Varicella Disease Research Articles

Fractional derivatives applied to MSEIR problems: Comparative study with real world data

In the present study, an epidemiological model (MSEIR) of varicella disease outbreak, also called the chickenpox, among school children in the Shenzhen city of China in 2015 is proposed under three most commonly used approaches, such as the Caputo, Caputo-Fabrizio and the Atangana-Baleanu-Caputo operators, while taking care of the dimensional consistency of the proposed model. With the help of the fixed point theory, it is proved that the dynamical model under consideration possesses a unique solution. Numerical simulations are carried out for the analysis of the model. Availability of the real data helps to provide evidence for the claims made in the present analysis for the three operators under consideration. Using the root sum squared approach, the efficiency rate of the fractional-order versions is found to be about 20%, 22.5% and 24.7% for the Caputo, the Caputo-Fabrizio and the Atangana-Baleanu-Caputo operators, respectively, for this particular MSEIR model.

Modeling chickenpox disease with fractional derivatives: From caputo to atangana-baleanu

Abstract This research study is conducted with the aim of getting analysis based upon four different types of frequently used models of ordinary differential equations related to the chickenpox outbreak among school children of Schenzen city of China in 2013. In this regard, three new models under kernels of power law type (Caputo), exponentially decaying type kernel (Caputo–Fabrizio), and the Mittag-Leffler type kernel (Atangana–Baleanu in the Caputo sense) have been proposed and deeply investigated to determine the model with highest efficiency rate. Within the proposed models, the dimensions of each differential equation for all state variables and parameters have been balanced by carrying the respective fractional-order parameter on every dimensional quantity involved in the model. The fixed point theory employed in the present study yielded the proof for existence and uniqueness of the solutions of the fractional-order models under investigation. Using true data for 25 weeks, it is found that the model consisting of Mittag-Leffler type non-singular and non-local kernel has highest capability to capture various features of the disease.

Implementing Universal Varicella Vaccination in Europe: The Path Forward.

Varicella is a common vaccine-preventable disease that usually presents as a mild disorder but can lead to severe complications. Before the implementation of universal varicella vaccination (UVV) in some European countries, the burden of varicella disease was broadly similar across the region. Despite this, countries adopted heterogeneous varicella vaccination strategies. UVV is currently recommended in 12 European countries. Known barriers to UVV implementation in Europe include (1) a perceived low disease burden and low public health priority; (2) cost-effectiveness and funding availability; (3) concerns related to a shift in varicella disease and incidence of herpes zoster and (4) safety concerns related to measles, mumps, rubella and varicella-associated febrile seizures after the first dose. Countries that implemented UVV experienced decreases in varicella incidence, hospitalizations and complications, showing overall beneficial impact. Alternative strategies targeting susceptible individuals at higher risk of complications have been less effective. This article discusses ways to overcome the barriers to move varicella forward as a truly vaccine preventable disease.

Varicella vaccine effectiveness over 10 years in Australia; moderate protection from 1-dose program

To examine the impact of Australia's single dose infant varicella vaccination program, we assessed single dose varicella vaccine effectiveness (VE) in preventing hospitalised disease using two methods. Clinically confirmed varicella cases from the Paediatric Active Enhanced Disease Surveillance (PAEDS) sentinel network were age-matched to 20 controls obtained from the Australian Immunisation Register. Conditional logistic regression models were used to estimate VE and compared with estimates obtained using our second approach. There were 78 hospitalised varicella cases during the post vaccine introduction period from January 2008 to December 2015, who were eligible for funded varicella vaccination. Median age at onset was 4.5 years and more than half (59%) were vaccinated. The majority of children received one vaccine brand (Varilrix, GSK). The estimated case-control VE for one dose of vaccine against hospitalised varicella was 64.7% (95% CI: 43.3-78.0%); estimates using the screening method were not significantly different. Exclusion of children who were immunocompromised did not significantly alter VE estimates. Although Australia's program has impacted on the burden of varicella disease, single dose VE against varicella hospitalisation is only moderate. Greater reductions in varicella disease could potentially be achieved by incorporation of a second vaccine dose into the program to minimise breakthrough disease and interrupt virus circulation.

2355. Clinically vs. Serologically Identified Varicella: A Hidden Infection Burden. Lessons of 10-Year Follow-up in Varicella Endemic Countries

BackgroundA randomized, controlled, long-term varicella vaccine efficacy study (NCT00226499) was conducted in several European countries with no universal varicella vaccination. The control group allows studying the immunological response profiles to natural varicella exposure and disease in children from 1 year of age onwards.MethodsOf 5,803 subjects enrolled in the study, 744 were vaccinated with 2 doses of measles-mumps-rubella vaccine as active control. Follow-up lasted for up to 10 years. Varicella case ascertainment was done by combining PCR testing of skin lesions, epidemiological context and blinded clinical case adjudication by independent experts. A confirmed case required a positive PCR result or a positive epidemiological context with a positive case adjudication.ResultsIn the control group, a total of 352 confirmed varicella episodes were captured; of which, 339 had an available serum sample taken before and after the episode at any of the year 1 or bi-yearly visits scheduled per protocol. All subjects were seronegative for anti-VZV antibodies before vaccination. The immunological profile showed that 96% of subjects with varicella episodes experienced an 8-fold increase of the anti-VZV titers when comparing the sample available after the episode vs. the one before the episode. The data indicate that the GMC levels were similar to that induced by 2-dose immunization with varicella vaccines, and persisted over many years after the varicella episode without indication of waning (figure). In subjects without any reported varicella episode, 8-fold increases of the anti-VZV titers between 2 successive blood samples were measured in up to 34% of consecutive pairs of serum samples. ConclusionTo our knowledge, this is the first long-term analysis of the immunological history of anti-varicella immunological profile in young children exposed to a high varicella force of infection. About one-third of subjects not vaccinated against varicella developed an anti-VZV immune response although no varicella disease was reported. Sub-clinical varicella may occur more frequently than anticipated. The total incidence of varicella infections might be under-estimated by syndromic surveys only. Funding: GlaxoSmithKline Biologicals SA.Disclosures P. Gillard, GSK: Employee and Shareholder, Salary. M. Povey, GSK: Employee, Salary. S. Carryn, GSK: Employee and Shareholder, Restricted shares, and Salary.

2473. How Does Acquiring a Vaccine-Preventable Disease Impact Parental and Physician Responses to Vaccine Hesitancy?

BackgroundVaccine hesitancy poses an urgent threat to public health. This study aims to determine the frequency of children diagnosed with vaccine-preventable diseases (VPDs) accompanied by parental vaccine hesitancy, how physicians counsel parents of these children, and parents’ intentions to vaccinate thereafter.MethodsA one-time survey was sent to pediatricians and pediatric subspecialists through the Canadian Paediatric Surveillance Program (CPSP).ResultsIn total, 925 pediatricians responded to the survey. 196 (21%) reported having seen a patient in the preceding 12 months who was diagnosed with a VPD whereby the patient or a sibling was not vaccinated or vaccination was delayed by parental choice. The most commonly diagnosed VPDs were pertussis (31%), varicella (27%), and pneumococcal disease (10%). The vast majority (94%) of pediatricians indicated that the VPDs were not acquired outside of Canada. The child’s vaccination status against the VPD prior to contracting the VPD was reported as follows: 81% (156/192) had no immunization and 19% had delayed immunization. When asked about intervention strategies, 23% (41/181) of respondents reported that they had used a formal strategy or structured approach to discuss vaccination with the vaccine-hesitant parent(s) prior to the patient contracting a VPD. 57% (101/178) reported that a formal strategy was used after the patient contracted the VPD. Respondents indicated that their impression was that 35% (64/183) of vaccine-hesitant parents would not vaccinate in the future; 33% (60/183) of respondents were unsure. 79% (147/186) of respondents reported that they were aware of existing tools to manage vaccine hesitancy (e.g., Canadian Paediatric Society Practice Point Working with vaccine-hesitant parents). Of those who were aware of existing tools, 69% (100/145) had used the tools.ConclusionPediatricians frequently encounter children with VPDs whose parents are vaccine hesitant. A substantial number of Canadian pediatricians are either unaware of existing tools to address vaccine hesitancy or are not using them. It was the pediatricians’ impression that a significant proportion of vaccine-hesitant parents would not vaccinate in the future despite their children having acquired a VPD.Disclosures All authors: No reported disclosures.

Varicella breakthrough infection and effectiveness of 2-dose varicella vaccine in China

Background2-dose varicella vaccination has been available in Ningbo city, China since 2014 in the private sector. This study aimed to evaluate the breakthrough varicella infection rate, and to examine overall and incremental effectiveness of 2-dose varicella vaccination among Chinese children. MethodsA retrospective investigation was done among native children born from 2008 to 2013 in active surveillance area in Ningbo, China. Between 2009 and 2016, demographic information and data on varicella vaccination were collected by Ningbo’s Immunization Information System, and information of varicella infections were obtained from China Information System for Disease Control and Prevention. The logistic regression was conducted to estimate varicella vaccine effectiveness (VE). ResultA total of 107,324 local children were enrolled in the cohort analysis and 95.11% of these children with no varicella disease history received at least 1-dose varicella vaccine from 2009 to 2016. The total breakthrough varicella infection rate (BVR) was 0.37% for all the vaccinated children and 0.04% for 2-dose vaccination. The annual BVR ranged from 0.01% to 0.49% for 1-dose of varicella vaccine and from 0.01% to 0.02% for 2-dose. The infection rates both in the unvaccinated children and the 1-dose children were decreasing after 2-dose vaccination implemented in 2014 (Unvaccinated: P < 0.001 for trend; 1-dose: P = 0.003 for trend). The VE against all varicella was 50.3% (95% CI: 39.8%–59.0%) for 1-dose (P < 0.001) and 98.7% (95% CI: 98.1%–99.1%) for 2-dose (P < 0.001), and the incremental VE was 97.4% (95% CI: 96.2%–98.2%) compared with 1-dose (P < 0.001). ConclusionThe 2-dose regimen provided excellent protection to prevent all varicella, and the universal 2-dose regimen of varicella vaccine should be recommended to prevent the varicella disease among children in China.

An economic evaluation of Varicella vaccination in Argentina

Background: In 2015, Argentina introduced universal varicella vaccination (UVV) as a one-dose programme offered at 15 months of age. The objective of this analysis was to evaluate the health and economic implications of scheduling options for a transition to two dose UVV, considering both monovalent varicella vaccines (V) and quadrivalent measles-mumps-rubella-varicella vaccines (MMRV) in Argentina. Methods & Materials: A dynamic transmission model of varicella disease was adapted using data from a recently conducted local study on varicella healthcare resource utilization and complications, and previously published Argentinian seroprevalence data. Strategies considered varied between long (> 4 years) and short (≤6 months) intervals between doses and use of V/MMRV formulations (age/coverage rate): Long V/V (V 15 months/90%, V 6 years/85%), Long V/MMRV (V 15 months/90%, MMRV 6 years/85%), Short V/MMRV (V 15 months/90%, MMRV 18 months/85%), Short MMRV/MMRV (MMRV 12 months/90%, MMRV 18 months/85%). MMRV vaccines were assumed in the base case to be 33% more costly than the component prices, and a grid search strategy was used to identify the price at which it would be more cost-effective to use MMRV instead of V. Costs were calculated in 2017 United States Dollars (USD), with costs and benefits discounted at 3%.; Payer and societal perspectives were considered over 100 years. Results: In the absence of UVV, the model predicts over 600,000 varicella cases, 80 deaths, and 68.8 million USD expenditure for treatment annually. The most effective strategy in reducing total varicella cases and deaths is the short V/MMRV, followed by Short MMRV/MMRV; although all strategies are cost saving compared to no vaccination, the least costly strategy is Long V/V, followed by Long V/MMRV and Short V/MMRV. From both the societal and payer perspectives, the most cost-effective strategy is Long V/V, followed by Short V/MMRV and Short MMRV/MMRV. Conclusion: 2 dose UVV is a cost-effective intervention in Argentina, and short intervals between doses will lead to the best health outcomes. The most cost-effective choices of schedule and product (V, MMRV) will be determined by the eventual price of the quadrivalent vaccine compared to the component vaccines.

Is varicella vaccination associated with pediatric arterial ischemic stroke? A population-based cohort study

Background and purpose: Varicella disease is a risk factor for pediatric Arterial Ischemic Stroke (AIS). Isolated case reports have emerged suggesting that varicella vaccination may also pose a risk for AIS. Methods: This retrospective population-based cohort study assessed the risk of AIS in children who received a varicella-containing vaccine, as compared to those who did not. The study cohort consisted of children born between January 1, 2006 and December 31, 2013, in the Canadian province of Alberta, where all routine childhood vaccinations are publicly-funded, and recorded in a central immunization repository. These data were linked with hospital discharge abstract data to identify children diagnosed with AIS. A Cox proportional hazard model assessed the risk of AIS in the 12 months following vaccination for children receiving a varicella vaccine between 11 and 23 months of age, as compared to non-vaccinated children. Results: Of the 368,992 children in the cohort, 325,729 were vaccinated with a varicella-containing vaccine between 11 and 23 months of age. The rate of AIS was 7.8 (95% CI 4.8–10.9) per 100,000 person years at risk in the 12 months following varicella vaccination, as compared to 6.8 (95% CI 1.3–12.2) for children who did not receive a varicella vaccine. The adjusted Hazard Ratio for the risk of AIS, controlling for other AIS risk factors, in vaccinated children as compared to non-vaccinated children was 1.6 (95% CI 0.7–3.7) in the 12 months following vaccination and 1.7 (95% CI 0.5–4.9) in the 30 days following vaccination. Conclusions: Our study found no evidence of an increased risk of AIS following varicella vaccination. This population-based cohort study provides reassurance to parents and clinicians regarding the safety of varicella vaccination.

Varicella-zoster-virus vaccination in immunosuppressed children with rheumatic diseases using a pre-vaccination check list

BackgroundThe goal of this study was to apply the varicella zoster virus (VZV) vaccine to patients with pediatric rheumatic diseases (PRD) at risk for severe chickenpox, without interrupting their current immunosuppression, including biological agents, using an immunological-based pre-vaccination checklist to assure safety. A pre-vaccination checklist was implemented to ensure adequate immune competence prior to immunization.MethodsThis prospective study included seronegative patients (VZV-IgG ≤200 mIU/ml) and patients who had previously received only a single dose of VZV vaccine. All vaccinees demonstrated clinically inactive PRD. Patients were categorized according to their actual treatment in low-intensity IS (LIIS) and high-intensity IS (HIIS) including biological therapy. The pre-vaccination checklist defined thresholds for the following basic laboratory tests: white blood cell count ≥3000/mm3, lymphocytes ≥1200/mm3, serum IgG ≥500 mg/dl, IgM ≥20 mg/dl, tetanus toxoid antibody ≥0.1 IU/ml. In case of HIIS additional specifications included a CD4+ lymphocyte count ≥200/mm3 and a positive T-cell function (via analyzable positive control of a standard tuberculosis interferon-gamma-release-assay (TB-IGRA) indicating mitogen-induced T cell proliferation). Patients who met the criteria of the pre-vaccination checklist received the first and/or second VZV vaccination. Immunologic response and side effects were monitored.ResultsTwenty-three patients were recruited of whom nine had already received one VZV immunization before initiating IS. All patients met the pre-vaccination checklist criteria despite ongoing IS. There was no overall difference in VZV-IgG levels when comparing the LIIS (n=9) and HIIS (n=14) groups. In total, 21 patients (91%) showed a positive vaccination response, after the first immunization the median VZV-IgG across all patients was 224 (59-1219) mIU/ml (median (range)), after booster immunization it increased to 882 (30-4685) mIU/ml. Two patients in the HIIS group failed to raise positive VZV-IgG, despite booster immunization. All nine patients receiving only the second immunization on IS reached high titers of VZV-IgG >500 mIU/ml (1117 (513-4685) mIU/ml). There were no cases of rash or other vaccine-induced varicella disease symptoms and no evidence of PRD flare.ConclusionsVZV vaccination is safe and largely immunogenic in children with ongoing IS fulfilling an immunological based pre-vaccination checklist. This new approach is based on immunologic function rather than on type of medications.Trial registration numberISRCRTN trial registration number 21654693, date of registration February 12, 2018, retrospectively registered.

The impact of immunization programs on 10 vaccine preventable diseases in Italy: 1900–2015

BackgroundVaccination has determined a dramatic decline in morbidity and mortality from infectious diseases over the last century. However, low perceived risk of the infectious threat and increased concern about vaccines’ safety led to a reduction in vaccine coverage, with increased risk of disease outbreaks. MethodsAnnual surveillance data of nationally communicable infectious diseases in Italy between 1900 and 2015 were used to derive trends in morbidity and mortality rates before and after vaccine introduction, focusing particularly on the effect of vaccination programs. Autoregressive integrated moving average models were applied to ten vaccine-preventable diseases: diphtheria, tetanus, poliomyelitis, hepatitis B, pertussis, measles, mumps, rubella, chickenpox, and invasive meningococcal disease. Results of these models referring to data before the immunization programs were projected on the vaccination period to estimate expected cases. The difference between observed and projected cases provided estimates of cases avoided by vaccination. ResultsThe temporal trend for each disease started with high incidence rates, followed by a period of persisting reduction. After vaccine introduction, and particularly after the recommendation for universal use among children, the current rates were much lower than those forecasted without vaccination, both in the whole population and among the 0-to-4 year olds, which is, generally, the most susceptible age class. Assuming that the difference between incidence rates before and after vaccination programs was attributable only to vaccine, more than 4 million cases were prevented, and nearly 35% of them among children in the early years of life. Diphtheria was the disease with the highest number of prevented cases, followed by mumps, chickenpox and measles. ConclusionsUniversal vaccination programs represent the most effective prevention tool against infectious diseases, having a major impact on human health. Health authorities should make any effort to strengthen public confidence in vaccines, highlighting scientific evidence of vaccination benefits.

Floods and Pestilence: Diseases in Philippine Urban Areas

Do floods affect the probability for urban households to suffer from diseases? We study Cagayan de Oro, a highly-urbanized city in the Philippines that exhibits many of the common characteristics of urban areas in middle-income countries. We find that bronchitis, respiratory tract infection, influenza, chicken pox, measles, typhoid fever, diarrhea, leptospirosis, dengue, hypertension, and heart diseases are each associated with either one or a combination of the flood variables: exposure, height, or duration. We quantify their incremental incidence due to flood exposure, and provide indicative estimates on their cost implications both to the government and to the disease-affected households. In general, results reveal that flood-induced diseases cause large cost to the government as well as heavy financial burden on affected families, particularly among the economically disadvantaged. Cost estimation is undertaken for the floodplains of Cagayan de Oro City, and expanded to all urban areas in the Philippines to serve as inputs for discussions on the expansion or redesign of policies aimed at ensuring people’s safety from disasters, diseases, and impoverishment within a typical urban setting.

Outbreak of varicella in preschool children despite one-dose vaccination.

Kurugöl Z, Gökçe Ş. Outbreak of varicella in preschool children despite one-dose vaccination. Turk J Pediatr 2018; 60: 56-62. In Turkey, a single-dose varicella vaccine was introduced into the National Immunization Program in 2013. Before this implementation, varicella vaccine had been available in the private sector since 2000. However, varicella outbreaks continued to occur in preschools and elementary schools. We investigated a varicella outbreak to estimate the effectiveness of 1-dose varicella vaccine and to evaluate potential risk factors for breakthrough disease. This study was carried out during a varicella outbreak in 3 preschools in İzmir, Turkey, in April 2016. Using questionnaires, data including children`s medical and vaccination histories were collected from their parents. Attack rates in vaccinated and unvaccinated children were calculated and the analyses of vaccine effectiveness and of risk factors for breakthrough disease were conducted. A total of 124 children were enrolled in the study. Of the 124 children, 77 (62%) had received 1-dose varicella vaccine before the outbreak. Varicella developed in 34 of 124 children during the outbreak, and 18 of them (53%) had breakthrough varicella. The attack rate was 23.4% among vaccinated children and 34% among unvaccinated children. The effectiveness of single-dose varicella vaccine was 33.6% against varicella disease of any severity and 82.5% against moderate or severe varicella. Children vaccinated 5 or more years before the outbreak had 3.5 times the risk of disease than those who had been vaccinated more recently (OR 3.5 [95% CI, 1.08-11.5]); p= 0.046). Age at vaccination ( < 15 months vs.≥15 months) and the brands of varicella vaccine were not associated with the increased risk of breakthrough varicella. Our study suggests that one-dose of varicella vaccine is not sufficient to prevent school outbreaks. A 2-dose varicella vaccination program may help to prevent varicella outbreaks and achieve effective control of the disease.

Evaluation of teachers’ knowledge about the early detection for chickenpox diseases at the primary schools in Al-Hilla City

Evaluation of teachers’ knowledge about the early detection for chickenpox diseases at the primary schools in Al-Hilla City

One or two doses of live varicella virus-containing vaccines: Efficacy, persistence of immune responses, and safety six years after administration in healthy children during their second year of life

BackgroundThis phase III B follow-up of an initial multicenter study (NCT00226499) will evaluate the ten-year efficacy of two doses of the combined measles-mumps-rubella-varicella vaccine (MMRV) and one dose of the live attenuated varicella vaccine (V) versus a measles-mumps-rubella control group (MMR) for the prevention of clinical varicella disease. Here we present efficacy results for six years post-vaccination. MethodsIn phase A of the study, healthy children aged 12–22 months from ten European countries were randomized (3:3:1) and received either two doses of MMRV, or one dose of combined MMR and one dose of monovalent varicella vaccine (MMR+V), or two doses of the MMR vaccine (control), 42 days apart. Vaccine efficacy against all and against moderate or severe varicella (confirmed by detection of viral DNA or epidemiological link) was assessed from six weeks up to six years post-dose 2 for the MMRV and MMR+V groups, and was calculated with 95% confidence intervals (CI). The severity of varicella was calculated using the modified Vázquez scale (mild ≤ 7; moderately severe = 8–15; severe ≥ 16). Herpes zoster cases were also recorded. Results5289 children (MMRV = 2279, mean age = 14.2, standard deviation [SD] = 2.5; MMR+V = 2266, mean age = 14.2, SD = 2.4; MMR = 744, mean age = 14.2, SD = 2.5 months) were included in the efficacy cohort. 815 varicella cases were confirmed. Efficacy of two doses of MMRV against all and against moderate or severe varicella was 95.0% (95% CI: 93.6–96.2) and 99.0% (95% CI: 97.7–99.6), respectively. Efficacy of one dose of varicella vaccine against all and against moderate or severe varicella was 67.0% (95% CI: 61.8–71.4) and 90.3% (95% CI: 86.9–92.8), respectively. There were four confirmed herpes zoster cases (MMR+V = 2, MMR = 2), all were mild and three tested positive for the wild-type virus. ConclusionsTwo doses of the MMRV vaccine and one dose of the varicella vaccine remain efficacious through six years post-vaccination.

Mothers'Awareness toward Chickenpox Disease for Preschool Children at Nursery School in Benha City

The purpose of this study was to assess mothers’ awareness toward chickenpox disease for preschool children. Research design: A descriptive research design was utilized in this study. Setting: This study was conducted in Revolution Nursery School, Omar Ben Abdul-Aziz Nursery School,Amr Ben El-Aas Nursery School. The sample: A convenient sample included 126 mothers and their preschool children, who were attending at the previously mentioned setting. Two instruments were used A structured interviewing questionnaire sheet for mothers awareness and Observational checklist to assess Nursery School Environment. Results of the study revealed that 64.3% of mothers of preschool child had average total knowledge score about chickenpox disease and 73.8% of mothers of preschool child had satisfactory total practice scores. Conclusion: The study conclude that three fifths of mothers of preschool child had average total knowledge score about chickenpox disease. Less than three quarters of mothers of preschool child had satisfactory total practice scores. Recommendations: Educational guidelines about management of chickenpox should be distributed between mothers of children. Further studies need to focus on improving knowledge and practices of mothers of child with chickenpox disease.

Mothers' Awareness toward Chickenpox Disease for Preschool Children at Nursery School in Benha City

Mothers' Awareness toward Chickenpox Disease for Preschool Children at Nursery School in Benha City

A cost-benefit analysis of varicella vaccination in Aragón.

Varicella, a contagious and infectious disease that is usually benign in children, may become complicated among adults and vulnerable children and may even be life-threatening. There are effective vaccines. A retrospective study was conducted about costs and resulting hospitalizations related to this disease in the population of Aragón in the 2004-2014 period. Costs were compared to the expenses that would have been incurred if those people had received the vaccine and also to the expenses of vaccinating the 1-year-old population over the entire period. A cost-benefit analysis was done to assess the economic impact of varicella vaccination. Data for the 11-year period were provided by the Autonomous Community of Aragón (Spain) and included annual varicella incidence, hospital discharges of varicella cases, costs of primary health care visits and hospitalizations for each year, costs of each workday as per the minimum annual salary and of drugs used). Capitalized costs were estimated and compared to capitalized expenses of vaccination, and a sensitivity analysis was performed. A benefit-cost ratio of 1.6 was obtained considering that all children who had varicella had been vaccinated and had received a booster dose. A benefit-cost ratio of 1.24 was obtained considering that the vaccine had been administered to every 1-year-old individual at a price of EUR 28.59 per vaccine. Over the 11-year period, 53% of hospitalizations corresponded to children younger than 5 years old. Public campaigns for the immunization of children younger than 4 years old with 2 doses lead to cost savings and are cost-effective because the vaccine price results in a benefit-cost ratio greater than 1. A major reduction is expected in the number of hospitalizations among children aged 3-4 years.

Varicella Vaccination Coverage among Adolescents Ages 13–17 Years, United States, National Immunization Survey, 2007–2014

BackgroundVaricella is typically a self-limiting disease but it can be more severe in adolescents and adults. In 2007, 2-doses of varicella vaccine were routinely recommended for children, with a catch-up second dose for persons who received 1 prior dose.MethodsWe used 2007–2014 NIS-Teen data to examine trends in ≥2 dose varicella vaccination coverage and proportions of adolescents with/without evidence of immunity to varicella. Evidence of immunity included receipt of ≥2 doses of varicella vaccine or varicella disease history. Additionally, using 2014 data, we assessed characteristics of ≥2 dose varicella vaccination coverage: 1) factors associated with ≥2 dose vaccination, 2) timing of receipt of second dose and 3) missed opportunities for second dose vaccination among adolescents who had received 1 prior dose of varicella vaccine.ResultsDuring 2007–2014, the proportion of adolescents with ≥2 doses of varicella vaccine increased from 8.3% to 66.9% in 13–15 year olds, and from 3.6% to 56.7% in 16–17 year olds. The proportion of adolescents with evidence of varicella immunity also increased for both age groups, from 68.0% to 84.1% in 13–15 year olds and from 78.6% to 83.4% in 16–17 year olds. Among adolescents who received ≥2 doses of varicella vaccine by 2014, a higher proportion of 13–15 year olds received their second dose at 4–6 years compared with 16–17 year olds (13.4% vs. 3.2%). Factors significantly associated with lower ≥2 dose coverage included non-Hispanic White race/ethnicity; rural residence; living at >133% of the income-to-poverty ratio; no 11- to 12-year well-child visit; not receiving an adolescent vaccine; and residence in a state with no 2-dose immunization school entry requirement. Among the 2,478 adolescents who received only 1-dose of varicella vaccine, 77.1% (1,922) had at least 1 missed opportunity to receive their second dose; potentially 2-dose coverage could have increased from 79.5% to 94.8%.ConclusionThe ≥2-dose varicella vaccination coverage and the proportion of adolescents with evidence of immunity to varicella increased during 2007 to 2014, though 16% lacked evidence of immunity in 2014. Though catch-up campaigns have succeeded, decreasing missed vaccination opportunities will help with further improvement.Disclosures All authors: No reported disclosures.

Estimating the Health and Economic Impact of Universal Varicella Vaccination in Jordan

BackgroundTo evaluate the impact of adding universal varicella vaccination (UVV) to the existing childhood vaccination programme in Jordan, and identify the most cost-effective strategy.MethodsA dynamic transmission model of varicella infection was calibrated to available varicella seroprevalence data within the region and validated against local epidemiological data. Local direct and indirect costs and healthcare utilization data were used. We considered the health and economic impact of one dose UVV administered concurrently with MMR at 12 months of age with 95% coverage, and two dose strategies with short (6 month) and long (4 year) intervals between First and Second dose. We took the societal perspective (direct and indirect costs) and discounted costs and QALYs by 3%/year to assess cost-effectiveness.ResultsThe model estimated the current burden of varicella at 172,000 cases/year, an incidence rate of 2,200/100,000 persons. In the 5th/25th year after vaccination, all strategies substantially reduced total varicella incidence by 89.5%/96.6% (1 dose), 92.3%/98.0% (2 dose short), and 90.5%/98.3% (2 dose long), compared with no vaccine (Figure 1). In the absence of vaccination, an estimated $47.89 M ($28.81 M direct, $19.08 indirect) was spent annually on varicella treatment. The average annual total treatment costs over 25 years from the societal perspective were $4.01M (1 dose), $3.34M (2 dose short), and $3.43M (2 dose long). Considering a willingness to pay (WTP) threshold of $3,600 USD / QALY and the societal perspective, the 1 dose program was the most cost-effective with cost savings of $83.40 USD and health gain of 4.127 × 10−5 QALYs per person. 2 dose programs are similarly cost-saving and highly effective, compared with a scenario of no vaccination; however, moving incrementally from a 1 dose strategy, incremental cost-effectiveness ratios (ICERS) were $6.9M/QALY (short vs. 1 dose) and $13.5M/QALY (long vs. short), both well as above the WTP threshold. All strategies reached.ConclusionOne or two dose UVV in Jordan will significantly reduce varicella disease burden and is cost saving relative to no vaccine over 25 years.Disclosures W. Hayajneh, Merck & Co., Inc.: Consultant, Consulting fee. J. Maalouf, Merck & Co., Inc.: Employee, Salary. B. Kuter, Merck & Co., Inc.: Employee, Salary.T. Weiss, Merck & Co., Inc.: Employee, Salary. V. Daniels, Merck & Co., Inc.: Employee, Salary. L. Wolfson, Merck & Co., Inc.: Employee, Salary.