Perspectives on the History and Epidemiology of the Varicella Virus Vaccine and Future Challenges.

The varicella attenuated virus vaccine, developed in Japan in the 1970s, has dramatically reduced the number of pediatric chickenpox cases over the past 30 years due to its widespread use. However, a small number of cases of chickenpox, shingles, aseptic meningitis, and acute retinal necrosis caused by vaccine strains have been reported. There are also issues that need to be addressed, such as breakthrough infections and the persistence of the preventive effect of vaccination. In addition, there is the possibility of the emergence of revertants or mutations in the vaccine strain. In recent years, subunit vaccines have been developed, their immune-stimulating effects have been demonstrated, and they are being applied clinically. In addition, development of an mRNA varicella vaccine is underway. In this review, the history and impact of the varicella vaccine are overviewed, as well as its future challenges.