UK healthcare professionals' attitudes towards the introduction of varicella vaccine into the routine childhood vaccination schedule and their preferences for administration.

BACKGROUND: Varicella (chickenpox) is a highly contagious disease caused by the varicella-zoster virus. Although typically mild, varicella can cause complications leading to severe illness and even death. Safe and effective varicella vaccines are available. The Joint Committee on Vaccination and Immunisation has reviewed the evidence and recommended the introduction of varicella vaccine into the UK's routine childhood immunisation schedule. OBJECTIVES: To explore UK healthcare professionals' (HCPs) knowledge and attitudes towards varicella vaccination, its introduction to the UK routine childhood immunisation schedule, and their preferences for how it should be delivered. DESIGN: We conducted an online cross-sectional survey exploring HCPs' attitudes towards varicella, varicella vaccine, and their preferences for delivery of the vaccine between August and September 2022 prior to the recommendation that varicella vaccine should be introduced. PARTICIPANTS: 91 HCPs working in the UK (81 % nurses/health visitors, 9 % doctors, 10 % researcher/other, mean age 48.7 years). RESULTS: All respondents agreed or strongly agreed that vaccines are important for a child's health. However, only 58% agreed or strongly agreed that chicken pox was a disease serious enough to warrant vaccination. Gaps in knowledge about varicella were revealed: 21.0% of respondents disagreed or were unsure that chickenpox can cause serious complications, while 41.8% were unsure or did not believe chickenpox was serious enough to vaccinate against. After receiving some basic information about chickenpox and the vaccine, almost half of the HCPs (47.3%) in our survey would prefer to administer the varicella vaccine combined with MMR. CONCLUSIONS: Given the positive influence of HCPs on parents' decisions to vaccinate their children, it is important to understand HCPs' views regarding the introduction of varicella vaccine into the routine schedule. Our findings highlighted areas for training and HCPs' preferences which will have implications for policy and practice when the vaccine is introduced.

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.

The introduction of two-dose varicella vaccination was an effective intervention to prevent varicella in Wuxi, China.Varicella vaccination is urgently needed in routine childhood immunization programmes.

Recognition & management of varicella infections and accuracy of antimicrobial recommendations: Case vignettes study in the US.

BACKGROUND: In 1995, the CDC recommended one-dose routine varicella immunization for children <12 years of age, expanding its recommendation to two doses in 2006. Today, with widespread varicella vaccination coverage, an estimated 3.5 million cases of varicella, 9,000 hospitalizations, and 100 deaths are prevented annually in the United States. Since varicella infections are now uncommon, health care providers (HCPs) may not recognize varicella infections and may prescribe inappropriate treatment. METHODS: An online survey of HCPs was conducted to assess recognition and management of varicella infections. Responses to eight varicella vignettes describing patients with varying varicella symptoms were analyzed and descriptive analyses performed. Stratified analysis comparing responses of those licensed before and in/after 1996 was also performed. RESULTS: 153 HCPs (50 nurse practitioners, 103 doctors) completed the survey. Mean age of respondents was 44 years. 62% were female, and 82% were licensed before 1996. Varicella infection was correctly diagnosed 79% of the time. HCPs correctly recognized uncomplicated varicella vignettes 85% of the time versus 61% of the time for complicated varicella vignettes. Antibiotics were recommended 17% of the time and antivirals 18% of the time, of which 25% and 69% (respectively) were not appropriate per guidelines. HCPs licensed before 1996 were better able to recognize varicella compared to those licensed later, but prescribed more antimicrobials medications to treat varicella. CONCLUSIONS: Although most HCPs recognized varicella infection, a sizable proportion could not recognize cases with complications, and some of the varicella cases were inappropriately treated with antibiotics and/or antivirals. Additional HCP training and high vaccination coverage are important strategies to avoid inaccurate diagnoses and minimize unnecessary exposure to antimicrobial/antiviral therapies.

Impact of universal varicella vaccination on the use and cost of antibiotics and antivirals for varicella management in the United States.

BACKGROUND: Our objective was to estimate the impact of universal varicella vaccination (UVV) on the use and costs of antibiotics and antivirals for the management of varicella among children in the United States (US). METHODS: A decision tree model of varicella vaccination, infections and treatment decisions was developed. Results were extrapolated to the 2017 population of 73.5 million US children. Model parameters were populated from published sources. Treatment decisions were derived from a survey of health care professionals' recommendations. The base case modelled current vaccination coverage rates in the US with additional scenarios analyses conducted for 0%, 20%, and 80% coverage and did not account for herd immunity benefits. RESULTS: Our model estimated that 551,434 varicella cases occurred annually among children ≤ 18 years in 2017. Antivirals or antibiotics were prescribed in 23.9% of cases, with unvaccinated children receiving the majority for base case. The annual cost for varicella antiviral and antibiotic treatment was approximately $14 million ($26 per case), with cases with no complications accounting for $12 million. Compared with the no vaccination scenario, the current vaccination rates resulted in savings of $181 million (94.7%) for antivirals and $78 million (95.0%) for antibiotics annually. Scenario analyses showed that higher vaccination coverage (from 0% to 80%) resulted in reduced annual expenditures for antivirals (from $191 million to $41 million), and antibiotics ($82 million to $17 million). CONCLUSIONS: UVV was associated with significant reductions in the use of antibiotics and antivirals and their associated costs in the US. Higher vaccination coverage was associated with lower use and costs of antibiotics and antivirals for varicella management.

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.

Early-Life Antibiotic Exposure Associated With Varicella Occurrence and Breakthrough Infections: Evidence From Nationwide Pre-Vaccination and Post-Vaccination Cohorts.

Background: Antibiotic-driven dysbiosis may impair immune function and reduce vaccine-induced antibody titers. Objectives: This study aims to investigate the impacts of early-life antibiotic exposure on subsequent varicella and breakthrough infections. Methods: This is a nationwide matched cohort study. From Taiwan's National Health Insurance Research Database, we initially enrolled 187,921 children born from 1997 to 2010. Since 2003, the Taiwan government has implemented a one-dose universal varicella vaccination program for children aged 1 year. We identified 82,716 children born during the period 1997 to 2003 (pre-vaccination era) and 48,254 children born from July 1, 2004, to 2009 (vaccination era). In the pre-vaccination era, 4,246 children exposed to antibiotics for at least 7 days within the first 2 years of life (Unvaccinated A-cohort) were compared with reference children not exposed to antibiotics (Unvaccinated R-cohort), with 1:1 matching for gender, propensity score, and non-antibiotic microbiota-altering medications. Using the same process, 9,531 children in the Vaccinated A-cohort and Vaccinated R-cohort were enrolled from the vaccination era and compared. The primary outcome was varicella. In each era, demographic characteristics were compared, and cumulative incidences of varicella were calculated. Cox proportional hazards model was used to examine associations. Results: In the pre-vaccination era, the 5-year cumulative incidence of varicella in the Unvaccinated A-cohort (23.45%, 95% CI 22.20% to 24.70%) was significantly higher than in the Unvaccinated R-cohort (16.72%, 95% CI 15.62% to 17.82%) (p<.001). In the vaccination era, a significantly higher 5-year cumulative incidence of varicella was observed in the Vaccinated A-cohort (1.63%, 95% 1.32% to 1.93%) than in the Vaccinated R-cohort (1.19%, 95% CI 0.90% to 0.45%) (p=0.006). On multivariate analyses, early-life antibiotic exposure was an independent risk factor for varicella occurrence in the pre-vaccination (adjusted hazard ratio [aHR] 1.92, 95% CI 1.74 to 2.12) and vaccination eras (aHR 1.66, 95% CI 1.24 to 2.23). The use of penicillins, cephalosporins, macrolides, or sulfonamides in infancy was all positively associated with childhood varicella regardless of vaccine administration. Conclusions: Antibiotic exposure in early life is associated with varicella occurrence and breakthrough infections.

[Varicella-zoster virus (VZV) acute retinal necrosis and recombinant zoster vaccine]. / Nécrose rétinienne aiguë due au virus de la varicelle et du zona et vaccin recombinant contre le zona.

Varicella zoster virus (VZV) is responsible for chickenpox. Like all herpes viruses, after primary infection it enters into latency and can be reactivated afterwards. Many forms of symptomatic reactivation of VZV exist including acute retinal necrosis (ARN), an ophthalmic emergency which can lead to blindness. ARN is treated starting with high-dose intravenous acyclovir then with oral valaciclovir for a total duration of up to 3 months. Symptomatic reactivations of VZV are public health issues. The new Swiss 2022 vaccination plan includes the recombinant vaccine Shingrix. It effectively prevents VZV symptomatic reactivations even in elderly and immuno suppressed patients.

Le virus de la varicelle et du zona (VZV) est responsable de la varicelle. Comme tous les virus herpétiques, après la primo-infection, il entre en latence et peut se réactiver plus tard. Il existe de nombreuses formes de réactivations symptomatiques du VZV, dont la nécrose rétinienne aiguë (NRA), qui est une urgence ophtalmique pouvant aboutir à la cécité. La NRA est traitée par aciclovir intraveineux à haute dose dans sa prise en charge initiale puis par valaciclovir per os pour une durée totale pouvant aller jusqu'à 3 mois. Les réactivations symptomatiques de VZV sont un enjeu de santé publique. Le nouveau plan de vaccination suisse 2022 intègre le vaccin recombinant Shingrix, qui permet de prévenir efficacement les réactivations symptomatiques de VZV chez les patients même âgés et immunosupprimés.

Reconstructing the transmission dynamics of varicella in Japan: an elevation of age at infection.

BACKGROUND: In Japan, routine two-dose immunization against varicella has been conducted among children at ages of 12 and 36 months since 2014, and the vaccination coverage has reached around 90%. To understand the impact of routine varicella vaccination, we reconstructed the epidemiological dynamics of varicella in Japan. METHODS: Epidemiological and demographic datasets over the past three decades were analyzed to reconstruct the number of susceptible individuals by age and year. To estimate the annual risk of varicella infection, we fitted a balance equation model to the annual number of cases from 1990 to 2019. Using parameter estimates, we reconstructed varicella dynamics starting from 1990 and modeled future dynamics until 2033. RESULTS: Overall varicella incidence declined over time and the annual risk of infection among children younger than 10 years old decreased monotonically starting in 2014. Conversely, varicella incidence among teenagers (age 10 to 14 years) has increased each year since 2014. A substantial number of unvaccinated individuals born before the routine immunization era remained susceptible and aged without contracting varicella, while the annual risk of infection among teenagers aged 10 to 14 years increased starting in 2011 despite gradual expansion of varicella vaccine coverage. The number of susceptible individuals decreased over time in all age groups. Modeling indicated that susceptibility rates among pre-school children aged 1 to 4 years will remain low. CONCLUSION: Routine varicella vaccination has successfully reduced infections in pre-school and early primary school age children, but has also resulted in increased infection rates among adolescents. This temporary increase was caused both by the increased age of susceptible individuals and increased transmission risk among adolescents resulting from the dynamic nature of varicella transmission. Monitoring susceptibility among adolescents will be important to prevent outbreaks over the next decade.

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.

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.

Acceptance of universal varicella vaccination among Swiss pediatricians and general practitioners who treat pediatric patients.

BACKGROUND: Over the last two decades, several countries have initiated universal varicella vaccination (UVV) programs in infants. In 2019, the Swiss National Immunization Technical Advisory Group (NITAG) decided to start evaluating the introduction of universal varicella vaccination. There is a theoretical concern that suboptimal vaccination coverage could lead to a shift in the varicella incidence to older age groups, thereby potentially increasing complication rates. To achieve a high vaccination coverage rate, it is important that practicing physicians comply with a potential recommendation for UVV. We studied the perception of varicella and the current vaccination behavior among Swiss pediatricians and general practitioners (GPs) who treat children. We also assessed their intention to advise parents to vaccinate their children against varicella in the event the Swiss NITAG will recommend UVV. METHODS: Primary data was collected through a structured, 20-min online survey with Swiss pediatricians and GPs who treat children. RESULTS: 150 physicians participated in the study: 40 GPs in the German-speaking part, 20 GPs in the French-speaking part, 67 pediatricians in the German-speaking part, and 23 pediatricians in the French-speaking part. The majority (64%) of all participants reported that they currently recommend varicella vaccination for risk groups according to the national immunization plan. About one third of physicians (35%) - predominantly pediatricians - currently already recommend it for all infants. In these situations, a measles, mumps, rubella, varicella combination vaccine is currently used by 58% for the first dose and by 59% for the second dose. 86% of participants stated that they would advise parents to have their children vaccinated against varicella in case of a recommendation for UVV by the Swiss NITAG. 68% responded that they expect many questions from parents and 65% agreed that they have good arguments to convey the importance of varicella vaccination. CONCLUSIONS: The survey study results show that most participating pediatricians and GPs indicated a favorable attitude towards childhood vaccination against varicella in the setting of a Swiss NITAG recommendation for UVV. This data shows the importance of NITAG recommendations in influencing vaccine education and supporting achievement of high coverage of varicella vaccination.

Routine Childhood Vaccines Given From 1 through 18 Years of Age.

In addition to the vaccines due in the first year of life, the US Advisory Committee on Immunization Practices recommends that children continue to receive vaccines regularly against a variety of infectious diseases. Starting at 12 to 15 months of life, these include the two-dose measles-mumps-rubella vaccine series and the two-dose varicella vaccine series. Also in the second year of life, infants should begin the two-dose hepatitis A vaccine series and complete the Haemophilus influenzae type B vaccine series as well as the pneumococcal conjugate vaccine series. Before 19 months of life, infants should receive the third dose of the poliovirus vaccine and the fourth dose of diphtheria-tetanus-acellular pertussis (DTaP) vaccine. The final doses of poliovirus and tetanus-diphtheria-acellular pertussis vaccines are both due at 4 to 6 years of life. Before each influenza season, every child should receive the influenza vaccine. Those less than 9 years of age who previously received less than two doses need two doses a month apart. At 11 to 12 years of life, all should get two doses of the human papillomavirus vaccine, the adolescent/adult version of the tetanus-diphtheria-acellular pertussis vaccine, and begin a two-dose series of meningococcal ACWY vaccine. Each of these vaccines is due when the vaccine works to protect against both an immediate risk as well as to provide long-term protection. Each vaccine-preventable disease varies in terms of the nature of exposure, the form of the morbidity, the risk of mortality, and potential to prevent or ameliorate its harm.

The impact of long-term moderate level of vaccination coverage for epidemiology of varicella in Lu'an, China: should we change immunisation strategy now?

As China implements the voluntary vaccination programme of one-dose of varicella vaccine (VarV) for decades, robust estimates of the impact of voluntary vaccination era on epidemiology of varicella are needed. We estimated the vaccination coverage (VC) of VarV by using surveillance data on immunisation. The descriptive epidemiological method was used to describe the changing epidemiology of varicella from 2007 to 2018. The screening method was used to estimate the vaccine effectiveness (VE) of VarV. The overall VC for VarV was 71.7%, ranged from 47.7% to 79.5% among 2008-2017 birth cohorts. In total, 16 660 varicella cases were reported during 2007-2018, the incidence increased from 10.0 cases per 100 000 population in 2007 to 65.2 cases per 100 000 population in 2018. A shift in age group of varicella was observed since 2012, with the age increased from 5-9 years to 10-14 years. The overall VE was 79.9%, and the VE increased from 60.1% in 2008 birth cohort to 96.2% in 2017 birth cohort. We found that the overall VE for VarV is moderate, but appears highly effective within 5 years after vaccination. In addition, a shift varicella infection to older ages has occurred at the long-term moderate level VC of one-dose VarV. Therefore, to contain the incidence of varicella and prevent any potential shift to older ages, the introduction of VarV into routine immunisation programme is likely needed in Lu'an.

Measuring Infection Transmission in a Stochastic SIV Model with Infection Reintroduction and Imperfect Vaccine.

An additional compartment of vaccinated individuals is considered in a SIS stochastic epidemic model with infection reintroduction. The quantification of the spread of the disease is modeled by a continuous time Markov chain. A well-known measure of the initial transmission potential is the basic reproduction number [Formula: see text], which determines the herd immunity threshold or the critical proportion of immune individuals required to stop the spread of a disease when a vaccine offers a complete protection. Due to repeated contacts between the typical infective and previously infected individuals, [Formula: see text] overestimates the average number of secondary infections and leads to, perhaps unnecessary, high immunization coverage. Assuming that the vaccine is imperfect, alternative measures to [Formula: see text] are defined in order to study the influence of the initial coverage and vaccine efficacy on the transmission of the epidemic.

Varicella in Adult Foreigners at a Referral Hospital, Central Tokyo, Japan, 2012-2016.

We report a case series of varicella among adult foreigners at a referral hospital in central Tokyo, Japan, during 2012-2016. This series highlights differences in varicella vaccination schedules by country and epidemiology by climate and identifies immigrants and international students as high-risk populations for varicella.

Insufficient awareness and vaccination practices for inflammatory bowel disease patients in China: A multi-center survey of Chinese gastroenterologists.

OBJECTIVE: The prevalence of inflammatory bowel disease (IBD) has been increasing worldwide, and the risk of infection has increased due to the use of immunosuppressive and biologic medications. Some of these infections can be prevented with vaccinations. The aim of this study was to evaluate the vaccination practices of Chinese gastroenterologists for patients with IBD. METHODS: Questionnaires based on quick response codes were sent using email and the WeChat platform to gastroenterologists at 20 hospitals in China. The vaccination practices of the gastroenterologists, including vaccinating for hepatitis B, hepatitis A, and varicella, were assessed. RESULTS: Of the 468 gastroenterologists who received the questionnaire, 307 (65.6%) completed it. Of the gastroenterologists who were most concerned about hepatitis B; 83.4% always or frequently asked about an infection history, 53.7% took an immunization history, and 73.6% tested patients for hepatitis B infection. However, few gastroenterologists did so for hepatitis A or varicella. The proportion of patients who were asked about an infection and immunization history and tested for varicella infection was 16.0%, 15.0%, and 9.4%, respectively. Only a few gastroenterologists recommended vaccination for patients without an infection before IBD medical treatment (26.7% for hepatitis A, 45.6% for hepatitis B, and 28% for varicella vaccination). CONCLUSION: Vaccination practices for patients with IBD used by Chinese gastroenterologists vary greatly, suggesting that education about immunization is needed.

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

OBJECTIVE: To identify number of children who received live vaccines outside recommended intervals between doses and calculate corrective revaccination costs. METHODS: We analyzed >1.6 million vaccination records for children aged 12 months through 6 years from six immunization information system (IIS) Sentinel Sites from 2014-15 when live attenuated influenza vaccine (LAIV, FluMist® Quadrivalent) was recommended for use, and from 2016-17, when not recommended for use. Depending on the vaccine, insufficient intervals between live vaccine doses are less than 24 or 28 days from a preceding live vaccine dose. Private and public purchase costs of vaccines were used to determine revaccination costs of live vaccine doses administered during the live vaccine conflict interval. Measles, mumps, rubella (MMR), varicella, combined MMRV, and LAIV were live vaccines evaluated in this study. RESULTS: Among 946,659 children who received at least one live vaccine dose from 2014-15, 4,873 (0.5%) received at least one dose too soon after a prior live vaccine (revaccination cost, $786,413) with a median conflict interval of 16 days. Among 704,591 children who received at least one live vaccine dose from 2016-17, 1,001 (0.1%) received at least one dose too soon after a prior live vaccine (revaccination cost, $181,565) with a median conflict interval of 14 days. The live vaccine most frequently administered outside of the recommended intervals was LAIV from 2014-15, and varicella from 2016-17. CONCLUSIONS: Live vaccine interval errors were rare (0.5%), indicating an adherence to recommendations. If all invalid doses were corrected by revaccination over the two time periods, the cost within the IIS Sentinel Sites would be nearly one million dollars. Provider awareness about live vaccine conflicts, especially with LAIV, could prevent errors, and utilization of clinical decision support functionality within IISs and Electronic Health Record Systems can facilitate better vaccination practices.

The changing epidemiology of herpes zoster over a decade in South Korea, 2006-2015.

BACKGROUND: In South Korea, the population is rapidly aging and the prevalence of comorbidities has increased. We investigated longitudinal changes in the herpes zoster (HZ) considering demographic changes and comorbidities in the era of universal single-dose varicella vaccination. METHODS: We used the population-based database of the National Health Insurance Service in South Korea, with approximately 50 million subscribers during 2006-2015. HZ cases were identified using ICD-10 codes and comorbid conditions were also collected. Incidence rates (IRs) and incidence rate ratios (IRRs) per year were calculated adjusting for age, sex, comorbidities and socioeconomic status, and the temporal trends were examined using segmented negative binomial regression analysis. RESULTS: Over a decade, the adjusted HZ IR increased significantly from 4.23 to 9.22 per 1000 person-years (adjusted IRR 1.05, 95% confidence interval [CI] 1.04-1.06). However, during 2012-2015, the increasing trends decelerated (adjusted IRR per year 1.01, 95% CI 0.98-1.04) and slope changes differed by age. There was a declining trend in children under 9 years, sustained increase in adults aged 30-39 years, and near-plateau in those aged 50-69 years. Nonetheless, the age distribution of HZ incidence did not change over a decade, with the peak in adults aged 60-79 years. HZ-associated hospitalization rates also increased, with a deceleration in the increasing trends during 2012-2015. CONCLUSIONS: The HZ burden increased independently of demographic changes and prevalence of comorbidities. However, different trajectories by age group necessitate continuous HZ surveillance for better understanding of these changes, and to provide evidence for development of preventive strategies.

Long-term immunogenicity of measles, mumps and rubella-containing vaccines in healthy young children: A 10-year follow-up.

Measles and mumps outbreaks still occur in countries that have successfully implemented universal routine immunization programs. Measles outbreaks are mostly associated to absent or incomplete vaccination, whereas for mumps outbreaks the combined effects of waning of immunity and circulating new strains are incriminated. It is therefore increasingly useful to characterize the long-lasting immunity induced by measles-, mumps, and rubella (MMR)-containing vaccines. In this 10-year study, 1887 healthy children aged 12-22 months, randomized to receive 1 or 2 doses of MMR-containing vaccines (Priorix or Priorix-Tetra; GSK), were included in an antibody persistence analysis. A total of 364 children in the 1-dose group received a second dose out of study according to their local vaccination schedule between Years 4 and 10 post-dose 1, and were included in a separate post-hoc analysis to evaluate the effect of the second dose when given later. Anti-measles, -mumps and -rubella antibody titers were measured by commercial ELISA kits (Enzygnost, Siemens) after each vaccine dose and at Years 1, 2, 4, 6, 8 and 10 post-vaccination. Antibodies against measles and rubella declined moderately after vaccination but remained well above the seropositivity threshold after 10 years. The anti-measles antibody titers elicited by Priorix-Tetra remained about 2-fold higher throughout the study as compared with Priorix. A second dose of MMR vaccine later in life had a minor and transient effect on anti-measles and anti-rubella waning titers. In contrast, anti-mumps antibody levels remained relatively stable over the 10-year follow-up and a second dose of MMR vaccine, given anytime over the 10-year period, had a boosting effect on anti-mumps antibody titers and seropositivity rates. In conclusion, 1 or 2 doses of MMR-containing vaccines given to children in their second year of life induced antibody responses against measles, mumps and rubella viruses that persisted at least up to 10 years post-vaccination. Clinical trial registration number: NCT00226499.