Update on trends in varicella mortality during the varicella vaccine era—United States, 1990–2016 (original) (raw)
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Human vaccines & immunotherapeutics, 2015
This manuscript describes trends in US varicella mortality 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 CDC during 1996-2013. We obtained data on deaths with varicella as underlying or contributing cause from the 2008-2011 Mortality Multiple Cause-of Death records and calculated rates to compare with the prevaccine and mature 1-dose varicella vaccination program eras. We also reviewed available records of varicella deaths reported to CDC through the national varicella death surveillance. 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 <20 years declined by 99% in 2008-2011 compared with prevaccine years. There was a 70% decline in varicella mortality rates among those <20 years in...
Varicella Mortality: Trends before Vaccine Licensure in the United States, 1970–1994
The Journal of Infectious Diseases, 2000
We examined varicella deaths in the United States during the 25 years before vaccine licensure and identified 2262 people who died with varicella as the underlying cause of death. From 1970 to 1994, varicella mortality declined, followed by an increase. Mortality rates were highest among children; however, adult varicella deaths more than doubled in number, proportion, and rate per million population. Despite declining fatality rates, in 1990-1994, adults had a risk 25 times greater and infants had a risk 4 times greater of dying from varicella than did children 1-4 years old, and most people who died of varicella were previously healthy. Varicella deaths are now preventable by vaccine. Investigation and reporting of all varicella deaths in the United States is needed to accurately document deaths due to varicella, to improve prevention efforts, and to evaluate the vaccine's impact on mortality. Varicella is a highly infectious disease that is preventable by vaccine. Before vaccine licensure in 1995, ∼4 million cases per year resulted in р9300 hospitalizations [1] and 100 deaths each year [2]. Children bore the brunt of the health burden, accounting for 190% of cases, 66% of hospitalizations, and 45% of deaths (Centers for Disease Control and Prevention [CDC], unpublished data); however, the risk of severe complications and death was highest among infants, adults [2], and immunocompromised individuals [3, 4]. Moreover, complications and deaths were described commonly among previously healthy individuals [5-9]. Use of the varicella vaccine, which is recommended for routine use among susceptible people 112 months old [10, 11], is anticipated to alter the epidemiology of varicella by shifting the largest proportion of cases from children to adults. High vaccine coverage in childhood, especially if combined with a catch-up immunization program at adolescence, is expected to lead to a dramatic overall reduction in varicella cases and complications among both children and adults [12]. There has been no long-term, comprehensive analysis of varicella mortality for all age groups in the United States. We, therefore, analyzed national mortality data to characterize varicella deaths among United States residents during 1970-1994, the 25year period before varicella vaccine licensure. These data will serve as baseline data for an evaluation of the impact of the vaccination program on varicella mortality in the United States.
Near Elimination of Varicella Deaths in the US After Implementation of the Vaccination Program
PEDIATRICS, 2011
The impact of the 1-dose varicella vaccination program on varicella deaths has been documented for the early stages of program implementation. During the first 6 years of the program, deaths for which varicella was listed as the underlying cause declined 66% overall and Ն74% for people younger than 50 years. WHAT THIS STUDY ADDS: Our study documents the impressive impact on varicella mortality of the 1-dose US vaccination program: a decline of 88% overall and 96% among subjects younger than 50 years. With the current 2-dose program, there is potential that these most severe outcomes could be eliminated.
New England Journal of Medicine, 2005
Varicella disease has been preventable in the United States since 1995. Starting in 1999, active and passive surveillance data showed sharp decreases in varicella disease. We reviewed national death records to assess the effect of the vaccination program on mortality associated with varicella. methods Data on deaths for which varicella was listed as an underlying or contributing cause were obtained from National Center for Health Statistics Multiple Cause-of-Death Mortality Data for 1990 through 2001. We calculated the numbers and rates of death due to varicella according to age, sex, race, ethnic background, and birthplace. results The rate of death due to varicella fluctuated from 1990 through 1998 and then declined sharply. For the interval from 1990 through 1994, the average number of varicellarelated deaths was 145 per year (varicella was listed as the underlying cause in 105 deaths and as a contributing cause in 40); it then declined to 66 per year during 1999 through 2001. For deaths for which varicella was listed as the underlying cause, ageadjusted mortality rates dropped by 66 percent, from an average of 0.41 death per 1 million population during 1990 through 1994 to 0.14 during 1999 through 2001 (P<0.001). This decline was observed in all age groups under 50 years, with the greatest reduction (92 percent) among children 1 to 4 years of age. In addition, by the period from 1999 through 2001, the average rates of mortality due to varicella among all racial and ethnic groups were below 0.15 per 1 million population, as compared with rates ranging from 0.37 per 1 million for whites to 0.66 per 1 million for other races in the period from 1990 through 1994. conclusions The program of universal childhood vaccination against varicella in the United States has resulted in a sharp decline in the rate of death due to varicella.
Impact of vaccination on the epidemiology of varicella: 1995-2009
Pediatrics, 2014
When varicella vaccine was licensed in the United States in 1995, there were concerns that childhood vaccination might increase the number of adolescents susceptible to varicella and shift disease toward older age groups where it can be more severe. We conducted a series of 5 cross-sectional studies in 1994 to 1995 (prevaccine), 2000, 2003, 2006, and 2009 in Kaiser Permanente of Northern California to assess changes in varicella epidemiology in children and adolescents, as well as changes in varicella hospitalization in people of all ages. For each study, information on varicella history and varicella occurrence during the past year was obtained by telephone survey from a sample of ∼8000 members 5 to 19 years old; varicella hospitalization rates were calculated for the entire membership. Between 1995 and 2009, the overall incidence of varicella in 5- to 19-year-olds decreased from 25.8 to 1.3 per 1000 person-years, a ∼90% to 95% decline in the various age categories (5-9, 10-14, and...
Impact of Vaccination on the Epidemiology of Varicella
WHAT'S KNOWN ON THIS SUBJECT: Varicella vaccine is effective, but there is concern that widespread use in young children may lead to a shift in the age of infection, with potentially more severe disease later in childhood and adolescence. WHAT THIS STUDY ADDS: This study documents that varicella vaccine resulted in a decline of varicella incidence and hospitalization in all age groups, with no shift to older age groups. abstract BACKGROUND: When varicella vaccine was licensed in the United States in 1995, there were concerns that childhood vaccination might increase the number of adolescents susceptible to varicella and shift disease toward older age groups where it can be more severe.
Epidemiology of Varicella Hospitalizations in the United States, 1995–2005
The Journal of Infectious Diseases, 2008
To describe the impact of the varicella vaccination program on varicella-related hospitalizations (VRHs) in the United States, data from the Varicella Active Surveillance Project (VASP) were used to compare rates of hospitalization and rates of complications among patients hospitalized for varicella-related conditions from 1995 to 2005. Of the 26,290 varicella cases reported between 1995 and 2005, 170 cases resulted in VRHs, including 1 case that resulted in death. Both VRH rates per 100,000 population and complications during VRH per 100,000 population decreased significantly between the early vaccination period (1995-1998) and the middle/late vaccination period (1999-2005). Infants and adults were at highest risk for VRH, and having been vaccinated against varicella was a protective factor. Varicella vaccination may have prevented a significant number of VRHs. The fact that 4 vaccinated children required hospitalization for varicella-relatedcomplications demonstrates that 1 dose of varicella vaccine does not prevent serious disease in all cases, even among previously healthy children. Although sometimes regarded as a benign childhood illness, infection with varicella-zoster virus (VZV) can cause severe morbidity and mortality, due to complications involving varicella pneumonia, encephalitis and other neurological complications, hemorrhagic conditions, and invasive bacterial infections [1-3]. Before implementation of the varicella vaccination program in the United States in 1995, VZV infection resulted in an average of 11,000-13,500 hospitalizations and 100-150 deaths each year [1, 4-7]. Age and depressed cellular immune function, due to either medical conditions Potential conflicts of interest: B.M.W. received research funding from Merck during 1987-2000, at The Children's Hospital of Philadelphia, and has served on Merck advisory boards during the past 5 years. All other authors report no potential conflicts. Financial support: supplement sponsorship is detailed in the Acknowledgments. The findings and conclusions in this report are those of the authors and do not necessarily represent the views of the Centers for Disease Control and Prevention,
Changing Varicella Epidemiology in Active Surveillance Sites—United States, 1995–2005
The Journal of Infectious Diseases, 2008
Significant reductions in varicella incidence were reported from 1995 to 2000 in the varicella active surveillance sites of Antelope Valley (AV), California, and West Philadelphia (WP), Pennsylvania. We examined incidence rates, median age, and vaccination status of case patients for 1995-2005. Coverage data were from the National Immunization Survey. By 2005, coverage among children 19-35 months of age reached 92% (AV) and 94% (WP); 57% and 64% of case patients in AV and WP, respectively, were vaccinated; and varicella incidence declined by 89.8% in AV and 90.4% in WP. Incidence declined in all age groups, especially among children !10 years of age in both sites and among adolescents 10-14 years of age in WP. In AV, since 2000, the incidence among adolescents 10-14 and 15-19 years of age increased. Implementation of school requirements through 10th grade in WP may explain the differences in the decline in incidence among adolescents. Continued surveillance will be important to monitor the impact that the 2-dose vaccine policy in children has on varicella epidemiology.
The Case against Universal Varicella Vaccination
International Journal of Toxicology, 2006
In 1995, the United States became the first country to implement a Universal Varicella Vaccination Program. Several questions remain: Is the varicella (chickenpox) vaccine needed? Is it cost effective as a routine immunization for all susceptible children? Or is it more beneficial for the disease to remain endemic so that adults may receive periodic exogenous exposures (boosts) that help suppress the reactivation of herpes zoster (shingles). In addition, as vaccination coverage becomes widespread, does loss of immunologic boosting cause a decline in vaccine efficacy and result in a reduced period of immunity? Scientific literature regarding safety of the varicella vaccine and its associated cost-benefit analysis have often reported optimistic evaluations based on ideal assumptions. Deleterious outcomes and their associated costs must be included when making a circumspect assessment of the Universal Varicella Vaccination Program.