Comparison of photometric and weight estimation of Mycobacterium content in homogenous BCG cultures containing Tween 80

A comparison of the weight and photometric methods of primary assay of BCG vaccine has been made, using a vaccine prepared in albumin-free medium but containing Tween 80. In the weight method, the bacteria were trapped on a membrane filter; for photometry a Pulfrich Elpho photometer and an instrument of Czech origin were used. The photometric results were the more precise, provided that the measurements were made within two days of completion of growth; after this time the optical density of the suspension began to decrease slowly. The lack of precision of the weighing method is probably due to the small weight of culture deposit (which was almost on the limit of accuracy of the analytical balance) and to difficulties in the manipulation of the ultrafilter.

Comparative trial of live measles vaccines in Czechoslovakia

The study reported in this article was conducted under the auspices of WHO as part of the Organization's programme on measles vaccination.In the spring of 1964, 416 children aged between 8 months and 3 years were inoculated with one or another of the following agents: Enders Edmonston B vaccine (alone or with gamma-globulin), Schwarz vaccine, Beckenham 20 vaccine, Milovanović vaccine, and a placebo.Seroconversion rates ranged from 91% to 100%, which indicates that the vaccines tested were highly immunogenic. The incidence of reactions was low, and from the clinical point of view acceptable. Clinical comparison of the reactions provoked by the different vaccines showed that the lowest rate was in the groups given Schwarz vaccine and Enders Edmonston B plus gamma-globulin, and the highest in the group given Beckenham 20 vaccine. However, the greater frequency of reactions observed with Beckenham 20 vaccine might have been due to the high dose given in the first stage of the trial.Complications were observed in 10 children, of whom four were in the placebo group. In three of the remaining cases a causal connexion with the vaccine could not be excluded with certainty.