“How do we know that the tetanus toxoid vaccine currently in use is effective in tetanus prevention? Actually, we do not know that. The scientific way of knowing (a.k.a. evidenced-based science) is through conducting randomized controlled trials (RCT). Tetanus toxoid vaccine has not been subjected to RCT to test its effectiveness in tetanus prevention. The vaccine was introduced into the civilian U.S. population in 1947 simply because its use in the U.S. military during World War II has been deemed ‘successful.’
The conclusion of ‘success’ was based on the following reasoning. During World War I, 70 unvaccinated U.S. soldiers have contracted tetanus, which amounted to 13.4 cases per 100,000 wounds. One the other hand, in World War II 12 U.S. soldiers were reported to contract tetanus, which amounted to only 0.44 cases per 100,000 wounds. Although the reduction in tetanus frequency among wounded soldiers during WWII compared to WWI is apparent, any conclusion about the role of the tetanus vaccine in this reduction is scientifically invalid.
Only an RCT could have established whether the vaccine should receive the credit. Otherwise, we can reasonably speculate that the reduction in tetanus during WWII compared to the previous war was simply due to better wound hygiene or lower risk of C. tetani wound exposure.
In the civilian U.S. population, tetanus mortality had been dropping dramatically during the first half of the 20th century before the vaccine introduction, and it continued to drop further after the vaccine introduction. Therefore, the vaccine’s role in tetanus reduction in the U.S. population cannot be inferred from the tetanus mortality statistics either.”
— Dr. Tetyana Obukhanych, immunologist
Courtesy: The Outliers