CDC Data Reanalysis Shows Strong, Statistically Significant Relationship Between MMR Vaccine & Autism
Note: After four long years, CHD Board Member, Dr. Brian Hooker‘s reanalysis of the CDC’s MMR-autism data from the original DeStefano et al. 2004 Pediatrics paper has been republished in the Winter 2018 Edition of the Journal of American Physicians and Surgeons. The data, when properly analyzed, using the CDC’s own study protocol, show a strong, statistically significant relationship between the timing of the first MMR vaccine and autism, specifically in African American males. In addition, a relationship also exists in the timing of the MMR vaccine and those individuals who were diagnosed with autism without mental retardation. These relationships call into question the conclusion of the original DeStefano et al. 2004 paper which dismissed a connection between the MMR vaccine and autism.
Main Points from Reanalysis:
- The rate of autism diagnoses has increased alarmingly in the U.S., and is about 25 percent higher in black children. Boys are far more likely than girls to receive this diagnosis.
- As early as 2001, the Centers for Disease Control and Prevention (CDC) had data showing an increased rate of autism diagnoses in black male school children in Atlanta who received their first measles-mumps-rubella (MMR) vaccination before 36 months of age.
- The original publication concerning the data downplayed the association, and no follow-up was conducted.
- Dr. Hooker noted that the CDC deviated from its original data analysis plan, possibly because of unwanted results.
- The relationship loses its statistical significance if the analysis is restricted to children with a Georgia birth certificate, which decreases the sample size by about 40 percent.
- Dr. Hooker reanalyzed the same data set using the same methodology of conditional logistic regression but didn’t exclude children lacking a Georgia birth certificate.
- By stratifying data for African-American males by birth year, Dr. Hooker also found a statistically significant higher risk of an autism diagnosis in children who had received the first MMR vaccine 1 year earlier, only in children born in 1990 or later. Thimerosal exposure increased in the early 1990s, and it was not removed from most pediatric vaccines until 2001-2004. Dr. Hooker suggests the possibility that there may be some interaction between increased mercury exposure and early MMR vaccination. Further study would be needed to explore this possibility.
- Dr. Hooker’s interest was sparked, he reports, by communication with a CDC whistleblower, a senior scientist, who had retained some of the original analyses.
- Dr. Hooker concludes that failure to follow-up on these observations represents a huge lost opportunity to understand possible reasons for the enormous increase in this devastating neurological disability.
Introduction from Dr. Hooker’s article:
“This study is a re-analysis of Centers for Disease Control and Prevention (CDC) data pertaining to the relationship of autism incidence and the age at which children got their first measles-mumps-rubella (MMR) vaccine. Statistically significant relationships were observed when African-American males were considered separately while looking at those individuals who were vaccinated prior to and after a 36-month age cut-off. CDC officials observed very similar relationships as early as November 2001, but failed to report them in their final publication. In addition, a relationship is seen when specifically considering children who received a diagnosis of autism without mental retardation. Although this was reported in the original 2004 paper, it was not discussed, nor was any follow-up study conducted. Preliminary results also suggest the possibility of a synergism between thimerosal exposure and MMR timing leading to a greater risk of autism.”
Conclusion from Dr. Hooker’s article:
“The first data set used by DeStefano et.al represents a huge lost opportunity to understand any role between the timing of the first MMR vaccine and autism. The re-analysis presented here elucidates effects that should at least merit further investigation. Specifically, increased risks of earlier vaccination are observed for African-American males and among cases of autism without MR. Both phenomena deserve additional study that could yield important clues regarding the current enormous increase in autism.”
Dr. Hooker’s Reanalysis of CDC Data on Autism Incidence and Time of First MMR Vaccination was published December 7, 2018 in the Journal of American Physicians and Surgeons.