epidemiology
revere | March 19, 2010As predicted, the pandemic of 2009 is beginning to yield more data, some of it directly applicable to pressing practical questions. The answers are still preliminary, and, as with all science, subject to revision. But it's what we have at the moment, and a letter that just appeared in the CDC sponsored journal Emerging Infectious Diseases, addresses an important question. During a flu outbreak, can hospitalized patients contract influenza from blood transfusions? Since people getting transfusions already have compromised health (else why would they be getting a transfusion?), they are at high…
revere | March 13, 2010If you check the blog for tomorrow's Sunday Sermonette, it will be an hour earlier, astronomically speaking. That's because in the US the clocks are shifted forward by an hour for "Day Light Savings Time," starting at 2 a.m. tomorrow morning (before the Sermonette goes up). The time shift will last until November 7, next fall. The sudden discontinuity in time keeping has uses other than energy conservation, however, and clever epidemiologists have used such circumstances for their own purposes for years. Here's one example.
One of the nice things about the switch back in the fall is that you…
ddobbs | March 11, 2010Helen Branswell, ace flu reporter, delivers the goodsl:
TORONTO A landmark study looking at how to limit the spread of influenza has shown what experts have long believed but hadn't until now proved: Giving flu shots to kids helps protect everyone in a community from the virus.
The study, led by Dr. Mark Loeb of McMaster University in Hamilton, Ont., showed the risk of catching the flu was lowered by nearly 60 per cent in communities where a substantial portion of kids aged three to 15 got flu shots.
That level of indirect protection is nearly as good as what healthy adults might expect…
revere | March 6, 2010Two days ago I went with my daughter to the pediatrician to check out her 20 month old who had a fever and rash. Viral origin, probably. Also an ear infection. Pretty much par for the course at this time of year. But lots of little ones and their older sibs weren't so lucky this flu season. As we've had too many occasions to mention, the severity of the 2009 pandemic has yet to be gauged, but trying to compare it to seasonal flu is misleading as its epidemiology is very different. Nowhere is this seen more clearly than in the melancholy figures for pediatric deaths.
Since the beginning of…
grrlscientist | March 2, 2010tags: handheld thermal cycler, LavaAmp, PCR, Polymerase Chain Reaction, DNA, molecular biology, Unreasonable Insitute, DIY, technology, Guido Núñez-Mujica, streaming video
Millions of people in the Global South suffer from neglected diseases, many of which could be treated, even cured, if they were detected early enough. But reliable, low cost diagnosis hasn't been available, as drug companies have no incentive to invest in the diseases of the poor. New pandemics can go undetected until they have spread out of control, like HIV, and treatable ailments can cripple impoverished communities…
revere | February 5, 2010We still don't know if we are experiencing a lull in flu or the virus has burned itself out for the season, but it's as good a time as any to reflect a bit on where we've been and where we still need to go. Being otherwise occupied (I'm sure you are sick of hearing about my grant writing obsession but not half as sick as I am about having it!), I'll start with something relatively straightforward: how CDC did on the epidemiology and surveillance front. Historically this is the agency's strong suit and so it is expected they would have acquitted themselves well. And pretty much, they did. A…
grrlscientist | January 27, 2010tags: health, medicine, TEDMED,health care, medical records, GPS, geography, geomedicine, Bill Davenhall, TEDTalks, streaming video
Where you live: It impacts your health as much as diet and genes do, but it's not part of your medical records. At TEDMED, Bill Davenhall shows how overlooked government geo-data (from local heart-attack rates to toxic dumpsite info) can mesh with mobile GPS apps to keep doctors in the loop. Call it "geo-medicine."
TEDTalks is a daily video podcast of the best talks and performances from the TED Conference, where the world's leading thinkers and doers give the…
revere | January 15, 2010Yet another cell phone and disease story, and while this one is on the "good news" side, it doesn't reassure me:
The millions of people who spend hours every day on a cell phone, may have a new excuse for yakking. A surprising new study in mice provides the first evidence that long-term exposure to electromagnetic waves associated with cell phone use may actually protect against, and even reverse, Alzheimer’s disease. The study, led by University of South Florida researchers at the Florida Alzheimer’s Disease Research Center (ADRC), was published today in the Journal of Alzheimer’s Disease.
“…
revere | January 14, 2010It's been over a year since we discussed the Journal of the American Medical Association (JAMA) article on bisphenol-A (BPA), a high volume chemical used in plastic components of food and drinks packaging and found in 90% of all Americans screened for the chemical. It is also a chemical that disrupts the endocrine system, a complex chemical signaling system that coordinates the actions and responses of various tissues and organs. The JAMA article examined self report in adults of cardiovascular disease and diabetes ("has a doctor ever told you that you had . . . ") and measured liver enzyme…
revere | January 12, 2010[Previous installments: here, here, here, here]
We'd like to continue this series on randomized versus observational studies by discussing randomization, but upon reviewing comments and our previous post we decided to come at it from a slightly different direction. So we want to circle back and discuss counterfactuals a little more, clarifying and adapting some of what we said for the coming randomization discussion.
Let me change the example to a more recent controversy, screening mammography for breast cancer. Should women under 40 get routine screening given that there is said (on the…
revere | January 9, 2010Continuing our discussion of causation and what it might mean (this is still a controverted question in philosophy and should be in science), let me address an issue brought up by David Rind in his discussion of our challenge. He discussed three cases where a rational person wouldn't wait for an RCT before taking action, even though there remained uncertainty. The first was a single case report of rabies survival after applying an ad hoc protocol. The next was use of parachutes while sky diving. The third was the first reports of antiretroviral therapy for AIDS. Here's what Rind said in his…
revere | January 8, 2010Let me start with an apology. This post is again fairly long (for a blog post). Blog readers don't like long posts (at least I don't). But once I started writing about this I was unable to stop at some intermediary point, although I might have made it more concise and less conversational. I haven't done either. Even worse, I didn't quite finish with the single point I wanted to make, so it will be continued in the next post. Hence the apology. Now to recap a bit and then get down to business.
My "challenge" from 10 days ago has drawn quite a response: over 40 quite substantive comments on the…
revere | January 6, 2010Rush Limbaugh has done a personal biopsy of the US health care system and found it healthy:
"Based on what happened to me here, I don't think there is one thing wrong with the American healthcare system. It is working just fine," he said.
Limbaugh, a multimillionaire, said he got no special treatment, but the staff made his stay "almost like a hotel." (Reuters via ABC News)
What "happened to him" was that the obese 58 year old media bloviator with enough internal rage to kill a dozen normal sized people was afraid he was having a heart attack and called his girl friend, Kathryn Rogers, to let…
revere | January 5, 2010Just a day into the New Year I was feeling feisty and issued a challenge to readers and the Evidence Based Medicine (EBM) blogosphere in general. I asked for a critique of a fictitious uncontrolled, non-randomized non-blinded small scale clinical study. It was truly a fictitious study. I made it up. But I had a template in mind and I intended to go somewhere with the example and I still do. But it will take longer to get there than I anticipated because it has raised a lot of things worth thinking and talking about in the meantime. I was going to wait a week to give people a chance to read…
revere | December 13, 2009Red wine has been touted for its health benefits but these don't seem to extend to warding off swine flu. The virology laboratory in Bordeaux in the southwest of France tested via RT-PCR over 1200 nasopharyngeal swabs between May 1 and the first week in October and found 186 positive for the new pandemic strain. They looked at five of these cases more closely, monitoring them for duration of viral shedding. Two of the five kept shedding for 2 to 4 weeks (paper in Eurosurveillance by Fleury et al., v. 14, #49, December 10, 2009).
The first case was a non-obese previously healthy male in his…
revere | December 10, 2009The other day the British Medical Journal (BMJ) published a clutch of articles about whether Tamiflu was as useful a drug as some have touted. I read the main article, another one of the Cochrane Collaborative meta-analyses of the studies they deem useful about any particular subject, and it didn't seem to make much news. It confirmed what their previous review had said about the neuriminidase inhibitor antivirals for influenza (Tamiflu and Relenza): these drugs work but their effect is modest. We've been saying the same thing for years here, not because we did a fancy meta-analysis, but…
revere | December 9, 2009Long time readers may have noticed that the subject of West Nile Virus (WNV) pops up periodically here (and here, here, here, here, here). It's more than a passing fancy. I was professionally involved in public health measures around West Nile after its introduction to the US in 1999 and have maintained an interest, even though flu occupies much (too much) of my time.
WNV is a mosquito-borne flavivirus of birds that occasionally infects humans (in this sense it is like bird flu, although only in this sense; bird flu is not passed from birds to humans via mosquitoes). The resulting infection…
revere | November 30, 2009Swine flu started in pigs (although we don't exactly when or where), adapted to and passed to humans who returned the favor and passed it back to pig herds. Then we heard that turkeys in Chile had contracted the virus, followed by ferrets and a house cat. We can infect animals cross species with flu in the laboratory, but all of these are cases acquired in the natural world by animals interacting with humans. Once cats were on the menu, the next question was dogs, another population "companion animal" (aka, pet) in the US and Western Europe (and literally a menu item in many parts of Asia).…
revere | November 27, 2009It seems swine flu is full of surprises that turn out not to be surprises. Or so it's claimed. Or not. Here is CDC's Dr. Anne Schuchat, the agency's chief health officer and spokesperson on swine flu, responding to NPR's Melissa Block's question about what has been her biggest surprise:
Dr. SCHUCHAT: I shouldn't have been surprised, but I have been surprised about this disproportionate toll that it's taking in pregnant women. I think I'd never lived before a pandemic before, and I actually hadn't seen the really sorry and just the tragic stories of healthy pregnant women coming down with such…
revere | October 30, 2009One frequently hears claims that the current swine flu pandemic has been exaggerated because there are "only" 1000 or so deaths, while seasonal flu is estimated to contribute to tens of thousands of deaths a year. There are two reasons why this is not an apt comparison. We've discussed both here fairly often. The first is that the epidemiology of a pandemic and seasonal flu are very different. Epidemiology studies the patterns of disease in the population and swine flu is hitting -- and killing -- a very different demographic from seasonal flu. Its victims are young and many are vigorous and…