Diphtheria and Tetanus Immunity Status among Greek Adults: Results from a Nationwide Seroprevalence Study

Diphtheria and tetanus could lead to serious morbidity. We aimed to evaluate immunity levels by measuring specific IgG antibodies for diphtheria and tetanus in serum samples from a nationally expanded sample of the Greek population. A geographically stratified sampling approach based on regional units (NUTS level 2) was applied by considering variables such as age group (30-80+) and sex. In total, 1201 persons (47.7% males and 52.3% females) participated in the survey. Bivariate analysis revealed a negative relationship between diphtheria and tetanus median antibody titers and age. The overall seropositivity rate for diphtheria IgG antibodies (≥0.10 IU/mL) was estimated at 31.5%. Regarding tetanus, the total seropositivity rate was estimated at 59.5% (tetanus IgG antibodies ≥0.10 IU/mL). Logistic regression analysis indicated that age groups <40 years and 40-59 years were independently associated with tetanus seropositivity. Logistic regression also revealed that male sex and being aged 60-69 years were independent risk factors for diphtheria-related seropositivity. Lastly, being resident of some regions was an independent risk factor for both diphtheria- and tetanus-related seropositivity. The present study shows that Greek adults are still not completely immune to diphtheria and tetanus. It is likely possible to achieve optimal immunization coverage by implementing serviceable public health initiatives after comprehending real community needs.