Today's study is another test of whooping cough vaccines. Sauer's was the popular one at this time, showing 92% efficacy in some studies, but a Lucy Mishulow had created one that used a stock strain of pertussis instead of needing to isolate a new one with every outbreak, as the Sauer version called for. Also, it could be grown on animal blood instead of human blood. This made it more potentially useful.
So Eli Shorr selected preschool children with known histories of illness to vaccine or keep as controls. He tried to divide families up evenly between vaccinated and controls, to make things as equivalent as possible. Half the subjects attended the same nursery school.
They compared different methods of inoculation: intramuscular, intracutaneous, and subcutaneous. After, they looked at levels of agglutinins in the blood as a measure of antibody response.
In order to compare, they gave a few children the Sauer vaccine, and some of the controls got an injection of sterile diluted milk as a placebo.
They found that about 36% of the subjects were definitely exposed to pertussis over the next 30 months; probably more that they didn't notice. 16% of those receiving Mishulow's vaccine got pertussis, 10 out of 63, though 6 of the 10 were very mild cases (no whooping even), and also 6 of the 10 got sick within the period Sauer thought might be too soon for immunity to develop, and 4 of them had smaller doses of vaccine too. So it might be said that only 10% of well-vaccinated subjects got sick.
With the Sauer vaccine, 1 of 11 (9%) got sick, but that one had gotten a low dose too.
Whereas with controls, 26 of 72 (36%) got pertussis. Big difference. And they weren't even observed for as long a period.
In terms of inoculation route, intracutaneous was abandoned early because it was difficult to give an adequate dose and reactions to it were overly severe. Reactions to the other routes were never severe; most just had slight tenderness, some had redness or a low fever for a day or two.
The antibody measurements were as expected, pretty high soon after vaccination but none or very low in unvaccinated group. Levels fell after 2-3 months, but it wasn't clear if that meant immunity went away or anything.
So overall, it seemed like Mishulow's vaccine was pretty good, but it was too small a study to compare to Sauer's very well. Googling "Lucy Mishulow" doesn't bring up many results, so I wonder if the vaccine turned out badly somehow, such that this vaccine researcher got mostly lost to the sands of time somehow. Maybe I'll find out later.
Citation: Shorr, E. Y. Prophylactic pertussis immunization. The Journal of Pediatrics 9, 49–55 (1936).
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