What is the post-exposure prophylaxis (PEP) treatment for rabies bat exposure?

Rabies Post-Exposure Prophylaxis for Bat Exposure

Initiate rabies post-exposure prophylaxis (PEP) immediately for all persons with any bite, scratch, or mucous membrane exposure to a bat, unless the bat is available for testing and tests negative for rabies. 1, 2, 3

Essential Components of PEP

For previously unvaccinated persons, rabies PEP consists of two critical components that must both be administered 3, 4:

• Rabies immune globulin (RIG): Administer as promptly as possible after exposure, along with the first vaccine dose. If not given on day 0, RIG can still be administered up to and including day 7 of the vaccine series. 3

• Rabies vaccine series: Administer intramuscularly in the deltoid muscle (or anterolateral thigh in infants/small children) on days 0,3,7, and 14 for previously unvaccinated persons. 4

• Previously vaccinated persons (those with documented prior complete pre-exposure or post-exposure vaccination with cell culture vaccine) should receive vaccine only—no RIG. 3, 4

Immediate Wound Management

Before administering biologics, perform thorough local wound care 4:

• Wash and flush all bite wounds and scratches immediately for approximately 15 minutes with soap or cleansing agent and copious amounts of water. 4

• Apply an iodine-containing or similarly viricidal topical preparation to the wound where available. 4

• Provide tetanus prophylaxis and bacterial infection control measures as indicated. 4

When to Consider PEP Even Without Obvious Bite

PEP should be considered even when a bite, scratch, or mucous membrane exposure is not apparent if there is reasonable probability that such exposure might have occurred. 1, 2 This unique recommendation for bats exists because bat bites often cause minimal injury that is difficult to detect, unlike larger carnivores. 1

Specific scenarios requiring PEP consideration include 1, 2:

• A bat is found in the same room as a sleeping person who awakens to find the bat present
• A bat is found in a room with a previously unattended child
• A bat is found with a mentally disabled person who cannot reliably report contact
• A bat is found with an intoxicated person who cannot reliably report contact

These situations warrant PEP unless the bat is available for testing and tests negative for rabies. 1

Rationale for Aggressive Bat PEP Recommendations

The CDC's aggressive approach to bat exposures is justified by several critical epidemiologic findings 1, 2:

• Bats are documented rabies reservoirs in all 49 continental United States and are the leading cause of human rabies deaths in the U.S. 1, 2

• Of 34 bat-associated human rabies cases reported in the U.S. from 1990-2007, only 6 had documented bites, while 15 had physical contact but no detected bite. 2

• Bat-related rabies virus variants (particularly those associated with silver-haired bats) may be more likely to cause infection even when inoculated into superficial epidermal layers. 1

• Transmission can occur from minor, seemingly underappreciated or unrecognized bites. 1, 3

Critical Management Steps

Capture and test the bat whenever possible 1, 2:

• Safe collection and submission of the bat for rabies testing can prevent unnecessary PEP if the bat tests negative (approximately 94% of submitted bats test negative). 1

• Do not delay PEP initiation while awaiting test results—treatment can be discontinued if the bat tests negative. 2, 4

• If the bat is unavailable for testing, proceed with full PEP. 1

Timing Considerations

Initiate PEP as soon as possible after exposure 3, 4:

• The sooner treatment begins, the better the outcome, as rabies virus follows a neural pathway and immunity from vaccine takes approximately one week to develop. 3

• However, if initiation is delayed for any reason, still administer both RIG and vaccine regardless of the interval between exposure and treatment. 3

• The incubation period is usually 2-6 weeks but can be as short as 10 days after severe bites near the face, neck, and arms. 3

Common Pitfalls to Avoid

• Do not fail to recognize that bat bites may be minor and easily overlooked, leading to delayed or missed PEP. 2

• Do not neglect to consider PEP for situations where a bat is found in a room with someone who cannot reliably report a bite (sleeping person, child, mentally disabled, or intoxicated person). 2

• Do not wait for bat testing results before initiating PEP—start immediately and discontinue only if the bat tests negative. 2, 4

• Do not confuse bat exposures with other animal exposures—bats require more aggressive PEP consideration due to the difficulty in detecting their bites. 1

Exposures That Do NOT Require PEP

PEP is not indicated for 1, 5:

• Contact with bat blood, urine, or feces (guano) alone
• Petting a bat without bite, scratch, or mucous membrane exposure
• Finding a bat roosting or flying in a room open to the outdoors when the person was awake and aware
• Household members who did not have direct contact with the bat or were awake and aware when in the same room

Human rabies is nearly 100% fatal once clinical symptoms develop, but appropriate and timely PEP is nearly 100% effective at preventing disease. 6, 7