Trends in United States varicella mortality was assessed «Leung J, Bialek SR, Marin M. Trends in varicella mortality in the United States: Data from vital statistics and the national surveillance system. Hum Vaccin Immunother 2015;11(3):662-8. »2 using national vital statistics system data for 2008-2011, the first years of the routine 2-dose varicella vaccination program, and characteristics of varicella deaths reported to Centers for Disease Control and Prevention during 1996-2013 (table «Annual Varicella-Related Deaths in the United States, 1990–2011»1). Data on deaths with varicella as underlying or contributing cause was obtained from the 2008-2011 Mortality Multiple Cause-of Death records. The annual average age-adjusted mortality rate for varicella as the underlying cause was 0.05 per million population during 2008-2011, an 87% reduction from the prevaccine years. Varicella deaths among persons aged under 20 years declined by 99% in 2008-2011 compared with prevaccine years. There was a 70% decline in varicella mortality rates among those under 20 years in 2008-2011 compared to 2005-2007.
| Outcome | Varicella listed as underlying cause of death | ||
|---|---|---|---|
| 1990–1994 | 2005–2007 | 2008–2011 | |
| Total average no. of deaths per year | 105 | 15 | 17 |
| Varicella listed as contributing cause of death | |||
| 1990–1994 | 2005–2007 | 2008–2011 | |
| Total average no. of deaths per year | 39.6 | 20.3 | 16.3 |
A report evaluated «Leung J, Marin M. Update on trends in varicella mortality during the varicella vaccine era, United States 1990-2016. Hum Vaccin Immunother 2018;1-11. »3 5 additional years of annual average mortality rate in the United States for varicella. Varicella death data from the 2012-2016 Mortality Multiple Cause-of Death records were used to calculate mortality rates during 2012-2016 and trends since the prevaccine period and end of 1-dose vaccination program (2005-2007). The annual average age-adjusted mortality rate for varicella as the underlying cause was 0.03 per million population during 2012-2016, a 94% reduction from prevaccine years and a 47% reduction from 2005-2007.
A topic in Clinical Evidence «Swingler G. What are the effects of interventions to prevent chickenpox in healthy adults and children? Clinical Evidence 2004;12:1053-1057.»1 summarizes the results of one systematic review including 2 placebo-controlled RCTs. The first RCT found that varicella vaccine reduced clinical chickenpox at 9 months (0/468 vs 38/446, ARR 8.5%, 95% CI 6.1% to 11.5%) and at 2 years (1/163 vs 21/161, OR 0.05, 95% CI 0.01 to 0.35). The second RCT found that varicalla vaccine reduced clinical chickenpox after a mean of 29 months (AR 5/166 vs 41/161, RR 0.12, 95% CI 0.05 to 0.29). Clinical Evidence category: Beneficial.