Other Contributing Factors in Neuropsychiatric Disorders 251concern emerged from reports that increased numbers of cases of narcolepsy
were apparent in nonvaccinated subjects infected with wild Influenza A
(H1N1) pandemic influenza virus. This suggested a role for the viral
antigen(s) in disease development [35–37]. Ahmed et al. (35) have found
that the peptide in influenza nucleopeptide A (one of the antigenic compo
nents in the Pandemrix influenza vaccine) shares an uncanny similarity with
human brain molecules (hypocretin receptor 2), which have been linked to
narcolepsy. Due to the enormous fear that emerged after reports that a
global influenza A (H1N1) pandemic would kill billions of humans in June
2009, mass vaccination campaigns were carried out using newly developed
monovalent influenza A (H1N1) pandemic vaccines. A number of coun
tries, using a range of vaccine protocols, carried out large scale immuniza
tions. An estimated 31 million doses of European AS03‐adjuvanted A
(H1N1) pandemic vaccine were used in more than 47 countries, and the
Canadian AS03‐adjuvanted A (H1N1) pandemic vaccine was given to 12
million people. As no similar narcolepsy association has been reported to
date with the AS03‐adjuvanted A (H1N1) pandemic vaccine made using the
Canadian inactivation/purification protocol, it appeared that the AS03
adjuvant alone may not be responsible for the narcolepsy association. To
date, no narcolepsy association has been reported with the MF59®‐adju
vanted A (H1N1) pandemic vaccine. The connection between narcolepsy
and the Pandemrix vaccine may be a factor in other cases where cross reac
tivity occurs. Looking back on the percentage of Americans vaccinated for
influenza, focusing on child‐bearing women, if this does contribute to
autism, then the rate of occurrence would be significantly higher.
Furthermore, a blanket association with influenza vaccine and development
of ASD may not be scientifically valid, since each year a new vaccine is pro
duced directed against the predicted new strain of influenza virus. Therefore,
it is unlikely that all different strains of anti‐influenza with variations in
antigenic molecules would have adverse effects on fetal brain development.
In addition, it appears that from the global H1N1 vaccination we have
learned that certain adjuvants may be better in prevention of potential nar
colepsy [38,39].
Most recently, Mahic et al. [38] have addressed the issue of influenza infec
tion during pregnancy. These investigators obtained information from ques
tionnaires and samples from the Autism Birth Cohort, a prospective birth
cohort comprising mothers, fathers, and offspring recruited in Norway from
1999 to 2008. Through questionnaires, referrals, and linkages to the Norwegian
National Patient Registry, they identified 338 mothers of children with ASD
and 348 frequency‐matched controls for whom plasma samples had been col
lected mid‐pregnancy and after delivery. They analyzed the influenza virus
sera from both groups and found that neither influenza A nor influenza B virus
infection was associated with increased ASD risk. Integration of reports of
symptoms of influenza‐like illness with serology revealed an increase in risk