I’ve started to take a closer look at the published numbers for SARS and MERS for comparisons.
Linked below is the consensus summary from WHO for SARS.
https://www.who.int/csr/sars/en/WHOconsensus.pdf
There’s a lot of technical data for anyone that’s interested in reading through it, but I found the following to be interesting regarding the incubation period...
BBM
“1. Incubation period
The estimates for the incubation period for SARS are starting to converge as tabled below. Estimates are derived from an analysis of SARS cases with single point exposures or exposure over a well-defined interval (Table 1). They will later be refined by the addition of laboratory data.
Most countries reported a median incubation period of 4-5 days, and a mean of 4-6 days. The minimum reported incubation period of 1 day was reported from China (4 cases) and Singapore (3 cases) and the maximum of 14 days was reported by China.
Donnelly et al analysed 1425 cases notified to 28 April in the Hong Kong Special Administrative Region of China (Hong Kong SAR) for whom epidemiological, demographic and clinical data were linked. The data were fitted to γ distributions by maximum likelihood estimation methods with allowance for censoring.
The maximum likelihood estimate of the mean and variance of the time from infection to onset was 6.37 days (95% CI 5.29-7.75) and 16.69 days respectively; therefore 95% of the patients would experience the onset of symptoms within 14.22 days of infection.5 Four Centres stated that the maximum observed incubation period was 10 days.
There was considerable discussion about the range of the incubation period and the effect of “outliers” at the upper end of the incubation period on existing recommendations on the isolation of cases and their contacts. “Outliers” beyond a 10-day maximum incubation period are few in number and have not necessarily been subjected to rigorous and standardized investigation.
However, it was noted that other mammalian coronavirus infections have long right-hand tails for incubation periods, so a long tail is also biologically plausible for the SARS-CoV. Statistical methods can be used to enable the inclusion of cases with defined periods of exposure rather than point exposures alone in order to increase sample size. There was also some concern that SARS cases arising from a single exposure may not be representative of all SARS cases.
Centres agreed that a detailed investigation of “outliers” is needed before public health policy is changed to extend the incubation period beyond 10 days, as any extension of the incubation period will have considerable impact on health service practice and resources. Participants also agreed on the need to combine data sets into a standardized international data set (Nd200 cases) to refine current estimates of incubation period. Although the focus of the investigation should be on the right-hand tail of the distribution (maximum incubation period) because of its public health importance, the shortest incubation periods seen in SARS influence the mean incubation period more than the upper tail and should also be reviewed.
It remains unclear whether the route of transmission influences the incubation period.”
Also, if you take a look at the” Case Fatality Rates” on pages 10 & 11 - specifically Table 3. - I think it’s very interesting (& IMO, very telling) that
the CFR (Case Fatality Ratios) average around 15% for all reporting areas with the exception of 1.
The People’s Republic of China (which has the largest reported cases by far) reported a CFR of 1.4%.
I’ll also add that with so many questions surrounding the accuracy of the numbers being reported, and with so many “assumptions” when comparing the 3 viruses, I don’t think we should forget that SARS has a mortality rate around 15% and MERS has a mortality rate around 34%
Just some interesting facts to consider....
now folks in the hood used to sacrifice that actually have to pick 0ne between two pairs of shoes will fare a lot better IMO
