Consistency testing of diphtheria and tetanus to replace potency testing for lot release.

Diphtheria and tetanus vaccines are among the most effective and safe vaccines in the EPI programme. Their mechanism of toxicity and clinical protection is well documented and toxin neutralising antibodies induced by the vaccines are generally accepted as correlates of protection. Despite these positive aspects there are still no generally accepted methods to estimate their potency for routine lot release.

Standardization of acellular pertussis vaccines.

In comparison with the current whole cell pertussis vaccine, the new generation of acellular pertussis vaccines opens new opportunities to improve the standardization of the product, because well defined and characterized components are used in these new products.However, different compositions, purification and inactivation methods are used by different manufacturers. Consequently the various acellular pertussis vaccines in the world are difficult to compare in a meaningful manner using simple laboratory tests.