“No field trials have compared the effectiveness and harms of all vaccines used according to various schedules listed in the recent BMJ infographic.6 12The time for such studies is ethically and logistically past.
The full evidence base to make such complex decisions as the timing of each vaccination, in conjunction with developmental issues and the effect each vaccine has on the response to the others, is seldom fully available when vaccination schedules are devised…despite concerns about overloading infants’ immune systems we can find no evidence of harm.
However, because detailed reports for most clinical trials of vaccines are not available, and have not been independently reviewed, we cannot be certain of vaccines’ harms profiles.[Emphasis added]
The evidence base used in designing schedules is incomplete We should start by carrying out a more accurate assessment of the magnitude of disease threats. Those vaccines not targeting impending or credible threats should then be phased out or delayed. We also need randomised trials comparing different vaccination schedules to provide good quality data on the potential harms of single or multiple vaccinations. All aspects of vaccination should be monitored and assessed by independent studies.” (Is the Timing of Recommended Childhood Vaccines Evidence-Based?Dr. Tom Jefferson and Dr. Vittorio Demicheli, BMJ (2016)
“Our findings show a positive correlation between the number of vaccine doses administered and the percentage of hospitalizations and deaths. Infants who receive several vaccines concurrently, as recommended by CDC, are significantly more likely to be hospitalized or die when compared with infants who receive fewer vaccines simultaneously. It also showed that reported adverse effects were more likely to lead to hospitalization or death in younger infants.
Of the 38,801 VAERS reports that we analyzed, 969 infants received two vaccine doses prior to the adverse event and 107 of those infants were hospitalized: a hospitalization rate of 11%.The hospitalization rate increased linearly from 11.0% for two doses to 23.5% for eight doses.
The mortality rate among vaccinated infants stratified by the number of vaccine doses they received. The mortality rate for infants who received five to eight vaccine doses was 5.4%; significantly higher than for infants who received one to four doses (3.6%)
Cochrane Collaboration safety review of the MMR vaccine (2005; 2012) The Cochrane reviewers determined that none of the studies upon which the safety of the MMR vaccine rests met the Cochrane Collaboration’s methodological criteria.
“The design and reporting of safety outcomes in MMR vaccine studies, both pre- and post-marketing, are largely inadequate.”
* no studies had a low risk of bias;* two studies had a moderate/unknown risk of bias;* eight studies had a High risk of bias.* All studies suffered from a lack of adequate description of exposure (vaccine content and schedules).* Another recurring problem was the failure of any study to provide descriptions of all outcomes monitored. In addition, there was an overall attrition rate of 33%.* “The methodological quality of many of the included studies made it difficult to generalise their results.”
The review concluded: “The design and reporting of safety outcomes in MMR vaccine studies, both pre- and post-marketing, are largely inadequate…lack of clarity in reporting and systematic bias made comparability across studies and quantitative synthesis of data impossible.”
When DTP and OPV were introduced in Guinea-Bissau in 1981, allocation by birthday resulted in a natural experiment of being vaccinated early or late.
Between 3 and 5 months of age, children who received DTP and OPV early had 5-fold higher mortality than still unvaccinated children.
In the only two studies of the introduction of DTP and OPV, co-administration of OPV with DTP may have reduced the negative effects of DTP.
5 Conclusions: DTP was associated with 5-fold higher mortality than being unvaccinated. No prospective study has shown beneficial survival effects of DTP. Unfortunately, DTP is the most widely used vaccine, and the proportion who receives DTP3 is used globally as an indicator of the performance of national vaccination programs.
It should be of concern that the effect of routine vaccinations on all cause mortality was not tested in randomized trials. All currently available evidence suggests that DTP vaccine may kill more children from other causes than it saves from diphtheria, tetanus or pertussis. Though a vaccine protects children against the target disease it may simultaneously increase susceptibility to unrelated infections. [Emphasis aded]