet we now know that 80% of people who acquire this infection do so without any symptoms whatsoever, and fewer than 1% develop encephalitis.
- Wonderful perspective from Dr. Elizabeth Rosenthal offering her advice on how to avoid coronavirus. Wash your hands frequently. Yep, that’s it — plus a few other things that fall squarely into the “common sense” category. The piece includes interesting anecdotes from when she covered SARS in 2002-3 as a journalist, living in China with her family.
- This online calculator estimates the effectiveness of screening travelers to detect people who have 2019-nCoV. You can move the sliders around on parameters such as incubation period, proportion who have fever, and R0 (transmissibility), among others. Not surprisingly, those most likely to be detected have both fever and a reported epidemiologic risk.
- Some patients with coronavirus disease have already received antiviral therapy with drugs demonstrating in vitro activity against the virus. In this report, a woman received lopinavir/ritonavir (along with oseltamivir). In another case, doctors received permission for compassionate use of the experimental drug remdesivir. Both patients improved — but obviously in these anecdotal cases, we don’t know if they would have improved anyway. A Chinese clinical trials registry cites at least one planned study. My virologist colleague Dr Jonathan Li summarized some of the background data in this thread.
- How did this novel coronavirus first spread to humans? This is critical information — not only for this outbreak, but also for prevention of future zoonotic infections. Excellent summary of ongoing work in this area.
- A pre-print reported that the novel coronavirus had insertions that bore an “uncanny” resemblance to HIV gp120 and Gag. This finding (later withdrawn) triggered a momentary spike in conspiracy theories that would be excellent evidence for the benefits of scientific peer review — which happened in this case anyway, only not in the usual way. For a good takedown, read this analysis.
- Many have tried to put the coronavirus outbreak in perspective by citing this year’s flu season. Here’s the brilliant opening from the linked piece:
The rapidly spreading virus has closed schools in Knoxville, Tenn., cut blood donations to dangerous levels in Cleveland and prompted limits on hospital visitors in Wilson, N.C. More ominously, it has infected as many as 26 million people in the United States in just four months, killing up to 25,000 so far.
In other words, a difficult but not extraordinary flu season in the United States …
So yes — get your flu shot! Listen to Dr. Stephenson!
#Influenza and #coronavirus are the same problem. It’s not a competition over which virus is the scariest. They are circulating at the same time which complicates diagnosis and treatment and add together to stress our health care systems. Flu #vaccine helps *both* outbreaks.
— Katy Stephenson (@k_stephensonMD) February 1, 2020
As for the title of this post …
— Paul Sax (@PaulSaxMD) February 2, 2020