What is the next step for a patient who was bitten by a dog, received rabies shots (Post-Exposure Prophylaxis (PEP)), but has rabies antibody titers (Rabies Ab (Antibody)) below detection?

Management of Patient with Undetectable Rabies Antibody Titers After Post-Exposure Prophylaxis

For a patient who received rabies post-exposure prophylaxis (PEP) after a dog bite but has antibody titers below detection, the appropriate next step is to administer two intramuscular doses (1.0 mL each) of rabies vaccine, one immediately and one 3 days later. 1

Understanding the Significance of Low Antibody Titers

The Advisory Committee on Immunization Practices (ACIP) provides clear guidance on this situation:

• For previously vaccinated persons who are exposed to rabies, determining rabies virus neutralizing antibody titer for decision-making about prophylaxis is inappropriate for three key reasons:

  • Several days are required to collect serum and determine test results
  • No definitive "protective" titer is known
  • While antibodies are important, other immune effectors also contribute to disease prevention 1

• Post-vaccination serologic testing is generally unnecessary for healthy individuals who have completed the recommended PEP regimen 1, 2

Management Algorithm

1. Confirm previous vaccination status:

   • If the patient received complete PEP with a cell culture vaccine, they are considered previously vaccinated regardless of antibody titer results 1

2. Administer booster doses:

   • Give 2 IM doses (1.0 mL each in the deltoid) of rabies vaccine
   • First dose: Immediately
   • Second dose: 3 days later 1

3. Do NOT administer Rabies Immune Globulin (RIG):

   • RIG is unnecessary and should be avoided in previously vaccinated persons
   • RIG could inhibit the strength or rapidity of the expected anamnestic response 1

Special Considerations

For Immunocompromised Patients

If the patient is immunocompromised, special management is required:

• Consult with public health officials 1, 3
• Consider antibody titer testing 2-4 weeks after booster doses 1
• Failure to seroconvert in immunocompromised patients may require additional intervention 3

Common Pitfalls to Avoid

1. Do not delay treatment while waiting for antibody test results - immediate administration of booster doses is the priority 1

2. Do not administer RIG to previously vaccinated individuals, even with low antibody titers 1

3. Do not use the gluteal area for vaccine injection as this results in lower neutralizing antibody titers 2

4. Do not interpret low antibody titers as evidence of vaccine failure in previously vaccinated individuals 1

Wound Management

Even for previously vaccinated individuals, proper wound management remains essential:

• Thoroughly cleanse with soap and water for at least 15 minutes
• Use virucidal agents if available
• Consider tetanus prophylaxis and antibiotics as indicated 4

Follow-up

• No routine follow-up antibody testing is required for healthy individuals after receiving the two booster doses 1
• For immunocompromised patients, consider consultation with public health officials regarding the need for follow-up antibody testing 1, 3

By following this approach, you can ensure appropriate management of patients with undetectable rabies antibody titers after previous PEP, minimizing the risk of this potentially fatal disease.