Epidemiology Of Varicella Research Articles

Epidemiology and economic burden of measles, mumps, pertussis, and varicella in Germany: a systematic review.

ObjectivesDespite the availability of vaccines and the existence of public vaccination recommendations, outbreaks of vaccine-preventable childhood diseases still cause public health debate. The objective of this systematic review was to provide an overview of the current epidemiology and economic burden of measles, mumps, pertussis, and varicella in Germany.MethodsWe systematically reviewed studies published since 2000. The literature search was conducted using PubMed and EMBASE. Also, we used German notification data to give an up-to-date overview of the epidemiology of the four diseases under consideration.ResultsThirty-six studies were included in our review. Results suggest that there is still considerable morbidity due to childhood diseases in Germany. Studies providing cost estimates are scarce. Comparative analyses of different data sources (notification data vs. claims data) revealed a potential underestimation of incidence estimates when using notification data. Furthermore, several studies showed regional differences in incidence of some of the diseases under consideration.ConclusionsOur findings underline the need for improved vaccination and communication strategies targeting all susceptible age and risk groups on a national and local level.Electronic supplementary materialThe online version of this article (doi:10.1007/s00038-016-0842-8) contains supplementary material, which is available to authorized users.

A deterministic model for highly contagious diseases: The case of varicella

The classic nonlinear Kermack–McKendrick model based upon a system of differential equations has been widely applied to model the rise and fall of global pandemic and also seasonal epidemic by introducing a forced harmonic infectivity which would change throughout the year. These methods work well in their respective domains of applicability, and for certain diseases, but they fail when both seasonality and high infectivity are combined. In this paper we consider a Susceptible–Infected–Recovered, or SIR, model with two latent states to model the propagation and evolutionary history of varicella in humans. We show that infectivity can be calculated from real data and we find a nonstandard seasonal variation that cannot be fitted with a single harmonic. Moreover, we show that infectivity for the present strains of the virus has raised following a sigmoid function in a period of several centuries. This could allow the design of vaccination strategies and the study of the epidemiology of varicella and herpes zoster.

Twenty Years of Medically-Attended Pediatric Varicella and Herpes Zoster in Ontario, Canada: A Population-Based Study.

ObjectiveTo determine if reductions in medically-attended pediatric varicella and herpes zoster occurred in Ontario, Canada, after publicly-funded varicella immunization was implemented in 2004.MethodsFor fiscal years (FY) 1992-2011, we examined data on varicella and herpes zoster physician office visits, emergency department (ED) visits, hospitalizations (including for varicella-associated skin and soft tissue infections [SSTI]), and intensive care unit (ICU) admissions, among those aged <18 years. The pre-vaccine, privately-available, and vaccine program eras were FY1992-1998, FY1999-2003, and FY2004-2011, respectively. We used Poisson regressionand Kruskal-Wallis tests (all at the p<0.05 level of significance), and compared rates using incidence rate ratios (IRRs) and 95% confidence intervals (CIs).ResultsIncidence of varicella office visits declined over the study period from a high of 25.1/1,000 in FY1994 to a low of 3.2/1,000 in FY2011. ED visits and hospitalizations followed similar patterns of decreasing rates later in the study period. IRRs comparing the vaccine program versus pre-vaccine eras were 0.29 (95%CI: 0.26-0.32) for office visits, 0.29 (95%CI: 0.21-0.40) for ED visits, and 0.41 (95%CI: 0.10-1.69) for hospitalizations. Annual declines in varicella office visits were 7.7%, 9.1%, 8.4%, and 8.4% per year among children aged <1 year, 1-4 years, 5-11 years, and ≥12 years, respectively (all p<0.001). Age-specific rates of varicella-associated SSTI declined significantly among children <12 years (p<0.001) and rates of ICU admissions decreased significantly for children <1 year (p = 0.02). (p<0.001) over the study period. For children aged 5-17 years, herpes zoster office visits decreased whereas ED visits increased (both p<0.001) and there was a small, non-significant (p = 0.07), decrease in hospitalizations.ConclusionMedically-attended varicella decreased during the study period, particularly since varicella vaccine was publicly-funded. Results suggest immunization program-related changes in varicella epidemiology, including herd effects, demonstrated by reductions in varicella in program-ineligible age groups. We did not observe a consistent impact on herpes zoster.

Impact of vaccination on the epidemiology of varicella.

Thank you for publishing reviews of our paper (Baxter R, Tran TN, Ray P, et al. Impact of vaccination on the epidemiology of varicella: 1995-2009. Pediatrics 2014;134:24-30), and for giving us a chance to respond. We agree with all the reviewers, that our study was very reassuring, in that it did not show a trend to worsening disease in older individuals, as a result of broad immunization of younger children. We appreciate the discussion of other areas of the world which are not as well immunized as our integrated medical care organization (Kaiser Permanente) (1,2), and the finding that even lower levels of immunization have been found to provide herd immunity.

The impact of ten years of infant universal Varicella vaccination in Sicily, Italy (2003–2012)

Introduction Universal varicella vaccination in Sicily was introduced in infant population since 2003, with a rapidly increasing coverage. Aim of the present study was to analyze changes in the epidemiology of varicella since the introduction of universal vaccination.Methods The study was performed by analyzing Sicilian administrative/clinical data on varicella case notifications and hospitalizations from 2003 to 2012 (ICD-9-CM discharge diagnosis codes 052 and 052.×). MMR+V and V coverage were also calculated for each birth cohort. Moreover, blood samples drawn in 2013/2014 from general population stratified by age were tested for varicella antibodies.Results From 2003 to 2012, 15 433 varicella cases were notified with a decreasing temporal trend (1.1/1000 population in 2003 to 0.1/1000 in 2012) (P < 0.001). In the same period, a total of 1145 patients were hospitalized with a diagnosis of varicella, with a 6-fold reduced risk of hospitalization over time (from 4.8 to 0.8/100 000 population per year; P < 0.001). Varicella vaccination coverage rates increased from 40% (2001 birth cohort) to 85% (2010 birth cohort), and inversely correlated with both notification and hospitalization rates (P < 0.001). Finally, 80.0% of subjects enrolled in the seroepidemiological survey were positive for varicella and seroprevalence increased significantly with age in both sexes (P < 0.001).Discussion The results show the impact of infant universal varicella vaccination in Sicily. Noteworthy, notifications and hospitalizations for varicella have significantly decreased after the introduction of universal vaccination, confirming the effectiveness of the adopted strategy.

Effectiveness of vaccination against varicella in children under 5 years in Puglia, Italy 2006–2012

In Italy, between 2003 and 2010, 8/21 Regions recommended varicella routine vaccination (URV). The National Immunization Plan (PNPV) 2012–2014 scheduled the introduction of URV nationwide in 2015, following the results achieved by the eight Regions. Puglia adopted varicella URV in 2006. This study describes epidemiology and costs of varicella in Puglia between 2003 and 2012. One-dose Vaccine Effectiveness (VE) against varicella of any severity and severe hospitalized cases in children was also evaluated. Vaccination coverage (VC) was estimated from the regional immunization registry. Incidence and hospitalization rates were calculated from computerised surveillance system for communicable diseases and hospital discharge registry (ICD9-CM codes: 052.x), respectively. URV impact was assessed by Incidence Rate Ratios (IIRs) and Hospitalization Risk Ratios (HRRs). Hospitalization costs were also evaluated. VE was estimated using the screening method, where PPV was VC in children aged <72 months and PCV was the proportion of cases vaccinated among notified or hospitalized cases, respectively. One-dose VC in children aged ≤ 24 months increased from 49% in the birth cohort 2006 to 91.1% in the cohort 2010; 2-dose VC was 64.8% and 28.8% in the 2005 and 1997 cohort, respectively. Comparing pre and post-vaccination era, incidence declined from 122.5 ×100 000 in 2003–2005 to 13.7 in 2009–2012 (IRR = 0.11, 95% CI = 0.10–0.12), hospitalization rate from 3.9 ×100 000 to 1.1 (HRR = 0.29, 95% CI = 0.21–0.4), hospitalization costs from 319 000 Euros/year to 106 000. One-dose VE against varicella of any severity and severe hospitalized disease was 98.8% and 99%, respectively. Our findings strongly support varicella URV introduction into the Italian Essential Health Interventions, as scheduled by 2015.

PIN40 - Epidemiology and Costs of Varicella and Herpes Zoster in Germany

PIN40 - Epidemiology and Costs of Varicella and Herpes Zoster in Germany

Challenges with controlling varicella in prison settings: experience of California, 2010 to 2011.

This article describes the epidemiology of varicella in one state prison in California during 2010 and 2011, control measures implemented, and associated costs. Eleven varicella cases were reported, of which nine were associated with two outbreaks. One outbreak consisted of three cases and the second consisted of six cases with two generations of spread. Among exposed inmates serologically tested, 98% (643/656) were varicella-zoster virus seropositive. The outbreaks resulted in > 1,000 inmates exposed, 444 staff exposures, and > $160,000 in costs. The authors documented the challenges and costs associated with controlling and managing varicella in a prison setting. A screening policy for evidence of varicella immunity for incoming inmates and staff and vaccination of susceptible persons has the potential to mitigate the impact of future outbreaks and reduce resources necessary to manage cases and outbreaks.

Impact of vaccination on the epidemiology of varicella: 1995-2009.

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 15-19 years of age). The proportion of varicella-susceptible children and adolescents also decreased in all age groups, including in 15- to 19-year-olds (from 15.6% in 1995 to 7.6% in 2009). From 1994 to 2009, age-adjusted varicella hospitalization rates in the general member population decreased from 2.13 to 0.25 per 100,000, a ∼90% decline. In the 15 years after the introduction of varicella vaccine, a major reduction in varicella incidence and hospitalization was observed with no evidence of a shift in the burden of varicella to older age groups.

Risk factors for susceptibility to varicella in newly arrived adult migrants in Canada

Varicella occurs at an older age in tropical compared to cold climates. Migrants from tropical countries provide the opportunity to gain insights into observed global differences in varicella epidemiology. Severity of varicella increases with age thus, description of risk factors for varicella susceptibility will identify those who would benefit most from vaccination. A total of 1480 migrants, with a mean age of 32 years, were recruited in the pre-vaccination period (2002-2004) in Montreal, Canada. A questionnaire was administered and serum varicella antibodies were measured. Overall 6% were susceptible and ranged from 0·8% to 14·1% in subgroups. Risk factors for susceptibility were younger age, recent arrival, and originating from a tropical country. This could be modified by conditions that increased the probability of person-to-person spread of varicella through direct contact in source countries such as larger community size or household crowding. Many new young adult migrants would benefit from targeted varicella vaccination programmes.

Varicella After the Perinatal Period

1. Molly C. Berkoff, MD, MPH 2. Wallace D. Brown, MD 1. Department of Pediatrics, Division of General Pediatrics and Adolescent Medicine, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC. 1. Acyclovir for Treating Varicella in Otherwise Healthy Children and Adolescents. Klassen TP, Hartling L. Cochrane Database Syst Rev. 2005;(4):CD002980 2. FDA Approval of an Extended Period for Administering VariZIG for Postexposure Prophylaxis of Varicella. MMWR Morb Mortal Wkly Rep . 2012;61(12):212 3. Prevention of Varicella: Recommendations for Use of Varicella Vaccines in Children, Including a Recommendation for a Routine 2-Dose Varicella Immunization Schedule. American Academy of Pediatrics Committee on Infectious Diseases. Pediatrics. 2007;120(1):221–231 [OpenUrl][1][Abstract/FREE Full Text][2] 4. Changing Varicella Epidemiology in Active Surveillance Sites-United States, 1995–2005. Guris D, Jumaan AO, Mascola L, et al. J Infect Dis. 2008:197(suppl 2):S71–S75 Formerly a common childhood infection that affected almost all children, varicella (chickenpox) is now relatively uncommon because of successful prevention with universal vaccination. Before available immunization, approximately 4 million cases of varicella disease were reported annually. By 2005, active surveillance sites documented a decrease in the incidence of varicella of approximately 90%. Varicella is the primary clinical manifestation of infection with varicella-zoster virus. The initial infection with the virus occurs from exposure to an infected person, and transmission occurs through contact with the respiratory tract, conjunctiva, and skin lesions. Approximately 80% to 90% of susceptible individuals will acquire the infection after exposure to an infected individual. After an incubation period of 10 to 21 days, an infected individual may experience a brief prodrome, including fever and malaise, for 2 days before the development of a pruritic rash containing 250 to 500 lesions in an unimmunized person. Lesions appear in crops and contain vesicles on an erythematous base, which eventually scab. Children who have been immunized and have breakthrough varicella typically will have fewer lesions (<50 … [1]: {openurl}?query=rft.jtitle%253DPediatrics%26rft.stitle%253DPediatrics%26rft.issn%253D0031-4005%26rft.aulast%253DCommittee%2Bon%2BInfectious%2BDiseases%26rft.auinit1%253D%2B%26rft.volume%253D120%26rft.issue%253D1%26rft.spage%253D221%26rft.epage%253D231%26rft.atitle%253DPrevention%2Bof%2BVaricella%253A%2BRecommendations%2Bfor%2BUse%2Bof%2BVaricella%2BVaccines%2Bin%2BChildren%252C%2BIncluding%2Ba%2BRecommendation%2Bfor%2Ba%2BRoutine%2B2-Dose%2BVaricella%2BImmunization%2BSchedule%26rft_id%253Dinfo%253Adoi%252F10.1542%252Fpeds.2007-1089%26rft_id%253Dinfo%253Apmid%252F17606582%26rft.genre%253Darticle%26rft_val_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Ajournal%26ctx_ver%253DZ39.88-2004%26url_ver%253DZ39.88-2004%26url_ctx_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Actx [2]: /lookup/ijlink?linkType=ABST&journalCode=pediatrics&resid=120/1/221&atom=%2Fpedsinreview%2F34%2F11%2F537.atom

PIN3 - Burden of Varicella in Latin America: A Systematic Review and Critical Analysis

PIN3 BurdeN of VarIcella IN latIN amerIca: a SyStematIc reVIew aNd crItIcal aNalySIS Yang H.K.1, Liaw K.L.2, Manoff S.2, Kuter B.1 1Merck & Co, Inc., West Point, PA, USA, 2Merck & Co, Inc., Upper Gwynedd, PA, USA Objectives: Varicella is a common, vaccine-preventable illness with significant public health impact in Latin America (LA). This study aimed to review the epidemiology and economic burden of varicella, and to perform a critical analysis of available data in LA. MethOds: A comprehensive literature review was conducted in major databases and government websites to identify published data on epidemiology and economic burden of varicella in LA. Study data were extracted systematically including incidence rates, lifetime prevalence, mortality, type and rates of complications, as well as use of health care resources (hospitalizations, physician office visits, others) and both direct and indirect costs associated with varicella. Critical analyses of study quality and data availability are performed for each country. Results: Published studies were identified from ten countries including Argentina, Bolivia, Brazil, Chile, Colombia, Ecuador, Mexico, Paraguay, Uruguay, and Venezuela. Annual incidence rates ranged from 20 per 100,000 in Uruguay up to 381 per 100,000 in Mexico. Incidence was highest among children < 10 years of age, bearing increased utilization of healt health care resources. Bimodal seasonal patterns of varicella were reported in Argentina, Mexico and Uruguay. Most frequent complications among hospitalized patients were skin and soft tissue infections, respiratory infections and neurological complications. Patients hospitalized for varicella stayed generally between 1-5 days. Critical analysis suggested that most published studies had limitations including data representativeness and study design issues. Data gaps in the epidemiology and economic burden of varicella were also found on the country level. cOnclusiOns: Currently there is limited information available on burden of varicella in Latin America, potentially due to the lack of mandatory reporting and active surveillance systems for varicella in the region. Country-specific epidemiological information and varicella-related health care resource utilization data are needed to elucidate the disease burden for developing appropriate immunization recommendations and informing decision makers about the value of varicella vaccination.

Impact of universal two-dose vaccination on varicella epidemiology in Navarre, Spain, 2006 to 2012

In 2007 in Navarre, Spain, universal varicella vaccination with two doses of Varivax was introduced in the childhood immunisation schedule for children aged 15 months and three years. This study describes changes in the epidemiology of varicella in the period 2006 to 2012 and evaluates vaccination effectiveness using epidemiological surveillance data. The incidence of varicella in children aged 0 to 14 years decreased by 98.1%, from 50.1 cases per 1,000 inhabitants in 2006, to 1.0 per 1,000 in 2012. Children aged one to eight years were the vaccinated cohorts, and their incidence of varicella decreased by 98.5% (p&lt;0.0001). In unvaccinated age groups, important reductions were also achieved between 2006 and 2012: 90.5% (p&lt;0.0001) in infants under one year of age, and 89.4% (p&lt;0.0001) in children aged nine years. In the period 2006 to 2012, the hospital admissions rate for varicella or its complications decreased by 89.0%, and in 2012, there was only one admission of a newborn with neonatal varicella. Vaccine effectiveness for at least one dose was 96.8% (95% confidence interval: 96.3-97.2%). Universal vaccination with two doses has reduced varicella circulation to minimum levels within five years and has proved highly effective.

Varicella Disease in Beijing in the Era of Voluntary Vaccination, 2007 to 2010

In China, varicella vaccine has been available in the private sector to children ≥12 months of age since 1998 with a single-dose indication. In December 2006, varicella became a notifiable disease in Beijing. We used surveillance data to describe varicella vaccine uptake from 2005 to 2010 and varicella epidemiology in Beijing from 2007 to 2010. Limited sociodemographic and clinical information was available from the passive surveillance system. Varicella vaccine coverage was estimated for each year for children born between 2004 and 2008 using the number of children in the immunization registry of each birth year as the denominator without adjustment for history of varicella. Vaccine coverage increased within each birth cohort between 2005 and 2010. The coverage at 2 years of age increased from 62.4% in 2005 to 74.1% in 2010 and was 80.4% in children 3-6 years of age in 2010. Between 2007 and 2010, 15,544 to 18,256 varicella cases were reported annually with stable overall incidence (range: 1.0-1.1/1000 persons), but the incidence in children 1-4 years of age decreased significantly from 6.2 per 1000 children in 2007 to 4.4 per 1000 children in 2010 (P < 0.001). Among adults (≥20 years of age), there were significant increases in the number and proportion of cases from 2557 (16.5%) in 2007 to 4277 (23.4%) in 2010 (P < 0.001). Moderately high 1-dose vaccine coverage in young children has been achieved with declining disease incidence, but varicella remains a common, seasonal disease in the population. Current epidemiology suggests that a government-funded varicella vaccine program that includes catch-up vaccination for older children, adolescents and adults needs consideration.

Varicella zoster virus in American Samoa: seroprevalence and predictive value of varicella disease history in elementary and college students

The epidemiology of varicella is believed to differ between temperate and tropical countries. We conducted a varicella seroprevalence study in elementary and college students in the US territory of American Samoa before introduction of a routine varicella vaccination programme. Sera from 515 elementary and 208 college students were tested for the presence of varicella-zoster virus (VZV) IgG antibodies. VZV seroprevalence increased with age from 76·0% in the 4-6 years group to 97·7% in those aged ⩾23 years. Reported history of varicella disease for elementary students was significantly associated with VZV seropositivity. The positive and negative predictive values of varicella disease history were 93·4% and 36·4%, respectively, in elementary students and 97·6% and 3·0%, respectively, in college students. VZV seroprevalence in this Pacific island appears to be similar to that in temperate countries and suggests endemic VZV circulation.

Varicella routine vaccination and the effects on varicella epidemiology – results from the Bavarian Varicella Surveillance Project (BaVariPro), 2006-2011

BackgroundIn 2004, routine varicella vaccination was recommended in Germany for children 11-14 months of age with one dose, and since 2009, with a second dose at 15-23 months of age. The effects on varicella epidemiology were investigated.MethodsData on varicella vaccinations, cases and complications were collected from annual parent surveys (2006-2011), monthly paediatric practice surveillance (Oct 2006 - Sep 2011; five varicella seasons) and paediatric hospital databases (2005-2009) in the area of Munich (about 238,000 paediatric inhabitants); annual incidences of cases and hospitalisations were estimated.ResultsVaricella vaccination coverage (1st dose) in children 18-36 months of age increased in two steps (38%, 51%, 53%, 53%, 66% and 68%); second-dose coverage reached 59% in the 2011 survey. A monthly mean of 82 (62%) practices participated; they applied a total of 50,059 first-dose and 40,541 second-dose varicella vaccinations, with preferential use of combined MMR-varicella vaccine after recommendation of two doses, and reported a total of 16,054 varicella cases <17 years of age. The mean number of cases decreased by 67% in two steps, from 6.6 (95%CI 6.1-7.0) per 1,000 patient contacts in season 2006/07 to 4.2 (95%CI 3.9-4.6) in 2007/08 and 4.0 (95%CI 3.6-4.3) in 2008/09, and further to 2.3 (95%CI 2.0-2.6) in 2009/10 and 2.2 (95%CI 1.9-2.5) in 2010/11. The decrease occurred in all paediatric age groups, indicating herd protection effects. Incidence of varicella was estimated as 78/1,000 children <17 years of age in 2006/07, and 19/1,000 in 2010/11. Vaccinated cases increased from 0.3 (95%0.2-0.3) per 1,000 patient contacts in 2006/07 to 0.4 (95%CI 0.3-0.5) until 2008/09 and decreased to 0.2 (95%CI 0.2-0.3) until 2010/11. The practices treated a total of 134 complicated cases, mainly with skin complications. The paediatric hospitals recorded a total of 178 varicella patients, including 40 (22.5%) with neurological complications and one (0.6%) fatality due to varicella pneumonia. Incidence of hospitalisations decreased from 7.6 per 100,000 children <17 years of age in 2005 to 4.3 in 2009, and from 21.0 to 4.7 in children <5 years of age.ConclusionsOverall, the results show increasing acceptance and a strong impact of the varicella vaccination program, even with still suboptimal vaccination coverage.

Epidemiology of varicella in Mexico

BackgroundThe epidemiological patterns of varicella-zoster virus (VZV) infection, which are strongly associated with climate, are characterized by more frequent infections occurring among children in temperate regions than in the tropics. In temperate regions, varicella exhibits a seasonal cyclic behavior in which the number of cases increases significantly during the winter and spring seasons, further supporting the role of environmental factors in disease transmission. However, the underlying mechanisms responsible for this distinctive behavior are not fully understood. In Mexico, information regarding the epidemiology of varicella is scarce, and the distribution of VZV infection has not been analyzed. ObjectivesIn this article we investigate the epidemiological patterns of varicella in Mexico and their relationship with different environmental and demographic factors. Study designA retrospective study was conducted using the data reported by the National Center of Epidemiological Surveillance and Disease Control. The overall varicella incidence was calculated and associated with temperature, overcrowding, age, gender and population density. ResultsThe epidemiology of varicella showed an intriguing pattern, in which warmer regions were characterized by higher incidences than in temperate regions. Young children were the most affected age group. There was no correlation between varicella incidence and overcrowding or population density. ConclusionsThe epidemiology of varicella in Mexico significantly departs from the characteristic patterns observed in other tropical latitudes, with some features resembling those commonly associated with temperate regions.

Epidemiological characteristics of varicella from 2000 to 2008 and the impact of nationwide immunization in Taiwan

BackgroundVaricella has an important impact on public health. Starting in 2004 in Taiwan, nationwide free varicella vaccinations were given to 1-year-old children.MethodsOur study investigated the epidemiological characteristics of varicella from 2000 to 2008, and assessed the change of varicella epidemiology after the mass varicella immunization. ICD-9-CM codes related to varicella or chickenpox (052, 052.1, 052.2, 052.7, 052.8, 052.9) were analyzed for all young people under 20 years of age through the National Health Insurance database of Taiwan from 2000 to 2008.ResultsCase numbers of varicella or chickenpox significantly declined after the nationwide immunization in 2004. Winter, particularly January, was the epidemic season of varicella. We found a significant post-vaccination decrease in incidence among preschool children, especially 3 to 6 year-old children-- the peak incidence was 66 per thousand for 4 and 5 year-old children before the nationwide immunization (2000 to 2003), and the peak incidence was 23 per thousand for 6 year-old children in 2008 (p < 0.001). Varicella-related hospitalization also significantly decreased in children younger than 6 years after the nationwide immunization.ConclusionThe varicella annual incidence and varicella-related hospitalization markedly declined in preschool children after nationwide varicella immunization in 2004.

Impact of universal vaccination on the epidemiology of varicella in Veneto, Italy

In 2005, universal varicella vaccination was introduced in the Veneto region, Italy. We examined trends in varicella incidence and hospitalization rates before and after vaccine introduction, and applied statistical models to assess vaccine effectiveness. Varicella incidence rates for 2000-2008 were calculated from the mandatory regional surveillance data and from a special surveillance system based on reports from a sample of family pediatricians that during the study period followed more than 40,000 children. To evaluate hospital admission rates, we analyzed the regional hospital discharge registry. The vaccine coverage rate was 6.8% in the 2004 birth-cohort and 78.6% in the 2008 cohort. Varicella incidence in 0-14 year-olds was 6136.8/100,000 person-years in 2000 and 4004.8 in 2008; hospitalization rates were 18.7 and 8.4. Incidence rates significantly decreased 2.5 years after beginning the universal vaccination, while hospitalization rates showed a significant decrease one year earlier. There was a remarkable decline of both varicella incidence and hospitalizations especially in 1-4 year-old children. This study confirms the positive impact of universal vaccination.

Does Monastic Life Predispose to the Risk of Saint Anthony's Fire (Herpes Zoster)?

The consequences of the epidemiology of varicella for zoster epidemiology are still debated. We therefore compared the frequency of herpes zoster in an adult population with virtually no varicella zoster virus (VZV) exposure with that in the general population (GP). We performed a national, multicenter, observational, exposed versus nonexposed, comparative study. The nonexposed population consisted of members of contemplative monastic orders (CMO) of the Roman Catholic Church living in 40 isolated monasteries in France. The exposed population consisted of a sample of the GP representative of the French population in terms of age group, sex, socio-occupational categories, and regions. The primary analysis population comprised 920 members of CMO (41.5% nuns; mean age, 64.2 years) and 1533 members of the GP (51.9% women; mean age, 64.6 years). The reported frequency of zoster was 16.2% among CMO and 15.1% in the GP (P = .27, adjusted for sex and age). The reported mean age of onset of zoster was 54.8 and 48.6 years, respectively (P = .06). This study failed to demonstrate an increased risk or earlier onset of zoster in members of CMO not exposed to VZV, compared with that in the GP. Although adults highly exposed to VZV could have a reduced risk of zoster, compared with the GP, our results suggest that the opposite is not true: adults not exposed to VZV are not at increased risk of zoster when compared with the GP, challenging the relevance of the assumptions and forecasts of current epidemiological models.