To the Editor: Human normal immunoglobulin (NIG) has historically been used to provide passive immunity against hepatitis A infection for susceptible travellers to areas where the virus is endemic.1 The introduction of effective hepatitis A vaccines in recent years (which result in active, long-term immunity to the virus) should have largely replaced the use of NIG for travel prophylaxis.2 However, the Australian Red Cross Blood Service still receives requests to supply NIG for travellers, even though the intended recipients have no contraindications to vaccination.

Requests for use of NIG for this purpose appear in many cases to be a consequence of the “out-of-pocket” cost to the patient of the hepatitis A vaccine, which is about $70–$100 (depending on the formulation used and the private dispensing fee charged). In contrast, NIG is provided free of charge to the recipient, but the community still incurs substantial costs related to blood collection and fractionation of plasma products. There is also the concern of unnecessary exposure of a healthy traveller to a pooled plasma product, which, despite blood donor screening, dedicated viral inactivation steps, and an excellent safety record in Australia, may theoretically transmit infectious agents. In addition, even if a small amount of NIG is used for this purpose, the plasma source would be better used for production of greater amounts of other scarce plasma-derived products (such as intravenous immunoglobulin).

While NIG can effectively prevent hepatitis A infection from developing in susceptible contacts, immunity is short-lived and likely to be inferior to the results of active vaccination.1-3 Accordingly, NIG is only indicated for at-risk people who have a contraindication to vaccination, or in whom there is insufficient time to mount an endogenous antibody response (active immunity develops within 7–10 days of vaccination,3 and vaccination may also prevent hepatitis A infection even when the vaccine has been administered up to a week after exposure4). Use of NIG is also appropriate where at-risk contacts may be unable to mount a protective antibody response because they have a congenital or acquired immune deficiency.

Although the extent of NIG use for travellers appears to be limited, we wish to highlight that, in the absence of contraindications to vaccination, it can no longer be advocated as best practice, and it is certainly not an appropriate cost-saving measure.