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Measles and measles vaccine in Japan
1Department of Medical Zoology, Nagoya University, School of Medicine, Japan.
Abstract:
Before the introduction of measles vaccine in 1971, measles was a common and well-recognized disease in Japanese children. Seroepidemiological studies conducted before the general use of the vaccine disclosed that measles epidemics differed from community to community; in rural areas, epidemics appeared at intervals of several years with the accumulation of susceptibles, and in urban areas, measles was endemic affecting younger children. The measles vaccines developed in Japan showed excellent safety and efficacy in the clinical trials for general use. Since 1978 measles vaccines have been routinely given to children aged 12 months or older, and incidence of measles decreased dramatically. However, the vaccine acceptance rate has been only as high as 85% to 90% and small-scale outbreaks of measles have been observed periodically among unimmunized children: Measles is far from being eradicated in Japan. This is primarily due to the insufficient vaccine acceptance rate, and more efforts towards mobilization of parents to have their children vaccinated are now in progress.
Insights
Measles vaccination significantly reduced disease incidence in Japan, but insufficient vaccine acceptance rates (85-90%) hinder eradication efforts. Continued mobilization of parents is crucial for increasing childhood immunization coverage.
Area of Science:
- Pediatrics
- Epidemiology
- Immunology
Background:
- Measles was a prevalent childhood disease in Japan before vaccine introduction in 1971.
- Pre-vaccine measles epidemics varied regionally, with rural areas experiencing periodic outbreaks and urban areas showing endemic transmission among younger children.
- Japanese measles vaccines demonstrated high safety and efficacy in clinical trials.
Purpose of the Study:
- To analyze the impact of measles vaccination on disease incidence in Japan.
- To identify factors contributing to the persistence of measles in Japan despite vaccination programs.
- To highlight the need for improved vaccine acceptance rates to achieve measles eradication.
Main Methods:
- Review of seroepidemiological studies on measles patterns before 1971.
- Analysis of routine measles vaccination data since 1978.
- Monitoring of measles incidence and outbreak reports in relation to vaccine acceptance rates.
Main Results:
- Routine measles vaccination, implemented in 1978, led to a dramatic decrease in disease incidence.
- Vaccine acceptance rates have plateaued between 85% and 90%.
- Small-scale measles outbreaks continue to occur periodically among unvaccinated children.
Conclusions:
- Measles vaccination has been highly effective in reducing disease burden in Japan.
- Insufficient vaccine acceptance is the primary barrier to measles eradication in Japan.
- Enhanced parental mobilization campaigns are necessary to improve childhood immunization rates and achieve elimination goals.