Rave reviews for 2-dose varicella program

Five years of the now recommended 2-dose varicella vaccine has dramatically reduced the incidence of chicken pox among all age groups, including among infants too young to be vaccinated.

Researchers from the Centers for Disease Control and Prevention and from the Los Angeles and Philadelphia Departments of Public Health looked at varicella incidence and disease characteristics in Antelope Valley, California, and West Philadelphia, Pennsylvania, during the 5 years following the 2006 switch from the 1-dose to 2-dose vaccine programs.

The results were dramatic. Both areas experienced 98% declines in incidence from 1995 to 2010. The declines occurred among the very young, among adults, and among the immune-compromised. In those aged younger than 1 year, for example, there was an 81% drop in Antelope Valley and a 41% drop in West Philadelphia.

Although the 2-dose program didn’t really change the number of lesions that people developed compared with the 1-dose version, it did reduce the number of hospitalizations. Varicella-related hospitalizations during the period 2006 to 2010 decreased by more than 40% compared with the period 2002 to 2005 and decreased by more than 85% compared with the period 1995 to 1998.

The 2-dose program also significantly reduced the number of outbreaks; 12 occurred in Antelope Valley during the period 2007 to 2010 compared with 47 during the period 2003 to 2006 and 236 during the period 1995 to 1998.

The fact that declines in incidence occurred even among infants too young to be vaccinated and among adults, in whom vaccination levels are low, demonstrates the benefit of achieving high levels of immunity among the population at large, concluded the researchers.

The most current varicella vaccine recommendations issued by the Advisory Committee on Immunization Practices can be found at www.cdc.gov/mmwr/preview/mmwrhtml/rr5604a1.htm.

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