5.5.5. What do we need to know about regimens, doses and schedules?

 What is the difference between intradermal and intramuscular vaccination?
Intramuscular vaccination is given deep into the deltoid (upper arm) muscle in adults and into the anterolateral area of the thigh in infants.

Rabies vaccination sites diagram. Image: WHO

Intradermal vaccination is given into the upper skin area over the deltoid muscle in adults or lateral thigh area of infants. A small bleb with an ‘orange peel’ appearance is confirmation that the vaccine was administered correctly.
One intradermal dose is 0.1 ml of vaccine and one intramuscular dose is an entire vial of vaccine, irrespective of the vial size.

The intradermal regimen requires considerably less vaccine than the intramuscular regimen. Therefore intradermal vaccination should be used when resources are limited and the number of patients requiring PEP every day at a health care facility is at least two or more. However, intradermal vaccination is not licensed in every country and healthcare providers also need special training on the ID administration of vaccine.

Intradermal administration of rabies vaccine in the Philippines. Photo: GARC

 What are the potential cost savings of intradermal compared to intramuscular vaccination?
Intradermal (ID) PEP regimens have cost- and dose-sparing effects, even in clinics with low patient throughput.
For cost-benefit comparisons of different PEP regimens under different clinic conditions, see these papers.

Photo courtesy of Saneekan Rosamontri

 Is there a single dose of rabies vaccine that is available?
No.

 How many doses of vaccine will I need to get for PrEP?
PrEP can be delivered either
— intradermally, with 2 doses of vaccine on each of days 0 and 7,
— OR intramuscularly, with one dose of vaccine on days 0 and 7

 How many doses of vaccine will I need to get for PEP?
PEP can be administered in one of two ways, either intramuscularly or intradermally.
— The WHO-recommended option is the intradermal regimen that involves two doses of vaccine administered on each of days 0, 3 and 7. This is the most cost-, dose- and time-sparing option.
Two intramuscular PEP regimens are also still considered valid options by WHO. These are
— One doses of vaccine administered on days 0, 3, 7 and a fourth dose between days 14 to 28;
— OR Two doses of vaccine administered on day 0, followed by 1 dose on days 7 and 21.

 I just had PEP recently, do I have to have it again? If you received a full course of PEP within the last three months, only local wound treatment is required; neither vaccine nor RIG is needed.

 Is it okay to switch between intramuscular and intradermal administration of CCV for PEP?
This is not recommended by the WHO.

 I am immunocompromised, should PrEP or PEP be different for me?
Individuals with documented immunodeficiency should be evaluated on a case-by-case basis. For PrEP they should receive the regimen as above, with an additional third vaccine dose between days 21 to 28. In the event of an exposure, a complete PEP course, including RIG, is recommended.

 I have had a delay in my PrEP/PEP schedule, what is the flexibility of the schedules?
The regimen should be followed as closely as possible. However, a one or two day deviation from the PEP/PrEP regimen is acceptable. In case of longer delays, you should contact a physician so that he/she can evaluate the situation.

 How often do I need to get a booster after I have had my PrEP?
Persons at continuous or frequent risk of exposure (workers in rabies vaccine production facilities, veterinarians living in highly endemic areas etc.) should have their titer (i.e. the quantity of antibody present in their blood) checked periodically: every 6 months for persons working with live rabies virus and every year for other professions at permanent risk of exposure to rabies. If their level falls below 0,5 IU /mL, they should receive one routine booster. Specific laboratory analyses are required to measure the level of antibody in serum samples of vaccinated individuals. These tests are costly and are currently only performed in international reference laboratories. According to WHO, other persons do not need a routine booster. However, the labels of licensed rabies vaccines do recommend periodic booster shots.

 Do I need to have a blood test to check my antibody level before I receive my booster vaccination after exposure? No.

 I have received part of the PEP regimen and the dog that bit me is still healthy, should I continue with the vaccination regimen and complete the entire PEP course?
There is no need to continue PEP if the dog is still healthy ten days after the exposure occurred.

 The doctor administered the vaccine into my buttocks, what do I do now?
The vaccine should be re-administered correctly, in the deltoid area, as soon as possible.

 What do I do if I have missed a dose of vaccine on the prescribed date?
The regimen should be followed as closely as possible. However, a one or two day deviation from the PEP/PrEP regimen is acceptable. In case of longer delays, you should contact a physician so that he/she can evaluate the situation.