We thank Dr Malerczyk and colleagues
for their useful catalog of the reported cases of imported rabies in the developed world. However, we have concerns about elements of the paper:
The authors indicate that the risk of acquiring rabies is “…small relative to the number of people traveling…” and mention that there were 45 million international travelers to Africa in 2009, with 14 rabies cases in their 21‐year series being ascribed to exposure in this area; however, they do not express their data as a rate. To us, while crude, over the 21‐year period in question, if there were 25 million travelers to Africa per year in 1990–1999 and 45 million/year in 2000–2010, the rate of rabies would be 1.9/100 million; even if there is a 10‐fold underreporting of cases, the rate remains tiny at 1.9/10 million.
The authors conclude that “…Pre‐exposure prophylaxis should (emphasis added) be administered to all (emphasis added) travelers to areas with a high risk for rabies and where vaccine, immunoglobulin or even access to medical care in general is not available or may be delayed…”. This advice is not as stated by the usually consulted (and cited by these authors) travel health sources, eg, WHO
recommends pre‐exposure prophylaxis for “…(t)ravelers with extensive outdoor exposure in rural high‐risk areas where immediate access to appropriate medical care may be limited…”, whereas ACIP
indicates “…some international travelers might (emphasis added) be candidates for pre‐exposure vaccination if they are likely to come in contact with animals in areas where dogs or other animal rabies is enzootic and immediate access to appropriate medical care…might be limited…”
The authors do not consider cost, whether expressed absolutely or relatively. Crudely, there were about 1.23 million Canadians traveling to Africa, Asia, or Central America (the countries of rabies exposure in the paper) in 2009.
Assuming this as a relatively stable “at risk” population and limiting consideration to vaccine cost, which is about $172 (Canadian) per intramuscular dose (or $516 per three dose pre‐exposure series) of RabAvert, “universal” pre‐exposure vaccination would cost a staggering $634,680,000/year. Even for a significantly smaller “at risk” cohort, such an approach would seem cost prohibitive, in particular when set against the absence of reports of Canadian deaths over the period in question.
A substantial problem is to know if modern rabies biologics are available in a particular country/locality. Without such information, it is likely that pre‐exposure vaccination will be offered more often than is necessary. We understand that the US CDC
is in the process of developing a database related to the availability of modern rabies biologics, country by country; this will be a major step forward in refining the use of pre‐exposure rabies vaccination among travelers.
The above is not intended to impugn the use of pre‐exposure rabies vaccination among travelers. Our organization offers/uses such vaccination regularly for suitable deployments or leisure travel. However, given the classic “low risk, high consequence” nature of travel‐associated rabies, the approach suggested by Malerczyk and colleagues is problematic. In our opinion, more appropriate is a nuanced process that, for example, takes into consideration individual‐specific risk factors and patient values and preferences.
Statistics Canada. Table 26: Person‐trips, person‐nights and expenditures of Canadian residents returning from countries other than the United States after a stay of one or more nights, by selected trip characteristics, 2009. Available at: http://www.statcan.gc.ca/pub/66-201-x/2009000/t033-eng.htm. (Accessed 2011 Dec 12)