Live vaccinations in dermatology for immunosuppressed patients: a narrative review

Given the higher susceptibility to infectious disease in patients receiving immunosuppressive therapies for inflammatory dermatologic conditions, immunization is important in this population. While live vaccines protect against life-threatening diseases, they can be harmful in immunosuppressed patients given the risk of replication of the attenuated pathogen and adverse reactions. The utilization of live vaccines in immunosuppressed patients depends on multiple factors such as the vaccine and therapy regimen. To provide an overview of evidence-based recommendations for the use of live vaccines in patients receiving immunosuppressive therapies for dermatological conditions. A literature search of the PubMed database was performed using keywords live vaccine, live-attenuated vaccine, dermatology, immunosuppressed, and immunocompromised, and specific immunosuppressive therapies: corticosteroids, glucocorticoids, methotrexate, azathioprine, cyclosporine, mycophenolate mofetil, biologics. Relevant articles written in English were included. Using these keywords, 125 articles were reviewed, of which 28 were ultimately selected. Recommendations for live vaccines can be determined on a case-by-case basis. Measles, mumps, rubella, varicella (MMRV) vaccines may be safely administered to patients on low-dose immunosuppressive agents while the yellow fever vaccine is typically contraindicated. It may be safe to administer live MMRV boosters to children on immunosuppressive therapies and the live herpes zoster vaccine to patients on biologics. Given poor adherence to immunization guidelines in immunosuppressed patients, dermatologists have a critical role in educating patients and general practitioners regarding live vaccines. By reviewing a patient's vaccination history and following immunization guidelines prior to initiating immunosuppressive therapies, physicians can mitigate morbidity and mortality from vaccine-preventable diseases.

Association Between Diabetes Mellitus and the Risk of Herpes Zoster: A Systematic Review and Meta-analysis

CONTEXT

Individuals with diabetes mellitus (DM) are susceptible to various infections.

OBJECTIVE

We estimated the risk of herpes zoster (HZ) among individuals with DM compared with individuals in the general population.

METHODS

We searched the PubMed, Embase, Cochrane Database of Systematic Reviews, Cochrane Central Register of Controlled Trials, Cumulative Index to Nursing and Allied Health Literature, and PerioPath databases from their inception to January 30, 2021, for studies on the risk of HZ in individuals with DM. Two authors independently screened all articles identified. The same 2 authors independently extracted the data. Four case-control studies and 12 cohort studies were included.

RESULTS

Meta-analyses were performed using fixed and mixed-effects models. In the pooled analysis, individuals with DM had a higher risk of developing HZ (pooled relative risk [RR]: 1.38; 95% CI, 1.21-1.57) than individuals in the general population. The results were consistent in subgroup analyses stratified by type of diabetes, age, and study design. In individuals with DM, cardiovascular disease had an additive effect on increasing the risk of HZ (pooled RR: 1.19; 95% CI, 1.11-1.28). There was a linear dose-response association between age and the risk of HZ in individuals with DM.

CONCLUSION

Individuals with DM have an increased risk of HZ compared with the general population. Varicella vaccination should be provided to individuals with DM regardless of their age, prioritizing older adults and those with cardiovascular disease. Varicella vaccination policies for individuals with DM should be updated based on the evidence.

Parental acceptance and knowledge of varicella vaccination in relation to socioeconomics in Sweden: A cross-sectional study

Varicella infection is a highly contagious disease which, whilst mild in most cases, can cause severe complications. Varicella vaccination is available privately in Sweden and is currently being reviewed for inclusion in the Swedish Public Health Agency's national immunisation program (NIP). A cross-sectional study of parents of Swedish children aged 1-8 years (n = 2212) was conducted to understand parental acceptance, beliefs and knowledge around varicella infection and vaccination. Respondents generally viewed varicella infection as a mild disease, with only a small proportion aware of potential severe complications. While 65% of respondents were aware of the vaccine, only 15% had started the course of vaccination as of February 2019. Further, 43% of parents did not intend to vaccinate, most commonly due to lack of inclusion in the NIP, but also due to perception of mild disease. Nevertheless, if offered within the NIP, 85% of parents would be highly likely to vaccinate their child. A number of statistically significant differences in awareness and behaviours were observed between sociodemographic subgroups. In general, women were more aware of vaccination (72%) compared to men (58%). Among unemployed or respondents with elementary school education, awareness was below 43%, and among respondents with high income the awareness was above 75%. Similarly, among unemployed or respondents with a low income the vaccination rate was as low as 30% compared with at least 57% among respondents with a high income. Respondents from metropolitan areas, those with university degrees and respondents with a higher income were more likely to be aware of the varicella vaccine and to have vaccinated their child. Whilst inclusion in the NIP is clearly the main driver for uptake, these identified knowledge gaps should inform educational efforts to ensure that all parents are informed of the availability and benefits of the varicella vaccine independent of socioeconomic status.

Waning Effectiveness of One-dose Universal Varicella Vaccination in Korea, 2011-2018: a Propensity Score Matched National Population Cohort

BACKGROUND

Despite high coverage (~98%) of universal varicella vaccination (UVV) in the Republic of Korea since 2005, reduction in the incidence rate of varicella is not obvious. The study aimed to evaluate the vaccine effectiveness (VE) of one-dose UVV by timeline and severity of the disease.

METHODS

All children born in Korea in 2011 were included for this retrospective cohort study that analyzed insurance claims data from 2011-2018 and the varicella vaccination records in the immunization registry. Adjusted hazard ratios by Cox proportional hazard models were used to estimate the VE through propensity score matching by the month of birth, sex, healthcare utilization rate, and region.

RESULTS

Of the total 421,070 newborns in the 2011 birth cohort, 13,360 were matched for age, sex, healthcare utilization rate, and region by the propensity score matching method. A total of 55,940 (13.29%) children were diagnosed with varicella, with the incidence rate 24.2 per 1000 person-year; 13.4% of vaccinated children and 10.4% of unvaccinated children. The VE of one-dose UVV against any varicella was 86.1% (95% confidence interval [CI], 81.4-89.5) during the first year after vaccination and 49.9% (95% CI, 43.3-55.7) during the 6-year follow-up period since vaccination, resulting in a 7.2% annual decrease of VE. The overall VE for severe varicella was 66.3%. The VE of two-dose compared to one-dose was 73.4% (95% CI, 72.2-74.6).

CONCLUSION

We found lower long-term VE in one-dose vaccination and waning of effectiveness over time. Longer follow ups of the vaccinated children as well as appropriately designed studies are needed to establish the optimal strategy in preventing varicella in Korea.

Health Impact and Cost-effectiveness Assessment for the Introduction of Universal Varicella Vaccination in Switzerland

BACKGROUND

Varicella, caused by the varicella-zoster virus, is a highly contagious infectious disease with substantial health and economic burden to society. Universal varicella vaccination (UVV) is not yet recommended by the Swiss National Immunization Program, which instead recommends catch-up immunization for children, adolescents and adults 11-40 years of age who have no reliable history of varicella or are varicella-zoster virus-IgG seronegative. The objective of this study was to perform an assessment of health impact and cost-effectiveness comparing UVV with current practice and recommendations in Switzerland.

METHODS

A dynamic transmission model for varicella was adapted to Switzerland comparing 2 base-case schedules (no infant vaccination and 10% coverage with infant vaccination) to 3 different UVV schedules using quadrivalent (varicella vaccine combined with measles-mumps-rubella) and standalone varicella vaccines administered at different ages. Modeled UVV coverage rates were based on current measles-mumps-rubella coverage of approximately 95% (first dose) and 90% (second dose). Direct medical costs and societal perspectives were considered, with cost and outcomes discounted and calculated over a 50-year time horizon.

RESULTS

UVV would reduce the number of varicella cases by 88%-90%, hospitalizations by 62%-69% and deaths by 75%-77%. UVV would increase direct medical costs by Swiss Franc (CHF) 39-49 (US $43-54) per capita and costs from a societal perspective by CHF 32-40 (US $35-44). Incremental quality-adjusted life-years per capita increased by 0.0012-0.0014. Incremental cost-effectiveness ratios for the UVV schedules versus the base-case were CHF 31,194-35,403 (US $34,452-39,100) per quality-adjusted life-year from the direct medical cost perspective and CHF 25,245-29,552 (US $27,881-32,638) from the societal perspective.

CONCLUSIONS

UVV appears highly effective and cost-effective when compared with current clinical practice and recommendations in Switzerland from both a direct medical costs perspective and societal perspective.

Cost-effectiveness of varicella and herpes zoster vaccination in Sweden: An economic evaluation using a dynamic transmission model

OBJECTIVES

Comprehensive cost-effectiveness analyses of introducing varicella and/or herpes zoster vaccination in the Swedish national vaccination programme.

DESIGN

Cost-effectiveness analyses based on epidemiological results from a specifically developed transmission model.

SETTING

National vaccination programme in Sweden, over an 85- or 20-year time horizon depending on the vaccination strategy.

PARTICIPANTS

Hypothetical cohorts of people aged 12 months and 65-years at baseline.

INTERVENTIONS

Four alternative vaccination strategies; 1, not to vaccinate; 2, varicella vaccination with one dose of the live attenuated vaccine at age 12 months and a second dose at age 18 months; 3, herpes zoster vaccination with one dose of the live attenuated vaccine at 65 years of age; and 4, both vaccine against varicella and herpes zoster with the before-mentioned strategies.

MAIN OUTCOME MEASURES

Accumulated cost and quality-adjusted life years (QALY) for each strategy, and incremental cost-effectiveness ratios (ICER).

RESULTS

It would be cost-effective to vaccinate against varicella (dominant), but not to vaccinate against herpes zoster (ICER of EUR 200,000), assuming a cost-effectiveness threshold of EUR 50,000 per QALY. The incremental analysis between varicella vaccination only and the combined programme results in a cost per gained QALY of almost EUR 1.6 million.

CONCLUSIONS

The results from this study are central components for policy-relevant decision-making, and suggest that it was cost-effective to introduce varicella vaccination in Sweden, whereas herpes zoster vaccination with the live attenuated vaccine for the elderly was not cost-effective-the health effects of the latter vaccination cannot be considered reasonable in relation to its costs. Future observational and surveillance studies are needed to make reasonable predictions on how boosting affects the herpes zoster incidence in the population, and thus the cost-effectiveness of a vaccination programme against varicella. Also, the link between herpes zoster and sequelae need to be studied in more detail to include it suitably in health economic evaluations.

Immunogenicity and safety of a quadrivalent meningococcal tetanus toxoid-conjugate vaccine administered concomitantly with other paediatric vaccines in toddlers: a phase III randomised study

Invasive meningococcal disease has high morbidity and mortality, with infants and young children among those at greatest risk. This phase III, open-label, randomised study in toddlers aged 12-23 months evaluated the immunogenicity and safety of meningococcal tetanus toxoid-conjugate vaccine (MenACYW-TT), a tetanus toxoid conjugated vaccine against meningococcal serogroups A, C, W and Y, when coadministered with paediatric vaccines (measles, mumps and rubella [MMR]; varicella [V]; 6-in-1 combination vaccine against diphtheria, tetanus, pertussis, polio, hepatitis B and Haemophilus influenzae type b [DTaP-IPV-HepB-Hib] and pneumococcal conjugate vaccine [PCV13])(NCT03205371). Immunogenicity to each meningococcal serogroup was assessed by serum bactericidal antibody assay using human complement (hSBA). Vaccine safety profiles were described up to 30 days post-vaccination. A total of 1183 participants were enrolled. The proportion with seroprotection (hSBA ≥1:8) to each meningococcal serogroup at Day 30 was comparable between the MenACYW-TT and MenACYW-TT + MMR + V groups (≥92 and ≥96%, respectively), between the MenACYW-TT and MenACYW-TT + DTaP-IPV-HepB-Hib groups (≥90% for both) and between the MenACYW-TT and MenACYW-TT + PCV13 groups (≥91 and ≥84%, respectively). The safety profiles of MenACYW-TT, and MMR + V, DTaP-IPV-HepB-Hib, and PCV13, with or without MenACYW-TT, were generally comparable. Coadministration of MenACYW-TT with paediatric vaccines in toddlers had no clinically relevant effect on the immunogenicity and safety of any of the vaccines.

Vaccination Coverage with Selected Vaccines and Exemption Rates Among Children in Kindergarten - United States, 2019-20 School Year

State and local school vaccination requirements serve to protect students against vaccine-preventable diseases (1). This report summarizes data collected by state and local immunization programs* on vaccination coverage among children in kindergarten (kindergartners) in 48 states, exemptions for kindergartners in 49 states, and provisional enrollment and grace period status for kindergartners in 28 states for the 2019-20 school year, which was more than halfway completed when most schools moved to virtual learning in the spring because of the coronavirus 2019 (COVID-19) pandemic. Nationally, vaccination coverage^† was 94.9% for the state-required number of doses of diphtheria and tetanus toxoids, and acellular pertussis vaccine (DTaP); 95.2% for 2 doses of measles, mumps, and rubella vaccine (MMR); and 94.8% for the state-required number of varicella vaccine doses. Although 2.5% of kindergartners had an exemption from at least one vaccine,^§ another 2.3% were not up to date for MMR and did not have a vaccine exemption. Schools and immunization programs can work together to ensure that undervaccinated students are caught up on vaccinations in preparation for returning to in-person learning. This follow-up is especially important in the current school year, in which undervaccination is likely higher because of disruptions in vaccination during the ongoing COVID-19 pandemic (2-4).

What We Know Now: An Economic Evaluation of Chickenpox Vaccination and Dose Timing Using an Agent-Based Model

OBJECTIVES

The value of chickenpox vaccination is still debated in the literature and by jurisdictions worldwide. This uncertainty is reflected in the inconsistent uptake of the vaccine, where some countries offer routine childhood immunization programs, others have targeted programs, and in many the vaccine is only privately available. Even across the countries that have universal funding for the vaccine, there is a diversity of schedules and dosing intervals. Using an agent-based model of chickenpox and shingles, we conducted an economic evaluation of chickenpox vaccination in Alberta, Canada.

METHODS

We compared the cost-effectiveness of 2 common chickenpox vaccination schedules, specifically a long dosing interval (first dose: 12 months; second dose: 4-6 years) and a short dosing interval (first dose: 12 months; second dose: 18 months).

RESULTS

The economic evaluation demonstrated a shorter dosing interval may be marginally preferred, although it consistently led to higher costs from both the societal and healthcare perspectives. We found that chickenpox vaccination would be cost-saving and highly cost-effective from the societal and healthcare perspective, assuming there was no impact on shingles.

CONCLUSION

Chickenpox vaccine was cost-effective when not considering shingles and remained so even if there was a minor increase in shingles following vaccination. However, if chickenpox vaccination did lead to a substantial increase in shingles, then chickenpox vaccination was not cost-effective from the healthcare perspective.

Vaccines for measles, mumps, rubella, and varicella in children

BACKGROUND

Measles, mumps, rubella, and varicella (chickenpox) are serious diseases that can lead to serious complications, disability, and death. However, public debate over the safety of the trivalent MMR vaccine and the resultant drop in vaccination coverage in several countries persists, despite its almost universal use and accepted effectiveness. This is an update of a review published in 2005 and updated in 2012.

OBJECTIVES

To assess the effectiveness, safety, and long- and short-term adverse effects associated with the trivalent vaccine, containing measles, rubella, mumps strains (MMR), or concurrent administration of MMR vaccine and varicella vaccine (MMR+V), or tetravalent vaccine containing measles, rubella, mumps, and varicella strains (MMRV), given to children aged up to 15 years.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (the Cochrane Library 2019, Issue 5), which includes the Cochrane Acute Respiratory Infections Group's Specialised Register, MEDLINE (1966 to 2 May 2019), Embase (1974 to 2 May 2019), the WHO International Clinical Trials Registry Platform (2 May 2019), and ClinicalTrials.gov (2 May 2019).

SELECTION CRITERIA

We included randomised controlled trials (RCTs), controlled clinical trials (CCTs), prospective and retrospective cohort studies (PCS/RCS), case-control studies (CCS), interrupted time-series (ITS) studies, case cross-over (CCO) studies, case-only ecological method (COEM) studies, self-controlled case series (SCCS) studies, person-time cohort (PTC) studies, and case-coverage design/screening methods (CCD/SM) studies, assessing any combined MMR or MMRV / MMR+V vaccine given in any dose, preparation or time schedule compared with no intervention or placebo, on healthy children up to 15 years of age.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data and assessed the methodological quality of the included studies. We grouped studies for quantitative analysis according to study design, vaccine type (MMR, MMRV, MMR+V), virus strain, and study settings. Outcomes of interest were cases of measles, mumps, rubella, and varicella, and harms. Certainty of evidence of was rated using GRADE.

MAIN RESULTS

We included 138 studies (23,480,668 participants). Fifty-one studies (10,248,159 children) assessed vaccine effectiveness and 87 studies (13,232,509 children) assessed the association between vaccines and a variety of harms. We included 74 new studies to this 2019 version of the review. Effectiveness Vaccine effectiveness in preventing measles was 95% after one dose (relative risk (RR) 0.05, 95% CI 0.02 to 0.13; 7 cohort studies; 12,039 children; moderate certainty evidence) and 96% after two doses (RR 0.04, 95% CI 0.01 to 0.28; 5 cohort studies; 21,604 children; moderate certainty evidence). The effectiveness in preventing cases among household contacts or preventing transmission to others the children were in contact with after one dose was 81% (RR 0.19, 95% CI 0.04 to 0.89; 3 cohort studies; 151 children; low certainty evidence), after two doses 85% (RR 0.15, 95% CI 0.03 to 0.75; 3 cohort studies; 378 children; low certainty evidence), and after three doses was 96% (RR 0.04, 95% CI 0.01 to 0.23; 2 cohort studies; 151 children; low certainty evidence). The effectiveness (at least one dose) in preventing measles after exposure (post-exposure prophylaxis) was 74% (RR 0.26, 95% CI 0.14 to 0.50; 2 cohort studies; 283 children; low certainty evidence). The effectiveness of Jeryl Lynn containing MMR vaccine in preventing mumps was 72% after one dose (RR 0.24, 95% CI 0.08 to 0.76; 6 cohort studies; 9915 children; moderate certainty evidence), 86% after two doses (RR 0.12, 95% CI 0.04 to 0.35; 5 cohort studies; 7792 children; moderate certainty evidence). Effectiveness in preventing cases among household contacts was 74% (RR 0.26, 95% CI 0.13 to 0.49; 3 cohort studies; 1036 children; moderate certainty evidence). Vaccine effectiveness against rubella is 89% (RR 0.11, 95% CI 0.03 to 0.42; 1 cohort study; 1621 children; moderate certainty evidence). Vaccine effectiveness against varicella (any severity) after two doses in children aged 11 to 22 months is 95% in a 10 years follow-up (rate ratio (rr) 0.05, 95% CI 0.03 to 0.08; 1 RCT; 2279 children; high certainty evidence). Safety There is evidence supporting an association between aseptic meningitis and MMR vaccines containing Urabe and Leningrad-Zagreb mumps strains, but no evidence supporting this association for MMR vaccines containing Jeryl Lynn mumps strains (rr 1.30, 95% CI 0.66 to 2.56; low certainty evidence). The analyses provide evidence supporting an association between MMR/MMR+V/MMRV vaccines (Jeryl Lynn strain) and febrile seizures. Febrile seizures normally occur in 2% to 4% of healthy children at least once before the age of 5. The attributable risk febrile seizures vaccine-induced is estimated to be from 1 per 1700 to 1 per 1150 administered doses. The analyses provide evidence supporting an association between MMR vaccination and idiopathic thrombocytopaenic purpura (ITP). However, the risk of ITP after vaccination is smaller than after natural infection with these viruses. Natural infection of ITP occur in 5 cases per 100,000 (1 case per 20,000) per year. The attributable risk is estimated about 1 case of ITP per 40,000 administered MMR doses. There is no evidence of an association between MMR immunisation and encephalitis or encephalopathy (rate ratio 0.90, 95% CI 0.50 to 1.61; 2 observational studies; 1,071,088 children; low certainty evidence), and autistic spectrum disorders (rate ratio 0.93, 95% CI 0.85 to 1.01; 2 observational studies; 1,194,764 children; moderate certainty). There is insufficient evidence to determine the association between MMR immunisation and inflammatory bowel disease (odds ratio 1.42, 95% CI 0.93 to 2.16; 3 observational studies; 409 cases and 1416 controls; moderate certainty evidence). Additionally, there is no evidence supporting an association between MMR immunisation and cognitive delay, type 1 diabetes, asthma, dermatitis/eczema, hay fever, leukaemia, multiple sclerosis, gait disturbance, and bacterial or viral infections.

AUTHORS' CONCLUSIONS

Existing evidence on the safety and effectiveness of MMR/MMRV vaccines support their use for mass immunisation. Campaigns aimed at global eradication should assess epidemiological and socioeconomic situations of the countries as well as the capacity to achieve high vaccination coverage. More evidence is needed to assess whether the protective effect of MMR/MMRV could wane with time since immunisation.

Women who received varicella vaccine versus natural infection have different long-term T cell immunity but similar antibody levels

BACKGROUND

Varicella-zoster virus (VZV) infection during pregnancy is associated with serious fetal anomalies. The live-attenuated VZV vaccine was approved in 1995, so many vaccinated women are now of childbearing age. The question of long-term immunity to varicella is critical because breakthrough chickenpox can occur after vaccination.

OBJECTIVE

To compare humoral and T cell immunity between women of childbearing age who were immunized by vaccination or chickenpox disease.

STUDY DESIGN

Non-pregnant females between 18 and 36 years old with a history of VZV immunization (n = 20) or prior chickenpox disease (n = 20) were recruited. IgG antibody titers and T cell responses were measured by flow cytometry-based methods in serum and peripheral blood, respectively.

RESULTS

There were no significant differences in median antibody titers between vaccinated and chickenpox groups (p = 0.34). The chickenpox group had significantly higher levels of VZV antigen-specific CD4 T cells (p = 0.004).

CONCLUSION

Natural infection induced higher VZV-specific T cell immune responses than vaccination.

Herpes zoster after vaccination with one dose varicella vaccine to a 4-year-old child

Clinical observations from the international literature report that herpes zoster occurs after varicella vaccination in immunocompetent children. We present the case of a four-year-old immunocompetent girl who developed herpes zoster after she had received one dose of varicella-zoster virus live attenuated vaccine at the age of 15 months. Continued surveillance for herpes zoster among vaccinated persons is important to evaluate the varicella vaccination program and to detect any changes in the epidemiology of herpes zoster. Vaccinated children appear to have a lower risk of herpes zoster than people who were infected naturally with varicella zoster virus (chickenpox).

Frequency and cost of live vaccines administered too soon after prior live vaccine in children aged 12 months through 6 years, 2014-2017

OBJECTIVE

To identify number of children who received live vaccines outside recommended intervals between doses and calculate corrective revaccination costs.

METHODS

We analyzed >1.6 million vaccination records for children aged 12 months through 6 years from six immunization information system (IIS) Sentinel Sites from 2014-15 when live attenuated influenza vaccine (LAIV, FluMist® Quadrivalent) was recommended for use, and from 2016-17, when not recommended for use. Depending on the vaccine, insufficient intervals between live vaccine doses are less than 24 or 28 days from a preceding live vaccine dose. Private and public purchase costs of vaccines were used to determine revaccination costs of live vaccine doses administered during the live vaccine conflict interval. Measles, mumps, rubella (MMR), varicella, combined MMRV, and LAIV were live vaccines evaluated in this study.

RESULTS

Among 946,659 children who received at least one live vaccine dose from 2014-15, 4,873 (0.5%) received at least one dose too soon after a prior live vaccine (revaccination cost, $786,413) with a median conflict interval of 16 days. Among 704,591 children who received at least one live vaccine dose from 2016-17, 1,001 (0.1%) received at least one dose too soon after a prior live vaccine (revaccination cost, $181,565) with a median conflict interval of 14 days. The live vaccine most frequently administered outside of the recommended intervals was LAIV from 2014-15, and varicella from 2016-17.

CONCLUSIONS

Live vaccine interval errors were rare (0.5%), indicating an adherence to recommendations. If all invalid doses were corrected by revaccination over the two time periods, the cost within the IIS Sentinel Sites would be nearly one million dollars. Provider awareness about live vaccine conflicts, especially with LAIV, could prevent errors, and utilization of clinical decision support functionality within IISs and Electronic Health Record Systems can facilitate better vaccination practices.

Vaccination Coverage with Selected Vaccines and Exemption Rates Among Children in Kindergarten - United States, 2018-19 School Year

State and local school vaccination requirements exist to ensure that students are protected against vaccine-preventable diseases (1). This report summarizes data collected by state and local immunization programs* on vaccination coverage among children in kindergarten in 49 states, exemptions for kindergartners in 50 states, and provisional enrollment and grace period status for kindergartners in 30 states. Nationally, vaccination coverage^† was 94.9% for the state-required number of doses of diphtheria and tetanus toxoids, and acellular pertussis vaccine (DTaP); 94.7% for 2 doses of measles, mumps, and rubella vaccine (MMR); and 94.8% for the state-required doses of varicella vaccine. Whereas 2.5% of kindergartners had an exemption from at least one vaccine,^§ 2.8% of kindergartners were not up to date for MMR and did not have a vaccine exemption. Nearly all states could achieve the recommended ≥95% MMR coverage if all nonexempt kindergartners were vaccinated in accordance with local and state vaccination policies.

National, Regional, State, and Selected Local Area Vaccination Coverage Among Adolescents Aged 13-17 Years - United States, 2018

The Advisory Committee on Immunization Practices (ACIP) recommends routine vaccination of persons aged 11-12 years to protect against certain diseases, including human papillomavirus (HPV)-associated cancers, meningococcal disease, and pertussis (1). A booster dose of quadrivalent meningococcal conjugate vaccine (MenACWY) is recommended at age 16 years, and serogroup B meningococcal vaccine (MenB) may be administered to persons aged 16-23 years (1). To estimate vaccination coverage among adolescents in the United States, CDC analyzed data from the 2018 National Immunization Survey-Teen (NIS-Teen) which included 18,700 adolescents aged 13-17 years.* During 2017-2018, coverage with ≥1 dose of HPV vaccine increased from 65.5% to 68.1%, and the percentage of adolescents up-to-date^† with the HPV vaccine series increased from 48.6% to 51.1%, although the increases were only observed among males. Vaccination coverage increases were also observed for ≥1 MenACWY dose (from 85.1% to 86.6%) and ≥2 MenACWY doses (from 44.3% to 50.8%). Coverage with tetanus and reduced diphtheria toxoids and acellular pertussis vaccine (Tdap) remained stable at 89%. Disparities in coverage by metropolitan statistical area (MSA)^§ and health insurance status identified in previous years persisted (2). Coverage with ≥1 dose of HPV vaccine was higher among adolescents whose parents reported receiving a provider recommendation; however, prevalence of parents reporting receiving a recommendation for adolescent HPV vaccination varied by state (range = 60%-91%). Supporting providers to give strong recommendations and effectively address parental concerns remains a priority, especially in states and rural areas where provider recommendations were less commonly reported.

Vaccine-derived varicella zoster infection in a kidney transplant recipient after zoster vaccine live administration

A 49-year-old kidney transplant recipient, presented with a skin rash, and interstitial infiltrates three weeks after receiving a live attenuated varicella-zoster vaccine. Varicella-zoster Oka-vaccine strain was detected in plasma by polymerase chain reaction and sequencing analysis targeting open reading frame 62 (ORF 62). She was treated successfully with intravenous acyclovir. Our case report supports the current contraindication of live attenuated varicella-zoster vaccine in the solid-organ transplant recipients. Recombinant subunit varicella-zoster vaccine may be the vaccine of choice in these patients; nevertheless, further information is required to establish its safety, efficacy, and optimal timing.

Vaccine Strain Varicella Infection in an Infant With Previously Undiagnosed Perinatal Human Immunodeficiency Type-1 Infection

A 15-month-old infant with a history of developmental delay and weight loss with multiple hospital admissions was diagnosed with a pustular lesion identified as vaccine strain varicella at the vaccination site. He was ultimately determined to be HIV infected following a protracted evaluation, which did not initially include HIV since his mother was confirmed HIV seronegative at 3 months gestation.

Increasing varicella incidence rates among children in the Republic of Korea: an age-period-cohort analysis

In the Republic of Korea, despite the introduction of one-dose universal varicella vaccination in 2005 and achieving a high coverage rate of 98.9% in 2012, the incidence rate has been increased sevenfold. This study aimed to investigate time trends of varicella incidence rate, assessing the age, period and birth cohort effects. We used national data on the annual number of reported cases from 2006 to 2017. A log-linear Poisson regression model was used to estimate age-period-cohort effects on varicella incidence rate. From 2006 to 2017, the incidence of varicella increased from 22.5 cases to more than 154.8 cases per 100 000. Peak incidence has shifted from 4 to 6 years old. The estimated period and cohort effects showed significant upward patterns, with a linear increasing trend by net drift. There has been an increase in the incidence among the Korean population regarding period and cohort despite the universal vaccination of varicella vaccine. Our data suggest the need for additional studies to address the current gap in herd immunity.

Global impact of varicella vaccination programs

Although varicella is usually a mild and self-limited disease, complications can occur. In 1998, the World Health Organization recommended varicella vaccination for countries where the disease has a significant public health burden. Nonetheless, concerns about a shift in the disease to older groups, an increase in herpes zoster in the elderly and cost-effectiveness led many countries to postpone universal varicella vaccine introduction. In this review, we summarize the accumulating evidence, available mostly from high and middle-income countries supporting a high impact of universal vaccination in reductions of the incidence of the disease and hospitalizations and its cost-effectiveness. We have also observed the effect of herd immunity and noted that there is no definitive and consistent association between vaccination and the increase in herpes zoster incidence in the elderly.

Management of chickenpox in pregnant women: an Italian perspective

Chickenpox is a highly contagious disease caused by primary infection of varicella zoster virus (VZV). The disease is spread worldwide and is usually benign but, in some groups of population like pregnant women, can have a severe outcome. Due to a not optimal vaccination coverage, a relatively high number of childbearing-aged women in a European country such as Italy tested seronegative for VZV and so are currently at risk of acquiring chickenpox during pregnancy, especially if they live in contact with children for family or work reasons. Only few data are available about the risk of infection in this setting: the incidence of chickenpox may range from 1.5 to 4.6 cases/1000 childbearing females and from 1.21 to 6 cases/10,000 pregnant women, respectively. This review is aimed to focus on the epidemiology and the clinical management of exposure to chickenpox during pregnancy. Particular emphasis is given to the accurate screening of childbearing women at the time of the first gynecological approach - the females who tested susceptible to infection can be counseled about the risks and instructed on procedure should contact occur - and to the early prophylaxis of the at-risk exposure. Lastly, the achievement of adequate vaccination coverage of the Italian population remains a cornerstone in the prevention of chickenpox in pregnancy.

National, Regional, State, and Selected Local Area Vaccination Coverage Among Adolescents Aged 13-17 Years - United States, 2017

The Advisory Committee on Immunization Practices (ACIP) recommends routine vaccination of persons aged 11–12 years with human papillomavirus (HPV) vaccine, quadrivalent meningococcal conjugate vaccine (MenACWY), and tetanus and reduced diphtheria toxoids and acellular pertussis vaccine (Tdap). A booster dose of MenACWY is recommended at age 16 years (1), and catch-up vaccination is recommended for hepatitis B vaccine (HepB), measles, mumps, and rubella vaccine (MMR), and varicella vaccine (VAR) for adolescents whose childhood vaccinations are not up to date (UTD) (1). ACIP also recommends that clinicians may administer a serogroup B meningococcal vaccine (MenB) series to adolescents and young adults aged 16–23 years, with a preferred age of 16–18 years (2). To estimate U.S. adolescent vaccination coverage, CDC analyzed data from the 2017 National Immunization Survey–Teen (NIS-Teen) for 20,949 adolescents aged 13–17 years.* During 2016–2017, coverage increased for ≥1 dose of HPV vaccine (from 60.4% to 65.5%), ≥1 dose of MenACWY (82.2% to 85.1%), and ≥2 doses of MenACWY (39.1% to 44.3%). Coverage with Tdap remained stable at 88.7%. In 2017, 48.6% of adolescents were UTD with the HPV vaccine series (HPV UTD) compared with 43.4% in 2016.^† On-time vaccination (receipt of ≥2 or ≥3 doses of HPV vaccine by age 13 years) also increased. As in 2016, ≥1-dose HPV vaccination coverage was lower among adolescents living in nonmetropolitan statistical areas (MSAs) (59.3%) than among those living in MSA principal cities (70.1%).^§ Although HPV vaccination initiation remains lower than coverage with MenACWY and Tdap, HPV vaccination coverage has increased an average of 5.1 percentage points annually since 2013, indicating that continued efforts to target unvaccinated teens and eliminate missed vaccination opportunities might lead to HPV vaccination coverage levels comparable to those of other routinely recommended adolescent vaccines.

Trends in herpes zoster epidemiology in Germany based on primary care sentinel surveillance data, 2005-2016

Herpes zoster (HZ) is caused by reactivation of the varicella-zoster-virus (VZV). Childhood varicella vaccination, as recommended in Germany in 2004, may reduce the risk of HZ in vaccinated children but also virus circulation and thus the booster possibility of latent infected persons. In this context we analyzed age-specific trends in HZ epidemiology in Germany using data on HZ-associated outpatient consultations in participating sentinel sites and HZ-associated cases in all hospitals since 2005. We analyzed two separate time periods that differed in sentinel management and data integrity. For the period 2005-2010, we found a decrease in HZ-associated outpatient consultations in 1- to 4-year-olds (IRR = 0.72, 95%CI 0.63-0.81, p<0.001). For the period 2013-2016, we observed a decrease in HZ-associated outpatient consultations in 10- to 14-year-olds (IRR = 0.85, 95%CI 0.78-0.93, p<0.01). Moreover, we detected an increase in the age groups 20 years and older except for the group 30-39 years. HZ-associated hospitalizations showed similar trends for the second time period (here 2012-2015). The decrease in HZ-associated outpatient consultations and hospitalizations in children started and continued over cohorts eligible for varicella vaccination and could be a result of their reduced HZ-risk. Whether the observed steady increasing HZ incidences for adults are associated with the varicella vaccination in children remains unclear and could not be investigated with our data.

Varicella-zoster virus and urologic practice: a case-based review

INTRODUCTION

Each year, varicella-zoster virus (VZV) affects nearly one million people in the United States, often in the form of herpes zoster, or shingles. The urologic system is a rare but often debilitating target. This paper reviews the epidemiology, symptomatology, diagnosis, and management of VZV as it relates to urologic practice.

MATERIALS AND METHODS

We performed a PubMed search using the query "herpes zoster" and "varicella-zoster virus" combined with multiple urological terms.

RESULTS

Infection caused by VZV, specifically the resurgent clinical infection herpes zoster (HZ), is prevalent and increasing. It often affects older men and women and those in immunocompromised states and usually manifests as a painful cutaneous rash. However, urological conditions such as voiding dysfunction, erectile issues, and flank pain have also been noted in conjunction with an HZ infection. Additionally, urological procedures and treatments may incite an HZ outbreak. Awareness and prompt treatment can ameliorate the intensity and duration of this infection.

CONCLUSIONS

An understanding of the atypical manifestations of HZ and disseminated VZV infection may aid urologic practitioners in avoiding misdiagnosis and delay of treatment.

Varicella Virus Vaccination in the United States

Varicella zoster virus (VZV) is the cause of chickenpox (varicella) and shingles (zoster), and was once responsible for over 4 million infections in the United States annually. The development of a live attenuated VZV vaccine was initially viewed with extreme skepticism. Nonetheless, a VZV vaccine was developed in the 1970s by Takahashi and his colleagues in Japan and was eventually licensed in the US. It is now known to be one of the safest and most effective vaccines available and is administered worldwide. Here are described important factors that contributed to the successful research and licensure of the highly successful VZV vaccine.

Incidence rate of breakthrough varicella observed in healthy children after 1 or 2 doses of varicella vaccine: Results from a meta-analysis

BACKGROUND

Although extensive varicella vaccination coverage has been reported in many countries, breakthrough varicella (BV) still occurs in healthy children. We performed a meta-analysis to understand whether 2 varicella vaccine doses are needed in children and, if so, to determine the best time to vaccinate.

METHODS

The BV incidence rates after 1 or 2 doses of varicella vaccine were pooled using random effects, and 95% confidence intervals (CI) were used to estimate the risk factors after vaccination.

RESULTS

A total of 27 original articles were included in this meta-analysis. The pooled average BV incidence rate in children vaccinated with 1 dose was 8.5 cases per 1,000 person years (PY) (95% confidence interval [CI], 5.3-13.7; random effects model) and 2.2 cases per 1,000 PY (95% CI, 0.5-9.3; random effects model) in children vaccinated with 2 doses. The pooled trend of the annual BV incidence rate from the first to eighth year fluctuated, with a peak annual incidence rate of 35.3 cases per 1,000 population in the fourth year. The meta-regression showed that design type, type of vaccine, and their interaction accounted for approximately 71.74% of the heterogeneity in the average BV incidence rate after 1 vaccine dose.

CONCLUSIONS

Two doses of varicella vaccine are more effective than a single dose, and 3-4 years between the first and second vaccinations may achieve higher efficacy.

Safety and immunogenicity of Bio Pox™, a live varicella vaccine (Oka strain) in Indian children: A comparative multicentric, randomized phase II/III clinical trial

Varicella or chickenpox is a highly contagious disease with a high secondary attack rate. Almost 30% of Indian adolescents lack protective antibodies against varicella, emphasizing the need of routine varicella immunization. The Oka VZV is a well-established, safe and efficacious vaccine strain that is highly immunogenic and produces lifelong protective immunity. The present multicentric, open label, randomized, controlled Phase II/III study, compared the Bio Pox™ (indigenous investigational vaccine) with a licensed vaccine, Varivax™ ^[a][a] Please note that this article refers to the product named VARIVAX as manufactured by Changchun Keygen Biological Products Ltd., China and marketed in India by VHB Life Sciences Limited, Mumbai, and not the product VARIVAX® owned by Merck Sharp & Dohme Corp., Rahway, New Jersey, USA. Merck Sharp & Dohme Corp. have asked us to make clear that the product manufactured by Changchun Keygen Biological Products Ltd. is unrelated to and is not sponsored, endorsed or otherwise authorised by Merck Sharp & Dohme Corp. , for its safety and immunogenicity profile in 252 healthy subjects in the age group of 1-12 y (cohort I: 6-12 years, II:1-6 years) in 3 tertiary medical institutions. Antibodies were measured by VZV Glycoprotein Enzyme Linked Immunoassay (IgG ELISA) kit. Seroconversion percentage in children having pre-vaccination anti VZV IgG titer <10 mIU/mL (< 5 gp ELISA units/mL) were 80% for Bio Pox™ and 77% for Varivax™ (p = 0.692). The seroconversion rate in the group receiving Bio Pox™ was non-inferior to the group that received Varivax™. There were mild local reactions for both the vaccines; none of the patient had fever or required hospitalization or medication. The Bio Pox™ was found to be safe and immunogenic in children against VZV infection.

Is chickenpox so bad, what do we know about immunity to varicella zoster virus, and what does it tell us about the future?

Varicella and zoster continue to cause significant morbidity and even mortality in children and adults. Complications include bacterial superinfection, central nervous system manifestations such as meningitis, encephalitis, and cerebellar ataxia, and pain syndromes especially post herpetic neuralgia. Many developed countries but not all, are now administering live attenuated varicella vaccine routinely, with a decrease in the incidence of disease, providing personal and herd immunity. There is some controversy, however, in some countries concerning whether a decrease in the circulation of wild type virus will result in loss of immunity to VZV in persons who have already had varicella. This manuscript reviews the complications of varicella and zoster in detail, the reasons for development of vaccines against these diseases, complications of vaccinations, and mechanisms by which immunity to this virus develops and is maintained. There are strong indications that the best way to control disease and spread of this virus is by vaccination against both.

Herpes zoster following varicella vaccination in children

Herpes zoster (HZ), or shingles, is commonly seen in older adults but does occur in children. Routine administration of the varicella vaccine started in 1995 in the United States; since then, the incidence of varicella and HZ has declined. We report a case of HZ in an otherwise healthy 19-month-old boy who had been vaccinated at 13 months of age and recovered fully after acyclovir treatment. We review previously reported cases of HZ in healthy vaccinated children.

Vaccination Coverage Among Children in Kindergarten - United States, 2015-16 School Year

State-mandated vaccination requirements for school entry protect children and communities against vaccine-preventable diseases (1). Each school year, federally funded immunization programs (e.g., states, territories, jurisdictions) collect and report kindergarten vaccination data to CDC. This report describes vaccination coverage estimates in all 50 states and the District of Columbia (DC), and the estimated number of kindergartners with at least one vaccine exemption in 47 states and DC, during the 2015-16 school year. Median vaccination coverage* was 94.6% for 2 doses of measles, mumps and rubella vaccine (MMR); 94.2% for diphtheria, tetanus, and acellular pertussis vaccine (DTaP); and 94.3% for 2 doses of varicella vaccine. MMR coverage increased in 32 states during the last year, and 22 states reported coverage ≥95% (2). A total of 45 states and DC had either a grace period allowing students to attend school before providing documentation of vaccination or provisional enrollment that allows undervaccinated students to attend school while completing a catch-up schedule. Among the 23 states that were able to voluntarily report state-level data on grace period or provisional enrollment to CDC, a median of 2.0% of kindergartners were not documented as completely vaccinated and were attending school within a grace period or were provisionally enrolled. The median percentage of kindergartners with an exemption from one or more vaccinations^† was 1.9%. State and local immunization programs, in cooperation with schools, can improve vaccination coverage by ensuring that all kindergartners are vaccinated during the grace period or provisional enrollment.

Notes from the Field: Varicella Outbreak Associated with Riding on a School Bus - Muskegon County, Michigan, 2015

On December 3, 2015, Public Health-Muskegon County (PHMC) in Michigan was notified by a local kindergarten-grade 2 school that a student aged 8 years (the index patient) had been sent home because of a rash suspected to be varicella (chickenpox); the rash had not been observed the previous day. Investigation by PHMC revealed that the student was one of five siblings in household A, none of whom had a history of having received any immunizations. During the preceding month the index patient's two older siblings (aged 12 years and 25 years) and two younger siblings (twins, aged 4 years) had been excluded from other schools in this rural district because of rashes that also were suspected to be varicella. Investigators also learned that a parent in household A had received a physician diagnosis of herpes zoster (shingles) nearly 7 weeks earlier, on October 20, after having been evaluated for a painful, unilateral trunk rash that had begun 3 days earlier, and for which acyclovir was prescribed. PHMC could not confirm whether any advice regarding prevention of possible transmission of varicella zoster virus to susceptible contacts was provided. The other children in household A had rash onsets on November 3, November 18 (two children), and November 22. The index patient rode a school bus and was the first student on and the last off each day; none of the index patient's four siblings attended the same school or rode on the same school bus as the index patient. Public health investigators subsequently linked three more cases in children to sharing the same school bus as the index patient.

National, Regional, State, and Selected Local Area Vaccination Coverage Among Adolescents Aged 13-17 Years - United States, 2015

The Advisory Committee on Immunization Practices (ACIP) recommends that adolescents aged 11-12 years routinely receive vaccines to prevent diseases, including human papillomavirus (HPV)-associated cancers, pertussis, and meningococcal disease (1). To assess vaccination coverage among adolescents in the United States, CDC analyzed data collected regarding 21,875 adolescents through the 2015 National Immunization Survey-Teen (NIS-Teen).* During 2014-2015, coverage among adolescents aged 13-17 years increased for each HPV vaccine dose among males, including ≥1 HPV vaccine dose (from 41.7% to 49.8%), and increased modestly for ≥1 HPV vaccine dose among females (from 60.0% to 62.8%) and ≥1 quadrivalent meningococcal conjugate vaccine (MenACWY) dose (from 79.3% to 81.3%). Coverage with ≥1 HPV vaccine dose was higher among adolescents living in households below the poverty level, compared with adolescents in households at or above the poverty level.(†) HPV vaccination coverage (≥1, ≥2, or ≥3 doses) increased in 28 states/local areas among males and in seven states among females. Despite limited progress, HPV vaccination coverage remained lower than MenACWY and tetanus, diphtheria, and acellular pertussis vaccine (Tdap) coverage, indicating continued missed opportunities for HPV-associated cancer prevention.

Varicella immunization requirements for US colleges: 2014-2015 academic year

OBJECTIVE

To obtain information on varicella prematriculation requirements in US colleges for undergraduate students during the 2014-2015 academic year.

PARTICIPANTS

Health care professionals and member schools of the American College Health Association (ACHA).

METHODS

An electronic survey was sent to ACHA members regarding school characteristics and whether schools had policies in place requiring that students show proof of 2 doses of varicella vaccination for school attendance.

RESULTS

Only 27% (101/370) of schools had a varicella prematriculation requirement for undergraduate students. Only 68% of schools always enforced this requirement. Private schools, 4-year schools, northeastern schools, those with <5,000 students, and schools located in a state with a 2-dose varicella vaccine mandate were significantly more likely to have a varicella prematriculation requirement.

CONCLUSIONS

A small proportion of US colleges have a varicella prematriculation requirement for varicella immunity. College vaccination requirements are an important tool for controlling varicella in these settings.

Strong Additional Effect of a Second Varicella Vaccine Dose in Children in Germany, 2009-2014

OBJECTIVES

Vaccine effectiveness (VE) of 1 and 2 varicella vaccine doses in children aged 1-4 years in Germany was evaluated to determine the additional effect of a second dose recommended at least 4 weeks after the first dose and before the second birthday.

STUDY DESIGN

To estimate the VE, the proportion of cases vaccinated was compared with the proportion of the population vaccinated using nationwide sentinel surveillance data from 2009-2014 and health insurance claims data covering the period January 2009-March 2014, respectively. A general linear model was used to estimate the OR of vaccination in the cases and the population and the corresponding CIs to observe the stability of the VE estimates over time, and to assess the incremental effectiveness of a second dose.

RESULTS

The overall VE after 1 dose was 86.6% (95% CI: 85.2-87.9), ranging between 94.6% (95% CI: 87.9-97.6) in the first quarter of 2011 and 50.3% (95% CI: 7.3-73.4) in the third quarter of 2013. The overall VE after 2 doses was 97.3% (95% CI: 97.0-97.6), ranging between 99.5% (95% CI: 97.8-99.9) in the second quarter of 2009 and 91.3% (95% CI: 85.7-94.8) in the third quarter of 2013. The incremental VE of 2 doses was 84.6% (95% CI: 81.7-86.9).

CONCLUSIONS

The substantially higher VE of 2 varicella vaccine doses compared with 1 dose in young children and the strong additional effect of the second dose support the public health relevance of a 2-dose schedule and the success of the early second vaccine dose.

Varicella-zoster virus: pathogenesis, incidence patterns and vaccination programs

Varicella or chickenpox is a common and highly contagious exanthematic disease caused by the varicella-zoster virus (VZV) that during primary infection has the ability to establish latency. VZV reactivation, even decades after primary infection, causes herpes zoster. In healthy immunocompetent subjects, children in particular, varicella results in mild to moderate illness and for this reason, regardless its high morbidity, it is not considered a public health priority. Varicella still represents the most widespread vaccine preventable childhood infectious disease in industrialized countries; due to its relevant burden on healthcare resources several countries has introduced varicella vaccination into the recommended routine childhood national immunization schedule. Nowadays, live attenuated monovalent and combined MMRV vaccines are licensed worldwide. The use of several millions of doses has demonstrated the excellent safety and efficacy level of varicella vaccines as well as of combined MMRV vaccines. Universal vaccination adopted in many countries with a two-dose strategy has allowed to significantly reducing morbidity and mortality of this infectious disease. Anyway, an ample international debate is ongoing on the time range to be used between the two doses, and on the safety issues related to the use as first-dose of MMRV vaccine. Taking into account the availability of a zoster vaccine in subjects older than 50 years of age, it will be relevant to clarify if an impact on exogenous boosters and on the epidemiology of herpes zoster can occur after the adoption of extensive varicella immunization.

Varicella Zoster Virus: A Common Cause of Stroke in Children and Adults

BACKGROUND

Varicella zoster virus (VZV) is a neurotropic, exclusively human herpesvirus. Primary infection causes varicella (chickenpox), after which the virus becomes latent in ganglionic neurons along the entire neuraxis. As cell-mediated immunity to VZV declines with advancing age and immunosuppression, VZV reactivates to produce zoster (shingles). One of the most serious complications of zoster is VZV vasculopathy.

METHODS

We reviewed recent studies of stroke associated with varicella and zoster, how VZV vasculopathy is verified virologically, vaccination to prevent varicella and immunization to prevent zoster, and VZV in giant cell arteritis (GCA).

FINDINGS

We report recent epidemiological studies revealing an increased risk of stroke after zoster; the clinical, laboratory, and imaging features of VZV vasculopathy; that VZV vasculopathy is confirmed by the presence of either VZV DNA or anti-VZV IgG antibody in cerebrospinal fluid; special features of VZV vasculopathy in children; vaccination to prevent varicella and immunization to prevent zoster; and the latest evidence linking VZV to GCA.

CONCLUSION

In children and adults, VZV is a common cause of stroke.

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.

[Decisional framework for varicella vaccine: challenges in the face of opportunity]

INTRODUCTION

Decision makers adopt interventions, including vaccines, which are most beneficial to populations. A transparent, unbiased, and comprehensive framework based on evidence-based criteria is a promising tool to guide decision-making on vaccine adoption: we developed a multi-dimensional framework conceived from the DECIDE - Evidence to decision Framework (EtD framework). We validated the framework by conducting a real data and evidence set collection on varicella vaccination and tested it with a multidisciplinary group.

METHODS

The EtD framework presented evidence concerning the varicella vaccination organized in six dimensions: Burden of disease, Vaccine characteristics and impact of immunization program, Values and preferences, Resource use, Equity and Feasibility. Two reviewers completed each dimension with information about varicella vaccine. A multidisciplinary group of 42 participants were asked to evaluate the information in the framework, decide whether to introduce varicella vaccine in the national immunization program, assess the usefulness, and propose some impovements of the decision-making tool.

RESULTS

From 33 responders (79%) out of 42, 61% supported the adoption of the varicella vaccine as part of the national immunization program. A half (50%) favored the monovalent vaccine while the other half chose the tetravalent vaccine. About 90% of responders found information in the EtD framework comprehensive, easy to understand, and presented in a way that helped make decisions.

CONCLUSIONS

Complete and transparent information are welcome. The EtD identified a situation of important divergences between policy makers regarding the introduction and the choice of vaccine. In our case study, for example, a third of the multidisciplinary group did not recommend the adoption of varicella vaccine.

The epidemiological situation of chickenpox in the Silesian voivodeship in the years 2011-2015 in view of data of the situation in Poland

INTRODUCTION

Despite the availability of preventive vaccination against chickenpox, this form of prevention is rarely used and is not available to the entire population of children. In order to evaluate an acquired immunity against the virus Varicella-Zoster examining of the presence of specific IgG antibodies to VZV in serum or plasma is required. The aim of this study was to assess the epidemiological situation of chickenpox in Śląskie Voivodeship in 2011-2015.

MATERIAL AND METHODS

The evaluation of the epidemiological situation of chickenpox in the past five years was based on analysis of data from the bulletin “Infectious diseases and poisonings in Poland” for the period 2011-2014 and 2015 data, received from the Provincial Sanitary and Epidemiological Stations. Analysis of the vaccinated population was made on the basis of data available in the bulletin “Vaccinations in Poland” for the period 2011-2014 and 2015 data obtained from the NIPH-PZH. Samples of patients from Śląskie were tested with the use of Novalisa Varicella-Zoster Virus (VZV) IgG - ELISA (Novatec Immunodiagnostic GMBH, Germany). Samples were delivered to the Laboratory of the Provincial Sanitary and Epidemiological Station in the course of 2011-2015.

RESULTS

Between 2011 and 2015, in Śląskie, 136 094 chickenpox cases were registered (14% of all occurring in Poland). Based on the number of cases, Śląskie is ranked second place, just after Mazowieckie, in which during the same period of time 143 392 illness were registered. The average annual incidence in Śląskie was 591 per 100 thousand residents. Between 2011 and 2015, a total of 360 serum samples were examined. The percentage of positive IgG in each year ranged between 59.6 and 75.7%.

CONCLUSIONS

Promoting vaccination and preventing the sick children to contact the healthy ones as well as the protection of adults susceptible to infection can improve the epidemiological situation regarding incidences of chickenpox. Thanks to vaccines the risk of incidence of chickenpox can be reduced or even the incidences can be prevented. Information about acquired immunity, acquired before the pregnancy, allows to take the action in order to protect the mother from getting chickenpox in form of a preventive vaccination.

MATHEMATICAL MODELLING OF VARICELLA SPREAD IN SLOVAKIA

AIM

Varicella is a highly contagious disease. In Slovakia, 15,000-30,000 cases are reported annually. However, vaccination against varicella is not widely used in Slovakia. The aim of this paper is to predict the influence of vaccination administrated in different ages on the disease occurrence in different age groups.

METHODS

Deterministic, age-stratified SIR (susceptible-infected-recovered) model with stable population was used for prediction of varicella spread in Slovakia.

RESULTS

Vaccination of a group designated as 0 influences the proportion of susceptible and infected persons in all age groups, vaccination of 10 years old ones affects only the proportion of susceptible and infected individuals older than 10 years.

CONCLUSION

The increase of vaccination coverage should have a positive impact on the incidence of varicella in Slovakia. In case of vaccination coverage of 0 group in the range of 30-75%, it is necessary to pay attention to the protection of older children and adults.

National, State, and Selected Local Area Vaccination Coverage Among Children Aged 19-35 Months - United States, 2014

The reduction in morbidity and mortality associated with vaccine-preventable diseases in the United States has been described as one of the 10 greatest public health achievements of the first decade of the 21st century. A recent analysis concluded that routine childhood vaccination will prevent 322 million cases of disease and about 732,000 early deaths among children born during 1994-2013, for a net societal cost savings of $1.38 trillion. The National Immunization Survey (NIS) has monitored vaccination coverage among U.S. children aged 19-35 months since 1994. This report presents national, regional, state, and selected local area vaccination coverage estimates for children born from January 2011 through May 2013, based on data from the 2014 NIS. For most vaccinations, there was no significant change in coverage between 2013 and 2014. The exception was hepatitis A vaccine (HepA), for which increases were observed in coverage with both ≥1 and ≥2 doses. As in previous years, <1% of children received no vaccinations. National coverage estimates indicate that the Healthy People 2020 target* of 90% was met for ≥3 doses of poliovirus vaccine (93.3%), ≥1 dose of measles, mumps, and rubella vaccine (MMR) (91.5%), ≥3 doses of hepatitis B vaccine (HepB) (91.6%), and ≥1 dose of varicella vaccine (91.0%). Coverage was below target for ≥4 doses of diphtheria, tetanus, and acellular pertussis vaccine (DTaP), the full series of Haemophilus influenzae type b (Hib) vaccine, hepatitis B (HepB) birth dose,† ≥4 doses pneumococcal conjugate vaccine (PCV), ≥2 doses of HepA, the full series of rotavirus vaccine, and the combined vaccine series.§ Examination of coverage by child's race/ethnicity revealed lower estimated coverage among non-Hispanic black children compared with non-Hispanic white children for several vaccinations, including DTaP, the full series of Hib, PCV, rotavirus vaccine, and the combined series. Children from households classified as below the federal poverty level had lower estimated coverage for almost all of the vaccinations assessed, compared with children living at or above the poverty level. Significant variation in coverage by state¶ was observed for several vaccinations, including HepB birth dose, HepA, and rotavirus. High vaccination coverage must be maintained across geographic and sociodemographic groups if progress in reducing the impact of vaccine-preventable diseases is to be sustained.

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

BACKGROUND

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.

METHODS

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.

RESULTS

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.

CONCLUSION

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.

Immunogenicity and safety of early vaccination with two doses of a combined measles-mumps-rubella-varicella vaccine in healthy Indian children from 9 months of age: a phase III, randomised, non-inferiority trial

OBJECTIVE

This study (NCT00969436) compared the immunogenicity and safety of measles-mumps-rubella (MMR) followed by MMR+varicella (V) vaccines to (1) 2 doses of combined MMRV and (2) MMR followed by MMRV, in Indian children.

DESIGN

Phase III, open, randomised, non-inferiority study.

SETTING

6 tertiary care hospitals located in India.

PARTICIPANTS

Healthy participants aged 9-10 months not previously vaccinated against/exposed to measles, mumps, rubella and varicella or without a history of these diseases.

INTERVENTIONS

Participants were randomised (2:2:1) to receive 2 doses of either MMRV (MMRV/MMRV group) or MMR followed by MMRV (MMR/MMRV group) or MMR followed by MMR+V (MMR/MMR+V, control group) at 9 and 15 months of age. Antibody titres against measles, mumps and rubella were measured using ELISA and against varicella using an immunofluorescence assay.

MAIN OUTCOME MEASURES

To demonstrate non-inferiority of the 2 vaccination regimens versus the control in terms of seroconversion rates, defined as a group difference with a lower bound of the 95% CI >-10% for each antigen, 43 days postdose 2. Parents/guardians recorded solicited local and general symptoms for a 4-day and 43-day period after each vaccine dose, respectively.

RESULTS

Seroconversion rates postdose 1 ranged from 87.5% to 93.2% for measles, 83.3% to 86.1% for mumps and 98.7% to 100% for rubella across the 3 vaccine groups. The seroconversion rates postdose 2 were 100% for measles, mumps and rubella and at least 95.8% for varicella across the 3 vaccine groups. Non-inferiority of MMRV/MMRV and MMR/MMRV to MMR/MMR+V was achieved for all antigens, 43 days postdose 2. The 3 vaccination regimens were generally well tolerated in terms of solicited local and general symptoms.

CONCLUSIONS

The immune responses elicited by the MMRV/MMRV and MMR/MMRV vaccination regimens were non-inferior to those elicited by the MMR/MMR+V regimen for all antigens. The 3 vaccination schedules also exhibited an acceptable safety profile in Indian children.

TRIAL REGISTRATION NUMBER

NCT00969436.

Systematic review of models assessing the economic value of routine varicella and herpes zoster vaccination in high-income countries

BACKGROUND

A systematic review was conducted to assess the cost-effectiveness of routine varicella and herpes zoster (HZ) vaccination in high-income countries estimated by modelling studies.

METHODS

A PubMed search was performed to identify relevant studies published before October 2013. Studies were included in the review if they (i) evaluated the cost-effectiveness of routine childhood or adolescent varicella vaccination and/or HZ vaccination targeting the elderly, and if they (ii) reported results for high-income countries.

RESULTS

A total of 38 model-based studies were identified that fulfilled the inclusion criteria. Routine childhood or adolescent varicella vaccination was cost-effective or cost-saving from a payer perspective and always cost-saving from a societal perspective when ignoring its potential impact on HZ incidence due to reduced or absent exogenous boosting. The inclusion of the potential impact of childhood varicella vaccination on HZ led to net quality-adjusted life-year (QALY) losses or incremental cost-effectiveness ratios exceeding commonly accepted thresholds. Additional HZ vaccination could partially mitigate this effect. Studies focusing only on the evaluation of HZ vaccination reported a wide range of results depending on the selected target age-group and the vaccine price, but most found HZ vaccination to be a cost-effective or marginally cost-effective intervention. Cost-effectiveness of HZ vaccination was strongly dependent on the age at vaccination, the price of the vaccine, the assumed duration of protection and the applied cost per QALY threshold.

CONCLUSIONS

While HZ vaccination is mostly considered cost-effective, cost-effectiveness of varicella vaccination primarily depends on the in- or exclusion of exogenous boosting in the model. As a consequence, clarification on the role of exogenous boosting is crucial for decision-making regarding varicella vaccination.