VARIABLES INFLUENCING THE PREPARATION OF INFLUENZA VACCINES WITH FORMALDEHYDE

Abstract

The effect of temperature, time of treatment, and the pH of the medium on the preparation of influenza vaccines with formaldehyde has been studied. It was found that both the infectivity and the hemagglutinin were destroyed more quickly as the pH was increased above pH 6 and the margin of safety that exists between virus inactivation and loss of antigenicity increased as the pH was decreased to about 6. From the experimental data it was possible to select numerous conditions of treatment which had a large margin of safety between virus inactivation and loss of antigenicity. Vaccines prepared with formaldehyde under various conditions and then lyophilized had retained their antigenicity after storage for [Formula: see text] years.