Multiple Vaccinations on Same Day Does Not Raise Autism Risk
Infants now receive dozens of shots at a time, but the latest study says that does not increase their risk of developing autism.
About one-third of parents are concerned about unsubstantiated claims
that vaccines can cause autism. And although research, including an
analysis by the Institute of Medicine, has not found a causal
relationship between vaccines and the developmental disorder, one in 10
parents still delay or refuse to vaccinate their children according to the Center for Disease Control’s childhood immunization schedule.
Intuitively, parents believe that the amount of antigens, or
immune-activating agents in the shots, over-burden young babies’
still-developing immune systems, making them more vulnerable to
developing autism. So many parents “shot-limit,” or stagger the
immunizations their infants receive, spreading them out rather than
vaccinating their children at the recommended 2, 4, and 6 month visits.
There is no evidence, however, that delaying the various doses of the 14
different vaccinations recommended in the U.S. are safer for kids.
And the latest study investigating the practice, published in the
Journal of Pediatrics, continues to show there is no association between autism and receiving “too many shots too soon.”
The researchers reviewed data involving 256 kids with autism spectrum
disorders (ASD) and 752 without ASDs. By examining their vaccination
schedules, the scientists calculated the maximum amount of antigens from
the shots each child received during a single doctor’s visit to
determine how stimulated the babies’ immune systems were to create
antibodies against the diseases for which they were vaccinated. They
also calculated the infants’ overall antigen exposure in three different
groupings — from birth to three months, from birth to seven months, and
from birth to two years, by which time most youngsters should have
received the bulk of their childhood immunizations.
(
MORE: Vaccine Safety: Why Parents’ Alternative Immunization Schedules May Cause Harm)
For each age grouping, the scientists compared exposure to
antibody-producing antigen and risk of ASDs. By age two, most properly
vaccinated children should have been exposed to about 315 different
antigens from disease-causing agents such as measles, tetanus and
pertussis. They could not find any increase in incidence of
autism-related diagnoses with increasing exposure to antigens as the
children received more immunizations, and concluded that neither the
number of vaccines a child gets before age two nor the number of
vaccines a child gets in a single day were associated with developing
autism.
The researchers acknowledge that children today receive more vaccines
than they have before, but that doesn’t mean they are being exposed to
more antigens. In the 1990s, for example, infants were exposed to
thousands of antigens, rather than the current 315, from their
immunizations. That’s because some shots have been redesigned to
stimulate antibody production with fewer antigens; the older version of
the pertussis, or whooping cough shot that included the whole bacterium,
for instance, produces around 3,000 different antibodies while the new
vaccine that incorporates only a snippet of the pathogen produces less
than six. The scientists also stress
that an infant’s immune system can successfully confront a heavy burden
of such bacterial or viral stimuli, and that babies are exposed to
hundreds of viruses in their environment.