This was an unusual study on a vaccine-like method of protecting children from whooping cough. Instead of using whole killed bacterial cells, they grew the cells and filtered them out, leaving only soluble factors the bacteria had produced externally, which they called "antigen." Then they inactivated this antigen so it wouldn't cause any problems but would still induce an immune response, treating it with formaldehyde and mild heat. This was sorta like how tetanus and diphtheria toxoid vaccines were produced.
Then they tested this antigen for how well it could a) treat whooping cough cases, b) prevent catching the disease when given when not at risk, and c) prevent catching the disease when given after being exposed.
Antigen Therapy
They had two main groups: children with whooping cough treated with antigen, and control children with whooping cough. The controls were treated with either vaccine or vaccine + antigen. They don't specify what they mean by "vaccine;" details are pretty sparse in general.
The average time before each group was similar, about 1.5 weeks, but the duration of disease after treatment was about 1.6 weeks for the antigen-treated and 3 weeks for controls, so a pretty big difference.
The number of complications in the groups was different too: About 0.7% of the antigen-treated had complications from the disease (bronchitis, conjunctival hemorrhage, otitis media), while 18% of controls had complications, including some deaths
Antigen Prophylaxis
Of those immunized without first being exposed, about 81% of those who did become exposed didn't get the disease, so they said it was 81% effective. That's not exactly how such trials should work; there should be controls.
They claimed this immunity lasted at least 5 months and up to 2.5 years, but I'm not sure how they determined this.
The same was true of those treated after being exposed: 76% didn't get the disease, but again there were no controls reported.
In terms of adverse reactions, some few patients had a short, mild fever, arm redness, or hives, but nothing worse.
Conclusions
So considering the lack of details, controls, and blinding, and how this approach didn't seem to be considered worthwhile either before or after this study, I'm not convinced it's very valuable.
Reference:
Then they tested this antigen for how well it could a) treat whooping cough cases, b) prevent catching the disease when given when not at risk, and c) prevent catching the disease when given after being exposed.
Antigen Therapy
They had two main groups: children with whooping cough treated with antigen, and control children with whooping cough. The controls were treated with either vaccine or vaccine + antigen. They don't specify what they mean by "vaccine;" details are pretty sparse in general.
The average time before each group was similar, about 1.5 weeks, but the duration of disease after treatment was about 1.6 weeks for the antigen-treated and 3 weeks for controls, so a pretty big difference.
The number of complications in the groups was different too: About 0.7% of the antigen-treated had complications from the disease (bronchitis, conjunctival hemorrhage, otitis media), while 18% of controls had complications, including some deaths
Antigen Prophylaxis
Of those immunized without first being exposed, about 81% of those who did become exposed didn't get the disease, so they said it was 81% effective. That's not exactly how such trials should work; there should be controls.
They claimed this immunity lasted at least 5 months and up to 2.5 years, but I'm not sure how they determined this.
The same was true of those treated after being exposed: 76% didn't get the disease, but again there were no controls reported.
In terms of adverse reactions, some few patients had a short, mild fever, arm redness, or hives, but nothing worse.
Conclusions
So considering the lack of details, controls, and blinding, and how this approach didn't seem to be considered worthwhile either before or after this study, I'm not convinced it's very valuable.
Reference:
Joslin, C. L. & Christensen, T. A. Prophylaxis and treatment of whooping cough with a pertussis antigen: Report of results. Am J Dis Child 60, 1269–1276 (1940).
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