Un vaccin rougeoleux suratténué a été mis au point par l'Institut Armand-Frappier (I.A.F.). Des essais cliniques ont été effectués pour étudier l'antigénicité et l'innocuité de ce vaccin ainsi que sa stabilité sous climat tropical. On l'a de plus comparé au vaccin régulièrement employé au Québec. Au cours des différents essais cliniques, il a été possible de démontrer: que le virus du vaccin rougeoleux I.A.F. n'était pas transmissible; que les réactions secondaires et les taux d'anticorps hémagglutinants et neutralisants provoqués par le vaccin I.A.F. étaient en tout point comparables à ceux du vaccin régulièrement employés dans la population et que le vaccin était stable sous climat tropical.

Responses to dose of 100 and 200 CCA units of a trivalent A/texas, A/USSR, and B/Hong Kong inactivated whole-virus vaccine produced by the Institut Armand-Frappier were evaluated in 667 adults volunteers in good health. No severe symptoms or clinical signs were observed. Temperature, mean systemic, reaction index and clinical signs in general were significantly higher among recipients of the larger dose of vaccine. No relationshop was noted between reactofenicity and serologic response. The presence of preexisting antibodies did not decrease the reactogenicity except in the case of A/USSR in the 26-50 age group. fourfold or greater increasees in titre occurred in nearly 100% of 249 seronegative recipients of A/Texas, irrespective of dose. Imn 274 seronegative recipients of A/USSR, such increases occured in 42% of those given 100 CCA units and in 67.8% in volunteers receiving 200 CCA units. In 230 seronegative recipients of B/Hong Kong, such increases occurred in 88.6% of those injected with 100 CCA units and 95.2% in those gfiven 200 CCA units. Seronegative subjects of 26 years of age and older had a better serologic response than those aged 18-25 with each dose of the A/USSR strain but there were no age differences in the response to the A/Texas and B/Hong Kong strains. The serologic response to 200 CCA units was significantly higher for the A/USSR strain in all age groups and for the B/Hong Kong strain in subjects aged 18-25.

By simply referring to one of three tables, derived from Fisher's exact factorial method and obtained with the aid of a computer, it is possible to decide readily if differences observed between two small and equal or unequal size series are statistically significant at probability levels of 0.10, 0.05 and 0.01. The same can be very helpful for planning experiments. Examples are given in various fields of biology.

A microtissue culture method for the assay of low concentrations of diphtheria antitoxin in human sera has been developed, using a monkey kidney cell (VERO) culture technique. Results obtained with sera from nonvaccinated children and with immune sera from children vaccinated with three and four injections of diphtheria pertussis tetanus vaccine were in agreement with antitoxin levels considered necessary to denote immunity to diphtheria. The use of microplates and organic buffer for culturing the animal cells improved the stability of the tissue culture system. The described method is sensitive, economical, and applicable for the titration of antitoxin in human sera particularly from infants and children from whom a minimum amount of serum is available.