How long does immunoglobulin work after a tick bite? - briefly
Immunoglobulin provides passive protection for approximately ten days, after which vaccine‑induced antibodies maintain immunity. «Duration of effect: about 10 days».
How long does immunoglobulin work after a tick bite? - in detail
Immunoglobulin administered after a tick exposure supplies immediate, passive protection against the specific pathogen for which the preparation is targeted. The protective effect persists as long as the circulating antibodies remain at concentrations above the protective threshold. Typical pharmacokinetic data indicate a half‑life of 21–28 days for human IgG preparations, resulting in detectable activity for approximately 4–6 weeks after a single dose.
Key determinants of the duration include:
- Dose and concentration – higher administered amounts raise initial serum levels, extending the period above the protective threshold.
- Patient body mass and renal function – larger volume of distribution or accelerated clearance shorten effective coverage.
- Nature of the antigen – some pathogens require higher antibody titres for neutralisation; the required level influences how long protection is considered adequate.
- Concurrent active immunisation – when a vaccine is given alongside immunoglobulin, the passive antibodies may interfere with the vaccine‑induced response, potentially delaying the onset of active immunity.
In practice, a single prophylactic infusion of tick‑borne encephalitis immunoglobulin provides sufficient neutralising activity for roughly one month. After that interval, endogenous antibody production, if stimulated by vaccination, should have reached protective levels; otherwise, a repeat dose may be recommended. Monitoring serum antibody titres can guide the timing of additional administrations.
«The passive protection afforded by immunoglobulin diminishes as the antibodies are catabolised, and the clinical relevance of the remaining titres determines the need for further intervention».