Varicella Immunization Research Articles

Updates to the Canadian Immunization Guide: April 2015 to October 2016.

The Canadian Immunization Guide (CIG) is a trusted, reader-friendly summary of information and advice on immunization that has been used by health care providers and policy makers for decades. It is continuously updated based on new recommendations from the National Advisory Committee on Immunization (NACI) and the Committee to Advise on Tropical Medicine and Travel (CATMAT), two external advisory bodies to the Public Health Agency of Canada. In September 2016, the CIG moved to a new web platform that has improved navigability and is more mobile friendly. Between April 2015 and October 2016, five new NACI statements were published and are reflected in the CIG. The objective of this article is to provide readers with highlights of recent key changes to active vaccine recommendations in the CIG. For example, for Hepatitis (HA) vaccine, it may now be administered to persons six months of age and older and considered for all individuals receiving repeated replacement of plasma-derived clotting factors. There are now new recommendations for the use of HA immunoglobulin post-exposure prophylaxis. For Human papillomavirus (HPV) vaccine, any of the authorized HPV vaccines in Canada, including HPV9 vaccine, can be used according to the recommended HPV immunization schedules. For influenza vaccine, adults with neurologic or neurodevelopment conditions have been added to the group for whom influenza vaccination is particularly recommended, high-dose influenza vaccine has been approved for use in Canada in adults ≥65 years of age and live attenuated influenza vaccine (LAIV) is no longer a preferentially recommended product for use in children and adolescents. On an individual basis, pneumococcal conjugate 13-valent (PNEU-C-13) vaccine may be recommended to immunocompetent adults aged 65 years and older if not previously immunized against pneumococcal disease. When it is given, it should precede the pneumococcal polysaccharide 23-valent (PNEU-P-23) vaccine. Varicella immune globulin may now be administered up to 10 days since last exposure for the purpose of disease attenuation and there were a number of minor changes to the criteria for assessing varicella immunity.

Time trends in pediatric Herpes zoster hospitalization rate after Varicella immunization

Herpes zoster (HZ) is an emerging concern for public health officials. The aim of this study was to determine whether universal Varicella immunization implemented in 2004 had an impact on HZ hospitalization in immunocompetent children in Greece. All HZ hospitalizations were recorded during the period 1999-2011. The overall attributable hospitalization rate was 13.89 cases/1000 hospital admissions (95%CI: 11.69-16.38 cases/1000 hospital admissions). HZ hospitalization rate remained unchanged during the study period. These data provide a basis for monitoring HZ hospitalization rate among children following universal toddler immunization.

The Epidemiology of Herpes Zoster After Varicella Immunization Under Different Biological Hypotheses: Perspectives From Mathematical Modeling.

The impact of varicella vaccination on the epidemiology of herpes zoster (HZ) critically depends on the mechanism of immunological boosting, through which reexposures to varicella-zoster virus are thought to reduce the individual risk of HZ development. However, the qualitative and quantitative dynamics of this process are largely unknown. Consequently, mathematical models evaluating immunization strategies need to rely on theoretical assumptions. Available varicella-zoster virus models can be classified in 3 main families according to the postulated effect of exogenous boosting: 1) progressive accumulation of immunity following repeated reexposures; 2) partial protection that wanes over time; or 3) full but temporary immunity against HZ. In this work, we review and compare quantitative predictions from the 3 modeling approaches regarding the effect of varicella immunization on HZ. All models predict a qualitatively similar, but quantitatively heterogeneous, transient increase of HZ incidence. In particular, novel estimates from the progressive immunity model predict the largest increase in natural HZ and the largest incidence of HZ cases from reactivation of the vaccine strain, which in the long term will likely outnumber prevaccination numbers. Our results reinforce the idea that a better understanding of HZ pathogenesis is required before further mass varicella immunization programs are set out.

Perspectives on optimal control of varicella and herpes zoster by mass routine varicella vaccination.

Herpes zoster arises from reactivation of the varicella-zoster virus (VZV), causing varicella in children. As reactivation occurs when cell-mediated immunity (CMI) declines, and there is evidence that re-exposure to VZV boosts CMI, mass varicella immunization might increase the zoster burden, at least for some decades. Fear of this natural zoster boom is the main reason for the paralysis of varicella immunization in Europe. We apply optimal control to a realistically parametrized age-structured model for VZV transmission and reactivation to investigate whether feasible varicella immunization paths that are optimal in controlling both varicella and zoster exist. We analyse the optimality system numerically focusing on the role of the cost functional, of the relative zoster-varicella cost and of the planning horizon length. We show that optimal programmes will mostly be unfeasible for public health owing to their complex temporal profiles. This complexity is the consequence of the intrinsically antagonistic nature of varicella immunization programmes when aiming to control both varicella and zoster. However, we show that gradually increasing-hence feasible-vaccination schedules can perform better than routine programmes with constant vaccine uptake. Finally, we show the optimal profiles of feasible programmes targeting mitigation of the post-immunization natural zoster boom with priority.

Impact of Subsidies and Socioeconomic Status on Varicella Vaccination in Greater Tokyo, Japan.

Although the control of varicella outbreaks is an important health issue, cost could present a major barrier for vaccination. The aim of this study is to investigate the association of vaccine subsidies and caregivers' socioeconomic status with varicella vaccine coverage of their children in Greater Tokyo, Japan, before the period that varicella vaccination was included in routine immunization program. Participants were recruited from two different cities. In Chiba city, parents of 18-month-old infants (N = 378) undergoing a medical examination in July 2013 were recruited at a clinic where no subsidy for varicella immunization was provided. In Nishitokyo city, parents of 24- to 30-month-old children (N = 315) undergoing a health checkup in July and August 2013 were recruited at a clinic where a partial subsidy was provided. The association between household income and varicella immunization was investigated by multivariate logistic regression stratified by city. Vaccine coverage was 61.0% in Chiba city and 73.3% in Nishitokyo city. In Chiba city, odds ratios of middle and high household income for varicella immunization were 4.22 [95% confidence interval (CI): 1.65-10.7] and 5.94 (95% CI: 1.89-18.6), respectively, compared to low household income. However, household income was not associated with varicella vaccination in Nishitokyo city. Neither working status nor education was associated with vaccination in both cities. While household income was associated with high vaccine coverage in the city with no vaccine subsidy, this association was not observed in the city where the subsidy was given, which suggests that cost is a barrier for varicella immunization. Thus, in countries where varicella vaccination is not included in routine immunization programs, introducing subsidies nationwide or routine immunization programs for varicella vaccination would be an important approach to eliminate inequality in vaccine coverage.

An economic analysis of varicella immunization in the Singapore military.

BackgroundVaricella outbreaks occur frequently in closed environments such as those of militaries. This paper compares the economic outcomes of varicella vaccination in enlisted servicemen without prior reported varicella infection or vaccination.MethodsWe analyzed the economic outcomes of a varicella vaccination program on all enlisted servicemen without prior reported varicella infection or vaccination in the Singapore Armed Forces (SAF) between December 11, 2010 – December 20, 2013, compared with the previous program of varicella vaccination only for selected personnel between December 1, 2007 – December 10, 2010.ResultsIn the at-risk population of all active SAF servicemen, the program of varicella vaccination for all servicemen without prior reported varicella infection or vaccination upon enlistment would save 72.0 work days per 1000 (95 % CI: 61.2 - 82.9), valued at SG$6,544 per 1000 (95 % CI: 6,524 - 6,564), i.e., costing SG$91.5 per work day saved (95 % CI: 78.7 - 107.3). This also results in a reduction of 2.7 varicella cases per 1000 and 5.43 outbreaks per 10000, or a total savings of SG$1,695 per 1000 (95 % CI: −2,730 - 6,834), taking into account the cost of work days lost over a three-year period, compared with the previous regime of vaccinations only for selected individuals.ConclusionThe varicella vaccination strategy targeting all enlisted servicemen without prior reported varicella infection or vaccination is able to prevent varicella infections and outbreaks, thus reducing absenteeism and days lost.

Invasive Group A Streptococcal Infections in Children: A Nationwide Survey in Finland.

The incidence of invasive group A streptococcus (iGAS) infections varies in time and geographically for unknown reasons. We performed a nationwide survey to assess the population-based incidence rates and outcomes of children with iGAS infections. We collected data on patients from hospital discharge registries and the electronic databases of microbiological laboratories in Finland for the period 1996-2010. We then recorded the emm types or serotypes of the strains. The study physician visited all university clinics and collected the clinical data using the same data entry sheet. We identified 151 children with iGAS infection. Varicella preceded iGAS infection in 20% of cases and fasciitis infection in 83% of cases. The annual incidence rate of iGAS infection was 0.93 per 100,000 in 1996-2000, 1.80 in 2001-2005 and 2.50 in 2006-2010. The proportion of emm 1.0 or T1M1 strains peaked in 1996-2000 and again in 2006-2010, to 44% and 37% of all typed isolates. The main clinical diagnoses of the patients were severe soft-tissue infection (46%), sepsis (28%), empyema (10%), osteoarticular infection (9%) and primary peritonitis (5%). Severe pain was the most typical symptom for soft-tissue infections. More than half of the patients underwent surgery and received clindamycin. The readmission rate was 7%, and the case fatality rate was 2%. The incidence rate of pediatric iGAS infections tripled during our study. The increase was not, however, the result of a change in the strain types causing iGAS. Varicella immunization would likely have prevented a significant number of the cases.

Hospitalization for Varicella and Zoster in Children with Inflammatory Bowel Disease

To evaluate the association between inflammatory bowel disease (IBD) and varicella- and herpes zoster-related pediatric hospitalizations. We performed a cross-sectional inpatient study using the triennial Healthcare Cost and Utilization Project Kids' Inpatient Database for years 1997-2012 to evaluate the association between a secondary diagnosis of IBD and a primary diagnosis of varicella or herpes zoster for hospitalized children ages 5-20 years. Billing codes were used to identify varicella, herpes zoster, ulcerative colitis, Crohn's disease, and other immunocompromising conditions. A logistic regression model was fitted to quantify the odds of varicella or zoster between these categories. There were 8 828 712 weighted admissions meeting the study criteria, 4434 with varicella and 4488 with herpes zoster. There was an association of IBD and immunocompromising conditions with hospitalization for varicella and herpes zoster. This association was stronger among children with Crohn's disease (varicella OR, 12.75; 95% CI, 8.30-19.59; zoster OR, 7.91; 95% CI, 5.60-11.18) compared with children with ulcerative colitis (varicella OR 4.25; 95% CI 1.98-9.12, zoster OR 3.90; 95% CI 1.98-7.67). IBD in children is associated with hospitalizations for varicella and herpes zoster. These results highlight the importance of efforts to vaccinate patients with IBD without varicella immunity, ideally before the initiation of immunosuppressive therapy. Furthermore, research is needed on the safety and efficacy of the varicella vaccine in children with IBD on immunomodulators or biologic therapy.

Efficacy of varicella (VZV) vaccination: an update for the clinician.

Varicella-zoster virus (VZV) infection causes two distinct clinical conditions. Primary varicella infection results in chickenpox, a contagious rash illness typically seen among children. VZV can reactivate years after the initial infection to cause herpes zoster (HZ) and lead to post-herpetic neuralgia, a common complication resulting in persistent pain that may last for years after the zoster rash resolves. A person's risk of having longer lasting and more severe pain associated with HZ increases with age. Since the introduction of VZV vaccines, the rates of infection, hospitalizations, and mortality have declined. In this review, we discuss in detail current VZV vaccines available for the prevention of VZV and HZ infections. Varilrix (GSK Biologicals, UK), Varivax (Merck, USA) and the combined measles, mumps, rubella, and varicella (MMRV) vaccine contain the live attenuated Oka strain of VZV for routine varicella vaccination. While Zostavax is the only HZ vaccine currently approved for use in the United States and the European Union [EMEA, 2011], a subunit vaccine candidate called HZ/su has recently shown improved efficacy for zoster prevention in two clinical trial phase III studies. VariZIG, a post-exposure prophylactic, uses zoster immune globulin to prevent VZV infection in those who have recently been in contact with VZV but lack evidence of varicella immunity and are contraindicated to receive the varicella vaccine. Further, we discuss the skin tropic and neurotropic factor VZV ORF7 gene and its involvement in varicella infection, reactivation and latency in ganglia. Ultimately, these studies can contribute to the development of a neuroattenuated vaccine candidate against varicella or a vector for delivery of other virus antigens.

Impact of Routine Varicella Immunization on Varicella Ambulatory Visits in a Tertiary Hospital in Athens, Greece

Impact of Routine Varicella Immunization on Varicella Ambulatory Visits in a Tertiary Hospital in Athens, Greece

Application of Oral Fluid Assays in Support of Mumps, Rubella and Varicella Control Programs.

Detection of specific viral antibody or nucleic acid produced by infection or immunization, using oral fluid samples, offers increased potential for wider population uptake compared to blood sampling. This methodology is well established for the control of HIV and measles infections, but can also be applied to the control of other vaccine preventable infections, and this review describes the application of oral fluid assays in support of mumps, rubella and varicella national immunization programs. In England and Wales individuals with suspected mumps or rubella, based on clinical presentation, can have an oral fluid swab sample taken for case confirmation. Universal varicella immunization of children has led to a drastic reduction of chickenpox in those countries where it is used; however, in England and Wales such a policy has not been instigated. Consequently, in England and Wales most children have had chickenpox by age 10 years; however, small, but significant, numbers of adults remain susceptible. Targeted varicella zoster virus (VZV) immunization of susceptible adolescents offers the potential to reduce the pool of susceptible adults and oral fluid determination of VZV immunity in adolescents is a potential means of identifying susceptible individuals in need of VZV vaccination. The main application of oral fluid testing is in those circumstances where blood sampling is deemed not necessary, or is undesirable, and when the documented sensitivity and specificity of the oral fluid assay methodology to be used is considered sufficient for the purpose intended.

Varicella Zoster Virus in the Nervous System.

Varicella zoster virus (VZV) is a ubiquitous, exclusively human alphaherpesvirus. Primary infection usually results in varicella (chickenpox), after which VZV becomes latent in ganglionic neurons along the entire neuraxis. As VZV-specific cell-mediated immunity declines in elderly and immunocompromised individuals, VZV reactivates and causes herpes zoster (shingles), frequently complicated by postherpetic neuralgia. VZV reactivation also produces multiple serious neurological and ocular diseases, such as cranial nerve palsies, meningoencephalitis, myelopathy, and VZV vasculopathy, including giant cell arteritis, with or without associated rash. Herein, we review the clinical, laboratory, imaging, and pathological features of neurological complications of VZV reactivation as well as diagnostic tests to verify VZV infection of the nervous system. Updates on the physical state of VZV DNA and viral gene expression in latently infected ganglia, neuronal, and primate models to study varicella pathogenesis and immunity are presented along with innovations in the immunization of elderly individuals to prevent VZV reactivation.

Varicella seroprevalence in healthcare workers in a tertiary hospital: an audit of cross-sectional data.

BackgroundThe seroprevalence of varicella in Southeast Asia is not well described especially in healthcare workers (HCW) in the region. We report the varicella seroprevalence among healthcare workers from a diverse range of countries working in a tertiary care hospital in Singapore.MethodsWe audited the results of annual HCW health screening, which included a varicella assay, from the years 2009 to 2014. During this period, there was a change in hospital policy mandating varicella immunity for all newly employed healthcare workers. The serological data were reviewed with employment records on occupation and nationality. Seroprevalence rates were determined by standard commercial enzyme linked immunosorbent assays for each year of testing. Odds of being immune in 2014 were compared by means of multiple logistic regression.ResultsA total of 10,585 samples were obtained from 6668 unique individuals over four separate cross-sections of the hospital workforce. A peak seroprevalence of 92.8 % (95 % CI 92.0–93.5) was recorded in 2014. Younger employees had a lower seroprevalence than their older colleagues. In a consolidated sample of 4875 members of the active workforce in October 2014, we identified that Indian nationals were less likely to be immune than their Singaporean national colleagues, odds ratio (OR) 0.26 (95 % CI 0.17–0.43, p < 0.001), while Chinese nationals were more likely to be immune, OR 4.34 (95 % CI 1.61–12.2, p = 0.004), after controlling for year of screening, gender, age-group and vocation. In 2014, being employed as administrative staff, OR 0.43 (95 % CI 0.29–0.64, p < 0.001) or contract service provider, OR 0.30 (95 % CI 0.19–0.47, p < 0.001), was also associated with a lower odds of being immune than being employed as a nurse.ConclusionsThere remain a small number of healthcare workers who are non-immune to varicella in our tertiary hospital. A new pre-employment policy of mandatory screening and vaccination may have increased rates of immunity but more needs to be done to ensure that all of our employees are immune to varicella to protect our vulnerable patients.

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.

Clinical and economic impact of various strategies for varicella immunity screening and vaccination of health care personnel

Exposure to patients with varicella or herpes zoster causes considerable disruption to a health care facility's operations and has a significant health and economic impact. However, practices related to screening for immunity and immunization of health care personnel (HCP) for varicella vary widely. A decision tree model was built to evaluate the cost-effectiveness of 8 different strategies of screening and vaccinating HCP for varicella. The outcomes are presented as probability of acquiring varicella, economic impact of varicella per employee per year, and cost to prevent additional cases of varicella. Monte Carlo simulations and 1-way sensitivity analyses were performed to address the uncertainties inherent to the model. Alternative epidemiologic and technologic scenarios were also analyzed. Performing a clinical screening followed by serologic testing of HCP with negative history diminished the cost impact of varicella by >99% compared with not having a program. Vaccinating HCP with negative screen cost approximately $50,000 per case of varicella prevented at the current level of U.S. population immunity, but was projected to be cost-saving at 92% or lower immunity prevalence. Improving vaccine acceptance rates and using highly sensitive assays also optimize cost-effectiveness. Strategies relying on screening and vaccinating HCP for varicella on employment were shown to be cost-effective for health care facilities and are consistent with current national guidelines for varicella prevention.

Provider-Level Characteristics Associated With Adolescent Varicella, Meningococcal, and Human Papillomavirus Immunization Initiation.

We examined patient- and provider-level factors associated with initiation of three adolescent immunizations among 13 to 18 year olds in an adolescent primary care clinic. Data were extracted retrospectively from medical records. Logistic regression models identified associations with immunization initiation. Post hoc analyses stratified by gender were conducted to examine provider-type contribution to human papillomavirus (HPV) immunization initiation. Among 2932 adolescents, rates of meningococcal and varicella immunization initiation differed by age. Girls were more likely to have initiated HPV immunization than boys. The probability of girls initiating HPV immunization was the same when last seen by advanced practice nurses (APNs) versus physicians, but the probability of boys initiating HPV immunization was lower when last seen by APNs. Differences in HPV immunization initiation were observed between genders, and for boys, between APN versus physician at last clinic visit. This may reflect changes to HPV immunization recommendations for boys and APNs having shorter clinic visits.

Sa1997 Identifying Fistulizing Crohn's Disease in a National Pediatric Inflammatory Bowel Disease Quality Improvement Collaborative Registry

immunized against varicella, and concerns exist regarding the safety and efficacy of this immunization in immunosuppressed patients. We aimed to evaluate the risk of varicellaand zoster-related hospitalization among children with IBD. Methods: A retrospective cohort study was performed utilizing data on varicellaand zoster-related hospitalizations from the 1997, 2000, 2003, 2006, 2009, and 2012 triennial Healthcare Cost and Utilization Project Kids' Inpatient Database (HCUP-KID). Hospitalizations with a primary diagnosis of varicella or herpes zoster were compared between children (ages 5 to 21) with and without IBD using logistic regression. Results: There were 12,219,138 admissions in the HCUP-KID database from 1997-2012, including 4,434 with varicella and 4,488 with zoster listed as the primary diagnosis. Children with IBD accounted for 57 (1.29%) and 74 (1.64%) of the varicellaand zoster-related hospitalizations, respectively. Primary admissions for varicella or zoster accounted for 0.4% of all hospitalizations of children carrying a diagnosis of IBD. Compared to children without IBD, those with IBD were at significantly higher risk for varicella-related hospitalization (OR 4.98, 95% CI 3.84-6.47) and zoster-related hospitalization (OR 6.35, 95% CI 5.04-7.99). This risk was higher among children with Crohn's disease (varicella OR 6.22, 95% CI 4.65-8.32, zoster OR 7.39, 95% CI 5.67-9.65) compared to children with ulcerative colitis (varicella OR 2.69, 95% CI 1.50-4.81, zoster OR 4.34, 95% CI 2.75-6.85). Conclusion: Children with IBD are at increased risk for varicellaand zosterrelated hospitalization. These results highlight the importance of efforts to immunize IBD patients without a history of varicella disease or varicella immunization, ideally before the initiation of immunosuppressive therapy. Furthermore, research is needed on the safety and efficacy of varicella vaccine in children with IBD on immunomodulators including antitumor necrosis factor-alpha agents.

Does chickenpox cause childhood stroke?

Journal of Paediatrics and Child HealthVolume 51, Issue 3 p. 349-349 Heads UpFree Access Does chickenpox cause childhood stroke? First published: 11 March 2015 https://doi.org/10.1111/jpc.12858_2AboutSectionsPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Varicella has been associated with acute ischaemic stroke (AIS) following chickenpox in case series and case control studies. A large study used self-controlled case series (SCCS) analysis to test whether children are at increased risk of stroke following chickenpox.1 SCCS analysis determines the incidence ratio (IR) of rare events. The association between an event (AIS) and the exposure (varicella) in a defined ‘risk period’ is determined by considering an individual as both a case (risk of event occurring within the observed ‘risk period’) and a control (risk of event occurring within the whole observation period excluding the risk period). The authors analysed four large UK general practice databases yielding >100 million person years of observation. Children had a fourfold increased risk of stroke in the 6 months after chickenpox (IR = 4.07; 95% confidence interval (CI) 1.96–8.45), adults had double the risk (IR = 2.13; 95% CI 1.05–4.36). In both adults and children, the association ceased to be statistically significant 7–12 months after chickenpox. An association between childhood stroke and varicella is biologically plausible because varicella can cause an inflammatory arteriopathy. The same group have also now reported an increased risk of AIS in adults following zoster, a risk that is reduced when antiviral medication is used.2 This emphasizes the importance of varicella immunisation and raises the question whether antivirals should be given to a child with chickenpox to prevent stroke. References 1Thomas SL et al. Clin. Infect. Dis. 2014; 58: 61– 68. CrossrefPubMedWeb of Science®Google Scholar 2Langan SM et al. Clin. Infect. Dis. 2014; 58: 1497– 1503. CrossrefPubMedWeb of Science®Google Scholar Reviewer: Dr Philip Britton, Children's Hospital at Westmead, NSW, philip.britton@health.nsw.gov.au Volume51, Issue3March 2015Pages 349-349 ReferencesRelatedInformation

The Impact of 2-Dose Routine Measles, Mumps, Rubella, and Varicella Vaccination in France on the Epidemiology of Varicella and Zoster Using a Dynamic Model With an Empirical Contact Matrix

PurposeVaricella has a high incidence affecting the vast majority of the population in France and can lead to severe complications. Almost every individual infected by varicella becomes susceptible to herpes zoster later in life due to reactivation of the latent virus. Zoster is characterized by pain that can be long-lasting in some cases and has no satisfactory treatment. Routine varicella vaccination can prevent varicella. The vaccination strategy of replacing both doses of measles, mumps, and rubella (MMR) with a combined MMR and varicella (MMRV) vaccine is a means of reaching high vaccination coverage for varicella immunization. The objective of this analysis was to assess the impact of routine varicella vaccination, with MMRV in place of MMR, on the incidence of varicella and zoster diseases in France and to assess the impact of exogenous boosting of zoster incidence, age shift in varicella cases, and other possible indirect effects. MethodsA dynamic transmission population-based model was developed using epidemiological data for France to determine the force of infection, as well as an empirically derived contact matrix to reduce assumptions underlying these key drivers of dynamic models. Scenario analyses tested assumptions regarding exogenous boosting, vaccine waning, vaccination coverage, risk of complications, and contact matrices. FindingsThe model provides a good estimate of the incidence before varicella vaccination implementation in France. When routine varicella vaccination is introduced with French current coverage levels, varicella incidence is predicted to decrease by 57%, and related complications are expected to decrease by 76% over time. After vaccination, it is observed that exogenous boosting is the main driver of change in zoster incidence. When exogenous boosting is assumed, there is a temporary increase in zoster incidence before it gradually decreases, whereas without exogenous boosting, varicella vaccination leads to a gradual decrease in zoster incidence. Changing vaccine efficacy waning levels and coverage assumptions are still predicted to result in overall benefits with varicella vaccination. ImplicationsIn conclusion, the model predicted that MMRV vaccination can significantly reduce varicella incidence. With suboptimal coverage, a limited age shift of varicella cases is predicted to occur post-vaccination with MMRV. However, it does not result in an increase in the number of complications. GSK study identifier: HO-12-6924.

Seroprevalence of measles, mumps, rubella and varicella antibodies in the United States population, 2009-2010.

Background. In the United States, measles, mumps, rubella, and varicella immunity is now primarily achieved through vaccination. Monitoring population immunity is necessary.Methods. We evaluated seroprevalence of antibodies to measles, mumps, rubella, and varicella using the National Health and Nutrition Examination Survey during 2009–2010.Results. Measles, mumps, rubella, and varicella seroprevalence was 92.0% (95% confidence interval [CI], 90.9%−93.0%), 87.6% (CI, 85.8%−89.2%), 95.3% (CI, 94.3%−96.2%), and 97.8% (CI, 97.1%−98.3%), respectively. United States (US)-born persons had lower mumps seroprevalence and higher varicella seroprevalence than non-US born persons.Conclusions. Seroprevalence was high (88%–98%) for all 4 viruses in the US population during 2009−2010.