# 3127
Dr. Richard Besser – Acting Director of the CDC - was back at the podium today for the CDC’s telephone conference/press briefing. Joining him was Dr. Nancy Cox, who is director of CDC's influenza division.
These pressers usually consist of a short update, followed by a Q&A period, and last 30-45 minutes. The audio file (mp3) and transcript of each of these daily briefings gets posted on the CDC’s H1N1 Flu (Swine Flu) Press Briefings page.
Today Dr. Besser expressed `cautious optimism’ over some of the signs they were seeing with this virus, but said we were not out of the woods yet. Thus far, the virulence (severity) of this virus seems on par with seasonal flu.
Of course, the worry is that could change.
The CDC expects to move away from using expensive (and scarce) laboratory resources to confirm cases, and will likely accept `probable’ cases in the near future.
A `probable’ case is one that has tested positive for Influenza A, but did not test positive for the H1 or H3 influenza virus. Although an H1N1 virus, the new virus isn’t picked up by the H1 test and is considered `untyped’.
Thus far, 99% of `probable’ cases that have gone on to be tested specifically for the virus, have turned out positive.
There are at least 700 `probable’ cases in 44 states, that have not been tested.
Even then, it is assumed that a great many people won’t see their doctors, or be tested, for the virus. Unless someone is experiencing serious symptoms, they are not being encouraged to seek medical care.
So the actual number of cases around the country really isn’t known, nor will it ever be. More important, right now, are trends and where the virus is now showing up.
The median age among confirmed cases is 16, with cases as young as 3 months and as old as 81 years. Most (62%) are under the age of 18.
Hospitalized cases (now totaling 35 out of the 286 confirmed cases) run roughly the same demographics.
Exactly why this virus appears to be targeting younger victims is unknown. It is possible that older people have been exposed to more H1N1 viruses over the years, and have picked up some level of immunity.
But right now, that is just one of several theories. This demographic could also be due to the fact that the virus was apparently imported into the US by students returning from Spring Break in Mexico.
Their contacts, and the first generation of new cases, are more likely to be among their age group.
Other good news relayed today is that the isolates being analyzed all seem to be very similar. That makes crafting a vaccine easier. There are also no signs of resistance developing to Oseltamivir (Tamiflu) or Zanamivir (Relenza).
Looking forward, the CDC will watch with particular interest how this virus acts in the Southern Hemisphere during our summer months. Influenza generally dies down in the Northern Hemisphere this time of year, but flu season is just getting started in places like Australia, South Africa, and New Zealand.
That could give us an early preview of our 2009-2010 seasonal flu season, and hopefully early warning of any dangerous changes in the virus.
