A patient who received three doses of rabies post‑exposure prophylaxis (one dose remaining) after a bite from a vaccinated dog last month now presents with a Grade 3 bite from an unvaccinated dog; how should rabies prophylaxis be managed?

Restart Complete Rabies PEP with HRIG Immediately

For this patient with an incomplete prior PEP series (3 of 4 doses) who now has a Grade 3 bite from an unvaccinated dog, treat as a previously unvaccinated person and initiate full post-exposure prophylaxis immediately: administer HRIG at 20 IU/kg infiltrated into the new wound plus restart a complete 4-dose vaccine series on days 0,3,7, and 14. 1, 2

Critical Decision Point: Why This Patient Needs Full PEP

The incomplete prior series does not count as "previously vaccinated" for this new exposure. The patient only received 3 of 4 doses from the previous exposure and never completed the series, meaning they cannot be considered adequately immunized. 1, 2

Key Distinctions:

• Previously vaccinated persons (who completed a full series) need only 2 booster doses on days 0 and 3 without HRIG 1, 3, 2
• This patient with an incomplete series requires the full unvaccinated protocol: HRIG plus 4 vaccine doses 1, 2

Immediate Management Protocol

Step 1: Wound Care (Within Minutes)

• Wash the wound thoroughly with soap and water for 15 minutes 1, 4
• Irrigate with povidone-iodine solution if available 1, 4
• Address tetanus prophylaxis and bacterial infection control as indicated 4

Step 2: HRIG Administration (Day 0 - Today)

• Calculate dose: 20 IU/kg body weight exactly (never exceed this dose as it suppresses active antibody production) 1, 2
• Infiltrate the full calculated dose around and into the new wound(s) if anatomically feasible 1, 2
• Inject any remaining volume intramuscularly at a site distant from vaccine administration 1, 2
• Critical timing: HRIG can be given up to and including day 7 after the first vaccine dose if initially missed, but not beyond day 7 1, 3

Step 3: Vaccine Series (Starting Day 0)

• Administer 1.0 mL intramuscularly on days 0,3,7, and 14 1, 2, 5
• Use deltoid muscle for adults; anterolateral thigh for young children 1, 2
• Never use gluteal area (associated with vaccine failure due to inadequate antibody response) 1, 2
• Do not administer vaccine in the same syringe or same anatomical site as HRIG 1, 2

Why the Previous Incomplete Series Doesn't Provide Adequate Protection

While research shows that even 3 doses can generate neutralizing antibodies 6, the patient never completed the series and cannot be considered adequately immunized for purposes of simplified re-exposure protocols. 1, 2 The CDC and FDA guidelines are explicit: only persons who have completed a recommended pre-exposure or post-exposure vaccination series qualify for the abbreviated 2-dose booster regimen. 1, 3, 2

Additional Risk Factors in This Case:

• Grade 3 bite (transdermal bite with bleeding) carries high rabies transmission risk 1
• Unvaccinated dog significantly increases rabies probability compared to the previous vaccinated dog exposure 4
• One month interval from incomplete series means no established immune memory response 3

Special Considerations

If the Dog Can Be Observed:

• Initiate PEP immediately without waiting for observation results given the Grade 3 severity and unvaccinated status 4
• If the dog remains healthy for 10 days, PEP can be discontinued 1, 4
• Dogs do not shed rabies virus in saliva more than 10 days before showing clinical signs 3

Common Pitfall to Avoid:

Do not treat this as a "re-exposure within 6 months" scenario requiring only 2 booster doses. 3 That simplified protocol applies only to persons who completed a full vaccination series, not those with incomplete prior PEP. 1, 3, 2

If Immunocompromised:

• Upgrade to 5-dose regimen (days 0,3,7,14, and 28) plus HRIG 1
• Mandatory serologic testing 1-2 weeks after final dose 1

Efficacy and Prognosis

When administered promptly and appropriately, this complete PEP regimen combining wound care, HRIG infiltration, and the 4-dose vaccine series is nearly 100% effective in preventing human rabies. 1, 7, 5 No failures have been documented in the United States since current biologics were licensed when the full protocol is followed correctly. 1