“Can't you use another vaccine”? Postrabies vaccination encephalitis
I read with interest the letter of Chau et al related to iatrogenic disseminated encephalomyelitis, in a man bitten “by his own apparantly normal dog”.1Whereas I appreciate the novelty of documenting such entities with brain MRI, I wish to question the reasoning behind the practice of antirabies vaccination in similar doubtful circumstances. I have commented on that issue in another occasion.2 I have also documented instances of excessive enthusiasm, often encountered in situations such as those under discussion, in a research project conducted at the Pasteur Institute in Tehran, Iran.3 There is no justification for vaccinating a person simply because of fear when the remedy itself is to be feared even more, as documented by Chuaet al.
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The authors reply:
We thank Derakhshan for his comments on our case report of iatrogenic disseminated encephalomyelitis after use of the suckling mouse brain postrabies exposure vaccination. We were not responsible for the postexposure vaccination, which was administered in a provincial hospital in central VietNam. However, in the circumstances (and in the absence of the human diploid cell tissue culture vaccine) we think that it was appropriate to use the vaccine in this case. The dog had previously been well behaved and it was highly uncharacteristic for it to bite its owner. After the event the dog disappeared into the forest and was not seen again. Hence, it was not possible to retrieve the brain for analysis, as is usual in most cases.
The mortality from rabies is essentially 100%, a figure that can be reduced dramatically by the expeditious use of the suckling mouse brain vaccine after exposure. We agree with Derakhshan's comments on excessive enthusisasm for any medication, and obviously the relative risks and potential benefits must always be balanced. In a disease with a 100% mortality, where a potentially effective treatment is associated with a severe side effect in only 1:27 000 cases it would seem reasonable to use the treatment. At this centre we vaccinate 2000 people every year after a dog bite, we see about 50 people a year die of rabies. We would therefore anticipate seeing a case of iatrogenic disseminated encephalomyelitis after use of the suckling mouse brain postrabies exposure vaccination once every 13.5 years. In the same period we would see 675 people dying from the disease.
