A study today, published in JAMA, points out the increased burden that pandemic H1N1 placed on pregnant women, and the apparent efficacy of early antiviral treatment in reducing mortality.
Mike Stobbe of the Associated Press has an overview, which is followed by the JAMA abstract, and a few comments of my own.
Study: Fast Tamiflu treatment saved many pregnant swine flu victims in US
MIKE STOBBE AP Medical Writer
ATLANTA (AP) — Quick treatment with flu medicine saved the lives of many pregnant women who were stricken by swine flu last year, according to the most complete analysis of deaths among expectant mothers.
The study by the Centers for Disease Control and Prevention counted 56 pregnant women who died from the new virus in 2009, confirming the dangers of the disease to this group.
Based primarily on U.S. figures from the first few months of the global epidemic, which began last April, CDC officials believe that though pregnant women account for just 1 percent of the population, they have at times accounted for as many as 5 percent of swine flu deaths.
Excerpts from the JAMA Abstract follow:
Alicia M. Siston, PhD; Sonja A. Rasmussen, MD; Margaret A. Honein, PhD; Alicia M. Fry, MD; Katherine Seib, BS; William M. Callaghan, MD; Janice Louie, MD; Timothy J. Doyle, MPH; Molly Crockett, MPH; Ruth Lynfield, MD; Zack Moore, MD; Caleb Wiedeman, MPH; Madhu Anand, MPH; Laura Tabony, MPH; Carrie F. Nielsen, PhD; Kirsten Waller, MD; Shannon Page, BS; Jeannie M. Thompson, MPH; Catherine Avery, CFNP; Chasisity Brown Springs, MSPH; Timothy Jones, MD; Jennifer L. Williams, MSN; Kim Newsome, MPH; Lyn Finelli, DrPH; Denise J. Jamieson, MD; for the Pandemic H1N1 Influenza in Pregnancy Working Group
Context Early data on pandemic 2009 influenza A(H1N1) suggest pregnant women are at increased risk of hospitalization and death.
Objective To describe the severity of 2009 influenza A(H1N1) illness and the association with early antiviral treatment among pregnant women in the United States.
Conclusions Pregnant women had a disproportionately high risk of mortality due to 2009 influenza A(H1N1). Among pregnant women with 2009 influenza A(H1N1) influenza reported to the CDC, early antiviral treatment appeared to be associated with fewer admissions to an ICU and fewer deaths.
You see a good deal of skepticism expressed online, and sometimes in the mainstream media, about the effectiveness and appropriateness of antiviral therapy for influenza.
Critics point out that the drug can have (rare) side effects and that it only reduces the duration of seasonal flu symptoms by an average of 1.3 days. A modest but measureable benefit.
Where Tamiflu – and other antivirals – appear to make a bigger difference is in reducing symptoms in those who have pre-existing risk factors or conditions – including pregnancy – or those who are experiencing influenza complications.
And among H5N1 bird flu cases around the world, those that have survived (40%) were likely to have received early antiviral intervention.
Granted, most of the `evidence’ for the effectiveness of antivirals comes from observational studies, which some researchers find wanting (see BMJ: A Review Of Tamiflu’s Efficacy Against Seasonal Influenza).
Randomized controlled trials (RCTs) – while considered the `gold standard’ for drug research – are nearly impossible to conduct ethically since you’d have to withhold potentially life saving treatment from randomly selected test subjects.
We would all like medicine to be based on treatments and drugs proved – beyond a shadow of a doubt – to be safe and effective . . . but sometimes we must accept a lower burden of proof -the preponderance of evidence - instead.
And right now, the evidence continues to point to antivirals as being a valuable tool in the treatment of severe influenza.
Lisa Schnirring of CIDRAP News has a very nice overview of this story entitled:
Lisa Schnirring Staff Writer
Apr 20, 2010 (CIDRAP News) – In the biggest and most detailed look yet at pandemic flu infections in pregnant women, researchers from the US Centers for Disease Control and Prevention (CDC) reported today that early antiviral treatment was linked to fewer intensive care unit (ICU) admissions and that severe illnesses and deaths are more likely to occur during the third trimester.
The CDC researchers, along with a Pandemic H1N1 Influenza in Pregnancy Working Group made up of health officials from several states, based their findings on reports of pregnant women who were sick with pandemic H1N1 infections through August plus more recent reports of women who were admitted to ICUs. The findings appear in the Apr 21 issue of the Journal of the American Medical Association (JAMA).