How long after a tick bite should immunoglobulin be administered? - briefly
Immunoglobulin should be administered as soon as possible after exposure, preferably within the first 24 hours, and it remains effective if given up to 72 hours post‑bite. Delays beyond this window markedly reduce prophylactic benefit.
How long after a tick bite should immunoglobulin be administered? - in detail
The administration of rabies immunoglobulin after a tick bite is part of post‑exposure prophylaxis (PEP) and must be performed promptly. The passive‑immunity product should be given as soon as the exposure is recognized, ideally within the first 24 hours. Efficacy remains acceptable up to seven days after the bite; beyond this period the benefit of immunoglobulin declines markedly, and active immunization alone is advised.
Key timing points:
- 0–24 hours – Immediate wound cleansing, infiltration of the full immunoglobulin dose around the bite site, followed by initiation of the vaccine series.
- 24 hours–7 days – Immunoglobulin may still be administered; the same infiltration technique is required, but the protective window narrows as viral replication progresses.
- >7 days – Passive immunization offers minimal additional protection; only the vaccine schedule is continued.
Dosage and delivery:
- Dose: 20 IU per kilogram of body weight.
- Distribution: as much as possible infiltrated into and around the wound; any remaining volume is injected intramuscularly at a distant site.
Special considerations:
- Immunocompromised patients: immunoglobulin should not be omitted even if presentation is delayed, because the host’s active response may be insufficient.
- Multiple bite sites: the total calculated dose is divided proportionally among all wounds.
- Allergic history: severe hypersensitivity to human immunoglobulin is a contraindication; alternative rabies‑specific monoclonal antibodies may be used.
The vaccine schedule accompanying immunoglobulin follows the standard PEP regimen: doses on days 0, 3, 7, and 14 (or day 28 for immunocompromised individuals). Completion of the series is essential for long‑term protection.
In summary, passive rabies immunoglobulin should be injected as soon as possible after a tick bite, with a practical upper limit of seven days; later administration provides little advantage, and the focus shifts to completing the active‑immunization schedule. «The earlier, the better» accurately reflects the clinical imperative for timely passive immunization.