Study finds delaying vaccines is risky
A study published in Pediatrics about delaying vaccination adds another dimension to vaccination hesitancy: deciding to vaccinate children later than the schedule recommended by the Advisory Committee on Immunization Practices, which advises the CDC—is linked to a higher risk of childhood seizures.
The researchers note that access sometimes forces parents to put off vaccinating their children, while others think an older child may be subject to fewer perceived risks.
The investigators survey of 5,667 children included children who stuck with ACIP's vaccination schedule for their first 24 month as well as those who did not. The overall data showed an increased seizure risk also known as incidence risk ratio, or IRR, was lower among children vaccinated on schedule, with the degree of risk varying by type of vaccination. For DTaP—the diphtheria, tetanus and pertussis vaccine, researchers said the seizure risk was slightly higher for children vaccinated behind schedule—"generally elevated but not significant”—when vaccinated later than 92 days, or three months after the recommended schedule.
Delaying the measles, mumps, rubella (aka the MMR) vaccine, however, showed a more significant difference, with the incidence risk among the later-vaccinated—meaning after 15 months of age—was 6.53, compared to 2.65 for children vaccinated between 12 and 15 months of age. Putting off the varicella vaccine put the risk at 3.64 if given between 16 months and 23 months of age, compared to a risk of 2.75 among children vaccinated on schedule at between 12 and 15 months.
Researchers note that regardless of the vaccination provided, seizure risk peaks between 16 and 18 months, regardless of vaccination status.