Simple or combined D,T,P and inactivated
polio vaccines adsorbed onto
calcium phosphate are prepared according to two procedures.
Antigens can be dialysed in a
sodium phosphate solution and quickly mixed with an equal volume of an equimolar
solution of
calcium chloride, the pH is adjusted to 6.8-7.
Toxoids added to the
phosphate solution are in this way entrapped within the 3-dimensional network during the formation of the precipitate.
Antigens can also be added to a
calcium phosphate gel
suspension prepared in advance. Results of animal experiments and of field trials using either
combined vaccines or simultaneous immunization with
diphtheria,
tetanus,
pertussis, meningococcal and several
viral vaccines:
polio,
rabies,
hepatitis-B, etc., will be presented. Several programs have been studied in developing countries, mainly with the aim at simplifying vaccination campaigns. The efficiency of a two-dose regimen with
DT vaccine has been ascertained, this has also been applied to pregnant women. Adsorbed
tetanus toxoid was successfully used as a diluent for freeze-dried
measles, meningococcal
polysaccharide and
rabies vaccines. Levels of circulating
antibodies and potency of
vaccines have been measured by new in vivo and in vitro methods. The choice of detoxified purified toxins is desirable for the preparation of
vaccines in order to prevent the occurrence of adverse reactions. Local and generalized reactions have been studied. Adverse Arthus-type reactions have been encountered and related with the presence of high levels of circulating
tetanus antibodies.(ABSTRACT TRUNCATED AT 250 WORDS)