Concerns About Rabies Vaccination After Cat Scratch Abroad - Family Medicine

Dr. Xiao Yongxun reply Family Medicine

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Dear Ms.
VV:
1.
Currently, there are two known rabies vaccines:
a.
Verorab® (Sanofi Pasteur), which is cultured in African green monkey kidney cells.

b.
Rabipur® (Novartis), which is a purified chick embryo cell vaccine.

2.
Clinically, it is preferable to use the same vaccine component and brand throughout the entire rabies vaccination schedule; although both vaccines are equally effective based on evidence.
If Rabipur® is unavailable and Verorab® is used instead, there is currently no absolute medical objection to this; the reverse is also true.
3.
In our country, the standard rabies vaccination schedule after a bite has long been five doses (Day 0, Day 3, Day 7, Day 14, Day 28); however, the Centers for Disease Control recently announced a revised schedule of four doses (Day 0, Day 3, Day 7, Day 14).
Nevertheless, for patients with concerns about immunocompromised status or other considerations, the five-dose regimen may still be administered.
4.
The antibody preparations for rabies include human rabies immune globulin (HRIG) and equine rabies immune globulin (ERIG).
The dosage for HRIG for all ages is 20 IU/kg, while the recommended dosage for ERIG is 40 IU/kg.
The World Health Organization does not recommend performing skin sensitivity tests prior to vaccination, as such tests cannot reliably predict the likelihood of allergic reactions.
In our country, HRIG is used, and from an immunological perspective, ERIG may be more likely to cause serum sickness and other allergic reactions than HRIG; however, I do not have specific literature to confirm this assumption.
Therefore, I believe it is advisable to consult local physicians abroad.
Regarding the timing of serological reactions, most occur within 1 to 2 hours, although delayed reactions are also possible.
In my experience with treating snake venom serum in the emergency room, we generally observe patients for several hours.
Due to limited experience with rabies immune globulin injections, it may be necessary for you to consult local physicians regarding the timing of allergic reactions.
5.
Precautions for administering immune globulin and vaccines:
(1) After injection, patients must be monitored for allergic reactions.

(2) If more than 7 days have passed since the first dose of rabies vaccine, there is no need to administer immune globulin.

(3) Immune globulin preparations and rabies vaccines should not be injected at the same site.

(4) Mixing immune globulin preparations with rabies vaccines in the same syringe is prohibited to prevent antigen-antibody neutralization reactions, which could affect immunogenicity.

(5) In cases of severe wounds or multiple injuries (especially in young children), if the standard dosage is insufficient to infiltrate the surrounding area of the injection site, the passive immune preparation may be appropriately diluted 2-3 times with saline before infiltration injection.

(6) If the wound has been sutured at the time of consultation, it is generally not recommended to remove the sutures; instead, HRIG can be infiltrated around the wound.
6.
Additionally, attention should be paid to the risk of wound infection, such as cellulitis or tetanus infections, which should also be addressed locally.
7.
If you have further questions, please consult your attending physician.
(The above information is referenced from the teaching materials of Professor Li Bing-ying from National Taiwan University.)

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Reply Date: 2019/10/14