Here's a common complaint about the annual flu vaccine: "The last time I got the shot, I ended up getting the flu anyway!" Epidemiological data seem to back up such anecdotes. According to an American Lung Association report from 2010, there was no sustained decline in influenza-associated deaths over the past decades. Among those older than 65, according to a New England Journal of Medicine review, flu hospitalization rates rose steadily between 1979 and 2001, despite an increase in vaccination rates among seniors from 32 percent in 1989 to 67 percent in 1997.
Such data make the vaccine seem useless. As a result, skepticism has lately moved beyond the usual anti-vaccine, tinfoil-hat crowd. In 2009, the Atlantic published a breathless pieceaccusing drug makers and doctors of foisting bad science on an unsuspecting public and asked, "But what if everything we think about fighting influenza is wrong? What if flu vaccine does not protect people from dying—particularly the elderly?" Last month, the New York Timescalled the flu vaccine a "bonanza" for vaccine manufacturers and gave largely uncritical coverage to a University of Minnesota researcher who claimed the vaccine "does not protect as promoted. It's all a sales job." Similarly provocative articles have run in Harper's ("Viral Marketing"), the Boston Globe ("Flu Shots Are Safe, But Do They Work?"), and the Wall Street Journal ("They Shoot Flu-Shot Skeptics, Don't They?").
Critics of flu-control efforts got a boost recently when the British Medical Journal accusedRoche, which makes the anti-viral drug Tamiflu, of hiding data about the drug's supposed impotence against the flu. In anticipation of a possible pandemic in 2009, the U.S. government stockpiled $1.5 billion worth of Tamiflu and other anti-flu drugs. Now the editor of the British Medical Journal is concerned those pills were oversold. Among the conspiracy-minded, flu-control efforts now have less to do with public health and more to do with corporate profits. The true threat to us all, proclaimed Helen Epstein in the New York Review of Books, isn't the virus at all, but the drug companies.
Informed debate over public health is, well, healthy. But it's wrong to portray the global medical community as a stooge of greedy drug makers. The flu vaccine isn't useless and neither is Tamiflu. It's just that they, like all infection-control measures, are not perfect. There is no question that the vaccine does enhance one's immune response to flu—and it certainly does not give people the flu. It's likely the shot hasn't led yet to a dramatic population-wide decrease in flu deaths. But the proper response isn't for us to finger-point at drug companies and public health officials and call for repealing vaccine efforts.
What critics of flu-control policies don't get is that any global effort to stop an infection always goes through a process in which doctors learn more over successive battles and refine their strategies. That is exactly what is now happening in the battle against flu. We are not witnessing the work of industry puppet-masters. This is the scientific process in action.
It's easy to demonize Big Pharma and just call for more and more studies before taking decisive action. But sometimes we have to move. Consider the chicken-pox vaccine, which was first licensed in the United States in 1995. Preliminary data suggested the vaccine could stop the disease, but the studies included only a few thousand children. Arguments against universal chicken pox vaccination sounded similar to those against flu shots—the illness is harmless, the vaccine doesn't reliably produce immunity, drug companies are running the show, and so on—but authorities persisted and endorsed universal vaccination. Within a few years, we realized that children needed two separate shots, not one, to get stronger immunity, and national policies were changed. Before vaccines, chicken pox killed 100 children and led to 10,000 hospitalizations annually, according to the Centers for Disease Control and Prevention. In school-age children, attack rates fell by almost 80 percent after vaccination began, and deathswere nearly eliminated.
Another example of unfolding science: RotaShield, a vaccine against the leading cause of infant diarrhea, was approved in 1998. When a very rare side effect emerged, the vaccine was pulled in 1999. Two new vaccines were developed and licensed in 2006 (Rotarix and RotaTeq), and those formulations may save hundreds of thousands of lives annually worldwide. Again, more tweaks may be needed over time. In fact, the American Academy of Pediatrics vaccine schedule is constantly changing in small ways—ask any pediatrician who has to keep up—as data filters back about new vaccines against HPV and meningococcus, among others.
Back to flu, which is far more complicated than, say, chicken pox. To begin with, most people who die of the flu aren't actually tested for it; hospitals and clinics aren't required to report flu cases to anyone (unless they involve young children); and most severe consequences of the flu are secondary problems like bacterial pneumonia or heart failure, which end up being listed as the cause of death. Thus, the flu's toll can be estimated only by using complex statistical models. Further, the virus mutates yearly, so the flu's impact varies hugely year by year and makes longitudinal comparisons impossible. Over the past 30 years, the annual American death toll wandered almost randomly between 3,000 and 50,000.
Now add the following: Vaccine makers have to guess what strains of the flu will predominate, so the vaccine may prevent anywhere from 0 to 50 percent of the flu in a bad-guess year and 70 to 90 percent in a good-guess year. The vaccine works best in school-age children and young adults, and unfortunately it works worst in babies and seniors, who sadly are the ones who get sickest. (In 2003, the CDC began requiring state health department to report child flu deaths and found 153 children died of the flu that season, which is more than any other vaccine-preventable illness.) Even more complicated: The nasal mist vaccine works best in children, but the shot is better for adults.
What about Tamiflu? In the event that a virulent flu pandemic occurred and no vaccine was available, antiviral drugs might be critical. In a key 2009 study during the H1N1 outbreak, stockpiled Tamiflu was given to large groups of contacts of newly-infected Singaporeans and cut the transmission rate by 95 percent. Tamiflu also appears to cut the risk of death in hospitalized flu patients. Critics of Tamiflu allege Roche obscured evidence unfavorable to the drug, but the debate is deep and fascinating. (Roche's response to them, in my opinion, seemed reasonable.)
Most importantly, what have we learned about flu control? We found that vaccinating the elderly failed to cut hospitalizations; therefore, doctors hypothesized that children are responsible for spreading most flu to older people. In 2010, a large study of elementary-school-based flu vaccine in Bell County, Texas achieved 50 percent vaccination rates of students and protected people of all ages from the flu (the so-called "herd immunity" effect). Similar findings were seen in a Canadian study. Incorporating this information, the CDC recommended in 2010that all people over 6 months old should be vaccinated. (To guard infants, we now know thatvaccinating pregnant women produces immunity in their newborns.) As in chicken pox control, these new flu policies show public health in evolution. In a few years, we will see if this works. In the meantime, the FDA earlier this year approved a new vaccine that includes four flu strains, instead of three, which may bolster effectiveness. It's another example of science in action.
In the meantime, Americans should learn from the death toll of flu-vaccine skepticism in Japan. It was the only industrialized country to have mandatory universal flu vaccine of children, which helped produce herd immunity, The program fell victim to skeptics and was repealed in 1994. The result? The New England Journal of Medicine reported that flu deaths rose by 40,000 per year—almost as many people as died immediately from the atomic bomb in Hiroshima.
In the end, it's easy to ascribe sinister motives to flu control efforts, especially if you're unwilling to tolerate uncertainty. With a slight shift in perspective, however, one can see our evolving flu control programs as a triumph of public health.
Advertisement
You have just read the article News for today's that category by title Flu vaccine safety: Tamiflu and vaccines save lives and show public health science in action. - Slate Magazine. You can bookmark this page with a URL http://news-these-days.blogspot.com/2012/12/flu-vaccine-safety-tamiflu-and-vaccines.html. Thank you!
Posted by: Tukiyooo
Flu vaccine safety: Tamiflu and vaccines save lives and show public health science in action. - Slate Magazine Updated at :
3:03 PM
Wednesday, December 19, 2012
Post a Comment