The varicella vaccine is on the World Bank's list of the most effective and safe medicines needed in a health system.
== See also ==Measles vaccineMMR vaccineMumps vaccineRubella vaccineVaricella vaccine== References ==== Further reading ==Centers for Disease Control and Prevention (CDC) (December 2005)
 However, according to the World Health Organization (WHO): "After observation of study populations for periods of up to 20 years in Japan and 10 years in the United States, more than 90% of immunocompetent persons who were vaccinated as children were still protected from varicella

