On 2015 Jul 27, Janet Kern commented:

The authors state, "Birth year changepoints were identified for 1980.9 [95% CI, 1978.6-1983.1], 1988.4 [95% CI, 1987.8-1989.0] and 1995.6 [95% CI, 1994.6-1996.6] for CA and U.S. data". For those that are knowledgeable about the Thimerosal issue, these are directly related to changes in the US vaccine schedule about Thimerosal. First for the 1981 date, in the late 1970s/early 1980s was when most states, including California adopted requirements that all children needed to be vaccinated to go to school and the expanded whole-cell DTP vaccine schedule (i.e., 5 doses vs. 3 doses). The whole-cell DTP vaccine contained 25 micrograms mercury per dose, so this first date corresponds to a significant increase in Thimerosal in vaccines in the US. For the second 1988 date, it corresponds to the approximate introduction of the Hib vaccine (first, with shots at 15-18 months, then followed very soon thereafter by the recommendation to be given as 4 shots starting at 2 months of age, and these generally contained 25 micrograms mercury per dose) and subsequently hepatitis B vaccine (3 shots starting on the day of birth, and these generally contained 12.5 micrograms mercury per dose) to be added to the US vaccine schedule. For the third 1996 date, it relates to what happened regarding the Hib vaccine. This vaccine started off as its own vaccine with 25 micrograms of mercury. Then in about 1992-1993, there was a combination vaccine that started to be marketed in the US whole-cell DTP-Hib vaccine, because this was a combined vaccine it contained 25 micrograms mercury. Then in about 1996, the acellular DTaP vaccine was recommended for administration to American infants, instead of the old whole-cell DTP vaccine. The acellular DTaP vaccine was generally manufactured without the Hib vaccine, so this resulted in American infants receiving increasing mercury dosing yet, again.

It is possible to see the consequences of the above changes in Thimerosal content in US vaccines and the risk of autism in the following published peer-reviewed studies:

(1) Young HA, Geier DA, Geier MR. Thimerosal exposure in infants and neurodevelopmental disorders: an assessment of computerized medical records in the Vaccine Safety Datalink. J Neurol Sci 2008;271:110-8. *** This study reveals a significant correlation between increasing/decreasing doses of mercury from Thimerosal-containing vaccines administered to birth cohorts in the United States from 1990 through 1996 and the increasing/decreasing prevalence of autism.

(2) Geier DA, Kern JK, King PG, Sykes LK, Geier MR. A case-control study evaluating the relationship between Thimerosal-containing haemophilus influenzae type b vaccine administration and the risk for a pervasive developmental disorder diagnosis in the United States. Biol Trace Elem Res 2015;163:28-38.

(3) Geier DA, Geier MR. An evaluation of the effects of Thimerosal on neurodevelopmental disorders reported following DTP and Hib vaccines in comparison to DTPH vaccine in the United States. J Toxicol Environ Health A 2006;69:1481-95. *** These studies reveal a significant correlation between the amount of Thimerosal children received from Thimerosal-containing Hib vaccines and the risk of autism.

(4) Geier DA, Geier MR. A comparative evaluation of the effects of MMR immunization and mercury doses from Thimerosal-containing childhood vaccines on the population prevalence of autism. Med Sci Monit 2004;10:PI33-9. *** This study reveals a significant correlation between increasing/decreasing doses of mercury from Thimerosal-containing vaccines administered to birth cohorts in the 1980s and early/middle 1990s and the increasing/decreasing prevalence of autism.

On 2015 Jul 27, Janet Kern commented:

The authors state, "Birth year changepoints were identified for 1980.9 [95% CI, 1978.6-1983.1], 1988.4 [95% CI, 1987.8-1989.0] and 1995.6 [95% CI, 1994.6-1996.6] for CA and U.S. data". For those that are knowledgeable about the Thimerosal issue, these are directly related to changes in the US vaccine schedule about Thimerosal. First for the 1981 date, in the late 1970s/early 1980s was when most states, including California adopted requirements that all children needed to be vaccinated to go to school and the expanded whole-cell DTP vaccine schedule (i.e., 5 doses vs. 3 doses). The whole-cell DTP vaccine contained 25 micrograms mercury per dose, so this first date corresponds to a significant increase in Thimerosal in vaccines in the US. For the second 1988 date, it corresponds to the approximate introduction of the Hib vaccine (first, with shots at 15-18 months, then followed very soon thereafter by the recommendation to be given as 4 shots starting at 2 months of age, and these generally contained 25 micrograms mercury per dose) and subsequently hepatitis B vaccine (3 shots starting on the day of birth, and these generally contained 12.5 micrograms mercury per dose) to be added to the US vaccine schedule. For the third 1996 date, it relates to what happened regarding the Hib vaccine. This vaccine started off as its own vaccine with 25 micrograms of mercury. Then in about 1992-1993, there was a combination vaccine that started to be marketed in the US whole-cell DTP-Hib vaccine, because this was a combined vaccine it contained 25 micrograms mercury. Then in about 1996, the acellular DTaP vaccine was recommended for administration to American infants, instead of the old whole-cell DTP vaccine. The acellular DTaP vaccine was generally manufactured without the Hib vaccine, so this resulted in American infants receiving increasing mercury dosing yet, again.

It is possible to see the consequences of the above changes in Thimerosal content in US vaccines and the risk of autism in the following published peer-reviewed studies:

(1) Young HA, Geier DA, Geier MR. Thimerosal exposure in infants and neurodevelopmental disorders: an assessment of computerized medical records in the Vaccine Safety Datalink. J Neurol Sci 2008;271:110-8. *** This study reveals a significant correlation between increasing/decreasing doses of mercury from Thimerosal-containing vaccines administered to birth cohorts in the United States from 1990 through 1996 and the increasing/decreasing prevalence of autism.

(2) Geier DA, Kern JK, King PG, Sykes LK, Geier MR. A case-control study evaluating the relationship between Thimerosal-containing haemophilus influenzae type b vaccine administration and the risk for a pervasive developmental disorder diagnosis in the United States. Biol Trace Elem Res 2015;163:28-38.

(3) Geier DA, Geier MR. An evaluation of the effects of Thimerosal on neurodevelopmental disorders reported following DTP and Hib vaccines in comparison to DTPH vaccine in the United States. J Toxicol Environ Health A 2006;69:1481-95. *** These studies reveal a significant correlation between the amount of Thimerosal children received from Thimerosal-containing Hib vaccines and the risk of autism.

(4) Geier DA, Geier MR. A comparative evaluation of the effects of MMR immunization and mercury doses from Thimerosal-containing childhood vaccines on the population prevalence of autism. Med Sci Monit 2004;10:PI33-9. *** This study reveals a significant correlation between increasing/decreasing doses of mercury from Thimerosal-containing vaccines administered to birth cohorts in the 1980s and early/middle 1990s and the increasing/decreasing prevalence of autism.