Is it safer to spread vaccines out on a slower schedule?
Here is what the checked sources say. Each title links to the original.
The Childhood Immunization Schedule and Safety: Stakeholder Concerns, Scientific Evidence, and Future Studies
An independent expert committee reviewed the evidence on the full childhood schedule. It "found no significant evidence to imply that the recommended immunization schedule is not safe." It was candid that few studies examine the schedule as a whole, and that alternative schedules have not been well studied. It recommended using existing health-plan data to compare children on alternative schedules, rather than new randomized trials, which it called unethical and infeasible.
Association between undervaccination with diphtheria, tetanus toxoids, and acellular pertussis (DTaP) vaccine and risk of pertussis infection in children 3 to 36 months of age
Asked whether being behind on DTaP shots raises whooping cough risk. In eight US health plans from 2004 to 2010, 72 children aged 3 to 36 months with lab-confirmed whooping cough were compared with 288 matched children; 12 of the 72 were hospitalized. Being behind meant doses missing or delayed, not a specific alternative schedule. Children behind by 3 doses had about 18.6 times the odds of whooping cough of on-time children (95% CI 4.9 to 70), and those behind by 4 doses about 28 times (95% CI 3.2 to 253).
On-time vaccine receipt in the first year does not adversely affect neuropsychological outcomes
Compared children who got their first-year vaccines on time with children whose vaccines were delayed or skipped, then looked at 42 measures of thinking, learning and behavior at ages 7 to 10. The study found no sign that on-time children did worse on any measure. After adjusting for other factors, on-time children scored better on 2 measures, though with many measures tested this is not evidence of a benefit. The authors conclude timely infant vaccination has no adverse effect on these outcomes.
Alternative Vaccination Schedules
A plain-language look at spreading out shots. It explains that delays leave children unprotected longer against preventable diseases such as whooping cough. It cites research that children whose parents intentionally delayed vaccines were less likely to finish them: 46.7% were fully vaccinated by 24 months versus 70.7% of other children. Delayed schedules were also linked to a higher risk of whooping cough.