Since various different trials of whooping cough vaccines had given confusing positive and negative results, Morris Siegel wanted to settle the question of whether any version was effective. Sadly, he failed.
This study vaccinated 1324 children in Brooklyn with different versions: Sauer's version from Eli Lilly, a similar version from the NY Department of Health, some versions from Lederle Labs or Povitzky, and then the NY Dept Health version delivered partially subcutaneously instead of all intradermally.
The subjects were under 6, with no history of pertussis, recruited or volunteers from the community. Controls were selected from the same neighborhoods and families. So it wasn't really randomized or placebo-controlled at all.
They followed up once a month with the subjects to get histories of pertussis. Cases were considered cases if whooping was present, or probable cases if there were other symptoms and exposure to a typical case. And cases that happened within a month of vaccination weren't counted either, since immunity hadn't kicked in yet.
So overall there were 1270 vaccinated subjects and 1016 controls that were observed throughout the study. about 80-90% were 1 to 4 years old, and 7-15% were less than a year.
Results
Overall, 3.6% of the vaccinated subjects got whooping cough, vs. 4.2% of the controls. Of the vaccinated, 76% of the cases had received what was considered a full course, three doses.
Not great. However, looking at the breakdown of vaccine versions, no one who got Sauer's vaccine or the similar NY Dept Health one got sick; most of the cases came from the Lederle Labs versions or similar. The intradermal route seemed best. So considering only the good versions, only 1.7% of subjects got sick, vs. 5.4% for all the other versions; worse than the controls. The biggest difference between them is the concentration: there were a lot more dead pertussis bacteria in the seemingly more effective versions.
One other positive thing though was that the age distribution of vaccinated cases was centered on children 2-3 years old, with fewer young infants getting sick than controls, which had a center around 1-2 years. So it's possible the vaccine shifted the age distribution toward older children, who can deal with it better.
Most of the cases happened after four months had passed since vaccination, possibly an indication of waning immunity; or possibly not, since diseases have some seasonality.
Overall, since it wasn't blinded or randomized, and there were so many different versions used in the vaccinated, it's hard to say much about the results. Though some versions seemed to do better than others, it's unclear whether all groups were exposed to the disease equally. So, almost worthless.
Reference:
This study vaccinated 1324 children in Brooklyn with different versions: Sauer's version from Eli Lilly, a similar version from the NY Department of Health, some versions from Lederle Labs or Povitzky, and then the NY Dept Health version delivered partially subcutaneously instead of all intradermally.
The subjects were under 6, with no history of pertussis, recruited or volunteers from the community. Controls were selected from the same neighborhoods and families. So it wasn't really randomized or placebo-controlled at all.
They followed up once a month with the subjects to get histories of pertussis. Cases were considered cases if whooping was present, or probable cases if there were other symptoms and exposure to a typical case. And cases that happened within a month of vaccination weren't counted either, since immunity hadn't kicked in yet.
So overall there were 1270 vaccinated subjects and 1016 controls that were observed throughout the study. about 80-90% were 1 to 4 years old, and 7-15% were less than a year.
Results
Overall, 3.6% of the vaccinated subjects got whooping cough, vs. 4.2% of the controls. Of the vaccinated, 76% of the cases had received what was considered a full course, three doses.
Not great. However, looking at the breakdown of vaccine versions, no one who got Sauer's vaccine or the similar NY Dept Health one got sick; most of the cases came from the Lederle Labs versions or similar. The intradermal route seemed best. So considering only the good versions, only 1.7% of subjects got sick, vs. 5.4% for all the other versions; worse than the controls. The biggest difference between them is the concentration: there were a lot more dead pertussis bacteria in the seemingly more effective versions.
One other positive thing though was that the age distribution of vaccinated cases was centered on children 2-3 years old, with fewer young infants getting sick than controls, which had a center around 1-2 years. So it's possible the vaccine shifted the age distribution toward older children, who can deal with it better.
Most of the cases happened after four months had passed since vaccination, possibly an indication of waning immunity; or possibly not, since diseases have some seasonality.
Overall, since it wasn't blinded or randomized, and there were so many different versions used in the vaccinated, it's hard to say much about the results. Though some versions seemed to do better than others, it's unclear whether all groups were exposed to the disease equally. So, almost worthless.
Reference:
Siegel, M. Active immunization against whooping cough with various specific vaccines. Am J Dis Child 56, 1294–1303 (1938).
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