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Guidance on Antiviral Drug Use during an Influenza Pandemic

December 21, 2008

guidanceLast week, DHHS released guidance intended to update the 2005 antiviral guidance published with the larger panflu plan. This plan incorporates a lot of the latest thinking regarding antiviral resistance and current stockpiles.

I’ve done a pretty thorough read-through of the public plan, and have some thoughts and criticisms. Mind you, the people who wrote this guidance are much smarter than I am, and really understand the problem. It was extremely well written, thoughtful and addressed all of the moral and ethical issues that needed to be addressed in the effort. The writers were given a truly impossible task, and made impossible decisions. I just happen to disagree with some of those decisions.

The guidance is laid out in two separate plans, one for focused on the public stockpiles at the CDC and at the many states. The second is intended to serve as guidance for private industry on stockpiling and distribution of antivirals.

Currently, there are 81 million courses of Tamiflu (oseltamivir) and Relenza (zanamivir) divided between the federal government (50M) and the states (31M). The guidance document describes how all 81 million courses should be used. There are, of course, many assumptions that lead into how these medications would be used–based mostly on the particulars of the pandemic strain.

The medications would be used mostly–vastly–for treatment purposes. 6 million courses would be utilized for controlling the pandemic before it explodes in the US. Two specific situations are described in the document:

1.      Containment or suppression of initial pandemic outbreaks overseas and in the United States – Mathematical model results suggest that a multifaceted response including public health measures and antiviral treatment, post-exposure prophylaxis, and geographically targeted prophylaxis may be effective in containing an initial pandemic outbreak and preventing a global pandemic.  Containment, even if not successful in preventing a pandemic, can slow the spread of disease to the United States allowing more time for preparedness.  An international containment response is likely to be coordinated by the World Health Organization and include many international partners.

2.      Use of antiviral medications among selected persons presenting for entry at U.S. borders early in the course of a pandemic as part of a risk-based strategy – A risk-based screening strategy will be implemented early in a pandemic in an attempt to slow the spread of the pandemic to the United States.  Antiviral prophylaxis for persons with possible exposure to pandemic illness can potentially reduce the risk of infection, transmission, development of illness, severity, mortality and lessen the need for quarantine facilities at ports-of-entry.

Use #2 makes total sense, I imagine it would be run by CDC DGMQ in the airports, though the health officials in ICE border stations would probably be given small apportionments. Use #1, though is vague–unnecessarily, I think. It makes good public health sense to flood the region were the initial pandemic outbreak occurs with antivirals. If it’s first noticed in a SE Asian country, there is good reason to push literally millions of courses into the country in an attempt to stamp out the disease through post-exposure and outbreak prophylaxis before it runs wild.  The vague part, though, is the explicit inclusion of the words, “and in the United States.” Would a good portion of the meds be shipped overseas to deal with the first outbreak and an amount be kept in the States for initial outbreaks here, or would it all be used for the initial outbreak even in the event that occurred overseas?

A similar amount of meds would be used for outbreak prophylaxis in closed settings such as nursing homes and prisons. This, again, is good public health. People in closed settings, especially folks with pre-existing health problems, during flu season are an increased risk for contracting the disease and for ultimately dying.

The rest of the meds are to be used for treatment. 79 million courses. If you get sick, you get Tamiflu. When the 79,000,000th course is dispensed, that’s it. If someone in your house gets sick, they get the meds and you don’t. This is interesting becuase in Appendices 2 and 8, the guidance notes that post-exposure prophylaxis (PEP) and targeted antiviral prophylaxis could have significant benefits and are, and I quote:

For seasonal influenza, PEP among household contacts of persons with influenza infection has been shown to be very effective in preventing illness.

The reason for not recommending PEP is because:

[t]reatment is preferred to prophylaxis in settings of limited antiviral drug supply as the need is clear and benefits likely to accrue for those who are treated.

I can’t really argue with that logic. It’s true, and it eliminates ethical problems with choosing prophylaxis over treatment. Like I said, the authors were faced with impossible choices and forced to make a decision. I just don’t like it.

And that’s it. That’s the whole 81 million courses of meds. Who could possibly be missing from the plan? Maybe, all of the health care workers, first responders and so-called critical infrastructure folks? Well, they do deal with those folks, if just in mentioning that they are a concern:

Fully implementing prophylactic antiviral drug strategies will require the establishment of stockpiles by employers in both public and private sectors.  This approach is consistent with the role employers play in protecting their workers and operations against other types of risk.

Basically, the private sector needs to pick up the slack for an estimated 103 million courses of antivirals. For healthcare workers, I can kind of see that. The workers most likely to be at, as OSHA puts it, very high risk are at hospitals, who have an easier time purchasing and rotating antiviral medications that can serve as a stockpile. The other folks, though, are a problem. Local and state police, fire fighters, EMS workers, gas workers, electric line crews, etc. by and large work for governments–governments that are right now slashing services and raising taxes just to make their budgets. How many can realistically purchase tens of thousands of courses of medications? Medications that could very well mean the continued functioning of our society? This is something that state and local governments simply don’t have the ability to do. This is, or should be, a federal government responsibility.

If a pandemic were to hit next week, the clinically diagnosed would be treated, the folks who work at GSK and Roche would get their meds, and the police and phone company repairmen (who are needed to make the social distancing recommendations that are depended upon heavily in this guidance document a reality) would be on their own and receive public stockpile meds only when they got sick. 

Now, I have to restate that I think this is a brilliant document, and truthfully, there are no good answers, let alone right answers. If what I wanted to be included in this plan was included, a whole host of other, probably more difficult problems would ensue. The real problem here is lack of stock. Future iterations of this document, and indeed the whole pandemic flu plan itself, should concentrate on further expanding the antiviral stockpile and coordinating with private business, most notably the health care delivery community and antiviral manufacturers to rotate stock into and out of the expanded stockpile, ensuring that there is a constant supply running from the manufacturers to the stockpile to the hospitals (absolutely during the meds active shelf-life) to the patients.

And, of course, none of this even speaks to my last post, on the burgeoning resistance issue.

Image credit: DHHS Pandemic Influenza Antiviral Guidance Document

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