Ferreting Out How Swine Flu Crowds Out Seasonal Flu

[indigo girl]

How the Flu Pandemic Looks to Us at This Point

Commentary from the Reveres over at Effect Measure:

...We admit that not watching flu evolve daily was a relief, although we did sneak peeks when we weren't supposed to. But it also proved to be like the stock market. The daily ups and downs sometimes obscure the bigger picture. So what does it look like now?

We have two contradictory impressions. One is that the pandemic has continued to develop in a very robust fashion. So it's a dynamic picture of change. The second is that it looks like a normal pandemic, just going about its business. We have been very struck by how , in general, we are accustomed to the experience of constant change, not just for influenza but for modern life in general and we are gestating a post on influenza as the disease of modernism par excellance. That's another of the benefits of stepping away from the daily view. It allows for some reflection. But that's for another day (soon, we hope). When it comes to the current status, WHO issued quite a nice one the day we were starting to pack up (August 28)

Read the rest over here: http://scienceblogs.com/effectmeasure/2009/09/how_the_flu_pandemic_looks_to.php

Yesterday one of the questions we asked was whether swine H1N1 would replace seasonal viruses this season. In previous pandemics one subtype completely replaced its seasonal predecessor: in 1957 H2N2 replaced the H1N1 that had been coming back annually at least since 1918; only 11 years later, in 1968, a pandemic with H3N2 replaced the H2N2. H2N2 is no longer circulating but in 1977 an H1N1 returned and has been co-circulating with H3N2 since then. This was a new situation. We could ask why this hadn't happened before with H2N2 and H1N1 or H2N2 and H3N2 or all three together; or we could ask why it happened after 1977 with H1N1 and H3N2. We still aren't sure of the answer, but the question has special pertinence at this point because it bears on whether we will be seeing three viruses this fall in the north (swine H1N1, seasonal H1N1, seasonal H3N2) or just the seasonal viruses or just the swine virus, or the swine virus and one of the others. We have a vaccine to cover some of the seasonal virus (there is a lingering question of a good match for the H3N2 component) but not yet one for swine flu. We can't wait to find out and I, for one, will be getting the seasonal vaccine as soon as it's my turn (which will be shortly at my medical center) and then get the swine flu vaccine when it's my turn in the queue as it becomes available. To me that seems the most prudent way to cover my bets, although I won't know until later whether it was the right choice. Meanwhile there is science to be done to help us understand all this, and within hours of yesterday's post appearing there was a paper published in PLoS Currents/Influenza [PLoS Currents: Influenza. 2009 Aug 25 [revised 2009 Aug 27]:RRN1011] that provided a tantalizing data point on the subject of the dynamics of infection with combinations of swine flu and the seasonal flu A subtypes.

Read on: http://scienceblogs.com/effectmeasure/2009/09/ferreting_out_how_swine_flu_cr.php

The Editors of Effect Measure are senior public health scientists and practitioners. Paul Revere was a member of the first local Board of Health in the United States (Boston, 1799). The Editors sign their posts "Revere" to recognize the public service of a professional forerunner better known for other things.