Immunization against scarlet fever using sodium ricinoleate as a detoxifying agent.

Scarlet toxin, the potency of which was 15,000 skin doses per cc., was treated with sodium ricinoleate so that the final dilution of the soap was 1 per cent and this mixture used to immunize against scarlet fever.

After a few preliminary tests it was found that the toxin had been completely neutralized by the soap, so that 1,000 skin test doses were perfectly safe for children. Early in our work we found that very much larger doses could be given. One hundred forty-eight children, ranging from one to sixteen years in age, with positive Dick tests, were treated with varying amounts of “neutralized” toxin. After having received one treatment of soap-toxin, they were given Dick retests in periods of time ranging from five to twenty-one days. The results are given in the accompanying table.

As may be seen from the above table, 96 per cent of the cases gave a negative Dick reaction three weeks after having received a single injection.

The treatment was followed by a mild local reaction in 15 per cent of the cases. The reaction consisted of a slight reddening and swelling about the area injected, appearing about twelve hours after the injection, and disappearing after thirty-six hours. In no case was a general reaction observed.

A group of nurses who were treated with 2,000 skin test doses experienced no inconvenience whatever from the treatment. There were sixteen in this group. In seventeen days only 37.5 per cent were negative. We believe, therefore, that larger doses are indicated for older children and adults. Since large doses cause the patient no inconvenience, we recommend using 4,000 skin doses, as the larger doses apparently give a higher percentage of immunity than the smaller ones.