Related Experiment Video
Updated: Aug 18, 2026
Strategies for Assessing Autistic-Like Behaviors in Mice
Published on: September 20, 2024
No effect of MMR withdrawal on the incidence of autism: a total population study
Hideo Honda1, Yasuo Shimizu, Michael Rutter
1Yokohama Rehabilitation Center, Yokohama, Japan. honda@yokohama.email.ne.jp
Background:
A causal relationship between the measles, mumps, and rubella (MMR) vaccine and occurrence of autism spectrum disorders (ASD) has been claimed, based on an increase in ASD in the USA and the UK after introduction of the MMR vaccine. However, the possibility that this increase is coincidental has not been eliminated. The unique circumstances of a Japanese MMR vaccination program provide an opportunity for comparison of ASD incidence before and after termination of the program.
Methods:
This study examined cumulative incidence of ASD up to age seven for children born from 1988 to 1996 in Kohoku Ward (population approximately 300,000), Yokohama, Japan. ASD cases included all cases of pervasive developmental disorders according to ICD-10 guidelines.
Results:
The MMR vaccination rate in the city of Yokohama declined significantly in the birth cohorts of years 1988 through 1992, and not a single vaccination was administered in 1993 or thereafter. In contrast, cumulative incidence of ASD up to age seven increased significantly in the birth cohorts of years 1988 through 1996 and most notably rose dramatically beginning with the birth cohort of 1993.
Conclusions:
The significance of this finding is that MMR vaccination is most unlikely to be a main cause of ASD, that it cannot explain the rise over time in the incidence of ASD, and that withdrawal of MMR in countries where it is still being used cannot be expected to lead to a reduction in the incidence of ASD.
Insights
The measles, mumps, and rubella (MMR) vaccine is unlikely to cause autism spectrum disorder (ASD). A study in Japan found ASD incidence rose after MMR vaccination rates declined, suggesting no causal link.
Area of Science:
- Epidemiology
- Vaccinology
- Developmental Pediatrics
Background:
- A claimed causal link exists between the measles, mumps, and rubella (MMR) vaccine and autism spectrum disorders (ASD).
- Previous studies noted increased ASD incidence in the USA and UK post-MMR introduction, but correlation does not equal causation.
- Japan's MMR vaccination program cessation offered a unique opportunity to study ASD incidence trends before and after vaccine withdrawal.
Purpose of the Study:
- To investigate the relationship between MMR vaccination and the incidence of ASD.
- To determine if MMR vaccination is a primary cause of ASD or contributes to its rising incidence.
- To assess the impact of MMR vaccine withdrawal on ASD rates.
Main Methods:
- Examined the cumulative incidence of ASD up to age seven in Yokohama, Japan, for birth cohorts from 1988 to 1996.
- Included all cases of pervasive developmental disorders (ICD-10) as ASD.
- Analyzed MMR vaccination rates and ASD incidence trends before and after the program's termination in 1993.
Main Results:
- MMR vaccination rates in Yokohama significantly decreased from 1988 to 1992, with no vaccinations administered from 1993 onwards.
- Cumulative ASD incidence up to age seven significantly increased for birth cohorts from 1988 to 1996.
- A dramatic rise in ASD incidence was observed, particularly starting with the 1993 birth cohort, coinciding with the MMR vaccine's withdrawal.
Conclusions:
- MMR vaccination is highly unlikely to be a primary cause of ASD.
- The MMR vaccine cannot explain the observed increase in ASD incidence over time.
- Discontinuing the MMR vaccine is not expected to reduce ASD incidence in countries where it is still administered.
Related Concept Videos
01:52Regression Toward the Mean
01:19Autism Spectrum Disorder
These core symptoms manifest differently among individuals, ranging from mild to severe. The disorder's complexity extends beyond its clinical presentation, encompassing a diverse range of biological, cognitive, and sociocultural influences.