Friday, May 1, 2009

CDC Daily Briefing

In CDC's daily press briefing on the H1N1 flu investigation focused on updating the numbers, emphasizing more cases to come, encouraging preparedness and awareness, and emphasizing that flu is an unpredictable disease.

Dr. Anne Schuchat noted that CDC is paying less attention to the numbers now, as cases continue to be reported and numbered reports are often out of date as soon as they are made. These numbers will have less and less meaning as we move forward. She said to expect more cases in more places, especially as states have increased capacity to recognize the virus and bolstered surveillance.

The median age of those who have been infected thus far is 17 years of age, with a range from one year to 81 years.

Dr. Schuchat also directed people to two new MMWRs from CDC's website, exploring the spread of the virus in a NYC school, and a second including information from the Mexican outbreak from the Mexican government. You can find those documents here:

A Note on Antivirals:
HHS Secretary Sebelius ordered another 13M courses of antiviral drugs to replenish the stock that was distributed to states from the Strategic National Stockpile. The USG also shipped 400,000 courses of antivirals to Mexico, in response to a request from the Mexican government. CDC will continue to monitor shifts in the genetic makeup of the virus and monitoring the potential of the virus to become resistant to antivirals (which is considered unlikely at this point).

She emphasized the importance of hand-washing and cough and sneeze etiquette in addition to isolation of the sick and avoiding crowded areas in regions with ongoing cases/outbreaks to slow the spread of the disease.

A Note on Vaccines:
CDC is now developing a seed strain of the virus for manufacturers to use to possibly manufacture a vaccine. This will take at least three weeks. She noted that CDC has not made the decision yet to manufacture the vaccine, and if they do decide to begin manufacturing a vaccine, further decisions need to be made about possible use of the vaccine and the like.

Nancy Cox, the Director of CDC's flu division noted that "the virus [circulating in Mexico, Canada, and the US] is 99-100% genetically identical. So it will be somewhat easier to create a vaccine because the viruses that are spreading are so similar to each other."

Attack Rate:
Dr. Schuchat: "There are many ways we can look at attack rates. And it's one of the tools epidemiologists use to understand the situation." CDC is looking at families with infected individuals to try to estimate an attack rate. From what they are seeing now, the attack rate is fairly high, around 25-30%. It easily transmitted; similar to what we see with seasonal influenza.

Virulence/Severity - How similar is this strain to the 1918 flu strain:
Dr. Cox: "What we have found by looking at the sequences of the virus is that we are not seeing the markers for virulence like with the 1918 virus. However, there are still many things we don't understand about the virulence of the 1918 virus. So we are continuing to look for markers."

More on pigs:
*** You cannot get H1N1 flu from pigs/swine. H1N1 is circulating among people. You contract H1N1 by coming into contact with someone who is ill with H1N1 or touching surfaces that have germs from the cough or sneeze of an H1N1-infected individual***

For more information:
Harvard opinion poll on H1N1:

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