A 17% increase in calls this summer to the CDC regarding potential human rabies exposures, marked by news of attacks by river otters (Lake Tahoe, Anchorage Alaska), beavers (New Jersey, Maryland) and bats (multiple national parks), seems to have been anticipated by a Clinician Outreach webinar from the CDC in April, and has prompted a recent Health Advisory.1,2
The CDC Clinician Outreach and Communication Activity (COCA) webinar in April indicated that some 4,000 animals are confirmed to have rabies each year in the US. The presenters considered a range of topics, including the difficulty in determining when post-exposure prophylaxis (PEP) is necessary, and the risk assessment that can be applied.
A Health Advisory issued by the CDC through the Health Alert Network (HAN) on September 10 details the increase in reported exposures, the utilization of the two rabies vaccines and two rabies immunoglobulin products licensed in the US, and relates guidance from the Advisory Committee on Immunization Practices (ACIP) on post-exposure prophylaxis.
In addition to the 17% increase in reports to the CDC in the period between July through August, the advisory reports a 33% and 76% increased use of rabies vaccines and human rabies immunglobulins (HRIG), respectively. It notes that a typical PEP course can cost between $11-14,000 per person and cautions that "following rabies PEP administration guidance helps ensure that lifesaving vaccines are available for persons who need it and extraneous costs are avoided."
The advisory notes that PEP is generally not recommended when the animal is available for a 10-day post exposure observation, rabies tests results are negative, or health officials determine the exposure does not pose a rabies risk.
The advisory emphasizes that correct PEP administration depends on previous rabies vaccination status: If not previously vaccinated, PEP should include HRIG and vaccine; but HRIG should not be given if the patient has previously received rabies vaccine.Although HRIG should be administered once when PEP is initiated, vaccination should not be delayed if HRIG is initially unavailable as it can be administered through the day of the 3rd vaccination dose (day 7).
Common Errors in Administering PEP
Here is some clinical guidance for providers when administering PEP:
- Administering rabies vaccine in the gluteal area.
- Failing to infiltrate HRIG into and around all identifiable wounds to the extent anatomically feasible.
- Administering HRIG and vaccine in the same syringe or anatomical site. (Mixing HRIG and the vaccine in same syringe could neutralize each other, potentially making both ineffective.)
- Forgetting to give HRIG to someone who needs it.
- Administering HRIG to a person who was previously vaccinated against rabies.
- Misclassifying previous vaccination history or immune status, resulting in omitted or unnecessary biologics doses.
- Using an incorrect rabies vaccine schedule.
- Unnecessarily restarting the rabies vaccine series after a schedule deviation.
In addition to guidance for the health professional and public health departments, the advisory offers several recommendations to the public, including the warning to keep distance from wildlife.
"Never approach animals who appear to be injured, sick, or dead, especially if you see animals during the day who are usually active at night (eg, bats, raccoons, etc). Contact your area’s animal control service for assistance when needed."
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