[HTML][HTML] Pre-Exposure Rabies Prophylaxis. Problems and Procedures.

FBJ Peck, KC Kohlstaedt - 1964 - cabidigitallibrary.org
FBJ Peck, KC Kohlstaedt
1964cabidigitallibrary.org
Rabies prophylaxis in man has long been a special problem when it involves particular
groups of persons with unusual risks of repeated exposure, such as veterinarians, dog
handlers, field naturalists, laboratory workers and those employed in endemic areas, where
wild or domestic animal bites are an occupational hazard. In these groups repeated
exposure formerly meant repeated treatment with vaccine of nervous tissue origin, thus
increasing the possibilities of severe reactions to the vaccine, especially those involving the …
Abstract
Rabies prophylaxis in man has long been a special problem when it involves particular groups of persons with unusual risks of repeated exposure, such as veterinarians, dog handlers, field naturalists, laboratory workers and those employed in endemic areas, where wild or domestic animal bites are an occupational hazard. In these groups repeated exposure formerly meant repeated treatment with vaccine of nervous tissue origin, thus increasing the possibilities of severe reactions to the vaccine, especially those involving the central nervous system. Now, however, there have become available 2 types of avianized vaccine (the duck embryo and the HEP chicken embryo vaccine), which, being almost devoid of encephalitogenic properties, may safely be used for the prophylactic immunization of man.
For such prophylaxis the schedule of immunization has ordinarily consisted of 3 doses of avianized vaccine given at approximately weekly intervals, followed in several months by a 4th or booster dose. Thus ANDERSON et al. [this Bulletin, 1960, v. 57, 899] administered duck embryo vaccine intradermally (0.2 ml. per dose) to 49 volunteers; 3 inoculations were given at intervals of 5 days, followed by a booster inoculation about 4 months later. Results of this trial showed 85% to have responded with antibody to the 3 primary inoculations and 96% to the booster dose; moreover, the average antibody titre after the booster dose was approximately 4 times that seen after the initial series of inoculations. Unfortunately, however, the results of other trials in which similar intradermal dosage schedules were employed proved to be anything but consistent, the antibody response having varied from 30% to 98% of those tested.
In order to determine, therefore, whether administration of the vaccine by a different route would be followed by a more consistent antibody response, 4 groups, each of about 50 volunteers, were inoculated subcutaneously. In this trial every participant received for initial immunization 3 doses of vaccine, each of 1.0 ml., given at weekly intervals, and then a 4th or booster dose of 1.0 ml. 10 months later. The results obtained were quite consistent, the percentage of antibody response in the groups tested being 86, 94, 95 and 94, respectively. Because of the relative ease of subcutaneous injection, it is now the method of choice for pre-exposure immunization.
From the results of the present investigation, as well as of other studies, in which booster doses of vaccine have been administered, it has been shown that a prompt anamnestic response, with significant antibody rise, follows the inoculation of a booster dose. This holds true for recipients of post-exposure therapy as well as for recipients of pre-exposure prophylaxis.
The authors conclude by making certain recommendations. For the pre-exposure prophylaxis of persons at risk it is recommended that 3 or 4 subcutaneous doses, each of 1.0 ml. of avianized vaccine, be given at weekly intervals, followed in 6-10 months by a booster dose of vaccine. If a person continues to work under risk, he should be revaccinated with a similar booster dose at intervals of approximately 2 years and again upon exposure. If the primary series of injections fails to elicit a booster response, injections should be continued until a detectable antibody response is obtained. In case of mild exposure of a person who has demonstrated an antibody response to antirabies treatment received in the past, a single booster dose should be given; in cases of severe exposure a full post-exposure treatment is indicated. G. Stuart.
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