What is the difference between Rabies Immunoglobulin (RIG) and Rabies Vaccine?

From the Guidelines

Rabies immunoglobulin (RIG) and the rabies vaccine are two distinct components of rabies prevention, with RIG providing immediate passive immunity and the vaccine stimulating long-term active immunity. The primary difference between the two is their mechanism of action and duration of protection. RIG provides immediate protection by administering ready-made antibodies directly into and around the wound at 20 IU/kg body weight [ 1 ], whereas the rabies vaccine stimulates the body to produce its own antibodies, providing long-term active immunity [ 1 ].

Key Differences

• RIG is administered only once, while the rabies vaccine is given as a series of shots (typically 4 doses on days 0,3,7, and 14) in the deltoid muscle [ 1 ].
• RIG provides immediate protection, while the vaccine develops lasting immunity [ 1 ].
• The combination of HRIG and vaccine is recommended for both bite and nonbite exposures reported by persons who have never been previously vaccinated for rabies [ 1 ].

Administration Guidelines

• HRIG should be administered only once, at the beginning of antirabies prophylaxis, to previously unvaccinated persons [ 1 ].
• The recommended dose of HRIG is 20 IU/kg (0.133 mL/kg) body weight, which should be thoroughly infiltrated in the area around and into the wounds [ 1 ].
• The rabies vaccine should be given as a series of shots, with the first dose administered as soon as possible after exposure (day 0), and additional doses on days 3,7,14, and 28 after the first vaccination [ 1 ].

From the FDA Drug Label

The essential components of rabies post-exposure prophylaxis are wound treatment and, for previously unvaccinated persons, the administration of both human rabies immune globulin (RIG) and vaccine. RIG should not be administered in the same syringe or needle or in the same anatomical site as vaccine. RIGAdminister 20 IU/kg body weight If anatomically feasible, the full dose should be infiltrated around the wound(s) and any remaining volume should be administered IM at an anatomical site distant from vaccine administration. VaccineHDCV, RVA, or PCEC 1. 0 mL, IM (deltoid area† ), one each on days 0‡, 3,7,14, and 28.

The main difference between Rabies Immunoglobulin (RIG) and Rabies Vaccine is:

• RIG provides immediate, passive immunity by administering antibodies against the rabies virus, and is given as a one-time dose, typically around the wound and at a distant site intramuscularly.
• Rabies Vaccine, on the other hand, provides active immunity by stimulating the body to produce its own antibodies against the rabies virus, and is given as a series of doses over a period of time, typically on days 0,3,7,14, and 28. Key points to note:
• RIG is only given to previously unvaccinated persons.
• RIG and Rabies Vaccine should not be administered in the same syringe or at the same anatomical site.
• The combination of RIG and Rabies Vaccine is recommended for both bite and nonbite exposures reported by persons who have never been previously vaccinated for rabies 2, 3.

From the Research

Difference between Rabies Immunoglobulin (RIG) and Rabies Vaccine

• Rabies Immunoglobulin (RIG) provides immediate, short-term protection against rabies by introducing antibodies into the body, whereas the rabies vaccine stimulates the body to produce its own antibodies against the rabies virus 4, 5, 6.
• RIG is typically administered immediately after exposure to the rabies virus, along with the first dose of the rabies vaccine, to provide rapid protection 4, 5, 6.
• The rabies vaccine, on the other hand, is given in a series of doses over a period of time, usually 28 days, to stimulate long-term immunity against the virus 4, 7, 8.
• RIG is usually administered in a single dose, either intramuscularly or locally into the wound, depending on the severity of the exposure and the patient's condition 5, 6.
• The use of RIG is particularly important in category III exposures, where the risk of rabies transmission is highest, such as in severe bites or licks on mucous membranes 4, 5.

Administration and Dosage

• The dosage of RIG is typically calculated based on body weight, although some studies suggest that local infiltration of RIG into the wound may be an effective and cost-efficient alternative 5.
• The rabies vaccine is usually administered in a standard dose, regardless of body weight, and is given in a series of injections over a period of time 4, 7, 8.

Efficacy and Protection

• Studies have shown that the combination of RIG and rabies vaccine provides the best protection against rabies, especially in severe exposures 4, 5, 6, 8.
• The use of rabies vaccine alone may not provide adequate protection against rabies, especially if administered too late after exposure or without the concurrent use of RIG 8.