In the primary analysis, DTP-vaccinated infants experienced mortalities five times greater than DTP-unvaccinated infants. Mortalities to vaccinated girls were 9.98 times those among females in the unvaccinated control group, while mortalities to vaccinated boys were 3.93 times the controls. Oddly, the scientists found that children receiving the oral polio vaccine simultaneously with DTP fared much better than children who did not. The OPV vaccine appeared to modify the negative effect of the DTP vaccine, reducing mortalities to 3.52 times those experienced among the control group. Overall, mortalities among vaccinated children were 10 times the control group when children received only the DTP.
Mogensen and his colleagues hypothesize that the DTP vaccine might weaken a child’s immune system against non-target infections. They conclude, “Though protective against the target disease, DTP may increase susceptibility to unrelated infections… DTP was associated with 5-fold higher mortality than being unvaccinated. No prospective study has shown beneficial survival effects of DTP.”