Varicella vaccination - the global experience

Parabolic Changes in Pain Scores Among Partial Herpes Zoster Patients: A Retrospective Study

Background

Herpes zoster (HZ) typically manifests in the acute phase with distinct blisters and severe neuropathic pain. Remarkably, a subset of patients initially presents with only a mild skin rash and moderate pain that gradually intensifies, following a parabolic pattern. Despite being frequently observed in clinical settings, the underlying causes of this trajectory and its potential connection with post-herpetic neuralgia (PHN) remain unclear.

Methods

To investigate this phenomenon in-depth, we conducted a meticulous retrospective study involving 529 eligible HZ patients. All these patients sought medical care at the Third Central Hospital of Tianjin, China, between January 2020 and December 2023.

Results

The research identified that 14.6% of the sample (77 patients) experienced pain scores aligning with a parabolic curve. This trend was significantly more prevalent in patients aged 60 and above, accounting for 90.9% of this group, and demonstrated a positive correlation with age. Moreover, 87.0% of these patients had pre-existing medical conditions, highlighting the potential role of comorbidities in influencing the pain trajectory. A concerning 45.5% of patients sought medical attention more than seven days after the onset of symptoms, a delay that could exacerbate neurological damage. Notably, among those following a parabolic pain pattern, 66.2% eventually developed PHN, a considerably higher rate compared to the broader patient population.

Conclusion

We emphasize that healthcare practitioners meticulously assess patients who initially report lower pain scores for high-risk factors potentially leading to parabolic pain increases, including being over 60 years old, having comorbid conditions, and delaying medical consultation beyond seven days from symptom onset. Early implementation of supplementary pain management therapies may mitigate the risk of PHN development and enhance the quality of life for patients. This study furnishes clinicians with a deeper understanding of the variations in HZ-related pain trajectories, promising to improve treatment approaches and prognoses for HZ patients while paving the way for enriched clinical practice in the future.

Economic burden of varicella in Bangkok, Thailand: A multicenter medical chart review study

Our multicenter, medical chart review, cost-of-illness study used a micro-costing approach to evaluate the economic burden associated with varicella in Bangkok, Thailand, from a societal perspective. We reviewed medical charts of adults and children with a primary diagnosis of varicella (2014-2018) from 4 hospitals in Bangkok. Reported healthcare resource utilization and missed school or workdays were extracted from medical charts. Mean direct, indirect, and total costs per patient were estimated for overall, adult, and pediatric patients (2020 USD). Of the 200 children and 60 adults, 99.6%, 5.4%, and 5.4% had a varicella-related outpatient visit, emergency department visit, and hospitalization, respectively. The mean direct medical cost was 33 USD for pediatric and adult patients. The mean cost of outpatient visits (8 vs 13 USD, P<0.001) and medications (7 vs 9 USD, P<0.001) was significantly lower among pediatric patients. Forty-eight children reported a mean of 5.8 school days lost, and 32 adult patients reported a mean of 7.4 workdays lost. The mean total cost per varicella patient was 89 USD, with the mean total cost higher for adult than pediatric patients (145 vs 72 USD, P<0.001). Indirect cost accounted for 63% of the total cost per patient (54% for pediatric patients and 77% for adult patients). There is a substantial economic burden associated with patients seeking varicella-related healthcare in Thailand, including considerable indirect costs.

Differential diagnosis of exanthematous viruses during the 2022 Mpox outbreak in Minas Gerais, Brazil

The monkeypox virus (MPXV) outbreak, primarily endemic to Africa, has spread globally, with Brazil reporting the second-highest number of cases. The emergence of MPXV in non-endemic areas has raised concerns, particularly due to the co-circulation of other exanthematous viruses such as varicella-zoster virus (VZV) and molluscum contagiosum virus (MOCV). To perform an accurate differential diagnosis of MPXV during the ongoing outbreak in Minas Gerais, Brazil, a 5PLEX qPCR assay targeting orthopoxviruses (OPV), VZV, and MOCV was used to retrospectively analyze all clinical samples that tested negative for MPXV in the initial screening conducted at Funed. In summary, our study analyzed 1,175 clinical samples received from patients suspected of MPXV infection and found a positivity rate of 33.8% (397 samples) for MPXV using the non-variola qPCR assay. Testing the 778 MPXV-negative clinical samples using the 5PLEX qPCR assay revealed that 174 clinical samples (22.36%) tested positive for VZV. MOCV DNA was detected in 13 and other OPV in 3 clinical samples. The sequencing of randomly selected amplified clinical samples confirmed the initial molecular diagnosis. Analysis of patient profiles revealed a significant difference in the median age between groups testing positive for MPXV and VZV and a male predominance in MPXV cases. The geographic distribution of positive cases was concentrated in the most populous mesoregions of Minas Gerais state. This study highlights the challenges posed by emerging infectious diseases. It emphasizes the importance of epidemiological surveillance and accurate diagnosis in enabling timely responses for public health policies and appropriate medical care.

IMPORTANCE

Brazil ranks second in the number of cases during the global monkeypox epidemic. The study, conducted in Minas Gerais, the second most populous state in Brazil with over 20 million inhabitants, utilized differential diagnostics, revealing a significant number of positive cases for other exanthematous viruses and emphasizing the need for accurate diagnoses. During the study, we were able to assess the co-circulation of other viruses alongside monkeypox, including varicella-zoster virus, molluscum contagiosum virus, and other orthopoxviruses. The significance of the research is underscored by the concentration of positive cases in populous areas, highlighting the challenges posed by emerging infectious diseases. This demographic context further amplifies the importance of the research in guiding public health policies and medical interventions, given the substantial population at risk. The study not only addresses a global concern but also holds critical implications for a state with such a large population and geographic expanse within Brazil. Overall, the study emphasizes the pivotal role of surveillance and precise diagnosis in guiding effective public health responses and ensuring appropriate medical interventions.

Effectiveness of two-dose vs. one-dose varicella vaccine in children in Shanghai, China: a prospective cohort study

Objective

Varicella, a highly contagious viral disease caused by the varicella-zoster virus (VZV), affects millions globally, with a higher prevalence among children. After the initial infection, VZV lies dormant in sensory ganglia and has the potential to reactivate much later, causing herpes zoster (HZ). Vaccination is one of the most effective methods to prevent varicella, and the two-dose varicella vaccine (VarV) regimen is widely used around the world. In China, the VarV has been included in the national immunization programme with a recommended single-dose regimen. This study aimed to compare the effectiveness of the two-dose vs. one-dose VarV regimen in children in Shanghai, China.

Materials and methods

A prospective cohort study was conducted in Shanghai, China, from September 2018 to December 2022. The study enrolled children aged 3-18 years who had received either the one-dose, two-dose, or 0-dose VarV regimen. Vaccination history, varicella infection status, and relevant variables, including demographic information (name, date of birth and sex) and medical history (clinical features of varicella and illness duration) were collected through medical record review and parental interviews.

Results

A total of 3,838 children were included in the study, with 407 in the 0-dose regimen group, 2,107 in the one-dose regimen group and 1,324 in the two-dose regimen group. The corresponding incidence density in these groups was 0.13, 0.05 and 0.03 cases per 1,000 person-days, respectively. The adjusted vaccine effectiveness (VE) was 81.7% (95%CI: 59.3-91.8%) for the two-dose regimen and 60.3% (95%CI: 29.3-77.7%) for the one-dose regimen, compared to the 0-dose regimen. The two-dose VarV regimen showed a protective effectiveness of 47.6% (95%CI: 2.5-71.9%) compared to the one-dose VarV regimen.

Conclusion

This study provides evidence supporting the greater effectiveness of the two-dose VarV regimen in preventing varicella infection compared to the one-dose regimen.

The clinical and economic costs associated with regional disparities in varicella vaccine coverage in Italy over 50 years (2020-2070)

Italy implemented two-dose universal varicella vaccination (UVV) regionally from 2003 to 2013 and nationally from 2017 onwards. Our objective was to analyze regional disparities in varicella outcomes resulting from disparities in vaccine coverage rates (VCRs) projected over a 50-year time-horizon (2020-2070). A previously published dynamic transmission model was updated to quantify the potential public health impact of the UVV program in Italy at the national and regional levels. Four 2-dose vaccine strategies utilizing monovalent (V) and quadrivalent (MMRV) vaccines were evaluated for each region: (A) MMRV-MSD/MMRV-MSD, (B) MMRV-GSK/MMRV-GSK, (C) V-MSD/MMRV-MSD, and (D) V-GSK/MMRV-GSK. Costs were reported in 2022 Euros. Costs and quality-adjusted life-years (QALYs) were discounted 3% annually. Under strategy A, the three regions with the lowest first-dose VCR reported increased varicella cases (+ 34.3%), hospitalizations (+ 20.0%), QALYs lost (+ 5.9%), payer costs (+ 22.2%), and societal costs (+ 14.6%) over the 50-year time-horizon compared to the three regions with highest first-dose VCR. Regions with low first-dose VCR were more sensitive to changes in VCR than high first-dose VCR regions. Results with respect to second-dose VCR were qualitatively similar, although smaller in magnitude. Results were similar across all vaccine strategies.

Effectiveness of the combined MMRV Priorix-Tetra™ vaccine against varicella in a large Italian region: A case-control study

Priorix-Tetra™ (MMRV GlaxoSmithKline Biologicals' vaccine) was developed based on the existing measles-mumps-rubella and varicella vaccines. In this study, we aimed to estimate the effectiveness of the combined measles-mumps-rubella-varicella Priorix-Tetra™ vaccine against varicella in real-world conditions. We conducted a post-marketing retrospective case-control study in the Apulia region of Italy in children aged 1-9 years born between January 1, 2008 and December 31, 2016. We assessed the effectiveness against varicella of all grades of severity (including hospitalisation) and against hospitalisation for varicella of a single and two doses of Priorix-Tetra™. Moreover, we also assessed effectiveness of monovalent varicella (monovalent-V) vaccine and any varicella vaccines. Vaccine effectiveness was calculated as (1-OR) x 100. We introduced demographic variables in the model to adjust Vaccine effectiveness (aVE) by potential confounders (sex and year of birth). We recorded 625 varicella cases and matched them with 1,875 controls. Among 625 cases, 198 had received a single MMRV dose, 10 two MMRV doses, 46 a single monovalent-V dose, none two monovalent-V doses; four a monovalent-V as first dose and MMRV as second dose, and one a MMRV as first dose and monovalent-V as second dose; 366 cases were not vaccinated. The aVE against varicella of all grades of severity was 77.0% and 93.0% after a single dose and after two doses of MMRV, respectively. The aVE against varicella of all grades was 72.0% after a single dose of monovalent-V vaccine. The aVE against varicella of all grades of severity was 76.0% after a single dose and 94.0% after two doses of any varicella vaccine. The aVE against varicella hospitalisation was 96% after a single dose of any varicella vaccine. Priorix-Tetra™ showed to be an effective vaccine and the two-dose schedule should be recommended to optimise immunisation programmes. A single dose was able to provide protection against varicella hospitalisation.

Viral Pneumonias

Viral pneumonia is usually community acquired and caused by influenza, parainfluenza, respiratory syncytial virus, human metapneumovirus, and adenovirus. Many of these infections are airway centric and chest imaging demonstrates bronchiolitis and bronchopneumonia, With the exception of adenovirus infections, the presence of lobar consolidation usually suggests bacterial coinfection. Community-acquired viral pathogens can cause more severe pneumonia in immunocompromised hosts, who are also susceptible to CMV and varicella infection. These latter 2 pathogens are less likely to manifest the striking airway-centric pattern. Airway-centric pattern is distinctly uncommon in Hantavirus pulmonary syndrome, a rare environmentally acquired infection with high mortality.

Parental perceptions of chickenpox and the varicella vaccine: A qualitative systematic review

BACKGROUND

In countries where varicella vaccination is not on the routine childhood immunisation schedule, such as those in the United Kingdom (UK), chickenpox is an almost universal disease of childhood. Chickenpox can cause serious complications, particularly in infants, pregnant women, and the immunocompromised. In November 2023 the varicella vaccine was recommended for inclusion in the UK routine childhood immunisation schedule. Successful rollout of the vaccine may be hindered by parental concerns about vaccine safety and efficacy, and perceptions of chickenpox as a mild illness.

OBJECTIVE

To examine parental perceptions of chickenpox and varicella vaccination, which may be crucial to effective vaccination campaigns.

DESIGN

Qualitative systematic review and thematic analysis.

METHODS

Six electronic databases were systematically searched for studies published between 2016 and 2023: CINAHL, EMBASE, MEDLINE, PsycInfo, PubMed, and Web of Science. The included studies were appraised against the Critical Appraisal Skills Program checklist for qualitative studies. Thematic analysis was used to analyse qualitative data, through the development of themes.

RESULTS

22 articles were included in this review, and five themes identified: perceptions that chickenpox is a mild illness, that parents have concerns about varicella vaccine efficacy and safety, a notion of natural immunity as superior, social determinants of health influence vaccine decision making, and vaccination is overwhelming perceived as a parental decision.

CONCLUSIONS

Whilst some parents displayed an acceptance and willingness to vaccinate against chickenpox, many expressed concerns, and perceived chickenpox as a routine unworrying childhood illness. Analysis demonstrated a knowledge gap in understanding UK parental opinions regarding chickenpox and varicella vaccination, highlighting the need for research in this area, particularly given ongoing reconsideration for inclusion in the UK vaccination schedule.

REGISTRATION

The review was registered on PROSPERO, registration ID CRD42021236120.

Conjunctival Lesions Secondary to Systemic Varicella Zoster Virus Infection

Purpose

To report and present images of a case in which discrete conjunctival lesions developed in the setting of primary varicella zoster virus infection (ie, chickenpox).

Methods

Case report and literature review.

Results

This report describes a young, unvaccinated male who developed an acutely painful, red eye in the setting of disseminated primary varicella zoster infection. The cutaneous rash was widespread and included lesions on both eyelids. The patient was found to have multiple discrete de-epithelialized lesions involving the palpebral and bulbar conjunctiva. Throughout the disease course, good visual function was maintained and there was no evidence of intraocular involvement. The ocular surface lesions resolved without sequelae after 1 week of treatment with topical antibiotic ointment.

Conclusions

Primary varicella zoster infection is an increasingly rare phenomenon in the setting of widespread vaccination. However, unvaccinated or undervaccinated individuals and other at-risk populations remain susceptible to developing severe infections. This case of chickenpox involved discrete conjunctival lesions that resolved without sequelae after conservative treatment with topical antibiotic ointment. While serious ophthalmic complications are uncommon in primary varicella infection, clinicians should be aware of the potential for ocular morbidity in this increasingly rare condition.

Global Landscape of Encephalitis: Key Priorities to Reduce Future Disease Burden

Encephalitis affects people across the lifespan, has high rates of mortality and morbidity, and results in significant neurological sequelae with long-term consequences to quality of life and wider society. The true incidence is currently unknown due to inaccurate reporting systems. The disease burden of encephalitis is unequally distributed across the globe being highest in low- and middle-income countries where resources are limited. Here countries often lack diagnostic testing, with poor access to essential treatments and neurological services, and limited surveillance and vaccination programs. Many types of encephalitis are vaccine preventable, whereas others are treatable with early diagnosis and appropriate management. In this viewpoint, we provide a narrative review of key aspects of diagnosis, surveillance, treatment, and prevention of encephalitis and highlight priorities for public health, clinical management, and research, to reduce the disease burden.

Real-World Effectiveness of the Varicella Vaccine among Children and Adolescents in Qatar: A Case-Control Study

BACKGROUND

Despite the availability of a highly efficacious vaccine, varicella outbreaks are still being reported globally. In this study, we evaluated the real-world effectiveness of varicella vaccination among children between the ages of 1 and 18 years old during the period 2017 to 2019 in Qatar.

METHODS

A matched case-control study was conducted that included all reported varicella-infected children who visited the primary healthcare system in Qatar from January 2017 to December 2019. The cases were children under the age of 18 years who were clinically diagnosed with varicella. The controls were of the same age, who visited the Primary Health Care Corporation (PHCC) during 2017-2019 with a skin rash where varicella infection was ruled out. The data on varicella vaccination for each participant were obtained from the electronic database in the PHCC during the study period.

RESULTS

We included 862 cases of varicella and 5454 matched controls, with a median age of 8 years (IQR 3-12); 47.4% were female and almost 50% were of Qatari nationality. The year 2019 had the highest varicella infection count with a total of 416 cases. The cases were less likely to be vaccinated against varicella, with approximately a quarter (25.6%) of cases and 36.7% of the controls having either one or two doses of the vaccine (p < 0.001). Compared to not being vaccinated, a single dose vaccination showed a 56% reduction in the odds of varicella infection [OR 0.44, 95% CI: 0.34-0.55; p < 0.000], and a two-dose vaccination showed an 86% reduction in the odds of varicella infection [OR 0.13, 95% CI: 0.06-0.29; p < 0.000].

CONCLUSION

In this multicultural setting, a two-dose varicella vaccination shows reasonable protection against varicella infection.

The epidemiology of varicella and effectiveness of varicella vaccine in Ganyu, China: a long-term community surveillance study

BACKGROUND

The real-world data of long-term protection under moderate vaccination coverage is limited. This study aimed to evaluate varicella epidemiology and the long-term effectiveness under moderate coverage levels in Ganyu District, Lianyungang City, Jiangsu Province.

METHODS

This was a population-based, retrospective birth cohort study based on the immunization information system (IIS) and the National Notifiable Disease Surveillance System (NNDSS) in Ganyu District. Varicella cases reported from 2009 to 2020 were included to describe the epidemiology of varicella, and eleven-year consecutive birth cohorts (2008-2018) were included to estimate the vaccine effectiveness (VE) of varicella by Cox regression analysis.

RESULTS

A total of 155,232 native children and 3,251 varicella cases were included. The vaccination coverage was moderate with 37.1%, correspondingly, the annual incidence of varicella infection increased 4.4-fold from 2009 to 2020. A shift of the varicella cases to older age groups was observed, with the peak proportion of cases shifting from 5-6 year-old to 7-8 year-old. The adjusted effectiveness of one dose of vaccine waned over time, and the adjusted VE decreased from 72.9% to 41.8% in the one-dose group.

CONCLUSIONS

The insufficient vaccination coverage (37.1%) may have contributed in part to the rising annual incidence of varicella infection, and a shift of varicella cases to older age groups occurred. The effectiveness of one dose of varicella vaccine was moderate and waned over time. It is urgent to increase varicella vaccine coverage to 80% to reduce the incidence of varicella and prevent any potential shift in the age at infection in China.

Measles and Varicella Vaccination Program in a Hospital: Implementation and Impact on Contact Tracing

Healthcare workers are recommended to get vaccinated against measles and varicella. This study aims to describe the implementation process of a measles and varicella vaccination program and report on the reduction in the number of susceptible healthcare workers exposed to measles, varicella, and disseminated herpes zoster at a tertiary hospital. The Consolidated Framework for Implementation Research (CFIR) model was used to describe the vaccination program implemented from October 2015 to September 2018. The number of exposed, reviewed, and susceptible healthcare workers during contact tracing for exposure to (a) measles and (b) varicella and disseminated herpes zoster in 2016, 2017, and 2018 is reported. A total of 6770 (95%) out of 7083 healthcare workers completed their immunization review by 2018. In 2016, 20 (10%) out of 198 healthcare workers exposed to measles were considered susceptible. In 2018, no one was found susceptible out of the 51 staff members exposed to measles (p < 0.01). For exposure to varicella and disseminated herpes zoster, seven (5%) out of 154 exposed healthcare workers were susceptible in 2016. In comparison, only two (1%) out of 377 exposed healthcare workers in 2018 were susceptible (p < 0.01). The vaccination program effectively reduced number of healthcare workers susceptible to measles, varicella, and disseminated zoster.

Antimicrobial use for the management of varicella in Thailand: a retrospective observational study

OBJECTIVE

To describe the clinical characteristics of varicella patients seeking medical consultation and the use of antimicrobials for their management in Thailand in the absence of universal varicella vaccination (UVV).

METHODS

A multicenter, retrospective chart review of 260 children and adults with a primary diagnosis of varicella was conducted at one private and three public hospitals in Bangkok, Thailand. Charts of varicella patients (inpatient or outpatient) were randomly selected over a 5-year period. Key outcomes included clinical complications and the use of antibiotics, antivirals, and other medications.

RESULTS

Charts of 200 children (mean age 5.7 years, range 0.3-16 years) and 60 adults (mean age 27.9 years, range 18-50 years) were reviewed. Fourteen patients (including 8 children) were hospitalized. Five percent of the children and none of the adults were immunocompromised. At least 1 varicella-related complication was reported by 7.3% (7% of children, 8.3% of adults, p = .778) of all patients, including 57.1% (62.5% of children, 50% of adults) of inpatients (p < .001, compared with outpatients). Skin/soft tissue infection (47.7%) and dehydration (47.4%) were the most common complications. Antivirals (mainly oral acyclovir) were prescribed to 46.5% of patients (31.5% of children, 96.7% of adults, p < .001). Antibiotics were prescribed to 20.8% of patients (19% of children, 26.7% of adults, p = .199). Topical, oral, and intravenous antibiotics were prescribed to 12.3%, 8.5%, and 1.2% of patients, respectively. Antimicrobial prescriptions were higher among adults (p < .001) and immunocompromised patients (p = .025). Apart from antimicrobials, acetaminophen (62.3%) and oral antihistamines (51.5%) were the most prescribed.

CONCLUSION

A considerable number of varicella patients, both children and adults, seeking medical consultation in Thai hospitals are prescribed antibiotics and antivirals, with one-fifth of patients being prescribed an antibiotic and almost half prescribed an antiviral. The study may be of interest to policymakers in Thailand and other Asia-Pacific countries considering UVV implementation.

Using Baidu Index Data to Improve Chickenpox Surveillance in Yunnan, China: Infodemiology Study

BACKGROUND

Chickenpox is an old but easily neglected infectious disease. Although chickenpox is preventable by vaccines, vaccine breakthroughs often occur, and the chickenpox epidemic is on the rise. Chickenpox is not included in the list of regulated communicable diseases that must be reported and controlled by public and health departments; therefore, it is crucial to rapidly identify and report varicella outbreaks during the early stages. The Baidu index (BDI) can supplement the traditional surveillance system for infectious diseases, such as brucellosis and dengue, in China. The number of reported chickenpox cases and internet search data also showed a similar trend. BDI can be a useful tool to display the outbreak of infectious diseases.

OBJECTIVE

This study aimed to develop an efficient disease surveillance method that uses BDI to assist in traditional surveillance.

METHODS

Chickenpox incidence data (weekly from January 2017 to June 2021) reported by the Yunnan Province Center for Disease Control and Prevention were obtained to evaluate the relationship between the incidence of chickenpox and BDI. We applied a support vector machine regression (SVR) model and a multiple regression prediction model with BDI to predict the incidence of chickenpox. In addition, we used the SVR model to predict the number of chickenpox cases from June 2021 to the first week of April 2022.

RESULTS

The analysis showed that there was a close correlation between the weekly number of newly diagnosed cases and the BDI. In the search terms we collected, the highest Spearman correlation coefficient was 0.747. Most BDI search terms, such as "chickenpox," "chickenpox treatment," "treatment of chickenpox," "chickenpox symptoms," and "chickenpox virus," trend consistently. Some BDI search terms, such as "chickenpox pictures," "symptoms of chickenpox," "chickenpox vaccine," and "is chickenpox vaccine necessary," appeared earlier than the trend of "chickenpox virus." The 2 models were compared, the SVR model performed better in all the applied measurements: fitting effect, R²=0.9108, root mean square error (RMSE)=96.2995, and mean absolute error (MAE)=73.3988; and prediction effect, R²=0.548, RMSE=189.1807, and MAE=147.5412. In addition, we applied the SVR model to predict the number of reported cases weekly in Yunnan from June 2021 to April 2022 using the same period of the BDI. The results showed that the fluctuation of the time series from July 2021 to April 2022 was similar to that of the last year and a half with no change in the level of prevention and control.

CONCLUSIONS

These findings indicated that the BDI in Yunnan Province can predict the incidence of chickenpox in the same period. Thus, the BDI is a useful tool for monitoring the chickenpox epidemic and for complementing traditional monitoring systems.

Universal varicella vaccination in Denmark: Modeling public health impact, age-shift, and cost-effectiveness

We modeled the long-term clinical and economic impact of two-dose universal varicella vaccination (UVV) strategies in Denmark using a dynamic transmission model. The cost-effectiveness of UVV was evaluated along with the impact on varicella (including age-shift) and herpes zoster burden. Six two-dose UVV strategies were compared to no vaccination, at either short (12/15 months) or medium (15/48 months) intervals. Monovalent vaccines (V-MSD or V-GSK) for the 1st dose, and either monovalent or quadrivalent vaccines (MMRV-MSD or MMRV-GSK) for the 2nd dose were considered. Compared to no vaccination, all two-dose UVV strategies reduced varicella cases by 94%-96%, hospitalizations by 93%-94%, and deaths by 91%-92% over 50 years; herpes zoster cases were also reduced by 9%. There was a decline in the total number of annual varicella cases in all age groups including adolescents and adults. All UVV strategies were cost-effective compared to no vaccination, with ICER values ranging from €18,228-€20,263/QALY (payer perspective) and €3,746-€5,937/QALY (societal perspective). The frontier analysis showed that a two-dose strategy with V-MSD (15 months) and MMRV-MSD (48 months) dominated all other strategies and was the most cost-effective. In conclusion, all modeled two-dose UVV strategies were projected to substantially reduce the clinical and economic burden of varicella disease in Denmark compared to the current no vaccination strategy, with declines in both varicella and zoster incidence for all age groups over a 50-year time horizon.

Seroprevalence of varicella-zoster virus antibody and immunogenicity of live attenuated varicella vaccine in healthcare workers in Taiwan

BACKGROUND

Healthcare workers (HCWs) without evidence of immunity to varicella-zoster virus (VZV) are recommended to undergo varicella vaccination. Immunogenicity of live attenuated varicella vaccine has rarely been investigated among HCWs in Taiwan.

METHODS

Anti-VZV immunoglobulin G (IgG) titer was checked for all HCWs at Changhua Christian Hospital from 2011 to 2017. One-dose and two-dose (separated by 4-8 weeks) vaccines were administered to HCWs with equivocal and negative anti-varicella IgG results, respectively. Follow-up anti-VZV IgG was determined at least 4 weeks after completion of vaccination. Factors associated with seroconversion to varicella vaccination were analyzed.

RESULTS

Among 2406 included HCWs, the anti-VZV IgG serostatus was tested positive, equivocal and negative in 1924 (79.9%), 117 (4.9%) and 365 (15.2%), respectively. The seroprevalence had decreased from 88.0% (235/267) in 2011 to 72.2% (270/374) in 2017 (p for trend <0.05). A total of 67.8% (327/482) HCWs completed scheduled vaccination and serological follow-up. The seroconversion rates for HCWs with baseline equivocal and negative anti-VZV IgG results were 100% (80/80) and 79.4% (196/247) after one- and two-dose vaccination, respectively. In multivariate analysis, obesity (adjusted odds ratio, 0.308; 95% confidence interval [CI], 0.11-0.94, p = 0.039) was the only factor statistically significantly associated with seroconversion to vaccination.

CONCLUSION

Decreasing trends of seroprevalence of VZV were observed among HCWs from 2011 to 2017. HCWs who were obese were less likely to respond to varicella vaccination.

Parental acceptance of and preferences for administration of routine varicella vaccination in the UK: A study to inform policy

OBJECTIVES

To explore acceptability of and preferences for the introduction of varicella vaccination to the UK childhood immunisation schedule.

DESIGN

We conducted an online cross-sectional survey exploring parental attitudes towards vaccines in general, and varicella vaccine specifically, and their preferences for how the vaccine should be administered.

PARTICIPANTS

596 parents (76.3% female, 23.3% male, 0.4% other; mean age 33.4 years) whose youngest child was aged 0-5 years.

MAIN OUTCOME MEASURES

Willingness to accept the vaccine for their child and preferences for how the vaccine should be administered (in combination with the MMR vaccine [MMRV], on the same day as the MMR vaccine but as a separate injection [MMR + V], on a separate additional visit).

RESULTS

74.0% of parents (95% CI 70.2% to 77.5%) were extremely/somewhat likely to accept a varicella vaccine for their child if one became available, 18.3% (95% CI 15.3% to 21.8%) were extremely/somewhat unlikely to accept it and 7.7% (95% CI 5.7% to 10.2%) were neither likely nor unlikely. Reasons provided by parents likely to accept the vaccine included protection from complications of chickenpox, trust in the vaccine/healthcare professionals, and wanting their child to avoid their personal experience of chickenpox. Reasons provided by parents who were unlikely included chickenpox not being a serious illness, concern about side effects, and believing it is preferable to catch chickenpox as a child rather than as an adult. A combined MMRV vaccination or additional visit to the surgery were preferred over an additional injection at the same visit.

CONCLUSIONS

Most parents would accept a varicella vaccination. These findings highlight parents' preferences for varicella vaccine administration, information needed to inform vaccine policy and practice and development of a communication strategy.

Epidemiology of Herpes Zoster in the pre-vaccination era: establishing the baseline for vaccination programme's impact in Spain

BackgroundHerpes zoster (HZ) affects 1 in 3 persons in their lifetime, and the risk of HZ increases with increasing age and the presence of immunocompromising conditions. In Spain, vaccination guidelines were recently updated to include the recommendation of the new recombinant zoster vaccine (RZV) for certain risk groups.AimTo describe the epidemiology of HZ-related hospitalisations in Spain in order to prioritise vaccination recommendations and define a baseline to monitor the effectiveness of vaccination policies.MethodsRetrospective study using the National Health System's Hospital Discharge Records Database, including all HZ-related hospitalisations from 1998 to 2018.ResultsThe 65,401 HZ-related hospitalisations, corresponded to an annual mean hospitalisation rate of 6.75 per 100,000 population. There was an increasing trend of HZ hospitalisations over the study period. This rate was higher in males and older age groups, particularly over 65 years. Comorbidities with higher risk of readmission were leukaemia/lymphoma (RR 2.4; 95% CI: 2.3-2.6) and solid malignant neoplasm (RR 2.2; 95% CI: 2.1-2.4). Comorbidities associated with higher risk of mortality were leukaemia/lymphoma (RR 2.9; 95% CI: 2.7-3.2), solid malignant neoplasm (RR 2.9; 95% CI: 2.7-3.1) and HIV infection (RR 2.2; 95% CI: 1.8-2.7).ConclusionOf all patients hospitalised with HZ, those with greater risk of mortality or readmission belonged to the groups prioritised by the current vaccination recommendations of the Spanish Ministry of Health. Our study provided relevant information on clinical aspects of HZ and established the base for future assessments of vaccination policies.

Opportunistic infections associated with Janus kinase inhibitor treatment for rheumatoid arthritis: A structured literature review

BACKGROUND

The availability of Janus kinase (JAK) inhibitors has transformed the management of rheumatoid arthritis (RA), helping patients achieve clinical remission. However, the emergence of opportunistic infections (OIs) associated with the use of JAK inhibitors has been reported. This structured literature review was conducted to summarize reports of OIs associated with JAK inhibitor treatment for RA in clinical trials.

METHODS

Structured searches were performed in MEDLINE® and Embase® to identify relevant clinical trial data through March 2021. Bibliographic searches of recent reviews were also conducted, and gray literature searches were used to supplement key gap areas. Publications were screened, extracted, and quality assessed. Data were narratively synthesized.

RESULTS

Following screening, 105 publications describing 62 unique clinical trials reporting the rates of OIs in RA patients treated with JAK inhibitors were included. Overall, the highest exposure-adjusted incidence rate was reported for herpes zoster (HZ) infection (any form), followed by OI (any) and tuberculosis based on limited data from clinical trials with approved doses of JAK inhibitors. Lack of head-to-head trials and differences in trial design preclude direct comparison across JAK inhibitors. Higher rates of OIs were noted in the Asian and Australian populations compared with the global population. Higher rates of OIs were also noted with increasing dose of JAK inhibitors in most clinical trial data.

CONCLUSIONS

HZ was the most common OI reported among RA patients using all currently approved JAK inhibitors in clinical trials, although tuberculosis and other OIs were also reported. More long-term safety studies in the real-world setting are needed to compare the risk of OIs between various JAK inhibitors.

Sero-Epidemiological Study of Varicella in the Italian General Population

The aim of this study was to analyze the seroprevalence of varicella in Italy and to evaluate the impact of varicella vaccination, which has been mandatory for newborns since 2017. The levels of VZV-specific IgG antibodies were determined by the ELISA method in residual serum samples obtained from subjects aged between 6 and 64 years and residing in 13 Italian regions. Overall, 3746 serum samples were collected in the years 2019 and 2020. The overall seroprevalence was 91.6% (89.9% in males and 93.3% in females; p = 0.0002). Seroprevalence showed an increasing trend (p < 0.0001) starting in the younger age groups: 6-9 years: 84.1%; 10-14 years: 88.7%; 15-19 years: 89.3%; 20-39 years: 93.1% and >40 years: 97.0%. The seroprevalence data obtained in the present study were compared with those relating to previous sero-epidemiological surveys conducted, respectively, in the years 1996-1997, 2003-2004 and 2013-2014, taking into consideration only data from regions monitored in all surveillance campaigns. The comparison highlighted for the period 2019-2020 showed significantly higher values in the age groups 6-9 (p < 0.001), 10-14 (p = 0.018) and 15-19 years (p = 0.035), while in adults, the trend did not change over time (ns). These results highlight the positive impact of varicella vaccination in Italy.

A Sample Guideline for Reverse Vaccinology Approach for the Development of Subunit Vaccine Using Varicella Zoster as a Model Disease

For the development of multi-peptide vaccine, identification of antigenic epitopes is crucial. If it is done using wet lab techniques, the identification process can be time-consuming, laborious, and cost-intensive. In silico tools, on the other hand, enable researchers to predict potential epitopes with little to no cost for further in vivo and in vitro testing. The rapid identification process using in silico tools helps in responding to health emergencies faster. Developing an efficient and high coverage vaccine is one of the ways to reduce morbidity and mortality rates of the diseases and protect the affected populations. In this chapter, we introduce the necessary tools and methodology for the identification and characterization of antigenic epitopes to design a multi-epitope vaccine using varicella-zoster virus as an example vector model.

Epidemiology of Varicella Zoster Virus and Herpes Zoster Virus in Gulf Cooperation Council Countries: A Review of the Literature

INTRODUCTION

The reactivation of varicella zoster virus (VZV) in previously infected individuals can cause herpes zoster (HZ), which is characterized by a localized, painful dermatomal rash. While there is a global trend of increasing HZ cases, there is a lack of research examining the epidemiology of HZ within the Gulf Cooperation Council (GCC) countries. Therefore, we aimed to critically appraise evidence on VZV and HZ epidemiology in the GCC countries and identify gaps in the current literature.

METHODS

A literature review was conducted via a comprehensive appraisal of the literature. PubMed and local-language journals were searched to identify articles related to HZ and VZV published up until 31 January 2022, with a sole focus on the GCC countries. Included studies reported on surveillance data, seroepidemiology, and patient outcomes for HZ and VZV, and comprised primary data reports, case series, case reports, narrative and systematic literature reviews, studies reporting HZ incidence or prevalence, and Ministry of Health reports.

RESULTS

Thirteen studies were found that reported on VZV seroprevalence in Saudi Arabia, the United Arab Emirates (UAE), and Qatar, ranging from 15.0% to 92.2%, while no data were identified for Bahrain, Kuwait, or Oman. There was very limited country-wide information on the incidence of HZ in GCC countries, and three identified studies reported HZ prevalence as seen in a single clinic, ranging from 0.62% to 2.3%. A single study from Saudi Arabia and government surveillance data reported on the impact of VZV vaccination on VZV infection, though there was no evidence on the impact of VZV vaccination on HZ.

CONCLUSION

There is a clear gap in the literature regarding the incidence of HZ infection, and the impacts of HZ and VZV vaccinations in the GCC countries. Further research into the epidemiology of HZ is necessary to inform the implementation of vaccination programs in the GCC countries.

Assessing vaccine effectiveness for varicella in Wuxi, China: a time-series analysis

OBJECTIVE

The varicella vaccine is not included in the national childhood immunization schedules in China. Varicella epidemics and outbreaks are frequently reported, and the evidence for the effectiveness of the varicella vaccine remains unclear. The aim of this study was to investigate varicella vaccine effectiveness in Wuxi, China.

METHODS

Varicella surveillance data were extracted from the China Information System for Disease Control and Prevention, and vaccination data were obtained from the Vaccination Integrated Service Management Information System of Jiangsu Province, China. Time-series analysis approaches were used to estimate varicella vaccine effectiveness.

RESULTS

A total of 16,093 varicella cases among children aged 1-6 years between January 2016 and December 2020 were analysed. A total of 217,297 children completed a two-dose varicella vaccination series. Compared with districts with lower vaccination rates, districts in Wuxi with higher varicella vaccination rates had a lower proportion of cases (p < 0.001). In the time-series approach, 0.8% fewer varicella cases were associated with a 1% increase in the two-dose varicella vaccination rate (p < 0.001), and similar effects were found in both the male and female populations.

CONCLUSIONS

Two-dose varicella vaccination was recommended as an effective health intervention to prevent varicella in Wuxi, China. Varicella vaccination is urgently needed in routine childhood immunisation programs.

Effects of meteorological factors on the incidence of varicella in Lu'an, Eastern China, 2015-2020

Varicella (chickenpox) is a serious public health problem in China, with the most reported cases among childhood vaccine-preventable infectious diseases, and its reported incidence has increased over 20-fold since 2005. Few previous studies have explored the association of multiple meteorological factors with varicella and considered the potential confounding effects of air pollutants. It is the first study to investigate and analyze the effects of multiple meteorological factors on varicella incidence, controlling for the confounding effects of various air pollutants. Daily meteorological and air pollution data and varicella cases were collected from January 1, 2015, to December 31, 2020, in Lu'an, Eastern China. A combination of the quasi-Poisson generalized additive model (GAM) and distributed lag nonlinear model (DLNM) was used to evaluate the meteorological factor-lag-varicella relationship, and the risk of varicella in extreme meteorological conditions. The maximum single-day lag effects of varicella were 1.288 (95%CI, 1.201-1.381, lag 16 day), 1.475 (95%CI, 1.152-1.889, lag 0 day), 1.307 (95%CI, 1.196-1.427, lag 16 day), 1.271 (95%CI, 0.981-1.647, lag 4 day), and 1.266 (95%CI, 1.162-1.378, lag 21 day), when mean temperature, diurnal temperature range (DTR), mean air pressure, wind speed, and sunshine hours were -5.8°C, 13.5°C, 1035.5 hPa, 6 m/s, and 0 h, respectively. At the maximum lag period, the overall effects of mean temperature and pressure on varicella showed W-shaped curves, peaked at 17.5°C (RR=2.085, 95%CI: 1.480-2.937) and 1035.5 hPa (RR=5.481, 95%CI: 1.813-16.577), while DTR showed an M-shaped curve and peaked at 4.4°C (RR=6.131, 95%CI: 1.120-33.570). Sunshine hours were positively correlated with varicella cases at the lag of 0-8 days and 0-9 days when sunshine duration exceeded 10 h. Furthermore, the lag effects of extreme meteorological factors on varicella cases were statistically significant, except for the extremely high wind speed. We found that mean temperature, mean air pressure, DTR, and sunshine hours had significant nonlinear effects on varicella incidence, which may be important predictors of varicella early warning.

A Dynamic Compartmental Model to Explore the Optimal Strategy of Varicella Vaccination: An Epidemiological Study in Jiangsu Province, China

Varicella (chickenpox) is highly contagious among children and frequently breaks out in schools. In this study, we developed a dynamic compartment model to explore the optimal schedule for varicella vaccination in Jiangsu Province, China. A susceptible-infected-recovered (SIR) model was proposed to simulate the transmission of varicella in different age groups. The basic reproduction number was computed by the kinetic model, and the impact of three prevention factors was assessed through the global sensitivity analysis. Finally, the effect of various vaccination scenarios was qualitatively evaluated by numerical simulation. The estimated basic reproduction number was 1.831 ± 0.078, and the greatest contributor was the 5-10 year-old group (0.747 ± 0.042, 40.80%). Sensitivity analysis indicated that there was a strong negative correlation between the second dose vaccination coverage rate and basic reproduction number. In addition, we qualitatively found that the incidence would significantly decrease as the second dose vaccine coverage expands. The results suggest that two-dose varicella vaccination should be mandatory, and the optimal age of second dose vaccination is the 5-10 year-old group. Optimal vaccination time, wide vaccine coverage along with other measures, could enhance the effectiveness of prevention and control of varicella in China.

Global varicella vaccination programs

Varicella (chickenpox) is an infectious disease caused by the highly contagious varicella zoster virus with a secondary attack rate greater than 90%. From this perspective, we aimed to establish the basis for a national varicella vaccine policy by reviewing vaccination programs and policies of countries that have introduced universal varicella vaccinations. As a result of the spread of varicella, an increasing number of countries are providing 2-dose vaccinations and universally expanding their use. In practice, the efficacy and effectiveness of vaccination differ among vaccines and vaccination programs. Optimized vaccination strategies based on each country's local epidemiology and health resources are required. Accordingly, it is necessary to evaluate the effectiveness of varicella vaccines in different settings. Given the short-term and fragmented vaccine effectiveness evaluation in Korea, it is necessary to evaluate its effectiveness at the national level and determine its schedule based on the evidence generated through these studies.

Long-term vaccine efficacy of a 2-dose varicella vaccine in China from 2011 to 2021: A retrospective observational study

Objective

A 2-dose varicella vaccine immunization strategy has been implemented in many cities in China, but there is few evidence on a long-term evaluation of the efficacy of the 2-dose varicella vaccine from China. This study aims to assess the long-term vaccine efficacy of the two doses varicella vaccine and analysis of its influencing factors.

Methods

A retrospective study was carried out in 837,144 children born between 2011 and 2017 in Ningbo, Easten China. The logistic regression was performed to estimate varicella vaccine effectiveness (VE).

Results

The overall VE of 2 doses of varicella vaccine compared without the vaccine was 90.31% (89.24-91.26%), and the overall incremental VE of 2 doses of varicella vaccine compared to the 1-dose was 64.71% (59.92-68.93%). Moreover, the varicella vaccination age of the second dose and the interval between 2 doses were both associated with VE. The VE compared to that without the vaccine in children vaccinated at <4 years old was 91.22% (95%CI: 90.16-92.17%) which was higher than in children vaccinated at ≥4 years old (VE: 86.79%; 95%CI: 84.52-88.73). And the effectiveness of the vaccine was 93.60% (95%CI: 92.19-94.75%) in children with the interval of the 2 doses ≤ 24 months significantly higher than in children with the interval of ≥36 months (VE: 85.62%, 95%CI: 82.89-87.91%).

Conclusions

This study provides evidence for long-term VE of the 2-dose varicella vaccine and the better age for 2-dose vaccination and the interval between 2 doses of the vaccine in China.

Changing Epidemiology of Varicella Outbreaks in the United States During the Varicella Vaccination Program, 1995-2019

We describe the changing epidemiology of varicella outbreaks informed by past and current active and passive surveillance in the United States by reviewing data published during 1995-2015 and analyzing new data from 2016 to 2019. Varicella outbreaks were defined as ≥5 varicella cases within 1 setting and ≥1 incubation period. During the 1-dose varicella vaccination program (1995‒2006), the number of varicella outbreaks declined by 80% (2003-2006 vs 1995-1998) in 1 active surveillance area where vaccination coverage reached 90.5% in 2006. During the 2-dose program, in 7 states with consistent reporting to the Centers for Disease Control and Prevention, the number of outbreaks declined by 82% (2016-2019 vs 2005-2006). Over the entire program (1995-2019), outbreak size and duration declined from a median of 15 cases/outbreak and 45 days duration to 7 cases and 30 days duration. The proportion of outbreaks with <10 cases increased from 28% to 73%. During 2016‒2019, most (79%) outbreak cases occurred among unvaccinated or partially vaccinated persons eligible for second-dose vaccination, highlighting the potential for further varicella control.

Relative efficacy of varicella vaccines: network meta-analysis of randomized controlled trials

OBJECTIVE

Although varicella vaccination is highly effective, no head-to-head randomized controlled trials (RCTs) have compared the efficacy of different vaccine formulations. This study assessed the relative efficacy of different varicella vaccines using network meta-analysis (NMA).

METHODS

We estimated the relative efficacies of varicella vaccines and dosing regimens from RCTs using Bayesian NMA. Modeling-based time-series NMA (MBNMA) was performed, accounting for differences in time since vaccination, to extrapolate long-term vaccine efficacy (VE).

RESULTS

Eight RCTs were included based on systematic review of biomedical databases. Efficacy data were reported for four varicella-containing vaccines: Varivax (V-MSD, one and two dose), Varilrix (V-GSK, one dose), Priorix-Tetra (MMRV-GSK, one dose), and Sinovac (V-Sinovac, one dose). All varicella vaccines were effective versus no vaccination. Two-dose V-MSD (98.29%, 95% credible interval [CrI] 96.08-99.23) showed significantly higher VE versus all one-dose varicella-containing vaccines, but no significant difference versus two-dose MMRV-GSK (95.19%, 95% CrI 90.3-97.63). Two-dose MMRV-GSK showed higher VE than one-dose V-GSK (66.47%; 95% CrI 43.02-79.43), but no significant differences in VE versus one-dose V-MSD or one-dose V-Sinovac. In one-dose comparisons, V-MSD showed significantly higher VE (93.09%, 95% CrI 89.13-95.96) than V-GSK, but no significant difference versus V-Sinovac (89.22%; 95% CrI 67.1-96.5). MBNMA indicated that protection against varicella was sustained without waning over the 10 year follow-up.

CONCLUSIONS

Our study reported higher VE for two-dose V-MSD and MMRV-GSK. Among one-dose formulations, one-dose V-MSD was more efficacious than one-dose V-GSK. Policymakers should take into consideration differences in VE when implementing one- versus two-dose strategies in universal vaccination programs.

The Long-Term Clinical and Economic Impact of Universal Varicella Vaccination in Slovenia

Background: Despite the substantial burden of varicella infection, Slovenia does not currently have a universal varicella vaccination (UVV) program. We modeled the long-term clinical and economic impact of implementing 2-dose UVV strategies compared with no vaccination in Slovenia. Methods: A previously published dynamic transmission model was adapted to the demographics, varicella seroprevalence, herpes zoster incidence, and contact patterns in Slovenia. Six 2-dose UVV strategies, vs no vaccination, were considered over a 50-year period, including monovalent vaccination (Varivax^® [V-MSD] or Varilrix^® [V-GSK]) at ages 12 and 24 months, or monovalent vaccination at 15 months followed by monovalent or quadrivalent vaccination (ProQuad^® [MMRV-MSD] or Priorix- Tetra^® [MMRV-GSK]) at 5.5 years. Costs, quality-adjusted life-years, and incremental cost-effectiveness ratios vs no vaccination were calculated to assess the economic impact of each strategy from payer and societal perspectives. Results: The incidence of varicella infection was estimated as 1228 per 100 000 population in the absence of UVV. Over 50 years, depending on vaccination strategy, UVV reduced varicella cases by 77% to 85% and was associated with substantial reductions in varicella deaths (39%-44%), outpatient cases (74%-82%), and hospitalizations (74%-82%). The greatest reductions were predicted with V-MSD (15 months/5.5 years) and V MSD/MMRV-MSD (15 months/5.5 years). Discussion: All 2-dose UVV strategies were cost-effective compared with no vaccination from payer and societal perspectives, with V-MSD (15 months/5.5 years) being the most favorable from both perspectives. Conclusion: Policymakers should consider implementing UVV to reduce the burden of varicella disease in Slovenia.

Modeling the Impact of Exogenous Boosting and Universal Varicella Vaccination on the Clinical and Economic Burden of Varicella and Herpes Zoster in a Dynamic Population for England and Wales

Universal varicella vaccination (UVV) in England and Wales has been hindered by its potential impact on exogenous boosting and increase in herpes zoster (HZ) incidence. We projected the impact of ten UVV strategies in England and Wales on the incidence of varicella and HZ and evaluated their cost-effectiveness over 50 years. The Maternal-Susceptible-Exposed-Infected-Recovered-Vaccinated transmission model was extended in a dynamically changing, age-structured population. Our model estimated that one- or two-dose UVV strategies significantly reduced varicella incidence (70–92%), hospitalizations (70–90%), and mortality (16–41%) over 50 years. A small rise in HZ cases was projected with UVV, peaking 22 years after introduction at 5.3–7.1% above pre-UVV rates. Subsequently, HZ incidence steadily decreased, falling 12.2–14.1% below pre-UVV rates after 50 years. At a willingness-to-pay threshold of 20,000 GBP/QALY, each UVV strategy was cost-effective versus no UVV. Frontier analysis showed that one-dose UVV with MMRV-MSD administered at 18 months is the only cost-effective strategy compared to other strategies. HZ incidence varied under alternative exogenous boosting assumptions, but most UVV strategies remained cost-effective. HZ vaccination decreased HZ incidence with minimal impact on the cost-effectiveness. Introducing a UVV program would significantly reduce the clinical burden of varicella and be cost-effective versus no UVV after accounting for the impact on HZ incidence.

Patient-reported quality of life in patients suffering from acute herpes zoster-a systematic review with meta-analysis

Objectives

Herpes Zoster (HZ) is a common painful, debilitating condition caused by reactivation of the varicella-zoster virus. It is characterized by a painful skin eruption which is very complex to treat. Studies have reported that HZ negatively affects Quality of Life (QoL), but no large systematic review on this topic has been published to date. This systematic review aims to summarize the current data on patient-reported QoL amongst patients diagnosed with HZ.

Methods

We searched Medline, Embase, Cochrane Library, CINAHL, and PsycINFO. The primary outcome was the change in percent impairment of QoL compared to normative data. Secondary outcomes were meta-analyses comparing reported QoL to a control group or normative data.

Results

We assessed a total of 536 studies for inclusion. Thirteen studies were included in the systematic review and five studies in the meta-analyses. The total number of patients was 5472.

Conclusions

This systematic review and meta-analysis found lower reported QoL amongst patients diagnosed with acute herpes zoster compared to normative values. Our data show that acute herpes zoster significantly reduces the quality of life of the patients affected.

Varicella vaccination in India's universal immunisation program -is it time?

We report two representative cases of complicated varicella in immunocompetent children highlighting the significant vaccine preventable varicella burden in the Indian population. A robust surveillance programme followed by incorporation of varicella vaccine in routine immunization would be the way forward to mitigate this illness.

The impact of universal varicella vaccination on the clinical burden of varicella in Colombia: A National database Analysis, 2008-2019

In 2015, one-dose universal varicella vaccination (UVV) was introduced in the Colombian National Immunization Program targeting children aged 12 months, expanding to a two-dose program in 2019. This study aimed to examine the effect of one-dose UVV on the burden of varicella in Colombia. A retrospective study was conducted using national databases to estimate incidence and mortality for the target (1-4 years old), non-target (less than 1 and 5 years and older) and overall (all age groups) populations from the pre-UVV period (January 2008-June 2015) to the post-UVV period (July 2015-December 2019). A time-series analyses with ARIMA modeling was used to project expected varicella incidence and mortality in the absence of UVV in the post-UVV period. UVV impact was estimated by comparing predicted and observed values, providing point estimates and prediction intervals (PI). Overall vaccination coverage rate was over 90 % from 2016-2019. Following UVV introduction, mean annual incidence rates reduced from 743.6 to 676.8 per 100,000 in the target population and from 203.2 to 198.1 per 100,000 in the overall population. Our study estimated a reduction in varicella incidence from 2017, with the highest reduction of 70.5 % (95 % PI: 78.2-54.2) and 54.8 % (95 % PI: 65.0-36.4) observed in 2019 for the target and the overall populations, respectively. The ARIMA model estimated UVV in Colombia to have prevented 198,236 varicella cases from 2015 to 2019. Mortality reduced in the overall population from 0.8 per 1,000,000 to 0.5 per 1,000,000 and from 1.3 per 1,000,000 to 0.5 per 1,000,000 in the target population, in the pre-UVV and post-UVV periods, respectively. However, these differences were not statistically significant. Our study showed a significant reduction in varicella incidence after implementation of a one-dose UVV program in Colombia, increasing over time. Further assessment is needed to evaluate the impact of a two-dose UVV program in Colombia.

Estimation of single-dose varicella vaccine effectiveness in South Korea using mathematical modeling

In South Korea, despite the implementation of a universal single-dose vaccination program for children aged 12–15 months in 2005, the varicella incidence rate remains significant. Prior case-control studies have reported that currently used varicella vaccines are extremely inefficacious. We estimated vaccine effectiveness (VE) by fitting a dynamic transmission model to age-specific varicella incidence data from 2007 to 2015 and available vaccine coverage data. The initial vaccine efficacy and primary failure rates were estimated to be 61.1% and 38.9%, respectively. The average duration of protection was 21.4 years. The mean VE [(1-relative risk) %] for the simulated data of 2004–2014 birth cohorts decreased from 59.8% to 50.7% over 9 years. This mathematical modeling study demonstrated that the single-dose vaccine exhibits moderate effectiveness, and a high proportion of primary failure could be a main cause of breakthrough infections. Therefore, a two-dose vaccination strategy should be considered.

Economic Evaluation of Universal Varicella Vaccination in Mexico

BACKGROUND

Universal varicella vaccination has proven to be cost-effective (CE) in countries where implemented. However, this has not been evaluated for Mexico.

METHODS

The yearly disease burden (varicella cases/deaths, outpatient visits, and hospitalizations) was derived from Mexican seroprevalence data adjusted to the 2020 population. The yearly economic burden was calculated by combining disease with Mexican unit cost data from both health care and societal perspectives. Four different vaccination strategies were evaluated: (1) 1 dose of varicella vaccine at 1 year old; (2) 2 doses at 1 and 6 years; (3) 1 dose of varicella vaccine at 1 year, and quadrivalent measles-mumps-rubella-varicella vaccine at 6 years; (4) 2 doses of measles-mumps-rubella-varicella vaccine at 1 and 6 years. We developed an economic model for each vaccination strategy where 20 consecutive birth cohorts were simulated. Vaccination impact (number of avoided cases/deaths) was evaluated for a 20-year follow-up period based on vaccine effectiveness (87% and 97.4% for 1 and 2 doses), and assuming a 95% coverage. We estimated annual costs saved, incremental cost-effectiveness ratio, and costs per life year gained.

RESULTS

Avoided cases during the 20-year follow-up with 1, and 2 doses were 20,570,722 and 23,029,751, respectively. Strategies 1 and 2 were found to be cost saving, and strategy 3 to be CE. Strategy 4 was not CE. Strategies 1 and 2 would allow saving annually $53.16 and $34.41 million USD, respectively, to the Mexican society.

CONCLUSIONS

Universal varicella vaccination, using 1 dose or 2 doses, would result in a cost-beneficial and CE public health intervention in Mexico.

Immunogenicity and Safety of a Booster Dose of Live Attenuated Varicella Vaccine, and Immune Persistence of a Primary Dose for Children Aged 2 to 6 Years

Aim: To evaluate the immunogenicity and safety of a booster dose of live attenuated varicella vaccine (VarV) manufactured by Sinovac (Dalian) Vaccine Technology Co. Ltd., and the immune persistence of a primary dose in 2- to 6-year-old children. Methods: A phase IV, open-label study was conducted in China. Children previously vaccinated with a single dose of VarV at 1~3 years old received one dose of homologous VarV in the first year, the second year, or the third year after the primary immunization as booster immunization. Immune persistence was evaluated in an immune persistence analysis set, while immunogenicity was evaluated in a per-protocol analysis set, and safety was evaluated in a safety analysis set. The primary endpoint was the seropositive rate and the seroconversion rate of VarV antibody. The trial was registered at ClinicalTrials.gov (NCT02981836). Results: From July 2018 to August 2020, a total of 849 vaccinated children received the booster vaccination of VarV, one booster dose for each child (301 vaccinated in the first year after primary immunization (Group 1), 276 vaccinated in the second year after primary immunization (Group 2), 272 vaccinated in the third year after primary immunization (Group 3)). The seropositive rates were 99.34%, 97.83%, and 98.16% in Groups 1–3, with GMTs of 1:22.56, 1:18.49, and 1:18.45, respectively. Thirty days after the vaccine booster dose, the seropositive rates of the three groups were all 100% and the seroconversion rates were 52.54%, 67.46%, and 66.67%, with GMTs of 1:68.49, 1:76.32 and 1:78.34, respectively. The seroconversion rates in Groups 2 and 3 were both higher than that in Group 1 (p = 0.0005 and p = 0.0008). The overall incidence of adverse reactions was 7.77%, with 7.64%, 8.33%, and 7.35% in Groups 1, 2, and 3, respectively. The main symptom among adverse reactions was fever, the incidence of which ranged from 5.07% to 6.64% in each group, and no vaccine-related serious adverse events occurred. Conclusions: VarV had good immune persistence in 1~3 years after primary immunization. A vaccine booster dose for children aged 1~3 years after primary immunization recalled specific immune response to varicella-zoster virus, with no safety concerns increased.

Randomised controlled trial showed long-term efficacy, immunogenicity and safety of varicella vaccines in Norwegian and Swedish children

AIM

Several countries, such as Norway and Sweden, have not implemented universal varicella vaccination. We present data for Norway and Sweden that were generated by a paediatric multi-country Phase III study over a 10-year period. This assessed the efficacy, antibody persistence and safety of two varicella vaccines containing the same Oka strain.

METHODS

This was an observer-blind, controlled trial conducted in 10 European countries. Children aged 12-22 months (n = 5803) were randomised 3:3:1 and vaccinated between 1 September 2005 and 10 May 2006. The two-dose group received two tetravalent measles-mumps-rubella-varicella vaccine doses. The one-dose group received one monovalent varicella vaccine dose after a measles-mumps-rubella vaccine dose. Control group participants received two measles-mumps-rubella vaccine doses. Main study outcomes were vaccine efficacy against confirmed varicella cases and incidence of adverse events.

RESULTS

Vaccine efficacy in the two-dose group was ≥92.1% in both Norwegian and Swedish children compared to 72.3% in Norway and 58.0% in Sweden in the one-dose group. Incidences of adverse events and serious adverse events were similar in the Norwegian and Swedish study populations.

CONCLUSION

Consistent with overall study results, high efficacy against varicella and acceptable safety profiles of the two varicella vaccines were observed in Norwegian and Swedish populations. These findings highlight the benefits of varicella vaccines, particularly when administered as a two-dose schedule.

Seroprevalence of Varicella in Pregnant Women and Newborns in a Region of Colombia

We estimate the seroprevalence of IgG antibodies to varicella zoster virus (VZV) based on the first serological study in a cohort of pregnant women and newborns from the Aburrá Valley (Antioquia-Colombia) who attended delivery in eight randomly chosen hospitals. An indirect enzyme immunoassay was used to determine anti-VZV IgG antibodies. Generalized linear models were constructed to identify variables that modify seropositivity. In pregnant women, seropositivity was 85.8% (95% CI: 83.4-85.9), seronegativity was 12.6% (95% CI: 10.8-14.6), and concordance with umbilical cord titers was 90.0% (95% CI: 89-91). The seropositivity of pregnant women was lower in those who lived in rural areas (IRR: 0.4, 95% CI: 0.2-0.7), belonged to the high socioeconomic status (IRR: 0.4, 95% CI: 0.2-0.7), and had studied 11 years or more (IRR: 0.6, 95% CI: 0.4-0.8). Among newborns, seropositivity was lower in those who weighed less than 3000 g (IRR: 0.8, 95% CI: 0.6-1.0). The high seropositivity and seronegativity pattern indicates the urgent need to design preconception consultation and vaccination reinforcement for women of childbearing age according to their sociodemographic conditions, to prevent infection and complications in the mother and newborn.

Effectiveness of varicella vaccine as post-exposure prophylaxis: a meta-analysis

BACKGROUND

To evaluate the effectiveness of varicella vaccine (VarV) as post-exposure prophylaxis (PEP) among children during varicella outbreaks.

MATERIAL AND METHODS

A comprehensive literature search was performed in PubMed, Embase, Web of Science, SinoMed, Wanfang and CNKI. Relevant outcomes included the incidence of varicella. Pooled estimates were calculated using a fixed-effects or random-effects model according to the heterogeneity among studies.

RESULTS

A total of 15 studies with 7,474 children that received one or two dosages of VarV as PEP and 183,827 children who received no VarV were included in the meta-analysis. In total, one-dose and two-dose VarV as PEP had 43% (95% confidence interval (CI):27%, 55%) and 60% (95%CI: 35%, 75%) efficacy, respectively. When PEP was applied within 3 days, the pooled VarV as PEP for prevention of varicella was 80% (95%CI: 68%, 88%); when PEP was administered beyond 3 days, the pooled VarV as PEP for the prevention of varicella was 50% (95%CI: 11%, 72%). If the PEP was implemented with a coverage of more than 80%, the VarV could prevent 82% of varicella cases from occurring (95%CI: 15%, 96%); if the PEP covered a maximum of 80% of the susceptible cases, the VarV could prevent 65% of varicella cases from occurring (95%CI: 50%, 76%).

CONCLUSION

The two-dose VarV had better efficacy than one-dose VarV in the control of varicella outbreaks, especially if PEP was applied within 3 days of an outbreak and in conjunction with a high coverage rate ≥80%.

Epidemiological Impact and Cost-Effectiveness of Varicella Vaccination Strategies in the United Kingdom

Background

Despite the burden of varicella, there is no universal varicella vaccination (UVV) program in the United Kingdom (UK) due to concerns that it could increase herpes zoster (HZ) incidence. We assessed the cost-utility of a first-dose monovalent (varicella [V]) or quadrivalent (measles-mumps-rubella-varicella [MMRV]) followed by a second-dose MMRV UVV program. GSK and MSD varicella-containing vaccines (VCVs) were considered.

Methods

Dynamic transmission and cost-effectiveness models were adapted to the UK. Outcomes measured included varicella and HZ incidences and the incremental cost-utility ratio (ICURs) over a lifetime horizon. Payer and societal perspectives were evaluated.

Results

The impact of V-MMRV and MMRV-MMRV UVV programs on varicella incidence was comparable between both VCVs at equilibrium. HZ incidence increased by 1.6%–1.7% over 7 years after UVV start, regardless of the strategies, then decreased by >95% at equilibrium. ICURs ranged from £5665 (100 years) to £18 513 (20 years) per quality-adjusted life-year (QALY) gained with V-MMRV and from £9220 to £27 101 per QALY gained with MMRV-MMRV (payer perspective). MMRV-MMRV was cost-effective in the medium- and long-terms with GSK VCV and only cost-effective in the long term with MSD VCV at a £20 000 per QALY gained threshold. Without the exogenous boosting hypothesis, HZ incidence decreased through UVV implementation. ICURs were most sensitive to discount rates and MMRV price.

Conclusions

A 2-dose UVV was demonstrated to be a cost-effective alternative to no vaccination. With comparable effectiveness as MSD VCV at lower costs, GSK VCV may offer higher value for the money.

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, using a vaccine with the BRD2 strain which is only used in China, 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.

Varicella-pox virus infection: features of the course, clinical manifestations, complications, and possibilities for prevention

Varicella zoster virus (VZV) is a pathogenic human herpes virus that causes chickenpox as a primary infection, after which it persists for a long time and latently in the peripheral ganglia. Decades later, the virus can reactivate spontaneously, or after exposure to a number of triggering factors, causing herpes zoster (shingles). The reasons for the long-term persistence of VZV are gradually being revealed, but some issues remain unknown at the moment. Chickenpox and its complications are especially difficult in immunocompromised patients, but they are often found in people without risk factors. The most frequent and important complication of VZV reactivation is postherpetic neuralgia; encephalitis, segmental motor weakness and myelopathy, cranial neuropathies, and gastrointestinal complications often develop. The only scientifically proven effective and affordable way of mass prevention at the moment is vaccination. Chickenpox vaccines are safe and effective in preventing morbidity and mortality associated with the disease.

Assessing the use of antibiotics and the burden of varicella in Belgium using a retrospective GP database analysis

Background

Varicella is a highly contagious infection that typically occurs in childhood. While most cases have a generally benign outcome, infection results in a considerable healthcare burden and serious complications may occur.

Objectives

The objective of this study was to characterize the burden of varicella in a real-world primary care setting in Belgium, including the rate of varicella-related complications, medication management and general practitioner (GP) visits.

Methods

The study was a retrospective observational study using data from a longitudinal patient database in a primary care setting in Belgium. Patients with a GP visit and a varicella diagnosis between January 2016 and June 2019 were eligible and data one month prior and three months after the diagnosis were included. Outcomes included varicella-related complications, antibiotic use, antiviral use, and GP follow-up visits. Antibiotic use could be specified by class of antibiotic and linked to a diagnosis. Complications were identified based on concomitant diagnosis with varicella during the study period.

Results

3,847 patients with diagnosis of varicella were included, with a mean age of 8.4 years and a comparable distribution of gender. 12.6% of patients with varicella had a concomitant diagnosis of a varicella-related complication. During the follow-up period, 27.3% of patients with varicella were prescribed antibiotics, either systemic (19.8%) and/or topical (10.3%). The highest rate of antibiotic prescriptions was observed in patients with complications (63.5%) and in patients younger than 1 year (41.8%). Nevertheless, 5.3% of the patients were prescribed antibiotics without a concomitant diagnosis of another infection. The most commonly prescribed systemic antibiotics were amoxicillin alone or combined with beta-lactamase inhibitor, and thiamphenicol. Fusidic acid and tobramycin were the most prescribed topical antibiotics. Antivirals were prescribed for 2.7% of the study population. 4.7% of the patients needed a follow-up visit with their GP.

Conclusions

This study reports a substantial burden of varicella in a primary care setting in Belgium, with high rates of complications and antibiotic use.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-021-06848-4.

Concordance of self-reported varicella history and serology among adolescent and adult refugee patients at a primary care clinic in Toronto, Canada

BACKGROUND

Previous studies have found higher rates of varicella susceptibility among migrants from tropical regions. This study seeks to estimate the prevalence of varicella susceptibility in a cohort of newly arrived refugees and refugee claimants at a primary care clinic in Toronto and to compare patients' self-reported history of varicella infection with serologic test results.

METHODS

We conducted a retrospective chart review of 1888 refugee patients aged 13 years and older rostered at a specialized primary care clinic in Toronto from December 2011 to October 2017. Basic sociodemographic variables, self-reported varicella history, and varicella serologic results were examined.

RESULTS

Based on serologic testing, 8.5% of individuals were varicella non-immune, with highest rates of varicella susceptibility among adolescents aged 13-19 years (13.5%). All adults over age 60 were varicella immune on serology (n = 56). A positive self-reported history of varicella infection was strongly predictive of varicella immunity on serology (PPV 96.8%; 95% CI: 95.2-97.9). A self-reported history of no prior varicella infection did not correlate reliably with serologic test results (NPV 15.8%; 95% CI: 13.3-18.0). A substantial proportion of patients (34.1%) were unsure of their varicella history.

CONCLUSION

Identification and immunization of varicella susceptible refugee newcomers remains a health care priority. Self-reported history of varicella infection had mixed reliability as a predictor of varicella immunity.

The comparison of seroconversion rates among different varicella vaccines administered Turkish children; MAV/06 and vOka

Varicella is a vaccine-preventable disease, and the incidence of varicella has declined since the introduction of varicella vaccine campaigns. A wild type of varicella zoster virus (VZV) was isolated from a 33-month-old child with varicella in Korea in 1989, a different strain (MAV/06). A live-attenuated varicella vaccine containing strain (MAV/06), Suduvax®, was developed in South Korea in 1994. Turkey introduced the varicella vaccine containing the MAV/06 strain (Varicella Vaccine-GCC, Green Cross, South Korea) in January 2019. Therefore, we aimed to compare the seroconversion rates among MAV/06 vaccine- and vOka-administered children. We prospectively collected blood samples from 98 received vOKA and 98 received MAV/06 children 6 weeks after administration, and seroconversion rates were determined by an indirect fluorescence assay (Anti-VZV IIFT IgG, Euroimmun, Germany). Seroconversion rate was significantly higher in vOka group than MAV/06 group (82.7% vs. 64.3%; p = .004). Of the children vaccinated with vOka strain, 17 children did not develop antibodies, 12 were weakly positive, and the remaining 69 children were strongly positive. Of the children who were administered MAV/06 strain, 35 were negative, 20 were weakly positive, and 43 were strongly positive. In conclusion, this study demonstrated that MAV/06 varicella vaccine had lower seroconversion rates and the strong seropositive cases were less common than vOka-administered children. Larger and prospective studies are needed.

Epidemiological impact of universal varicella vaccination on consecutive emergency department visits for varicella and its economic impact among children in Kobe City, Japan

INTRODUCTION

Previous studies reported a dramatic decline in the incidence of varicella and varicella-related deaths after implementing universal varicella vaccination (VarV). Although previous studies reported the effectiveness and economic impact of VarV, they were unknown in the emergency department (ED) setting.

METHODS

To determine the effectiveness and economic impact of VarV in the ED, Kobe, Japan, we retrospectively reviewed the clinical database of consecutive patients younger than 16 years presenting to our primary ED from 2011 to 2019.

RESULTS

Of the 265,191 children presenting to our ED, 3,092 patients were clinically diagnosed with varicella. The number of patients with varicella was approximately 500 annually, before introducing the universal two-dose VarV for children aged 1 to <3 years in October 2014, in the Japanese national immunization program, and decreased to approximately 200 in 2019. The number of patients with varicella younger than 1 year (ineligible for the vaccination) also decreased. Regarding the economic impact, the medical cost in our ED reduced after the introduction of VarV was JPY 4.1 million (US$ 40,049) annually. From the central data, approximately 95% of children were vaccinated after October 2014; however, a relatively large percentage of infected unvaccinated children (59.0%) presented to ED in this study. After the implementation of the universal VarV, infection was mainly observed in older children (i.e., the unvaccinated generation).

CONCLUSIONS

Our data showed the effectiveness and economic impact of VarV in the ED setting. Additionally, our data suggested that the public vaccination program should include older unvaccinated children and other unvaccinated individuals.