Andrew Rouse and Tom Marshall: Informed consent, the doctor and H1N1 immunisation

How does a doctor obtain informed consent for H1N1 immunisation consistent with General Medical Council guidance? The Department of Health’s guidance does not provide sufficient information for this.  This is our attempt to rectify this omission, providing information required for informed consent consistent with good professional practice. We outline the main principles of General Medical Council on the responsibilities of doctors in seeking informed consent into practical guidance. 

Principle: The doctor must explain the potential treatment options, including no treatment.
The options are to be immunised or not.

Principle: For each option, the doctor must explain the benefits and the risks of treatment
H1N1 immunisation reduces the probability of developing symptomatic H1N1 influenza, of being hospitalised for influenza and of dying from influenza. The illness is of short duration (half of patients recover within a week) and similar to seasonal influenza.

Department of Health’s planning assumptions are that up to 50% of children aged under 16 years will become infected, up to 30% of working-aged adults and fewer than 15% of adults aged over 65 years. Of those infected, up to 1% will require hospitalisation and up to 0.1% may die. We don’t know the efficacy of H1N1 immunisation but is probably similar to seasonal flu vaccine, preventing approximately two thirds of illness, flu related hospital admissions and death.

We suggest that doctors use a graphical decision aid like the one shown. This is supported by evidence. [1]  This makes clear that even in the worst case scenario, without immunisation most people will remain well and that hospitalisation and death are rare. (Figure 1) Although immunisation increases the chances of remaining free from H1N1, one in ten of those immunised become symptomatic.

figure 1




Figure 1: The effect of immunisation of 10,000 adults on their probability of not developing symptomatic influenza, being hospitalised or dying from H1N1 influenza.

figure 2




Figure 2: The effect of immunisation of 10,000 adults on their probability of not developing symptomatic influenza, being hospitalised or dying from H1N1 influenza. Vertical axis has been altered for hospitalisation and death.* Scale altered to show effects on hospital admission and death
Figure 2 illustrates the effects of immunisation on the chances of hospital admission or death. Because the benefit is very small we must magnify the vertical axis 100 times (hospital admission) and 1000 times (death).

Principle: The doctor must describe anticipated adverse effects of treatment
A doctor can advise that it is as safe as the seasonal influenza vaccine in routine use in the UK. Since one quarter of the population is immunised each year, it appears that neither public nor profession have any great concerns about adverse effects.

Principle: The doctor must make clear any potential conflicts of interest they or their organisation may have when offering advice.

General practitioners payments for immunisation are small and are unlikely to be a serious conflict of interest. However doctors must maintain a good relationship with their employer and the Department of Health sees “high uptake of vaccines amongst healthcare workers is critical.”   A suitably worded poster on the surgery wall should make clear the potential conflict between the employer’s objectives and the doctor’s professional duty towards their patient.

Principle: The doctor must ensure that decisions are voluntary, since “patients may be put under pressure by employers, insurers, relatives or others, to accept a particular investigation or treatment.”

A doctor must always ensure that a patient is not under pressure to be treated, especially where employers such as the Department of Health or the military have made it clear that they expect staff to be immunised. [2]

How reliable are the data?

How should a doctor answer this question? The origins of Department of Health data are not as transparent as published research. The information is as trustworthy as any recent UK government information. Evidence for the effectiveness of influenza vaccines is not very strong. There is no strong evidence from randomised controlled trials and observational have major weaknesses. A sceptical view is that, “Evidence from systematic reviews shows that inactivated vaccines have little or no effect on the effects measured”. [3]

Herd immunity

H1N1 vaccine coverage will not reach levels at which herd immunity could possibly arise. The health benefit of H1N1 immunisation is only realised by the immunised person.


Pregnant women have the same chances of contracting H1N1 infection as others of their age. The Department of Health has analysed data from overseas and concluded that they are four times more likely to have complications (or die). [4] However we don’t recommend routine seasonal flu immunisation for pregnant women.


Some patients may request H1N1 immunisation for reasons of altruism towards their employer or family. So long as the decision is voluntary and the patient consents, the doctor should immunise.

So what would you do, Doc?

Significant numbers of UK general practitioners are as sceptical about benefits of immunisation as they are about other investigations and treatments.  [5] GPs should be free to give their own opinion on whether they would accept immunisation, or not. 

[1] O’Connor AM., Bennett CL, Stacey D, Barry M, Col NF, Eden KB, Entwistle VA, Fiset V, Holmes-Rovner M, Khangura S, Llewellyn-Thomas H, Rovner D. Decision aids for people facing health treatment or screening decisions. Cochrane Database of Systematic Reviews 2006, Issue 3. Art. No.: CD001431. DOI: 10.1002/14651858.CD001431.pub2

[2] Beasley C., Middleton K. A (H1N1) Swine influenza: vaccination delivery [Department of Health letter to NHS Directors of Nursing] 16th Sept 2009

[3] Jefferson T. Influenza vaccination: policy versus evidence British Medical Journal 2006; 333:912-915, doi:10.1136/bmj.38995.531701.80

[4] Jamieson DJ, Honein MA Rasmussen SA, Williams JL Swerdlow DL, Biggerstaff MS, Lindstrom S, Louie JK, Christ CM, Bohm SR, Fonseca VP, Ritger KA, Kuhles DJ, Eggers P, Bruce H, Davidson HA, Lutterloh W, Harris ML, Burke C, Cocoros N, Finelli L, MacFarlane KF, Shu B, Olsen SJ, the Novel Influenza A (H1N1) Pregnancy Working Group. H1N1 2009 influenza virus infection during pregnancy in the USA The Lancet 2009; 374: 451-458.

[5] Anekwe L. One in two GPs ‘will refuse swine flu vaccine’ Pulse 24th August 2009