[Prospective observation of breakthrough cases and analysis of antibody dynamic changes after two doses of varicella]

Objective: To investigate the breakthrough rate and antibody level of children vaccinated two doses varicella vaccine in Tianjin city, and to compare them with those vaccinated one dose. Methods: A total of 1 112 children who were vaccinated two doses varicella vaccine were selected as the experimental group. According to the same street and township, children who had received only one dose within one year of age difference, and whose first injection time was less than one month from the first dose of varicella vaccine in the experimental group were selected as the control group. A three-year prospective observation was conducted on the incidence of varicella in the two groups. 108 pairs of children in the two groups were selected to collect antivaricella serum in the first to third year. The rate of breakthrough cases, antibody level and antibody positive rate were compared by χ² test, t-test and variance analysis between and within the two groups in three years. Results: The cumulative breakthrough rate of the experimental group was 0.54%(6/1 112), which was lower than that of the control group 3.96% (44/1 112, χ²=29.544, P<0.001). The GMC level of antibody in the experimental group decreased year by year (F=18.291, P<0.001), and the GMC level in the control group also decreased year by year (F=91.383, P<0.001). There was significant difference in GMC level between the two groups (P<0.001). The difference of antibody positive rate in the experimental group was statistically significant in three years (χ²=11.107, P<0.01), there was significant difference in the positive rate between the first year and third year (P<0.01), there was no significant difference in the positive rate of the control group in three years (χ²=3.351, P>0.05). The positive rate of the experimental group was higher than that of the control group (P<0.001). Conclusion: Two doses varicella vaccine can significantly improve the antibody level and positive rate, but it still shows a downward trend with the extension of time. It is necessary to consider strengthening immunization according to the actual situation.

[An investigation on serum antibody level of varicella-zoster virus in healthy population in Beijing]

Objective: To assess the level and trend of varicella-zoster virus (VZV) antibody among healthy population in Beijing in 2017, after the five-year implementation of the two doses varicella vaccination strategy in 2012, and to provide evidence for scientific evaluation of immunization strategy. Methods: A total of 2 144 subjects in ten age groups from 8 districts of Beijing city were recruited in this study using cross-sectional survey based on multi-stage cluster random sampling method. Serum samples were collected and VZV antibody was detected by ELISA. The influencing factors of antibody concentration and positive rate were analyzed and compared with the study in 2012. The antibody concentration and antibody positive rate were analyzed by nonparametric test and χ² test respectively. Results: The ratio of subjects with registered residence in Beijing city to other provinces was 1∶1. The ratio of male to female was 1∶1.08. The median concentration of VZV antibody was 341.4 (78.6, 1 497.8) mIU/ml, and the total antibody positive rate was 71.1% (1 524/2 144). There were significant differences in antibody positive rate (χ²=736.39, P<0.01) and antibody concentration (χ²=740.34, P<0.01) among different age groups. The antibody positive rate generally increased with age (χ²_trend=7.32, P_trend<0.01). Among 862 children under 14 years old, the antibody positive rate of two doses vaccination 72.8% (182/250) was significantly higher than that of one dose vaccination 51.9% (154/297) (χ²=25.14, P<0.01). There was significant difference between 1-4 years old group (χ²=11.71, P<0.01) and 10-14 years old group (χ²=5.95, P=0.02), but not in 5-9 years old group (χ²=3.00, P=0.07). Compared with the study in 2012, the antibody positive rate increased in 5-9 years old group (χ²=14.35, P<0.01) and decreased in 1-4 years old group (χ²=11.51, P=0.01) in 2017. Conclusion: The recommended varicella booster vaccination has significantly improved the VZV antibody level of children in Beijing city. In the future, it is necessary to explore a more optimized two doses varicella vaccination schedule for children in combination with epidemiological evidence.

Effect of universal varicella vaccination and behavioral changes against coronavirus disease 2019 pandemic on the incidence of herpes zoster

Background

Since 2014, universal varicella vaccination has reduced the varicella and herpes zoster (HZ) incidence in vaccine recipients and increased the incidence in the child-rearing generation until 2017.

Objective

This study aimed to understand the future epidemiologic trends of HZ after the disappearance of varicella epidemics and during the coronavirus disease 2019 (COVID-19) pandemic.

Methods

The Miyazaki Dermatologist Society has been monitoring and analyzing the incidence of HZ patients after universal vaccination since 1997.

Results

The HZ incidence in Oka varicella vaccine recipients aged 0–4 years decreased with the reduction in chickenpox incidence. The HZ incidence among those aged 5–9 years increased between 2015 and 2017 and decreased thereafter. From 2014–2020, the HZ incidence continued to increase to 36.6%, 51.3%, 70.2%, 56.7%, and 27.3% among those aged 10–19, 20–29, 30–39, 40–49, and 50–59 years, respectively. The HZ incidence in patients aged ≥ 60 years increased by 2.3% annually from 2014 to 2020, corresponding to an annual 2% increase since 1997, and was unaffected by varicella epidemics. COVID-19 infection control measures, lifestyle changes and the resulting stress did not affect the HZ incidence in 2020.

Conclusion

Universal varicella vaccination eliminated varicella epidemics, and HZ was reduced in vaccine recipients. The HZ incidence for those aged 10–59 years increased from 2014 to 2020, in contrast to those aged ≥ 60 years, which is attributable to booster immunity expiration due to varicella contact in this age group.

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.

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.

[Varicella vaccination]

Chickenpox is generally considered a benign childhood disease. However, serious complications may arise. A safe and efficient vaccine is available, and universal chickenpox vaccination is already introduced in many countries. Denmark, among other countries, has been reluctant to introduce the vaccine due to insufficient information on disease burden and concerns regarding herpes zoster incidence and a potential age shift. In this review, we present current knowledge regarding the disease burden of chickenpox in Denmark and discuss perspectives on introducing the vaccine in Denmark.

Live Attenuated Varicella Vaccine: Prevention of Varicella and of Zoster

Michiaki Takahashi developed the live attenuated varicella vaccine in 1974 . This was the first, and is still the only, herpesvirus vaccine. Early studies showed promise, but the vaccine was rigorously tested on immunosuppressed patients because of their high risk of fatal varicella; vaccination proved to be lifesaving. Subsequently, the vaccine was found to be safe and effective in healthy children. Eventually, varicella vaccine became a component of measles mumps rubella vaccine, 2 doses of which are administered in the USA to ~90% of children. The incidence of varicella has dropped dramatically in the USA since vaccine-licensure in 1995. Varicella vaccine is also associated with a decreased incidence of zoster and is protective for susceptible adults. Today, immunocompromised individuals are protected against varicella due to vaccine-induced herd immunity. Latent infection with varicella zoster virus occurs after vaccination; however, the vaccine strain is impaired for its ability to reactivate.

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.

Common Features Between Stroke Following Varicella in Children and Stroke Following Herpes Zoster in Adults : Varicella-Zoster Virus in Trigeminal Ganglion

The cerebral arteries are innervated by afferent fibers from the trigeminal ganglia. Varicella-zoster virus (VZV) frequently resides in the trigeminal ganglion. Reports of arterial ischemic stroke due to VZV cerebral vasculopathy in adults after herpes zoster have been described for decades. Reports of arterial ischemic stroke due to post-varicella cerebral arteriopathy in children have also been described for decades. One rationale for this review has been post-licensure studies that have shown an apparent protective effect from stroke in both adults who have received live zoster vaccine and children who have received live varicella vaccine. In this review, we define common features between stroke following varicella in children and stroke following herpes zoster in adults. The trigeminal ganglion and to a lesser extent the superior cervical ganglion are central to the stroke pathogenesis pathway because afferent fibers from these two ganglia provide the circuitry by which the virus can travel to the anterior and posterior circulations of the brain. Based on studies in pseudorabies virus (PRV) models, it is likely that VZV is carried to the cerebral arteries on a kinesin motor via gE, gI and the homolog of PRV US9. The gE product is an essential VZV protein.

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.

Impact of varicella vaccine on nosocomial outbreaks and management of post exposure prophylaxis following in a paediatric hospital

Introduction

In 2015, varicella vaccine was introduced to the National Immunization Programme in a one-dose regimen for infants aged 15 months. The aim of this study was to describe and compare the epidemiologic characteristics, management strategies and costs of varicella outbreaks in Ricardo Gutierrez Children’s Hospital (HNRG) from 2000 to 2019, before (PreV period) and after (PostV period) the introduction of the varicella vaccine.

Methods

A retrospective, analytic study of the impact of nosocomial varicella outbreaks at the HNRG, based on active epidemiologic surveillance. We compared nosocomial varicella outbreaks rates (per 10,000 discharges) between PreV and PostV, excluding the intervention year (2015).

Results

During PreV, an average of 15.87 (13.91–18.02) outbreaks per year was observed and in PostV 5.5 per year (3.44–8.32). Outbreaks adjusted by all cause discharges showed a reduction of 59.13% (-36.68%, -73.62%) after vaccine introduction.

Considering that in PreV the average of susceptible cases per outbreak was 5.0 and in PostV 7.8, with a cost per susceptible of AR$ $6,522 (80.27 USD) PreV and 6,708 PostV the economic impact on the reduction of outbreaks after the introduction of the vaccine, showed an estimated average savings per year of AR$ -252,128 AR$ (-3,103.11 USD).

Conclusions

The number of annual varicella hospital outbreaks at the HNRG decreased significantly after varicella vaccine was introduced to NIP in Argentina with a relevant reduction in terms of costs.

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.

Incidence of varicella and herpes zoster after inclusion of varicella vaccine in national immunization schedule in Turkey: time trend study

The aim of the study was to investigate changes in the incidences of Varicella and Herpes Zoster (HZ) following introduction of single dose Varicella vaccine (VV) in Turkey. Changes in the incidences of varicella and HZ per 100,000 population were compared with pre (2011-2012) and post-VV period (2018-2019) throughout years between years 2011 and 2019 both for children and adults. In children ≤5 years of age, the annual incidences of varicella significantly decreased from 290 per 100000 children in 2011 to 24 per 100000 children in 2019 [p = .0001]. Also, for children ≤5 years the mean annual incidence of varicella decreased significantly [326/100000 ±51/100000 vs 23/100000 ± 1/100000; p = .014] between pre- and post-VV period. Moreover, the annual incidences of varicella significantly decreased from 43 per 100000 children in 2011 to 26 per 100000 children in 2019 in children age between 6 and 17 years. On the other hand, incidence of varicella in adult population (age >17 years) did not change significantly. Besides, the annual incidences of Herpes Zoster did not change significantly in children age stratas but significant increment observed in adult population. This increment was significant in adult age strata of 18-44 years, but non-significant in age strata of 45-64 years and >64 years. Thus, our study showed a significant reduction in the incidences of Varicella in children age stratas whereas significant increment in the incidence of HZ in adult population after the implementation of VV into the NIP of Turkey.

Seroprevalence survey for Varicella among healthcare workers and medical students in Italy

Varicella is a potentially serious infectious disease caused by Varicella-Zoster Virus (VZV). In Italy childhood varicella vaccine have gradually introduced into national immunization program since 2003 and from 2017 a two-doses schedule has been stated nationally for all newborns and has become compulsory for school attendance. VZV exposures among healthcare workers (HCWs) and patients can be really dangerous and expensive. According to Centers of Disease Control and Italian national immunization plan health care, institutions should verify that all HCWs have clear evidence of immunity to VZV and should ensure that susceptible subjects will receive 2 doses of VZV vaccine. Currently, the vaccination of HCWs is not compulsory in Italy and the risk of varicella infection among these subjects is not well known. We evaluated the clinical records of 840 HCWs (256 male and 584 female) who underwent the annual occupational screening, from 1st January to 31st August 2018. HCWs were divided into three subgroups according to their age: 18-30, 31-40, and over 40 years old. We compared the mean values of IgG-specific antibodies between the age group through analysis of variance (ANOVA). A total of 784 (93.33%) HCWs were protected for VZV IgG antibodies level. There wasn't a significant difference between male and female while was found between age group (P < 0.001). Protection levels for varicella are inadequate among HCWs. Despite the epidemiology of varicella in general population has changed with the implementation of the childhood varicella vaccination program transmission of VZV in hospitals is still a serious problem, so it is necessary to increase prevention activities in these settings, including vaccination.

Epidemiology of varicella and effectiveness of varicella vaccine in Hangzhou, China, 2019

Background: The varicella vaccine (VarV) is not included in the national childhood immunization schedules in China, although 2-dose VarV (VarV2) were recommended for children at 1 and 4 years of age in Hangzhou since 2014. However, the reported incremental vaccine effectiveness (VE) of VarV2 varies widely among studies. We described the epidemiological characteristics of varicella in Hangzhou, assessed the VE of VarV, so as to provide scientific evidence on optimization and adjustment of immunization strategies for varicella prevention in China. Methods: All varicella cases diagnosed in a hospital in Hangzhou are reported to China Information System for Disease Control and Prevention (CISDCP). The demographic information of reported varicella cases onset from January 1 to December 31, 2019 was extracted from CISDCP on Jan 31, 2020. The demographic information was obtained from the information system of the National Center for Disease Prevention and Control. We conducted a 1:1 matched case-control study to assess the effectiveness of VarV. Participant data were collected with standardized questionnaires. VarV vaccination status was checked by using Hangzhou Immunization Information System (HZIIS). Results: A total of 11,813 varicella cases were reported in Hangzhou, China, 2019, without any death. Annual estimated incidence of varicella was 120 cases per 100,000 populations in 2019. The overall estimated incidence rate of varicella was high, especially for persons aged 10-19 years old and in suburb areas. The seasonal pattern was apparent, mostly due to the cases among students and children in kindergarten. In total, 218 varicella cases and 218 matched controls were included for evaluating the VE of VarV. VarV vaccination produced a high level of protection against varicella, while VE of VarV2 was even better. VE of VarV1 was 91.0% (95%CI: 81.6%-95.8%), and VE was 98.0% (95.5%-99.2%) for VarV2. Conclusion: Continuous monitoring and management of varicella cases is necessary, especially in those endemic areas, high-risk populations, and peak periods; a 2-dose VarV strategy is highly recommended, and relevant health institutions should consider the inclusion of VarV in the national immunization program to better control varicella epidemic and reduce the burden of varicella.

Chickenpox in Poland in 2019

BACKGROUND

Chickenpox is a common disease in Poland, which is usually mild, but can lead to serious complications. Vaccination is an effective form of prevention. Prior to universal vaccination against chickenpox, high incidence was recorded in many countries. In Poland, since 2003, vaccinations have been carried out recommended for people who did not suffer from chickenpox and, since 2009, obligatory vaccinations for children up to 12 years of age particularly vulnerable to infection and children around them.

AIM

To assess epidemiological situation of chickenpox in Poland in 2019, including vaccination coverage in Polish population, in comparison to previous years.

METHODS

Assessment of the epidemiological situation of chickenpox in Poland in 2019 was based on the results of the analysis of aggregate data published in the annual bulletins: "Infectious diseases and poisoning in Poland in 2019" and "Protective Vaccination in Poland in 2019." In addition, the recommendations from the Protective Vaccine Program for 2019 were used.

RESULTS

In 2019, 180 641 cases of chickenpox were registered in Poland, i.e. 17.2% more than in the previous year. The incidence of chickenpox in 2019 was 470.6 per 100 thousand and was higer than in 2018. The lowest incidence was registered in the Dolnośląskie Voivodeship - 297.9/100 thousand, the highest in the Śląskie Voivodeship - 555.9/100 thousand. Children aged 0-4 years became ill the most (89 611). The incidence of chickenpox in men was higher than in women, and in rural areas it was higher than in urban areas. Hospitalization due to chickenpox in 2019 covered 1 156 people, which accounted for 0.64% of the total number of registered cases.

SUMMARY

In 2019, there was a growth in the number of chickenpox cases compared to the previous year, the incidence remains lower than in 2012-2014. An effective method of disease prevention is vaccination against chickenpox, which, despite the lack of common funding, is carried out in a growing population. Further improvement of the epidemiological situation requires health education of the society in the field of primary prevention, which is based on vaccinations. As recommended, the chickenpox vaccination course consists of two doses of the vaccine separated by at least 6 weeks from the previous dose.

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.

Pox Parties for Grannies? Chickenpox, Exogenous Boosting, and Harmful Injustices

Some societies tolerate or encourage high levels of chickenpox infection among children to reduce rates of shingles among older adults. This tradeoff is unethical. The varicella zoster virus (VZV) causes both chickenpox and shingles. After people recover from chickenpox, VZV remains in their nerve cells. If their immune systems become unable to suppress the virus, they develop shingles. According to the Exogenous Boosting Hypothesis (EBH), a person's ability to keep VZV suppressed can be 'boosted' through exposure to active chickenpox infections. We argue that even if this hypothesis were true, immunization policies that discourage routine childhood varicella vaccination in order to prevent shingles for other people are unethical. Such policies harm children and treat them as mere means for the benefit of others, and are inconsistent with how parents should treat their children and physicians should treat their patients. These policies also seem incompatible with institutional transparency.

Post-marketing surveillance of adverse events following measles, mumps, rubella and varicella (MMRV) vaccine: retrospecive study in apulia region (ITALY), 2009-2017

Since 2006, some Italian Regions introduced the active offer of measles, mumps, rubella, and varicella (MMRV) vaccine for all newborns during the second years of life. In 2011, Italian Drug Authority (AIFA) recommended the discontinuation of the MMRV use for an increased risk of febrile seizures following vaccination; furthermore, some Regions (such as Apulia, that introduced MMRV offer in 2009) chose to continue the use of MMRV and Ministry of Health recommended to guarantee supplemental monitoring of safety of the vaccine. In Italy, the surveillance of Adverse Events following immunization (AEFIs) is currently carried out by AIFA and Regional Health Authorities; this paper aims to summarize the results of MMRV-vaccine surveillance of AEFIs program carried out in Apulia. From the AIFA database, we selected MMRV AEFIs that occurred in Apulia (about 4,000,000 inhabitants) from 2009 to 2017. For serious AEFIs, we applied the WHO causality assessment algorithm, using for cases hospitalized information from individual medical records. In the 8 years of observation, 155 MMRV-AEFIs (reporting rate: 37.9×100,000 doses) occurred of which 26 were classified as serious (6.3×100,000 doses) and 22 led to hospitalization. Performing causality assessment, for 10 the classification was "consistent causal association to immunization" (reporting rate: 2.4×100000 doses), for 2 indeterminate, for 13 "inconsistent causal association to immunization" and for 1 not-classifiable. No case of febrile seizure resulted consistent to vaccination. All consistent serious AEFIs were completely resolved at subsequent follow-up.

[Revised multidisciplinary guidelines 'Varicella'; broader indication for post-exposure prophylaxis]

Post-exposure prophylaxis (PEP) with varicella zoster immunoglobulins (VZIG) should be administered as soon as possible after exposure to the virus, but always within ten days; in the previous guidelines this was within 96 hours. In cases of perinatal exposure, PEP with VZIG should be administered to neonates if the mother develops clinical chickenpox between seven days before delivery and seven days after delivery; in the previous guidelines this was between five days before delivery and two days after delivery. A new chapter on the treatment of chickenpox has been added to the guidelines.

Incidence of herpes zoster among varicella-vaccinated children, by number of vaccine doses and simultaneous administration of measles, mumps, and rubella vaccine

INTRODUCTION

Children may receive measles-mumps-rubella (MMR) and varicella (VAR) vaccines separately or as measles-mumps-rubella-varicella (MMRV). We examined whether pediatric herpes zoster (HZ) incidence varied by pattern of varicella vaccine administration.

METHODS

In six integrated health systems, we examined HZ incidence among children turning 12 months old during 2003-2008. All received varicella and MMR vaccines on recommended schedules. Cases were identified through 2014 using ICD-9 codes. Incidence was examined by number of varicella vaccine doses and same-day MMR.

RESULTS

Among 199,797 children, overall HZ incidence was 18.6/100,000 person-years in the first-dose MMR + VAR group, 17.9/100,000 person-years in the MMRV group, and 7.5/100,000 person-years in the VAR-alone group. HZ incidence was lower following the second dose than before the second dose in all first-dose groups.

CONCLUSIONS

HZ incidence was not meaningfully different between the MMRV and MMR + VAR first-dose groups. Overall and within first-dose groups, HZ incidence was lower among children receiving two varicella vaccine doses.