• Why do we vaccinate against varicella?

    New study out in Pediatrics describing the efficacy of the varicella (chicken pox) vaccine:

    Objective: Varicella has been preventable by vaccination in the United States since 1995. Previous studies reported a 66% decline in mortality rate during the first 6 years of the program. Since then, vaccination coverage has increased substantially. We updated the analysis of US varicella mortality for 2002–2007 and assessed the impact of the first 12 years of the US varicella vaccination program on varicella deaths.

    Methods: National data on deaths for which varicella was listed as an underlying or contributing cause were obtained from the Mortality Multiple Cause-of-Death records from the US National Center for Health Statistics. We calculated the age-adjusted and age-specific mortality rates for 2002–2007 and trends since the prevaccine years.

    I made a chart from their data showing the number of deaths per year from varicella. Keep in mind that you’re seeing the average number of deaths per year when years are grouped, and that the vaccine went into play in the mid-1990′s:

    I’d ask you to look specifically at the babies (the blue line). Remember, we don’t even vaccinate kids younger than one, so any benefits they are seeing are from herd immunity. This is an aspect of immunization which is discussed too rarely. You don’t just vaccinate your kids to protect them; you vaccinate them to protect all children. And when other children get vaccinated, they are protecting yours. The number of babies who died in 2004, 2005, 2006, and 2007 with varicella as the underlying cause was zero.

    Vaccinate your kids.

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