So what about the R0 of 2019-nCoV, also known as the coronavirus that has claimed over three dozen lives in China and infected (at least) 1,000 people? Naturally, since the disease is most active in China which is notoriously opaque especially when it comes to matters that can cause a mass panic, the best one can do is guess, and that’s what the World Health Organization did yesterday when it issued a statement on the coronavirus epidemic with the following projection:
Human-to-human transmission is occurring and a preliminary R0 estimate of 1.4-2.5 was presented. Amplification has occurred in one health care facility. Of confirmed cases, 25% are reported to be severe. The source is still unknown (most likely an animal reservoir) and the extent of human-to-human transmission is still not clear.
Needless to say, while 2.5 is quite high, and in line with that of the Spanish flu epidemic which infected about half a billion people back in 1918, killing as many as 100 million before it eventually fizzled out, the real coronavirus R0 number may end up being far higher. That is the working hypothesis of Jonathan Read, a UK expert on the transmission and evolutionary dynamics of infectious diseases, who has published a paper with four colleagues that estimates transmission parameters for the Wuhan coronavirus, calculates that the R0 of 2019-nCoV to be between 3.6-4.0 or roughly the same as SARS, and reaches a conclusion about spread of the coronavirus epidemic that is frankly terrifying.
In “Novel coronavirus 2019-nCoV: early estimation of epidemiological parameters and epidemic predictions”, Reed et al, write that with an R0 of between 3.6 and 4.0, roughly 72-75% of transmissions “must be prevented by control measures for infections to stop increasing.”
This is a major problem because Reed estimates that only 5.1% of infections in Wuhan are identified (as of Jan 24), “indicating a large number of infections in the community, and also reflecting the difficulty in detecting cases of this new disease.” Furthermore, since all of this is happening in China which is not known for making the most socially-beneficial decisions under pressure, there is an ominous possibility that Reed is actually overly optimistic.
Huge public hygiene crisis seems to have erupted in #Wuhan. This video clip was once posted on Weibo but now deleted. The lady in the clip says dead bodies were left at hospital aisles untreated whereas doctors are taking care of other patients alongside them. #WuhanPneumonia pic.twitter.com/8ARaEHDbXC
— Ezra Cheung (@ezracheungtoto) January 24, 2020