Good News, Bad News on Tamiflu
#244
In a news report widely circulated yesterday regarding an interview with a Vietnamese Virologist named Dr. Menno de Jong, we learn that some of our assumptions about the treatment of the H5N1 bird flu virus in humans may not be correct.
Nothing surprising there, really. We seem to learn that the rules with avian influenza are a bit different nearly every day.
First the good news.
Patients who are seven or eight days into their illness can reportedly still be helped by the administration of Tamiflu, or other antivirals. Dr. Menno De Jong urges that doctors not give up on bird flu patients, even when their cases are in advanced stages.
This flies in the face of conventional wisdom, which states that to be effective, Tamiflu must be given within the first 24 hours. But the good doctor is quick to point out that the patient’s prospects improve greatly, the earlier the medicine is administered.
"In my experience, there is a clear suggestion that there was still virus replication [when there was] a late start in treatment," De Jong said in Singapore during a conference on avian flu. "In four of my patients, there was very rapid clearance of the virus from the throat, and all four survived."
De Jong, head of virology at the Hospital for Tropical Diseases in Ho Chi Minh City in Vietnam, stated the antiviral Tamiflu could still be useful in fighting bird flu many days after the onset of symptoms because the avian virus would still be multiplying.
De Jong treated 17 H5N1 patients in Vietnam in 2004 and 2005, 12 of whom died.
Curiously, Dr. De Jong has been widely quoted by the anti-Tamiflu crowd as being dubious over the use of Tamiflu for the past year, and its critics have used his report in the New England Journal of Medicine, published in late 2005, to damn the drug.
Tamiflu found ineffective in bird flu treatment
Updated Wed. Dec. 21 2005 11:08 PM ET
CTV.ca News Staff
The drug most of the world is counting on to prevent an avian flu pandemic may not be a failsafe defence, according to a New England Journal of Medicine report.
The authors say they have found evidence the H5N1 virus can mutate into a form unaffected by Tamiflu -- rendering the world's ever-growing stockpiles of the drug ineffective if the mutated strain were to spread.
According to the study, completed by Dr. Menno de Jong at the Hospital for Tropical Diseases in Ho Chi Minh City, Vietnam, four out of eight avian flu patients who were given the medication died despite the treatment.
http://tinyurl.com/y7792u
This seeming contradiction, or reversal, isn’t one at all. It is simply a good example of how some people can twist and turn a scientific study’s words to suit their own agenda.
There are apparently a large number of people who, for a variety of reasons, want Tamiflu to be a failure. So they latch onto reports like the one above, and spin it to their advantage.
Some of these people are selling alternative medications, or treatments. Others resent the involvement of former Defense Secretary Donald Rumsfeld’s stake in the drug, certain that the rush to stockpile the drug is nothing more than a cynical plot by the Bush administration to line his pockets.
Tamiflu is an imperfect drug, if one expects it to be a cure-all for avian flu. As the article above points out, it is not a `failsafe defence (defense)’. It can help reduce the replication of the virus, sometimes dramatically, and can be lifesaving. But there are worries that the virus may develop resistance to the drug. In some instances, we’ve seen signs of that.
But as Dr. De Jong points out, it can have a dramatic affect on avian flu patients. And right now, it is our best defense against the infection. While 12 of the 17 patients Dr. De Jong treated succumbed to the disease, it should be noted that most of his patients arrived at the hospital in the late stages of the disease.
Overall, this would seem to be good news. Tamiflu is apparently effective, albeit nowhere near 100% of the time, even when administered late in the illness.
But there is a flip side to this coin: one that I haven’t seen mentioned. The Bad news.
If Tamiflu is still an effective treatment 8 days into the illness, then the virus is still replicating unchecked by the body’s immune system after more than a week. In normal influenza, viral reproduction begins to halt after around 48 hours. The body’s immune system gets a handle on the invader, and suppresses it. Flu patients, under normal circumstances, are no longer infectious after about a week.
Not so, apparently, with the H5N1 virus.
The implications of this are, in my estimation, potentially very serious. This means that antivirals may need to be administered for longer than previously thought. And it also means that infected patients may remain infectious for longer than we expected.
Our much-lauded Tamiflu stockpile is based on the working assumption that each patient would need 10 pills, or 2 pills a day for 5 days. It has been stated repeatedly in this blog, and elsewhere, that an effective course of treatment could be easily double or triple that amount, dramatically reducing the number of patients that could be treated by our strategic stockpile.
And the longer a patient remains infectious, and shedding the virus, the longer they remain a hazard to others, especially caregivers. This includes healthcare workers, and family members caring for the sick at home. This will increase the load on isolation wards, and increase the drain on PPE’s (Personal Protective Equipment: Masks, gowns, gloves), and potentially increase the number of people exposed.
So, while the news of Tamiflu’s continued effectiveness even late into the illness may sound good, it is really a doubled edged blade.
Admittedly, by now, we should be used to this. The H5N1 virus has proven to be a formitable foe, and should it become a pandemic, we are unlikely to find easy ways to defeat it.
