The daily CDC conference call was not particularly informative, but these daily briefings are still extremely valuable. Things are happening fairly fast but nothing we didn’t expect. There are now 40 confirmed US cases in the same 5 states (California, NY, Texas, Kansas, Ohio). The 28 new cases sere contributed by the New York prep school that had the state’s first 8 cases. These additional ones are the result of continued case finding. Acting CDC Director said that the only laboratory confirmed human to human transmission is in the Kansas husband and wife (he had just returned from Mexico), but that it was quite clear there was person to person spread as for seasonal flu.
The US cases have ranged in age from 7 to 54, with a median age (the age at which half are older and half younger) of 16. This is certainly related to the fact that the 20 youngest are several children and the prep school students. WHO/PAHO, CDC and the Mexican public health authorities are working hard on developing the descriptive epidemiology and the epidemic curve for Mexico. Descriptive epidemiology gives the features of the cases in terms of person, place and time, while the epi curve portrays the number of cases over time and tells us, among other things, if new cases are appearing faster, slowing down, leveling off or decreasing. Descriptive epidemiology also tells us about the case fatality ratio (CFR, commonly but mistakenly called the case fatality rate) and the spectrum of illness severity (virulence), two critical pieces of information. Finally, the same data will be used to develop information on transmission (generation time, basic reproductive rate). In future posts I’ll probably explain many of these terms as they are being thrown around in the news and the blogs.
Besser said, in answer to a question, that CDC was working with USDA on evaluating the role of hog farms, if any. The only other piece of news was that CDC has issued a travel advisory for Mexico, essentially advice that US citizens avoid non-essential travel to the country. When asked about similar advice issued by European Union Health Commissioner about travel to the US, Besser said given the small number of cases here that it was premature. I guess it depends on whose ox is being gored. Elsewhere, laboratory confirmed cases have been found in Canada, Scotland and Spain, with suspect cases in Israel, Australia and New Zealand.
Meanwhile, WHO is reported to be ready to raise the pandemic threat level from 3 to 4. Rather than say, “About time,” I’ll just say, “A day late and a dollar short.” WHO has hurt itself badly by its failure to recognize this for what it is. While CDC has been pro-active, WHO has been timid and slow. It’s a shame.