Neutralizing antibody response after intradermal rabies vaccination in hemodialysis patients

Abstract

Abnormal immune function in chronic hemodialysis (HD) patients could impair immunologic responsiveness to various vaccinations. Such inadequate response makes the HD patients to be at risk of certain fatal but preventable diseases including rabies. Although the effectiveness of rabies vaccination has been established in healthy subjects, the responsiveness of the current rabies vaccination has never been examined in HD patients. The effectiveness of post-exposure rabies vaccine was assessed in 20 stable thrice-a-week chronic HD patients who received adequate dialysis and did not have history of rabies vaccination during the last 20 years. All participants received the standard intradermal Thai Red Cross post-exposure rabies vaccination. Blood samples were obtained for determination of rabies neutralizing antibody (Nab) before the first dose (day 0) and on days 14 and 90 after vaccination. Prior to simulated vaccination, six of twenty patients already had Nab titers above the protective levels of 0.5 IU/mL while the remaining fourteen patients showed undetectable Nab. All subjects reached Nab titers above 0.5 IU/mL(acceptable level for rabies protection) by days 14 after vaccination. The geometric mean titers (GMTs) on days 14 after vaccination were 3.2 + 3.1 IU/mL (range 0.81–9.17 IU/mL). At day 90 after vaccination, 13 of 14 patients had Nab titers above the protective levels, resulting in the response rate of 92.8%. The GMTs of Nab on day 90 after vaccination were 5.09 + 1.79 IU/mL (0.42–25.0 IU/mL). There were no correlations between Nab titers and patient characteristics. No serious adverse reactions were detected. In conclusion, chronic HD patients receiving adequate dialysis have excellent protective immunological response after intradermal post-exposure rabies vaccination as WHO recommendation.