BOOSTER VACCINATION AGAINST DIPHTHERIA AND TETANUS IN MAN - COMPARISON OF CALCIUM-PHOSPHATE AND ALUMINUM HYDROXIDE AS ADJUVANTS .2.

Diphtheria and tetanus antibody levels were measured before and four w eeks after booster vaccination of 313 Danish military recruits partici pating in a clinical trial to compare aluminium hydroxide and calcium phosphate as adjuvants in diphtheria-tetanus vaccines (DT). Twenty-eig ht percent of the men had a diphtheria pre-vaccination content below a protective level of 0.01 IU ml(-1). The calcium phosphate adsorbed va ccine showed the highest efficacy for both antigens. Adverse reactions were rare bur more frequent in the calcium group than in the aluminiu m group. No correlation was found between pre- or post-vaccination lev els and adverse reactions and both vaccines gave rise to specific IgE formation. The results show that calcium phosphate is more effective b ut not a safer alternative to aluminium hydroxide when compared in vac cines containing 1.0 mg ml(-1) of Ca or of Al.