252 Maternal Antibodies to Fetal Brain Neurons and Autism
for women who tested positive for influenza infection with symptoms, but this
increase was not statistically significant (P<0.05) in comparison with women
who tested negative for influenza infection and who were without symptoms.
The authors proposed that even though evidence of gestational influenza virus
infection alone (by laboratory test) was not associated with risk, positive labo
ratory tests and symptoms of influenza‐like illness cannot yet be definitively
ruled out as a risk factor for ASD. This means that there may be a slight risk for
ASD, according to the authors. We believe that this is like looking for a needle
in a haystack, and the risk may be minuscule and may not be related to the
influenza infection during pregnancy and there may be other factors.
A comprehensive report by Persson et al. [39] who analyzed over 3.3 million
individuals vaccinated with Pandemrix and compared them with 2.5 million
control individuals for any neurological and immunological diseases, including
narcolepsy, concluded that for a large number of selected neurological and
immune‐related diseases, there was neither confirmation or any causal asso
ciation with Pandemrix nor did it refute entirely a small excess risk. They
confirmed an increased risk for a diagnosis of narcolepsy in individuals below
20 years of age and observed a trend towards an increased risk amongst young
adults between 21 years old and 30 years old [39]. Here, we would remind the
readers that environmental factors, which were not considered in the large‐
scale analyses, may be contributing to some of these unusual issues. Flavored
drinks that are so prevalent in fast food, and flavored food that contain EDCs
and plastic bottles that could leach out bisphenol A and other neurodamaging
chemicals must be kept in mind.Other Viral and Nonviral Infections
As we have described in detail, there is a great body of research that suggests
maternal infections during pregnancy are associated with the risk of neurode
velopmental disorders, including ASD [37–40]. The major reason for such
an association is that there are numerous pathogenic agents that infect a
growing fetus, particularly during early fetal development when the BBB is
still weak and infectious agents can penetrate the fetal brain. We will
describe a detailed account of BBB development during various stages of
fetal development shortly, but at this juncture it is sufficient to state that
the fetal brain is not equally susceptible to infectious agents at all stages of
development and protective mechanisms keep the fetus free from most of
the infections at later stages of development, as opposed to early stages of
fetal development. A prime example of the development of a stronger BBB
is congenital Rubella infection [41]. In the case of maternal infection with
Rubella, the virus crosses the placenta and infects the fetus prior to week 18 of
gestation, but after weeks 18–20 of gestation there are unlikely to be any con
genital defects in the fetus [42,43]. Similarly, in the current pandemic of the Zika