Tag Archives: influenza

No advice to patients about the risks of multi-dose vaccine vials

Influenza virus vaccine, Fluzone®. Photo: United States Centres for Disease Control and Prevention

The Australian Government has commenced its H1N1 influenza vaccination program and the Department of Health and Ageing (DoHA) has published the consent form that patients are being asked to sign. You can look at a copy of the consent form here.

Vaccine delivery and consent

The Panvax® influenza vaccine (manufactured by CSL Ltd) is being supplied in multi-dose vials, the use of which is known to be associated with the risk of contamination of the vaccine and the risk of cross-infection of vaccinated patients. In August, the Australasian Society for Infectious Diseases raised their concerns about the use of multi-dose vials with the Commonwealth Chief Medical Officer, Dr Jim Bishop, and urged the Government to abandon its vaccination plan until single-dose vials became available. Nonetheless, despite those concerns, DoHA has pressed ahead with its vaccination plan.

In a couple of earlier postings I asked how the public would be informed about the risks associated with multi-dose vials so that each patient would be able to make an informed choice about whether to get vaccinated now or to wait until single-dose pre-filled syringes are available. If you look at the consent form you will see that that issue has now been settled. Patients will not be told anything!

The Bolam Principle

After seeing the consent form for the first time yesterday, I wrote to DoHA earlier today. I asked (1) why is there no mention on the consent form of the risks of using multi-dose vials? and (2) why DoHA has not heeded the very specific admonishments of the High Court in its 1992 judgement in the medical negligence case of Rogers v Whitaker? [1]

The reply that I received did not address either of those questions. In fact, it didn’t even try to answer them. Instead (and revealingly) the response simply quoted an unrelated and irrelevant earlier media release: “The vaccine will be distributed in multi-dose vials. This is consistent with countries around the world also delivering mass vaccination programs. Guidelines for the safe use of the vials have been developed by Australia’s specialist immunisation reference group, the Australian Technical Advisory Group on Immunisation in consultation with the Royal Australian College of General Practitioners and the Australian Nursing Federation.”

In other words, “doctor knows best”. Patients do not need to be told about the risks because DoHA is delivering the vaccine in a form that is consistent with medical opinion about the best method of delivery. On the humorous side, the reference to the “specialist immunisation reference group” reminded me of the famous line at the end of the film, Raiders of the Lost Ark, when Harrison Ford asks what has been done with the Ark. He is told, “I assure you, top men are working on it right now.” Harrison Ford then asks naively, “Who?” The answer: “Top men”.

More seriously, I remarked (above) that the response from DoHA was revealing. How so? Readers who are familiar with the law of medical negligence will recognize that the approach taken by DoHA is entirely consistent with a legal doctrine known as the “Bolam Principle”. To quote from the judgement in Rogers v Whitaker, “The Bolam principle may be formulated as a rule that a doctor is not negligent if he acts in accordance with a practice accepted at the time as proper by a responsible body of medical opinion even though other doctors adopt a different practice.” The problem with that approach for doctors, nurses and for DoHA is that the High Court refused to accept the Bolam principle as the basis on which to determine medical negligence cases! Instead, the High Court decided that the law, “should recognize that a doctor has a duty to warn a patient of a material risk inherent in the proposed treatment” and added that “a risk is material if, in the circumstances of the particular case, a reasonable person in the patient’s position, if warned of the risk, would be likely to attach significance to it …”

In other words, with regard to vaccinations, the issue is not about how likely it is that a risk of contamination or cross-infection will materialize; it is not about how dangerous such contamination is likely to be; it is not about whether the doctor is doing everything as well as they know how; it is not about whether having a vaccination is more likely to protect you from a serious H1N1 infection than it is to create a problem of its own. It is simply about patient autonomy—the right of each competent individual to decide for themselves whether or not to be vaccinated.

How do the risks with multi-dose vials arise?

A multi-dose vial is a bottle that has enough vaccine in it for about 12 people. The bottle is sealed with a permeable cap. The doctor or nurse attaches a needle to the end of a syringe, sticks the needle through the cap, and draws up enough of the vaccine for a single dose. The patient then gets injected with the vaccine. What could possibly go wrong?

Scenario 1: The person doing the vaccinations could accidentally reuse the syringe and needle for more than one patient. If the first patient to receive the vaccine has a disease that is transmissible by needle stick, then the second person to be vaccinated with the same needle might become infected with that disease. Sure, the guidelines say that a new needle and new syringe must be used; but, the nature of accidents is that they are accidental. If they were not, we would assume that some sort of deliberate malfeance was involved! The nature of a mistake is that something that should have been done is not done, or that something that should not have been done is done without the person doing it having done so deliberately. By refusing to acknowledge the risk of a mistake, the DoHA consent form tacitly implies that in the history of vaccination, no needle or syringe has ever been accidentally reused when the guidelines say that needles and syringes should not be reused. Furthermore, they suggest that such an accident could not ever happen.

If the form had spelled out those tacit implications would you believe them? Do you believe in Santa Claus? Interestingly, in contrast to the implications of the DoHA consent form, the United States Centers for Disease Control specifically acknowledges that things can happen contrary to safety guidelines.

Scenario 2: Person A has an infection and has a vaccination with a new syringe and new needle. The person giving the vaccinations accidently begins to reuse the equipment but realises their mistake, but only after they have put the used needle back through the cap of the bottle of vaccine and transferred infective material from the used needle to the vaccine. The remaining vaccine in the multi-dose vial might then infect up to 11 more people even if new needles and syringes are used for each of them.

Scenario 3: The vaccine becomes contaminated after the vial is opened and that the contamination occurs independently of any particular person being vaccinated.

As I remarked in an earlier post, none of the risks with the mutli-dose vials will necessarily lead a person to refuse the vaccine but that is a decision for the patient and not for the doctor.

How could DoHA go so wrong?

My guess—but that is all it is—is that DoHA sought medical advice about how to phrase the consent form but did not seek legal advice from someone familiar with the law of medical negligence. Traditions take a long time to change and the idea that the medical profession knows what is best is well entrenched. If you think that you know what is best for your patients and you are convinced that the risk associated with the use of multi-dose vials is small, then in your presumptive though unintended arrogance you might just neglect to mention those risks! For a discussion of similar problems that arise in psychological practice, you might like to have a look at a paper [2] that Angela O’Brien-Malone and I wrote for Australian Psychologist.

References

[1] Rogers v. Whitaker, F.C. 92/04 (High Court of Australia 1992).

[2] O’Brien-Malone, A., & Diamond, M. R. (2006). Tell your patients you might hurt them. Australian Psychologist, 41(3), 160-167(8). DOI: 10.1080/00050060600776366

Contributors: Mark R. Diamond, Angela O’Brien-Malone

Swine Flu vaccination and consent — you read it here first

Image: Mark Diamond

The Age newspaper this morning is carrying a story [1] on the new Panvax ® H1N1 influenza vaccine manufactured by CSL Ltd. About two thirds of the way through the article, there is a paragraph reading

“Concerns include the development of a consent form that each recipient must sign. There is not yet enough data from trials of the drug to inform patients of the risks involved.”

It’s five days since I first wrote about the difficulties of patient consent in relation to the new vaccine so it’s pleasing to see that the issue will now get a wider airing.

There are some interesting difficulties implied in the quoted comment. The suggestion is that the information in which patients would be interested would be information that relates to the trials alone. I’m not convinced that that would be true for three reasons. Briefly, they are (i) the frequency of rare events is difficult to estimate from small samples such as the samples used in the trials, (ii) the risks of cross-contamination are largely related to human factors, and we know that human performance is frequently better when it is being watched (as in the trials) than when it is not, (iii) the population who made up the trial sample is different from the population that is likely to be first-vaccinated, and (iv) some of the adverse consequences might take a long time to show up.

Estimating the frequency of rare events

For the sake of argument, assume that the probability of a vial of vaccine being contaminated is 1 per 100,000 doses administered. If there are only 400 people in the trials then the chance that there will be an actual contamination is relatively small, and the chance of the contamination being detected is even smaller. Once a vial is contaminated and the contamination is not detected, then given a 10 dose vial and assuming a 100 percent infection rate from contaminated needles, one can expect 4–5 people to become infected. So cross-contamination might be rare, but given an occurrence the infections then cluster.

Patient differences

The people that the government is proposing to vaccinate are an unusual subset of the whole population. They include, at a higher rate than average, the people whose health or resistance has in some way already been compromised and so, I think, are more likely than the average person to have an infection of some sort. As a consequence, by estimating by the probability of cross-infection from the trial data, one is likely to under-estimate the actual risk in the mass vaccination program.

Human performance

If you are a health practitioner and you know that you are part of a study on the risks of using multi-dose vials, then you are likely to perform better than if you were just giving vaccinations without being studied. The likely change in your behaviour, which is known as the Hawthorne effect, will result in the risk of cross-infection being underestimated.

Delayed consequences

If the cross-infection that you get is Creutzfeldt–Jakob disease (CJD), then your infection is unlikely to show up for a long time and will also result in the risks being underestimated. Nonetheless, harking back to the Rogers v. Whitaker decision that I referred to in the earlier posting, I expect that patients would consider the CJD risk to be “material” even if it is very very very very small.

[1] Miller, N. (2009). Doctors urge delay on vaccine. The Age. 29 August 2009. http://www.theage.com.au/national/doctors-urge-delay-on-vaccine-20090828-f2k6.html

Contributors: Mark R. Diamond

Swine Flu vaccine and patient consent

Influenza virus vaccine, Fluzone®. Photo: United States Centres for Disease Control and Prevention

The Australian Health Minister Nicola Roxon announced on Thursday, 20 August 2009 that, before the end of the month, the Australian government will take delivery of two million doses of the new CSL vaccine (Panvax ®) against the novel H1N1 (“Swine Flu”) virus, and that the vaccine would be supplied by CSL in multi-dose vials. The Australasian Society for Infectious Diseases reacted to the announcement by writing to the Commonwealth Chief Medical Officer, Professor Jim Bishop, urging him to delay distribution of the vaccine until it could be supplied in single dose vials. Multi-dose vials, they said, pose too great a risk of infection (as a result of contamination) to the people being vaccinated. Professor Bishop, responded by saying that the government’s pandemic plan had always included the use of multi-dose vials because they were more efficient and could be distributed more quickly.

I’ll probably return in a later posting to the matter of how one might rationally assess the risks of the proposed vaccinations. Here, I want only to highlight an interesting side issue related to patient consent to medical procedures.

In 1992, in judgement in the case of Rogers v Whitaker [1992] HCA 58; (1992) 175 CLR 479 (19 November 1992) the High Court of Australia made it clear that medical professionals have a responsibility to explain the material risks of proposed medical procedures to their patients. In particular, they said that, “a risk is material if, in the circumstances of the particular case, a reasonable person in the patient’s position, if warned of the risk, would be likely to attach significance to it or if the medical practitioner is or should reasonably be aware that the particular patient, if warned of the risk, would be likely to attach significance to it. ” It might be a cumbersome way of saying things, but it strongly suggests that if you are a doctor or a nurse about to give me a vaccination then it is incumbent upon you to explain to me, in a way that I can understand, what the material risks are of having the vaccination. It is not up to me to know all about the possible risks; nor is it up to me to formulate questions about things that I did not know I needed to know. That is the responsibility of the health professional.

It’s worth noting that, in the view of the High Court, probability per se is not of much relevance! The fact that a possible adverse consequence of treatment has only a small probability of occurring is not important in determining whether I should be told about the possibility of that consequence. Indeed, in the original trial of Whitaker v. Rogers, evidence was presented on behalf of Dr Rogers to show that the consequence that Whitaker suffered (sympathetic ophthalmia) occurred on average only once in 14,000 procedures (0.007 percent).

So, to return to the present matter of the multi-dose vials. I expect that most people being vaccinated would attach significance to the fact that multi-dose vials are more likely to lead to fatal infection by a contaminant than are single dose vials. I also think people would attach significance to each of the following: (i) that the usual Australian practice has been to use single dose vials, (ii) that any vaccinations that a person has previously had in Australia would most likely have been from single-dose vials, and (iii) that the use of multi-dose vials was part of a pandemic plan that was developed for dealing with infection by virulent avian influenza — an infection that has a 50 percent case-fatality rate as opposed to the current H1N1 virus that has a case-fatality rate of less that 0.4 percent.

I am not suggesting that every (or even any) person informed of the facts in the preceding paragraph would necessarily decide against being vaccinated. But then the High Court made it pretty clear that what I think, or what a nurse thinks, or what a doctor thinks is of no consequence when it is you who is being vaccinated. Your right is to be given the information and to make your decision in the way that you think best.

So, one can imagine the conversations that should ensue. But will they? Will Professor Bishop direct his staff to remind health-practitioners that they should warn patients about the increased risks associated with multi-dose vials?

Contributors: Mark R. Diamond