The Impact of Varicella Vaccination on the Incidence of Varicella and Herpes Zoster in the United States: Updated Evidence From Observational Databases, 1991-2016.

BACKGROUND: Universal childhood vaccination against varicella began in the United States as a 1-dose schedule in 1996, changing to a 2-dose schedule in 2006. The exogenous boosting hypothesis, which postulates that reexposure to circulating wild-type varicella delays the onset of herpes zoster, predicts a transient increase in the incidence of herpes zoster, peaking in adults 15-35 years after the start of varicella vaccination. METHODS: This was a retrospective study of administrative claims data from the MarketScan Commercial and Medicare databases between 1991-2016. Outcome measures were the incidences of herpes zoster per 100 000 person-years, by calendar year and age category, and the annual rates of change in herpes zoster by age category, in an interrupted time series regression analysis, for the periods of 1991-1995 (prevaccine), 1996-2006 (1-dose vaccination period), and 2007-2016 (2-dose vaccination period). RESULTS: The annual incidences of herpes zoster increased throughout the period of 1991-2012 in all adult age categories, with a plateau in 2013-2016 that was most evident in the ≥65 age group. In 1991-1995, the herpes zoster incidences increased at annual rates of 4-6% in age categories 18-34, 35-44, 45-54, and 55-64 years. In the same age categories during 1996-2006 and 2007-2016, the herpes zoster incidences increased at annual rates of 1-5%. CONCLUSIONS: Although the annual incidence of herpes zoster in adults has continued to increase, the rates of change decreased during both the 1- and 2-dose vaccination periods. The hypothesized increase in herpes zoster predicted from modelling of the exogenous boosting hypothesis was not observed.

Burden of varicella in Latin America and the Caribbean: findings from a systematic literature review.

BACKGROUND: Varicella is typically mild and self-limiting, but can be associated with complications and even death. The limited data available on varicella in Latin America and the Caribbean (LAC) indicate substantial burden in countries where varicella vaccine is not part of publicly funded childhood national immunization programs. METHODS: A systematic literature review of published studies was complemented by "gray" literature on varicella incidence, complications, mortality, and economic consequences, in the absence and presence of universal varicella vaccination (UVV) in LAC. RESULTS: Seroprevalence data indicate that varicella is usually a disease of childhood in LAC. Varicella incidence rates, while unreliable in the absence of mandatory reporting, show a trend to increased incidence due to greater urbanization and population density. The introduction of UVV in national immunization programs has led to significant reductions in varicella incidence in these areas. CONCLUSIONS: Varicella continues to pose a substantial healthcare burden in LAC. The future introduction of UVV in additional countries is predicted to provide substantial reductions in cases, with important economic benefits. For countries that have already implemented UVV, the challenge is to maintain high rates of coverage and, where relevant, consider inclusion of a second dose to reduce breakthrough cases. Given the significant proportion of the region now implementing UVV, a regional recommendation in order to prevent any potential for age-shifts in varicella infection might be considered.

The use of antibiotics in the treatment of pediatric varicella patients: real-world evidence from the multi-country MARVEL study in Latin America & Europe.

BACKGROUND: Varicella is a highly contagious childhood disease. Generally benign, serious complications necessitating antibiotic use may occur. The objective of this study was to characterize the rate, appropriateness and patterns of real-world antibiotic prescribing for management of varicella-associated complications, prior to universal varicella vaccination (UVV) implementation. METHODS: Pooled, post-hoc analysis of 5 international, multicenter, retrospective chart reviews studies (Argentina, Hungary, Mexico, Peru, Poland). Inpatient and outpatient primary pediatric (1-14 years) varicella cases, diagnosed between 2009 and 2016, were eligible. Outcomes, assessed descriptively, included varicella-associated complications and antibiotic use. Three antibiotic prescribing scenarios were defined based on complication profile in chart: evidence of microbiologically confirmed bacterial infection (Scenario A); insufficient evidence confirming microbiological confirmation (Scenario B); no evidence of microbiological confirmation (Scenario C). Stratification was performed by patient status (inpatient vs. outpatient) and country. RESULTS: Four hundred one outpatients and 386 inpatients were included. Mean (SD) outpatient age was 3.6 (2.8) years; inpatient age was 3.1 (2.8) years. Male gender was predominant. Overall, 12.2% outpatients reported ≥1 infectious complication, 3.7% ≥1 bacterial infection, and 0.5% ≥1 microbiologically confirmed infection; inpatient complication rates were 78.8, 33.2 and 16.6%, respectively. Antibiotics were prescribed to 12.7% of outpatients and 68.9% of inpatients. Among users, ß-lactamases (class), and clindamycin (agent), dominated prescriptions. Scenario A was assigned to 3.9% (outpatients) vs 13.2% (inpatients); Scenario B: 2.0% vs. 6.0%; Scenario C: 94.1% vs. 80.8%. CONCLUSIONS: High rates of infectious complications and antibiotic use are reported, with low rates of microbiological confirmation suggesting possible antibiotic misuse for management of varicella complications.

Varicella in Poland: economic burden in children 1-12 years of age in Poland, 2010-2015.

BACKGROUND: The safety and efficacy of live-attenuated varicella zoster virus (VZV) vaccines in preventing varicella and reducing associated morbidity and mortality in real-world have been previously shown. In Poland, VZV vaccination is only mandatory for certain high-risk individuals. Here, we have conducted an evaluation of the clinical and economic burden of varicella in Poland. METHODS: Multicenter, retrospective chart review of varicella inpatients and outpatients aged 1-12 years with a primary diagnosis between 2010 and 2015. Varicella-related outcomes included the incidence of complications, the proportion of patients reporting healthcare resource utilization (HCRU), and frequency of HCRU. Direct costs were derived from per patient resource use multiplied by unit costs, and indirect costs were calculated as loss of revenue of caregivers reporting work days missed. The overall annual cost of varicella in Poland was estimated based on the calculated direct and indirect costs per case and the estimated number of varicella cases. All costs are presented in 2015 Polish zloty (PLN) / Euros (€). RESULTS: A total of 150 children with varicella were included, of which 75 were outpatients and 75 were inpatients with a mean (± SD) age of 3.9 (±2.6) and 4.2 (±2.3) years, respectively. Complications were experienced by 14.7% of outpatients and 82.7% of inpatients, of which the most common were skin and soft tissue infections and dehydration. The rate of HCRU was as follows: over-the-counter medications (80.0% outpatients, 81.3% inpatients), prescription medications (80.0% outpatients, 93.3% inpatients), tests/procedures (0.0% outpatients, 69.3% inpatients), and allied health professional consults (0.0% outpatients, 24.0% inpatients). Total (direct and indirect) cost per varicella case was 5013.3 PLN (€ 1198.1) for inpatients and 1027.2 PLN (€ 245.5) for outpatients, resulting in an estimated overall annual (2015) cost of varicella in Poland of 178,198,320 PLN (€ 42,588,385) among children aged 1-15 years. CONCLUSIONS: Significant clinical and economic burden is associated with varicella in Poland. These results may be used to foster discussion related to the implications of implementing routine VZV vaccination in Poland.

Economic burden of varicella in children 1-12 Years of age in Hungary, 2011-2015.

BACKGROUND: Although live-attenuated varicella-zoster virus (VZV) vaccines have been proven to be safe and effective in preventing varicella and real-word evidence shows routine childhood immunization programs are effective in dramatically reducing varicella associated morbidity and mortality, varicella vaccine is not included in the National Immunization Program (NIP) in Hungary. The purpose of this study was to evaluate the clinical and economic burden associated with varicella in Hungary. METHODS: This was a multicenter, retrospective, chart review study of patients aged 1-12 years with a primary varicella diagnosis between 2011 and 2015. Healthcare resource utilization (HCRU) associated with varicella, unit costs, and work loss were used to estimate direct and indirect costs. All costs are presented in 2015 HUF / Euros (€). RESULTS: 156 children with varicella were included (75 outpatients, 81 inpatients), with a mean age of 4.4 (SD: 2.0) and 3.7 (SD: 2.1) years, respectively. One or more complications were reported by 12.0% of outpatients and 92.6% of inpatients, the most common being dehydration, skin and soft tissue infections, pneumonia, keratoconjunctivitis, and cerebellitis. HCRU estimates included use of over-the-counter (OTC) medications (96.0% outpatients, 53.1% inpatients), prescription medications (9.3% outpatients, 70.4% inpatients), tests/procedures (4.0% outpatients, 97.5% inpatients), and consultation with allied health professionals (2.7% outpatients, 30.9% inpatients). The average duration of hospital stay (inpatients) was 3.6 (95% CI: 3.2, 4.1) days. The total combined direct and indirect cost per varicella case was 228,146.7 Hungarian Forint (HUF)/€ 736.0 for inpatients and 49,790.6 HUF/€ 106.6 for outpatients. The overall annual cost of varicella in Hungary for children aged <15 years in 2015 was estimated at 1,903,332,524.3 HUF/ € 6,139,980.4. CONCLUSION: Varicella is associated with substantial clinical burden in Hungary, resulting in the utilization of a significant amount of healthcare resources. These results support the need for routine vaccination of all healthy children to reduce the varicella-associated disease burden.

Health outcomes of bedaquiline in the treatment of multidrug-resistant tuberculosis in selected high burden countries.

BACKGROUND: Less than one-third of patients who are estimated to be infected with multidrug-resistant tuberculosis (MDR-TB) receive MDR-TB treatment regimens, and only 48% of those who received treatment have successful outcomes. Despite current regimens, newer, more effective and cost-effective approaches to treatment are needed. The aim of the study was to project health outcomes and impact on healthcare resources of adding bedaquiline to the treatment regimen of MDR-TB in selected high burden countries: Estonia, Russia, South Africa, Peru, China, the Philippines, and India. METHODS: This study adapted an existing Markov model to estimate the health outcomes and impact on total healthcare costs of adding bedaquiline to current MDR-TB treatment regimens. A price threshold analysis was conducted to determine the price range at which bedaquiline would be cost-effective. RESULTS: Adding bedaquiline to the background regimen (BR) resulted in increased disability-adjusted life years (DALYs) averted, and reduced total healthcare costs (excluding treatment acquisition costs) compared with BR alone in all countries analyzed. Addition of bedaquiline to BR resulted in savings to healthcare costs compared with BR alone in all countries analyzed, with the highest impact expected in Russia (US$194 million) and South Africa (US$43 million). The price per regimen at which bedaquiline would be cost-effective ranged between US$23,904-US$203,492 in Estonia, Russia, Peru, South Africa, and China (high and upper middle-income countries) and between US$6,996-US$20,323 in the Philippines and India (lower middle-income countries); however, these cost-effective prices do not necessarily address concerns about affordability. CONCLUSIONS: Adding bedaquiline to BR provides improvements in health outcomes and reductions in healthcare costs in high MDR-TB burden countries. The range of prices per regimen for which bedaquiline would be cost-effective varied between countries.

The dynamics of measles in sub-Saharan Africa.

Although vaccination has almost eliminated measles in parts of the world, the disease remains a major killer in some high birth rate countries of the Sahel. On the basis of measles dynamics for industrialized countries, high birth rate regions should experience regular annual epidemics. Here, however, we show that measles epidemics in Niger are highly episodic, particularly in the capital Niamey. Models demonstrate that this variability arises from powerful seasonality in transmission-generating high amplitude epidemics-within the chaotic domain of deterministic dynamics. In practice, this leads to frequent stochastic fadeouts, interspersed with irregular, large epidemics. A metapopulation model illustrates how increased vaccine coverage, but still below the local elimination threshold, could lead to increasingly variable major outbreaks in highly seasonally forced contexts. Such erratic dynamics emphasize the importance both of control strategies that address build-up of susceptible individuals and efforts to mitigate the impact of large outbreaks when they occur.

Strategic planning for measles control: using data to inform optimal vaccination strategies.

BACKGROUND: In response to repeated requests for assistance in evaluating the health benefit and cost implications of adjustments to national measles immunization strategies, the World Health Organization (WHO) has developed the Measles Strategic Planning (MSP) tool to harness routinely available data to estimate effectiveness and cost effectiveness of vaccination strategies. METHOD: The MSP tool estimates measles incidence and mortality through a country-specific cohort model, using a probability of infection dependent on population immunity levels. This method approximates measles transmission dynamics without requiring detailed data that would prohibit use in low- and middle-income countries. Coupled with cost data, the tool estimates incremental costs and cost effectiveness of user-defined vaccination strategies over 5-10 year planning periods. RESULTS: The MSP tool produces valid estimates of measles incidence in settings with low to moderate vaccination coverage. Early adopters report that the tool facilitates decision making by minimizing the amount of time required to assess the impact of vaccination strategies on population immunity. CONCLUSIONS: By clearly illustrating what vaccination strategies can effectively protect against measles at the least cost to immunization programs, the MSP tool supports evidence-based decision making for effective and comprehensive measles control.

Timing of Monovalent Vaccine Administration in Infants Receiving DTaP-based Combination Vaccines in the United States.

BACKGROUND: The recommended US infant immunization schedule includes doses of diphtheria, tetanus, acellular pertussis (DTaP), inactivated poliovirus (IPV), Haemophilus influenzae type b (Hib) and hepatitis B virus (HepB) during the first 6 months of life. Little information is available about the timing of associated, complementary monovalent vaccine administration in infants receiving DTaP-based pentavalent combination vaccines. METHODS: This was a retrospective cohort study of infants born between July 1, 2010, and June 30, 2018, in the US MarketScan commercial claims and encounters database. Descriptive statistics were used to assess vaccine administration patterns. Multivariate logistic regression was performed to explore factors associated with coadministration of DTaP-IPV/Hib and HepB. RESULTS: Among infants who received DTaP-HepB-IPV (n = 129,885), 93.7% had claims for at least 2 Hib doses; most (91.5%-98.3%) of these doses were administered on the same day as DTaP-HepB-IPV doses. Among infants who received DTaP-IPV/Hib (n=214,172), 95.3% had claims for ≥2 doses of HepB. Although coverage was high, 59.2% received the second HepB dose on the same day as the first DTaP-IPV/Hib dose, and 44.6% received the third dose of HepB on the same day as the third DTaP-IPV/Hib dose. Differences in coadministration of the second and third HepB doses with DTaP-IPV/Hib were associated with the region of residence, provider type, health plan type and coadministration of pneumococcal conjugate vaccine and rotavirus vaccine. CONCLUSIONS: Almost all infants received the appropriate, complementary monovalent vaccine series. However, this study found variability in the timing of HepB doses in relation to DTaP-IPV/Hib doses with many infants not completing the HepB series until 9 months of age.

Use of health care resources for varicella in the paediatric population, Jordan.

BACKGROUND: The exact burden of varicella is not well quantified in Jordan. AIMS: This study aimed to estimate the varicella burden in paediatric patients in Jordan who sought care in a hospital-based setting. METHODS: This was a multicentre, retrospective review of medical records of patients aged 0-14 years with a primary varicella diagnosis in Jordan between 2013 and 2018. The data assessed were: use of health care resources for varicella (outpatient and inpatient visits, tests and procedures, and medication use), and clinical complications of the infection. Estimated costs were based on health care resources used (direct costs) and lost revenue to the child's caregiver (indirect costs) for outpatients and inpatients. RESULTS: In total, 140 children with varicella were included: 78 outpatients, mean age (standard deviation) 4.4 (3.2) years, and 62 inpatients, mean age 4.0 (3.8) years. No outpatients had varicella-related complications, while 32 (52%) inpatients had ≥ 1 complication. The use of health care resources was higher for inpatients than outpatients, including prescription medication use - 94% of inpatients versus 6% of outpatients. Total costs of varicella were estimated at US$ 66.1 (95% CI: 64.1-68.1) per outpatient and US$ 914.7 (95% CI: 455.6-1373.9) per inpatient. CONCLUSIONS: Varicella is associated with considerable use of health care resources in Jordan and may be responsible for annual costs of US$ 11.5 million. These results support universal varicella vaccination in Jordan.

Burden of disease caused by Haemophilus influenzae type b in children younger than 5 years: global estimates.

BACKGROUND: Haemophilus influenzae type b (Hib) is a leading cause of childhood bacterial meningitis, pneumonia, and other serious infections. Hib disease can be almost completely eliminated through routine vaccination. We assessed the global burden of disease to help national policy makers and international donors set priorities. METHODS: We did a comprehensive literature search of studies of Hib disease incidence, case-fatality ratios, age distribution, syndrome distribution, and effect of Hib vaccine. We used vaccine trial data to estimate the proportion of pneumonia cases and pneumonia deaths caused by Hib. We applied these proportions to WHO country-specific estimates of pneumonia cases and deaths to estimate Hib pneumonia burden. We used data from surveillance studies to develop estimates of incidence and mortality of Hib meningitis and serious non-pneumonia, non-meningitis disease. If available, high-quality data were used for national estimates of Hib meningitis and non-pneumonia, non-meningitis disease burden. Otherwise, estimates were based on data from other countries matched as closely as possible for geographic region and child mortality. Estimates were adjusted for HIV prevalence and access to care. Disease burden was estimated for the year 2000 in children younger than 5 years. FINDINGS: We calculated that Hib caused about 8.13 million serious illnesses worldwide in 2000 (uncertainty range 7.33-13.2 million). We estimated that Hib caused 371,000 deaths (247,000-527,000) in children aged 1-59 months, of which 8100 (5600-10,000) were in HIV-positive and 363,000 (242,000-517,000) in HIV-negative children. INTERPRETATION: Global burden of Hib disease is substantial and almost entirely vaccine preventable. Expanded use of Hib vaccine could reduce childhood pneumonia and meningitis, and decrease child mortality. FUNDING: GAVI Alliance and the Vaccine Fund.

Burden of disease caused by Streptococcus pneumoniae in children younger than 5 years: global estimates.

BACKGROUND: Streptococcus pneumoniae is a leading cause of bacterial pneumonia, meningitis, and sepsis in children worldwide. However, many countries lack national estimates of disease burden. Effective interventions are available, including pneumococcal conjugate vaccine and case management. To support local and global policy decisions on pneumococcal disease prevention and treatment, we estimated country-specific incidence of serious cases and deaths in children younger than 5 years. METHODS: We measured the burden of pneumococcal pneumonia by applying the proportion of pneumonia cases caused by S pneumoniae derived from efficacy estimates from vaccine trials to WHO country-specific estimates of all-cause pneumonia cases and deaths. We also estimated burden of meningitis and non-pneumonia, non-meningitis invasive disease using disease incidence and case-fatality data from a systematic literature review. When high-quality data were available from a country, these were used for national estimates. Otherwise, estimates were based on data from neighbouring countries with similar child mortality. Estimates were adjusted for HIV prevalence and access to care and, when applicable, use of vaccine against Haemophilus influenzae type b. FINDINGS: In 2000, about 14.5 million episodes of serious pneumococcal disease (uncertainty range 11.1-18.0 million) were estimated to occur. Pneumococcal disease caused about 826,000 deaths (582,000-926,000) in children aged 1-59 months, of which 91,000 (63,000-102,000) were in HIV-positive and 735,000 (519,000-825,000) in HIV-negative children. Of the deaths in HIV-negative children, over 61% (449,000 [316,000-501,000]) occurred in ten African and Asian countries. INTERPRETATION: S pneumoniae causes around 11% (8-12%) of all deaths in children aged 1-59 months (excluding pneumococcal deaths in HIV-positive children). Achievement of the UN Millennium Development Goal 4 for child mortality reduction can be accelerated by prevention and treatment of pneumococcal disease, especially in regions of the world with the greatest burden. FUNDING: GAVI Alliance and the Vaccine Fund.

Validation of the shake test for detecting freeze damage to adsorbed vaccines.

OBJECTIVE: To determine the validity of the shake test for detecting freeze damage in aluminium-based, adsorbed, freeze-sensitive vaccines. METHODS: A double-blind crossover design was used to compare the performance of the shake test conducted by trained health-care workers (HCWs) with that of phase contrast microscopy as a "gold standard". A total of 475 vials of 8 different types of World Health Organization prequalified freeze-sensitive vaccines from 10 different manufacturers were used. Vaccines were kept at 5 degrees C. Selected numbers of vials from each type were then exposed to -25 degrees C and -2 degrees C for 24-hour periods. FINDINGS: There was complete concordance between HCWs and phase-contrast microscopy in identifying freeze-damaged vials and non-frozen samples. Non-frozen samples showed a fine-grain structure under phase contrast microscopy, but freeze-damaged samples showed large conglomerates of massed precipitates with amorphous, crystalline, solid and needle-like structures. Particles in the non-frozen samples measured from 1 microm (vaccines against diphtheria-tetanus-pertussis; Haemophilus influenzae type b; hepatitis B; diphtheria-tetanus-pertussis-hepatitis B) to 20 microm (diphtheria and tetanus vaccines, alone or in combination). By contrast, aggregates in the freeze-damaged samples measured up to 700 microm (diphtheria-tetanus-pertussis) and 350 microm on average. CONCLUSION: The shake test had 100% sensitivity, 100% specificity and 100% positive predictive value in this study, which confirms its validity for detecting freeze damage to aluminium-based freeze-sensitive vaccines.

The clinical and economic burden of varicella in the Middle East: a systematic literature review.

This systematic literature review was conducted to better understand the epidemiology and burden of varicella across the Middle East, gain insight into the evidence to support using universal varicella vaccination (UVV), and identify potential data gaps. Both epidemiology and economic data on the burden of varicella were limited and varied significantly. Most of the data focussed on varicella burden in the absence of a UVV program. In the absence of UVV, varicella incidence is increasing across this region with varicella infection associated with substantial morbidity. Although limited, data on the impact of vaccination at a population level indicated UVV programs reduce varicella incidence and hospitalizations, in line with global experience. Further research and action are needed to better understand varicella epidemiology in the Middle East, increase awareness and understanding in the region, and provide local data to support national public-health decisions regarding the implementation of UVV programs.

Budget impact analysis of multiple varicella vaccination strategies: a Mexico perspective.

A number of live-attenuated varicella vaccines are produced globally that provide protection against the varicella zoster virus. In Mexico, varicella vaccination is not included in the national immunization program and is recommended for use only in high-risk subgroups. We developed a budget impact model to estimate the impact of universal childhood immunization against varicella on the national payer system in Mexico. A scenario of no varicella vaccination was compared to scenarios with vaccination with a single dose at 13 months of age, in alignment with the existing program of immunization with the measles-mumps-rubella vaccine. Nine different vaccination scenarios were envisioned, differing by vaccine type and by coverage. Varicella cases and treatment costs of each scenario were computed in a dynamic transmission model of varicella epidemiology, calibrated to the population of Mexico. Unit costs were based on Mexico sources or were from the literature. The results indicated that each of the three vaccine types increased vaccine acquisition and administration expenditures but produced overall cost savings in each of the first 10 years of the program, due to fewer cases and reduced varicella treatment costs. A highly effective vaccine at 95% coverage produced the greatest cost savings.

WHO and UNICEF estimates of national infant immunization coverage: methods and processes.

WHO and the United Nations Children's Fund (UNICEF) annually review data on immunization coverage to estimate national coverage with routine service delivery of the following vaccines: bacille Calmette-Guérin; diphtheria-tetanus-pertussis, first and third doses; either oral polio vaccine or inactivated polio vaccine, third dose of either; hepatitis B, third dose; Haemophilus influenzae type b, third dose; and a measles virus-containing vaccine, either for measles alone or in the form of a combination vaccine, one dose. The estimates are based on government reports submitted to WHO and UNICEF and are supplemented by survey results from the published and grey literature. Local experts, primarily national immunization system managers and WHO/UNICEF regional and national staff, are consulted for additional information on the performance of specific immunization systems. Estimates are derived through a country-by-country review of available data informed and constrained by a set of heuristics; no statistical or mathematical models are used. Draft estimates are made, sent to national authorities for review and comment and modified in light of their feedback. While the final estimates may not differ from reported data, they constitute an independent technical assessment by WHO and UNICEF of the performance of national immunization systems. These country-specific estimates, available from 1980 onward, are updated annually.

Cost-effectiveness analysis of universal varicella vaccination in Turkey using a dynamic transmission model.

BACKGROUND: In 2013, Turkey introduced one-dose universal varicella vaccination (UVV) at 12 months of age. Inclusion of a second dose is being considered. METHODS: We developed a dynamic transmission model to evaluate three vaccination strategies: single dose at 12 months (1D) or second dose at either 18 months (2D-short) or 6 years of age (2D-long). Costs and utilization were age-stratified and separated into inpatient and outpatient costs for varicella and herpes zoster (HZ). We ran the model including and excluding HZ-related costs and impact of exogenous boosting. RESULTS: Five years post-introduction of UVV (1D), the projected varicella incidence rate decreases from 1,674 cases pre-vaccine to 80 cases/100,000 person-years. By 25 years, varicella incidence equilibrates at 39, 12, and 16 cases/100,000 person-years for 1D, 2D-short, and 2D-long strategies, respectively, using a highly effective vaccine. With or without including exogenous boosting impact and/or HZ-related costs and health benefits, the 1D strategy is least costly, but 2-dose strategies are cost-effective considering a willingness-to-pay threshold equivalent to the gross domestic product. The model predicted a modest increase in HZ burden during the first 20-30 years, after which time HZ incidence equilibrates at a lower rate than pre-vaccine. CONCLUSIONS: Our findings support adding a second varicella vaccine dose in Turkey, as doing so is highly cost-effective across a wide range of assumptions regarding the burden associated with varicella and HZ disease.

Varicella healthcare resource utilization in middle income countries: a pooled analysis of the multi-country MARVEL study in Latin America & Europe.

Varicella is a mild and self-limited illness in children, but can result in significant healthcare resource utilization (HCRU). To quantify/contrast varicella-associated HCRU in five middle-income countries (Hungary, Poland, Argentina, Mexico, and Peru) where universal varicella vaccination was unimplemented, charts were retrospectively reviewed among 1-14 year-olds. Data were obtained on management of primary varicella between 2009-2016, including outpatient/inpatient visits, allied healthcare contacts, tests/procedures, and medications. These results are contrasted across countries, and a regression model is fit to extrapolated country-level costs as a function of gross domestic product (GDP). A total of 401 outpatients and 386 inpatients were included. Significant differences between countries were observed in the number of skin lesions among outpatients, ranging from 5.3% to 25.4% of patients with ≥250 lesions. Among inpatients, results were less variable. Average ambulatory medical visits ranged from 1.1 to 2.2. Average hospital stay ranged from 3.6 to 6.8 days. Use of tests/procedures was infrequent in outpatients, except in Argentina (13.3%); among inpatients, a test/procedure was ordered for 81.3% of patients, without regional variation. Prescription medications were administered in 44.4% of outpatients (range 9.3%-80.0%), and in 86% of inpatients (range 70.4%-94.9%). Total estimated spending on varicella treatment in the absence of vaccination was predicted from income levels (GDP) with an exponential function (R2 = 0.89). This study demonstrates that substantial HCRU is associated with varicella resulting in significant public health burden that could be alleviated through the use of varicella vaccination. Differences observed between countries possibly reflect treatment guidelines, healthcare resource availabilities and physician practices.

Burden of varicella in the Asia-Pacific region: a systematic literature review.

INTRODUCTION: Varicella is a highly contagious infection that can lead to serious complications, particularly in high-risk groups; however, it is vaccine preventable. Disease awareness and understanding of the disease burden can strongly influence vaccine coverage. This review provides insight into the current epidemiology and the importance of varicella from both public health and economic perspectives across the Asia-Pacific (APAC) region. Areas covered: A systematic literature review was conducted to identify studies on the incidence, seroprevalence, fatality rate and complication rate of varicella. Economic burden studies were also captured. Altogether, 125 studies were identified across the region; these were supplemented by government reports (gray data). Reported vaccine coverage varied from 2.8% to 97%; a key influencing factor was inclusion of the varicella vaccine in national immunization programs. In general, varicella incidence in the unvaccinated population was highest in children ≤5 years old and seroprevalence increased with age. Economic analyses highlighted the cost-saving potential of vaccination programs, especially from a societal perspective. Expert opinion: Varicella-related data varied greatly across the APAC region, highlighting the need to better understand the burden of varicella in this area, and particularly identified the need for better surveillance and reporting.