Influenza treatment
revere | May 10, 2009The spate of swine flu articles in The New England Journal of Medicine last week included an important "Perspective, The Signature Features of Influenza Pandemics — Implications for Policy," by Miller, Viboud, Baliska and Simonsen. These authors are familiar to flu watchers as experienced flu epidemiologists and analysts of archival and other data. Analysis of archival data is sometimes described as archeo-epidemiologic research. In their NEJM article Miller et al. summarize what they see as some common features in the three flu pandemics of the last century (so the generalization that there…
revere | May 9, 2009Maryn McKenna has a great piece at CIDRAP News today about something that should worry all of us as we wait to see if the other shoe drops with swine flu. Our acute care health services system is so brittle it won't take much to break it:.
With the global outbreak of novel H1N1 influenza (swine flu) entering its fourth week, physicians at emergency rooms, clinics, and hospitals around the United States say they are overwhelmed with "worried well" who have as much as doubled their patient loads.
All the clinicians work at medical centers that have planned and practiced for pandemics and…
revere | May 8, 2009Late yesterday The New England Journal of Medicine published a number of papers on the recent swine flu outbreak. The first paper, "Emergence of a Novel Swine-Origin Influenza A (H1N1) Virus in Humans" by large federal-state team of epidemiologists describes 642 confirmed cases in 41 states as of May 5, 2009, two days before publication. What I find remarkable is the speed the problem was recognized -- literally days. Identification of the virus was first made in the CDC laboratory on April 15, just 3 weeks ago. Now we are already reading scientific papers providing a wealth of detail.
Among…
revere | May 7, 2009It seems a conversation on one of the comment threads about "swine flu parties" at Effect Measure has made the New York Times:
One of the first open debates of the idea of intentional self-infection was on Effect Measure, a public health blog with many posts by thoughtful people who say they are clinicians, epidemiologists, veterinarians and other professionals, sometimes in government, but who post under pseudonyms to speak freely.
On April 28, a user calling herself OmegaMom posted: “Just a quick note — I just got a Tweet from a mom suggesting ‘swine flu parties’ because the U.S. version…
revere | May 7, 2009Breathing easier, may be an apt phrase for an almost audible collective sigh of relief. So far, the incipient swine flu pandemic is not extremely nasty. Is this perhaps premature? The world's premier scientific journal, Nature, and many flu scientists, suggest it is:
Complacency, not overreaction, is the greatest danger posed by the flu pandemic. That's a message scientists would do well to help get across.
[snip]
There is ample reason for concern: a new flu virus has emerged to which humans have no immunity, and it is spreading from person to person. That has happened only three times in the…
revere | May 6, 2009How fast flu spreads is related to how many susceptible people an infectious person can infect (a measure called R0) and also something called the serial interval. The serial interval is the average length of time between the start of one infection and the start of the infection of that case's infected contacts. The horter the serial interval the faster a virus can spread. So what is the serial interval for this virus and how can we determine it? The answer to the first question is the usual. We don't know yet. The answer to the second one tells us a little about why we don't know and why we…
revere | May 5, 2009As I write this the US has 279 confirmed cases and one death from H1N1/2009 in 36 states. WHO has tallied 1085 1124 cases in 21 countries with 25 deaths. There is a backlog of samples waiting for confirmation, so by the time you read this the counters will probably have rolled upward, especially as state laboratories become facile with the new primers and are able to do their own confirmation. And predicting an increasing case count is about all anyone can say with certainty at this point. What we said once about flu pandemics can be said just as appropriately for the flu virus: "If you've…
revere | May 4, 2009Cytokine storm is a graphic phrase that doesn't do justice to the complexity of one of the things that made the 1918 H1N1 virus so virulent and is also implicated in the frightful case fatality of H5N1 ("bird flu"). The current H1N1/2009 is not showing a propensity to cause this nasty effect, but the subject has come up several times in the comments. The post I am sending you to was written just before the current outbreak. It is about recent work that is trying to unravel the mechanism behind the serious immune system dysregulation called cytokine storm. While it's mainly about cutting edge…
revere | May 4, 2009There have been questions in the comments about where the CDC estimate of 36,000 to 40,000 influenza related deaths a year comes from. It's a figure I've used a number of times here to say generally that regular old seasonal influenza may be a mild disease for some but not for many others. Even if you don't die of flu, it can be a miserable illness and lay you low for several weeks of acute illness and months of fatigue and malaise. Now the 36,000 deaths number is taking on a life of its own, so it's time to explain exactly what it is and what it isn't. There are more things it isn't that it…
revere | May 2, 2009Laurie Garrett of the Council on Foreign Relations and a well-known authority on emerging infectious diseases was on PBS's Newshour last night and she made a very important but little appreciated point. Mexico has made a major national sacrifice for global public health by shutting down its country and interrupting transmission of disease. The cost to Mexico has already been enormous it will continue to pay in other ways. The reputation of the government has suffered because of the way it handled this -- the lack of transparency, the initial slow footedness (which of course it denies), its…
revere | May 1, 2009[NB: I have been traveling and offline all day. No way I can even read much less respond to the many excellent comments, tips, questions. Thanks to all. Help each other. Back at home base now.]
Closing US borders with Mexico for swine flu is fruitless since the virus is already planted in a dozen or more countries. And while right wing xenophobes are trying to blame Mexican immigrants, most of the international spread has come from commercial travelers, either tourists or business people. If we had sealed the borders, would it have included all American nationals in Mexico? Somehow I don't…
revere | May 1, 2009Just a brief note to remind everyone about the case definitions CDC is using for reporting on swine flu (or whatever name we collectively settle on). In order to make sure numbers are comparable from day to day and place to place we have to decide on criteria for knowing we have something to count. Is someone with flu-like symptoms to be counted as a case? Or do we confine it to someone with laboratory proved infection with the virus? Should there be different categories of diagnostic certainty?
For the moment, CDC is using the following definitions for suspected, probable and confirmed cases…
revere | April 30, 2009There is a tendency to be preoccupied with the latest in fast moving events, but I want to pause for a moment to make a point that has been lost in the discussion: we are witnessing a medical science landmark. Never before have we watched a flu outbreak of global dimensions unfold in real time. Nor have we ever had the opportunity to alter the course of such an outbreak.
I have been critical of WHO for being late to the party, but they are fully on board now and by raising the pandemic threat level to phase 5 have done something very important: served notice that it's time to mobilize…
revere | April 29, 2009In June 2005 a reader over at the old site suggested we put up some of our flu related material on Wikipedia. That sounded like a great idea to me. Even better, why not start a special purpose wiki -- a flu wiki -- to harvest the vast knowledge of the hivemind? Many, if not most, of the problems that would plague us in a pandemic weren't medical or even scientific in nature. They were things like, how do you prepare your small business for the possibility that the one person who knows how to unjam the fax machine is out sick for 4 weeks? Two other bloggers were also doing flu stuff at that…
revere | April 29, 2009As is usual (routine? no, nothing routine about this) in an evolving epidemic contradictory and confusing numbers are appearing. Some of them are the result of information lags (tallies not being updated), some are the result of using different criteria for counting (suspect versus probable versus lab confirmed, etc.), some are just rumors. WHO is saying that in Mexico there are only 7 confirmed deaths, 19 more lab confirmed cases, 159 probable cases and some 1300 being evaluated, based on official reporting to them by officials of a member state, the Mexico. Everyone knows there are many…
revere | April 28, 2009CDC guidelines for antiviral therapy for swine flu infection:
This swine influenza A (H1N1) virus is sensitive (susceptible) to the neuraminidase inhibitor antiviral medications zanamivir and oseltamivir. It is resistant to the adamantane antiviral medications, amantadine and rimantadine. (CDC)
What are these antiviral drugs and how do they work? Over the years here we've discussed this pretty often, so I went back and retrieved one of our older posts (from 2007). I've done some editing but it's pretty much the same as when I wrote it about bird flu. Same principles.
Oseltamivir (which we…
revere | April 28, 2009As cases continue to accrue in different places we will hear more talk about quarantine and isolation. These are two terms that are frequently confused, which is too bad, because isolation makes sense for influenza and quarantine doesn't. So what do they mean?
What quarantine and isolation have in common is they are both designed to interrupt the transmission of a disease that spreads from person to person. Quarantine is the legally enforceable segregation of people who people who have been or may have been exposed but who aren't (yet) sick. Some people talk about "voluntary quarantines," but…
revere | April 27, 2009One of the things we'd like to know about the swine flu virus is its Case Fatality Ratio (CFR, commonly called a case fatality rate, although it isn't technically a rate but a proportion). But what is a CFR? And how is it different from a mortality rate?
The CFR is an estimate of the probability that someone with the swine flu will die of it (technically, before dying from something else or recovering). The higher the CFR, the more virulent the virus. So what's virulence? Virulence refers to the severity of the disease the virus produces. Rabies is a virulent virus. Everybody dies from it…
revere | April 27, 2009The 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…
revere | April 27, 2009Usually "What did you expect?" is a rhetorical question, but we have a more serious point to make. Let's start with the familiar and move on to the less familiar. Many of you are coming here to find the latest news about swine flu. It's an imprecise term that covers two different things: what has happened that is new, in the sense of surprising and we didn't already know it would happen; and what is the current situation. Overnight (in the US) Europe (Spain) registered its first confirmed case. That's additional data but not surprising. We know this virus is seeded out there and we shouldn't…