What is the duration of validity of the rabies vaccine (Rabies Immunoglobulin)?

Duration of Validity of Rabies Vaccine

The rabies vaccine provides adequate protection for 2 years after primary vaccination, after which antibody titers should be checked and a booster dose administered if levels fall below protective thresholds. 1

Primary Vaccination Series

• The standard primary rabies vaccination series consists of three 1.0-mL injections of human diploid cell vaccine (HDCV) or purified chick embryo cell vaccine (PCECV) administered intramuscularly in the deltoid area on days 0,7, and 21 or 28 2
• Within 28 days after primary vaccination, a peak rabies antibody titer is reached and the animal or person can be considered immunized 3
• The primary series establishes both adequate immunity against rabies virus and creates immunologic memory for future exposures 2

Duration of Protection and Monitoring

• Two years after primary pre-exposure vaccination, 93%-98% of persons who received the 3-dose pre-exposure series intramuscularly and 83%-95% of persons who received the 3-dose series intradermally still showed complete neutralization of challenge virus at a dilution of 1:5 1
• Studies have shown that approximately 29% of subjects may have inadequate antibody titers (<0.5 IU/ml) at two years post-vaccination 4
• Antibody titers decline at a rate of approximately 1.20% per month after vaccination, regardless of whether it was primary or booster vaccination 5

Risk-Based Booster Schedule

Continuous Risk (Laboratory workers, vaccine production facilities)

• Serum should be tested for rabies antibody every 6 months 1
• A booster dose is required if serum titer falls below complete neutralization at a 1:5 serum dilution by the Rapid Fluorescent Focus Inhibition Test (RFFIT) 1, 2

Frequent Risk (Veterinarians, animal handlers, spelunkers)

• Serum should be tested for rabies antibody every 2 years 1
• A booster dose is required if titer is less than complete neutralization at a 1:5 serum dilution by RFFIT 1
• Alternatively, a booster can be administered directly without testing 1

Infrequent Risk

• No routine boosters are required after primary vaccination series 1

Factors Affecting Antibody Duration

• Male gender, higher BMI (>25), and longer intervals between doses (>21 days between first and third doses) are associated with faster decline in antibody titers 4
• Women tend to maintain approximately 51% higher antibody titers compared to men 5
• The type of vaccine used can affect long-term antibody persistence 4

Booster Response

• After booster vaccination due to non-protective titer, studies show the geometric mean titer (GMT) increases by approximately 678%, reaching levels 2.5 times higher than those elicited by the primary vaccine series 5
• Good responders to a booster dose, with titers ≥30 IU/mL, may be protected for at least 10 years 6

Post-Exposure Considerations

• Previously vaccinated individuals exposed to rabies should receive two IM doses of vaccine, one immediately and one 3 days later, without rabies immunoglobulin 1, 2
• The booster response is rapid in previously vaccinated individuals, providing immediate protection 1

Special Considerations

• Immunosuppressed individuals should have their antibody titers checked after vaccination 1, 2
• Failures to seroconvert in immunosuppressed individuals should be managed in consultation with appropriate public health officials 1

Common Pitfalls to Avoid

• Do not use antibody titers as a substitute for current vaccination in managing rabies exposures 3
• Do not administer rabies immunoglobulin to previously vaccinated individuals during post-exposure prophylaxis 1
• Do not delay the third dose of the primary series beyond 21 days, as this may lead to inadequate antibody titers 4
• Do not administer rabies vaccine in the gluteal area, as this results in lower neutralizing antibody titers 3