What to do with a patient presenting for their second rabies (Rabies Immunoglobulin) vaccine who currently has an upper respiratory infection and fever?

Proceed with the Second Rabies Vaccine Despite Upper Respiratory Infection and Fever

Once rabies postexposure prophylaxis has been initiated, it should not be interrupted or discontinued because of mild systemic adverse reactions such as fever from an upper respiratory infection. 1

Key Management Principles

Continue Vaccination on Schedule

• Rabies prophylaxis must proceed without interruption regardless of concurrent mild illnesses like upper respiratory infections with fever 1
• The risk of rabies (which is nearly 100% fatal once symptomatic) far outweighs any concerns about administering vaccine during a minor febrile illness 1
• Local or mild systemic reactions—including fever—are not contraindications to continuing the vaccine series 1

Symptomatic Management

• Manage the patient's fever and URI symptoms with anti-inflammatory and antipyretic agents such as ibuprofen or acetaminophen 1
• These medications can be given before or after vaccination to improve patient comfort without compromising vaccine efficacy 1
• Antihistamines may also be considered if needed for symptom management 1

Important Clinical Context

Why Continuation is Critical

• There are no true contraindications to rabies postexposure prophylaxis once initiated, given the uniformly fatal nature of rabies 1
• The patient's risk of acquiring rabies must be the primary consideration in any decision about continuing vaccination 1
• Interrupting the vaccine series could leave the patient vulnerable during the critical window before adequate antibody response develops 1

Conditions That Would Warrant Caution (But Not This One)

The guidelines specifically address situations requiring special consideration, and a simple URI with fever is not among them:

• Serious hypersensitivity reactions (anaphylaxis, severe allergic reactions) would require careful management but still continuation with premedication 1
• Severe immunosuppression requires completion of the series with possible antibody titer checking afterward, but not discontinuation 1
• Neuroparalytic reactions are extremely rare and would require consultation, but even these must be weighed against rabies risk 1

Common Pitfalls to Avoid

• Do not delay or postpone the scheduled vaccine dose due to minor concurrent illnesses 1
• Do not confuse this scenario with pre-exposure prophylaxis, where elective vaccination can be postponed for illness; postexposure prophylaxis is urgent and non-elective 1
• Do not administer the vaccine and rabies immunoglobulin in the same anatomical site if this is the first dose requiring RIG 2

Practical Approach

1. Administer the second rabies vaccine dose as scheduled 1
2. Provide symptomatic treatment for the URI and fever with antipyretics 1
3. Reassure the patient that mild illness does not compromise vaccine effectiveness 1
4. Ensure completion of the full 4-dose series (days 0,3,7,14) for previously unvaccinated persons 2, 3
5. Monitor for any serious reactions (extremely rare), keeping epinephrine available 1

The Advisory Committee on Immunization Practices is explicit that once rabies prophylaxis begins, it proceeds regardless of minor concurrent illnesses, as the consequences of inadequate rabies treatment are catastrophic 1.