Most shots in the dark miss. Scientists learn this early in their career – most of the guesses we make as to how things work will turn out to be wrong. In fact, a proper understanding of science requires thorough knowledge of all the ways in which humans deceive themselves into believing things that are not true. In fact, most shots in well-lit conditions (informed by prior knowledge) miss. Ignoring prior knowledge results in chances that are all but hopeless.
Therefore the title of the 1985 book DPT: A Shot in the Dark by Harris Coulter and Barbara Loe Fisher, is perhaps unintentionally ironic. The book sparked the first modern popular concern about the risk of neurological damage from vaccines, in this case the pertussis vaccine that is part of the DTP vaccine.Fisher, of the National Vaccine Information Center (NVIC) still promotes the book and its content, even though the science has progressed in the last 25 years.
At the time the whole cell pertussis vaccine was part of the diptheria, tetanus, pertussis vaccine (DTwP). This combination has been largely replaced with the DTaP vaccine, which contains an acellular pertussis component. This change was partly due to safety issues, rare cases of neurological disease (seizures and encephalopathy) following DTwP being given. DTaP has a lower incidence of fever, seizures, and other side effects.