tetanus and diphtheria seroprevalence in patients infected with human immunodeficiency virus

background and objectives: hiv infected patients are at risk for vaccine-preventable infections such as tetanus and diphtheria (td). in these patients, these antibodies tend to decline faster. due to the limited data, this study assessed the seroprevalence of tetanus and diphtheria antibodies in hiv infected patients in tehran, iran. materials and methods: this case-control study was carried out in 180 hiv infected patients from iranian hiv/aids research center in tehran and 90 matched healthy controls. the serum samples were checked with elisa for tetanus and diphtheria antibodies. results:a total of 180 hiv positive patients with mean age 36.9±9.2 years and 90 matched controls were enrolled in the study. tetanus antibody was lower in hiv group when compared with control group. there was no significant difference in the mean serum levels of diphtheria antibody in hiv positive patients when compared with the controls. about 93.3% and 96.6% of hiv infected patients had protective diphtheria and tetanus antibodies respectively. mean tetanus and diphtheria antibodies levels were not significantly different based on the circulating cd4+ cells. conclusion: hiv positive cases, who had received primary td vaccination before they contracted hiv infection, can be expected to be protected against diphtheria, whereas revaccination against tetanus must be considered.