Winter Vaccinations Increase Autism Risk – New Study From California

A new statistical study [full abstract below] from the School of Medicine at the University of California, Davis shows a potential and small association in time in at best 6% of cases between between the month a child is conceived in California and the risk of developing autism.  This could indicate that winter vaccinations increase the risk of a child in California developing an autistic condition [explained below]. 

Winter conception (December through March) was associated with no more than a 6% increased risk compared with summer  (OR = 1.06, 95% CI = 1.02-1.10): [Month of Conception and Risk of Autism Zerbo, Ousseny; Iosif, Ana-Maria; Delwiche, Lora; Walker, Cheryl; Hertz-Picciotto, Irva Epidemiology., POST AUTHOR CORRECTIONS, 3 May 2011 doi:  10.1097/EDE.0b013e31821d0b53].

These results support an hypothesis that children conceived in winter months are at greater risk of developing autistic conditions when vaccinated during winter months. 

The study authors conclude:

Conclusions: Higher risks for autism among those conceived in winter months suggest the presence of environmental causes of autism that vary by season.”

Winter conceptions result predominantly in winter vaccinations

Children conceived in winter in the USA [December to March] will receive two doses of the Hepatitis B vaccine predominantly in winter in the period August to January ie. from birth and during the following two months. [Download .pdf of US vaccine schedule].

These children will also receive another 7 vaccines predominantly during the winter months. Some of these are repeated up to 3 times.  This is in the period aged two to six months [ie. seven vaccines: RV, DTaP, Hib, PCV, IPV].  This corresponds to the months of October through May for prior winter conceptions.

These children will also receive another series of vaccines predominantly during the winter in the period August through April aged 12 to 18 months: HepB DTaP Hib IPV Varicella MMR PCV Influenza HepA (2 doses).

Irresponsible Headline Grabber UC Davis Medics

As at least 94% of autistic childrens’ conditions clearly have nothing whatsoever to do with the month of conception the greedy publicity seeking widely announced publication of such a paper is grossly medically and ethically irresponsible.  Will parents now seek only to conceive children during May to August, being misled by the headlines in the media?  What might be the social implications – lower rates of conceptions, strains in marriages, increased divorce rates, burdens on health professionals concentrated on birth “booms” at particular times of year?   With such a small effect it is impossible to conclude anything from such a study.  The fact the authors had to look in the records of seven million children is not a strength but a weakness.  This is a result of increasing the size of the sample population until the calculation a such small difference becames “statistically” significant when in smaller populations it may not be.  Statistical significance is not a basis upon which to decide whether there is a real-world cause and effect relationship.  

These kinds of observational statistical studies should be treated with great caution. They are at best used only to consider hypotheses for later research. They do not prove cause but only associations. They can never prove there is no causal association even if they do not find a statistical association. With such a small effect as this study – no more than 6%, whilst the statistician might calculate the results are statistically significant, other errors not accounted for may mean such a small result is of no significance. It is notable the authors did not set out provisos like these to the world’s media when this study was being publicised.

The authors from a medical school [and therefore not necessarily trained scientists] did not appear to investigate a correlation to month of vaccination, nor between northern and southern California births [seasonal temperature differences can be significant], nor between regressive autistic conditions [appearing after birth from around the time of vaccination at 12-18 months] and autistic conditions apparent from birth.

Abstract:

Month of Conception and Risk of Autism Zerbo, Ousseny; Iosif, Ana-Maria; Delwiche, Lora; Walker, Cheryl; Hertz-Picciotto, Irva Epidemiology., POST AUTHOR CORRECTIONS, 3 May 2011 doi:  10.1097/EDE.0b013e31821d0b53].

Background: Studies of season of birth or season of conception can provide clues about etiology. We investigated whether certain months or seasons of conception are associated with increased risk of autism spectrum disorders, for which etiology is particularly obscure.

Methods: The study population comprises 6,604,975 children born from 1990 to 2002 in California. Autism cases (n = 19,238) were identified from 1990 through 2008 in databases of the California Department of Developmental Services, which coordinates services for people with developmental disorders. The outcome in this analysis was autism diagnosed before the child’s sixth birth date. The main independent variables were month of conception and season of conception (winter, spring, summer, and fall). Multivariate logistic regression models were used to estimate odds ratios (ORs) with their 95% confidence intervals (CIs) for autism by month of conception.

Results: Children conceived in December (OR = 1.09 [95% CI = 1.02-1.17]), January (1.08 [1.00-1.17]), February (1.12 [1.04-1.20]), or March (1.16 [1.08-1.24]) had higher risk of developing autism compared with those conceived in July. Conception in the winter season (December, January, and February) was associated with a 6% (OR = 1.06, 95% CI = 1.02-1.10) increased risk compared with summer.

Conclusions: Higher risks for autism among those conceived in winter months suggest the presence of environmental causes of autism that vary by season.

One Response

  1. […] Read more…. This entry was written by admin, posted on May 8, 2011 at 3:53 am, filed under Vaccines and tagged autism risk, vaccines. Bookmark the permalink. Follow any comments here with the RSS feed for this post. Post a comment or leave a trackback: Trackback URL.          […]

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