Revised adult immunization guideline recommended by the korean society of infectious diseases, 2014

Recommendations for Adult Immunization by the Korean Society of Infectious Diseases, 2023: Minor Revisions to the 3rd Edition

The Korean Society of Infectious Diseases has been regularly developing guidelines for adult immunization since 2007. In 2023, the guidelines for the following seven vaccines were revised: influenza, herpes zoster, pneumococcal, tetanus-diphtheria-pertussis (Tdap), human papillomavirus (HPV), meningococcal, and rabies vaccines. For the influenza vaccine, a recommendation for enhanced vaccines for the elderly was added. For the herpes zoster vaccine, a recommendation for the recombinant zoster vaccine was added. For the pneumococcal vaccine, the current status of the 15-valent pneumococcal conjugate vaccine and 20-valent PCV was described. For the Tdap vaccine, the possibility of using Tdap instead of tetanus-diphtheria vaccine was described. For the HPV vaccine, the expansion of the eligible age for vaccination was described. For the meningococcal vaccine, a recommendation for the meningococcal B vaccine was added. For the rabies vaccine, the number of pre-exposure prophylaxis doses was changed. This manuscript documents the summary and rationale of the revisions for the seven vaccines. For the vaccines not mentioned in this manuscript, the recommendations in the 3rd edition of the Vaccinations for Adults textbook shall remain in effect.

Prior pneumococcal vaccination improves in-hospital mortality among elderly population hospitalized due to community-acquired pneumonia

BACKGROUND

Pneumococcal vaccination is a preventive method to reduce pneumonia related mortality. However, real-world data on efficacy of the pneumococcal vaccine in reducing mortality is lacking, especially in elderly patients. This study was conducted to assess the effects of prior pneumococcal vaccination in elderly pneumonia patients.

METHODS

The data was procured from the Health Insurance Review and Assessment and Quality Assessment database. Hospitalized patients who met the criteria of community-acquired pneumonia (CAP) were included and they were grouped according to vaccination state. Patients were aged ≥ 65 years and treated with beta-lactam, quinolone, or macrolide. Patients were excluded when treatment outcomes were unknown.

RESULTS

A total of 4515 patients were evaluated, and 1609 (35.6%) of them were vaccinated prior to hospitalization. Mean age was 77.0 [71.0;82.0], 54.2% of them were male, and mean Charlson comorbidity index (CCI) was 3.0. The patients in the vaccinated group were younger than those in the unvaccinated group (76.0 vs. 78.0 years; P < 0.001), and showed higher in-hospital improvement (97.6 vs. 95.0%; P < 0.001) and lower 30-day mortality (2.6 vs. 5.3%; P < 0.001). After adjusting confounding factors such as age, gender, CURB score and CCI score, the vaccinated group demonstrated a significant reduction in 30-day mortality (hazard ratio [HR] 0.58, 95% confidence interval [CI] 0.41-0.81; P < 0.01) and in-hospital mortality (HR 0.53, 95% CI0.37-0.78; P < 0.001) compared to the unvaccinated group in multivariate analysis. Vaccinated group showed better 30-day survival than those in non-vaccinated group (log-rank test < 0.05).

CONCLUSIONS

Among elderly hospitalized CAP patients, prior pneumococcal vaccination was associated with improved in-hospital mortality and 30-day mortality.

A phase 3 randomized trial of the safety and immunogenicity of 20-valent pneumococcal conjugate vaccine in adults ≥ 60 years of age in Japan, South Korea, and Taiwan

BACKGROUND

Pneumococcal infections are associated with high disease burden in older individuals in Japan, South Korea, and Taiwan. The 20-valent pneumococcal conjugate vaccine (PCV20) was developed to extend protection beyond earlier pneumococcal vaccines.

METHODS

This phase 3 randomized, double-blind study investigated the safety and immunogenicity of PCV20 in participants ≥ 60 years of age from Japan, South Korea, and Taiwan. Participants were randomized to receive PCV20 or 13-valent pneumococcal conjugate vaccine (PCV13). One month after vaccination, PCV20 recipients received a saline injection and PCV13 recipients received 23-valent polysaccharide vaccine (PPSV23). Primary immunogenicity objectives were to demonstrate noninferiority of PCV20 to PCV13 (13 matched serotypes) or PPSV23 (7 additional serotypes) for serotype-specific opsonophagocytic activity (OPA) geometric mean titers (GMTs) 1 month after vaccination with PCV20, PCV13, or PPSV23. Noninferiority for each serotype was declared if the lower bound of the 2-sided 95% CI for OPA geometric mean ratio (GMR) was > 0.5. Safety endpoints included local reactions, systemic events, adverse events (AEs), and serious AEs.

RESULTS

Overall, 1421‬ participants were vaccinated (median age [range]: 65 [60-85] years). PCV20 was noninferior to PCV13 for all 13 matched serotypes and to PPSV23 for 6 of 7 additional serotypes. Although statistical noninferiority was missed for serotype 8 (lower bound of the 2-sided 95% CI for OPA GMR = 0.5, thus not meeting the statistical noninferiority criterion of > 0.5), secondary immunogenicity endpoints for serotype 8 were supportive of a robust immune response. The incidence of AEs and the frequency and severity of local reactions and systemic events were generally similar after PCV20 and PCV13. No safety concerns were identified.

CONCLUSION

PCV20 generated robust immune responses to all vaccine serotypes in older adults in Japan, South Korea, and Taiwan. The safety and tolerability profile was similar to PCV13. PCV20 is expected to help protect against all 20 vaccine serotypes. NCT04875533.

Cost-effectiveness of high-dose quadrivalent influenza vaccine versus standard-dose quadrivalent influenza vaccine for older people in a country with high influenza vaccination rate

The highdose quadrivalent influenza vaccine (QIVHD) has shown improved protection against influenza and its complications in older adults. We aimed to evaluate the costeffectiveness of QIVHD compared with QIVSD among Korean adults aged ≥ 65 years in reducing influenzarelated disease burden. We evaluated the 2016/2017 and 2017/2018 seasons and their average values using a static decision tree model. The difference in efficacy between standard-dose (SD) and high-dose (HD) was calculated based on the results of a clinical trial comparing Fluzone® High-Dose Vaccine and Fluzone® Vaccine in older adults. Incremental cost-effectiveness ratios (ICERs) were assessed from the healthcare system perspective. A discount rate of 4.5% was applied to life-year-gained (LYG) values and utilities. We performed deterministic and probabilistic sensitivity analyses to account for both epidemiological and economic sources of uncertainty. In the analysis of the 2017/2018 season, the QIV-HD strategy generated an excess of 0.00182 life-years (Lys)/person and 0.003953 quality-adjusted life-years (QALYs)/person compared with QIV-SD. The ICER was 6,467.56 United States Dollars (USD)/QALY. In the analysis from the 2016/2017 season, QIV-HD caused a surplus of 0.00117 Lys/person and 0.003272 QALYs/person compared with QIV-SD. ICER was 7,902.46 USD /QALY. From the average data of the 2016/2017 and 2017/2018 seasons, an excess of 0.00147 Lys/person and 0.003561 QALYs/person were generated using QIV-HD compared with QIV-SD, while the ICER was 7,190.44 USD /QALY. From the healthcare system perspective, QIV-HD was a more cost-effective vaccination option in reducing influenza-related disease burden and healthcare costs in Koreans aged ≥ 65 years compared with QIV-SD.

Safety and immunogenicity of sequential administration of PCV13 followed by PPSV23 in pneumococcal vaccine-naïve adults aged ≥ 65 years: Comparison of booster effects based on intervals of 0.5 and 1.0 year

OBJECTIVE

An open-label study was conducted to compare the safety and immunogenicity of a sequential administration of 13-valent pneumococcal conjugate vaccine (PCV13) followed by 23-valent pneumococcal polysaccharide vaccine (PPSV23) between an interval of 0.5 (0.5-y) and 1 year (1.0-y) in adults aged ≥ 65 years.

METHODS

Pneumococcal vaccine-naïve adults aged ≥ 65 years (n = 129) received a sequential administration with an interval of 0.5-y or 1.0-y or received a single administration of PPSV23 (single PPSV23). We evaluated the immunogenicity before and 1 month after each vaccination and at 0.5-y intervals for 2 years. The primary endpoint was the increase in geometric mean fold rises (GMFRs) of immunoglobulin G (IgG) or opsonophagocytic activity (OPA) for eight common serotypes one month after one dose of PPSV23. The secondary endpoint was the safety profile for one dose of PPSV23.

RESULTS

One month after administration of PPSV23, the GMFRs of IgG considerably increased for five of eight serotypes in the 1.0-y interval group, whereas the GMFRs of IgG considerably increased for two serotypes in the 0.5-y interval group. Furthermore, GMFRs of OPA markedly increased for all eight serotypes in the 1.0-y interval group, while GMFRs of OPA markedly increased for four serotypes in the 0.5-y interval group. At 2 years after initial vaccination, GMFRs of IgG or OPA were higher for all serotypes, except for serotype 3, than those in the single PPSV23 group irrespective of intervals. No significant difference was found in the frequencies of local reactions of all grades between the two intervals.

CONCLUSIONS

The 1.0-y interval provided better booster effects induced by PPSV23 than those of the 0.5-y interval in a sequential administration in pneumococcal vaccine-naïve adults aged ≥ 65 years. No difference was found in the safety profile between both intervals.

Safety and efficacy of recombinant and live herpes zoster vaccines for prevention in at-risk adults with chronic diseases and immunocompromising conditions

Compared with the general population, older adults with immune senescence and individuals who are immunocompromised (IC) due to disease or immunosuppressive therapy are at increased risk for herpes zoster (HZ) and its associated complications, which can be debilitating and life-threatening. Vaccination can be an effective strategy against HZ and studies have shown that HZ vaccination in IC individuals can elicit immune responses and provide protection from infection. Recently, the first approvals have been granted in the United States and the European Union for the recombinant HZ vaccine (RZV) in adults ≥ 18 years of age at risk of HZ due to immunodeficiency or immunosuppression. Existing systematic reviews have highlighted the risks for HZ in limited immunocompromising conditions and have only examined clinical data for RZV. This review details the risks and burden of HZ in a broad range of clinically relevant IC populations and summarizes key efficacy and safety data for RZV and live HZ vaccine in these individuals. Research has shown IC individuals can benefit from HZ vaccination; however, these insights have yet to be fully incorporated into vaccination guidelines and clinical care. Clinicians should consider HZ vaccination in eligible at-risk populations to protect against HZ and its associated complications and thereby, reduce the burden that HZ poses on the healthcare system. Electronic health records and linked personal health records could be used to identify and contact patients eligible for HZ vaccination and provide clinical decision support-generated alerts for missing or delayed vaccinations. This review will help clinicians identify eligible IC individuals who may benefit from HZ vaccination. A video abstract linked to this article is available on Figshare https://doi.org/10.6084/m9.figshare.21517605.

Global herpes zoster incidence, burden of disease, and vaccine availability: a narrative review

Herpes zoster (HZ) is a neurocutaneous disease that causes significant morbidity worldwide. The disease is caused by the reactivation of the varicella-zoster virus (VZV), which leads to the development of a painful, vesicular rash and can cause complications such as post-herpetic neuralgia and vision loss. Globally, the incidence of HZ is increasing, and it incurs billions in cost annually to the healthcare system and to society through loss of productivity. With the advent of effective vaccines such as the live attenuated vaccine, Zostavax®, in 2006, and more recently the adjuvant recombinant subunit vaccine, Shingrix®, in 2017, HZ has become a preventable disease. However, access to the vaccines remains mostly limited to countries with developed economies, such as the United States and Canada. Even among countries with developed economies that license the vaccine, few have implemented HZ vaccination into their national immunization schedules due to cost-effectiveness considerations. In this review, we discuss the currently available HZ vaccines, landscape of HZ vaccine guidelines, and economic burden of disease in countries with developed and developing economies, as well as barriers and considerations in HZ vaccine access on a global scale.

Clinical Manifestations of Herpes Zoster Associated with Complications in Children

Herpes zoster (HZ) is caused by latent varicella-zoster virus (VZV) reactivation when VZV-specific cell-mediated immunity declines. Information on HZ in children is limited. Therefore, we retrospectively investigated HZ's clinical course and complications in children. We extracted the outpatient and hospitalization medical records of pediatric patients (<19 years) primarily diagnosed with HZ (ICD-10 B02 code) between January 2010 and November 2020. HZ was defined as a typical unilateral dermatomal vesicular rash where HZ was the treating physician's primary diagnosis. Recognized HZ complications included combined bacterial skin infection, ophthalmic zoster, zoster oticus without facial paralysis, meningitis, and PHN. We identified 602 HZ cases, among which 54 developed HZ complications and were included in our analysis. The median age was 14.7 years, most patients were aged ≥13 years (42, 79%), and none were aged <4 years. Fifty-three were immunocompetent, and only one had systemic lupus erythematosus. The most frequent complication was zoster ophthalmicus (n = 26, 48%). HZ complications were also observed in immunocompetent or vaccinated children exhibiting a head or neck rash before and after VZV immunization. Current VZV vaccination programs may be insufficient in preventing HZ complications. Therefore, close varicella and HZ burden monitoring and the establishment of effective VZV vaccination programs are imperative.

Effectiveness of Pneumococcal Vaccination Against Hospitalized Pneumococcal Pneumonia in Older Adults: A Prospective, Test-Negative Study

BACKGROUND

Despite use of the 13-valent pneumococcal conjugate vaccine (PCV13) and 23-valent pneumococcal polysaccharide vaccine (PPSV23) over the last decade, the disease burden of pneumococcal pneumonia is still high. We evaluated the field effectiveness of PCV13, PPSV23, and sequential vaccination against pneumococcal pneumonia in older adults.

METHODS

This prospective multicenter study was conducted in adults aged ≥ 65 years with hospitalized community-acquired pneumonia (CAP) between September 2015 and August 2017. The case-control test-negative design was used to estimate vaccine effectiveness (VE) against pneumococcal CAP.

RESULTS

Of 1,525 cases with hospitalized CAP, 167 (11.0%) were identified as pneumococcal CAP. In the elderly aged ≥65 years, the adjusted VE of pneumococcal vaccines against pneumococcal CAP was statistically insignificant: 40.0% (95% CI -10.8% to 67.5%) for PCV13 and 11.0% (95% CI, -26.4% to 37.3%) for PPSV23. However, in the younger subgroup (aged 65-74 years), sequential PCV13/PPSV23 vaccination showed the highest adjusted VE of 80.3% (95% CI 15.9% to 95.4%), followed by single-dose PCV13 (adjusted VE 66.4%; 95% CI 0.8% to 88.6%) and PPSV23 (adjusted VE 18.5%; 95% CI -38.6% to 52.0%).

CONCLUSIONS

Sequential PCV13/PPSV23 vaccination is most effective for preventing pneumococcal CAP among the elderly aged 65-74 years.

Efficacy and effectiveness of a 23-valent polysaccharide vaccine against invasive and noninvasive pneumococcal disease and related outcomes: a review of available evidence

Introduction: Routine pneumococcal vaccination for adults aged ≥60 or ≥65 years and those with underlying at-risk and high-risk conditions is recommended in many countries. However, studies estimating the effectiveness of 23-valent pneumococcal polysaccharide vaccine (PPSV23) have revealed mixed results, partly due to variability in study design and endpoints used to assess outcomes.Areas covered: The authors conducted a literature review of independently randomized trials and real-world studies published from 2010 to 2020 that assessed the effectiveness and efficacy of PPSV23 against vaccine-type or any-serotype invasive and noninvasive pneumococcal disease in adults aged ≥60 years. The authors also evaluated differences in study design that may contribute to the heterogeneity of available evidence.Expert opinion: Policy decisions regarding the inclusion of vaccines into national immunization plans should consider study quality and limitations. This review shows that PPSV23 is effective against vaccine-type invasive pneumococcal disease and vaccine-type pneumococcal pneumonia and can lower the burden of vaccine-type pneumococcal pneumonia. PPSV23-conferred protection may be lower in adults aged ≥75 years, those with certain underlying conditions, and individuals who were vaccinated >5 years before disease onset. This is an important finding that supports the benefit of PPSV23 vaccination for older adults.

A systematic review of the burden of pertussis disease in infants and the effectiveness of maternal immunization against pertussis

Introduction Infants too young to be fully immunized are the most vulnerable to severe pertussis disease. To close this susceptibility gap, passive infant immunization through vaccination of pregnant women against pertussis was first introduced in 2011 in the United States and has been extended since then to more than 40 countries. Areas covered We conducted two systematic literature searches to describe the worldwide burden of pertussis disease in infants <6 months of age since 2005, and the effectiveness and impact of maternal pertussis vaccination in preventing infant pertussis since 2011. Expert opinion Pertussis disease incidence rates in infants aged <2-3 months were substantial in all countries with available data, exceeding 1000 cases per 100,000 population during outbreaks. Virtually all pertussis deaths occurred in this age group. Data from Africa, Eastern Mediterranean, and Asia were limited, but suggest a similar or higher disease burden than in Europe or the Americas. Estimates of effectiveness of second/third trimester pertussis vaccination in preventing pertussis disease in <2-3 months old infants were consistently high (69%-93%) across the observational studies reviewed, conducted in various settings with different designs. Maternal vaccination programs appear to be achieving their goal of reducing the burden of disease in very young infants. Plain language summary What is the context? Pertussis, also known as whooping cough, is a highly contagious disease of the respiratory tract. Infants too young to be fully vaccinated are at the highest risk of severe pertussis disease, hospitalization, and death. Vaccinating pregnant women against pertussis with a Tdap vaccine is recommended in more than 40 countries as a safe and effective strategy to protect infants for the first months of life. What is new? This review summarizes recent literature describing the burden of pertussis disease in infants worldwide prior to the introduction of maternal vaccination programs; pertussis disease incidence rates in infants aged <2-3 months were substantial in all countries with available data, exceeding 1000 cases per 100,000 population during outbreaks. Immunization of pregnant women with a Tdap vaccine can prevent about 70-90% of pertussis disease and up to 90.5% of pertussis hospitalizations in infants under 3 months of age. What is the impact? Limited available data suggest that incidence rates of pertussis disease after the introduction of Tdap maternal immunization have declined in infants. Current knowledge supports the implementation of Tdap maternal immunization programs.

Recommendations for influenza and Streptococcus pneumoniae vaccination in elderly people in China

Influenza and pneumonia can be prevented by vaccination, but they remain major causes of morbidity and mortality in age-related diseases. In most areas of China, the rates of influenza and pneumococcal vaccination are relatively low and public awareness of vaccination remains insufficient. Thus, it is essential to recommend influenza and Streptococcus pneumoniae vaccination to elderly people in clinical practice. Based on recently published studies and related documents issued by several vaccination authorities, such as the World Health Organization, the National Health and Wellness Committee, the Chinese Center for Disease Control and Prevention, the US Centers for Disease Control and Prevention, and the US Advisory Committee on Immunization Practices, we propose official recommendations for influenza and S pneumoniae vaccination in elderly people in China.

Serotype Distribution and Antimicrobial Resistance of Invasive and Noninvasive Streptococcus pneumoniae Isolates in Korea between 2014 and 2016

Background

Several factors contribute to differences in Streptococcus pneumoniae serotype distribution. We investigated the serotype distribution and antimicrobial resistance of S. pneumoniae isolated between 2014 and 2016 in Korea.

Methods

We collected a total of 1,855 S. pneumoniae isolates from 44 hospitals between May 2014 and May 2016, and analyzed the serotypes by sequential multiplex PCR. We investigated the distribution of each serotype by patient age, source of the clinical specimen, and antimicrobial resistance pattern.

Results

The most common serotypes were 11A (10.1%), followed by 19A (8.8%), 3 (8.5%), 34 (8.1%), 23A (7.3%), and 35B (6.2%). The major invasive serotypes were 3 (12.6%), 19A (7.8%), 34 (7.8%), 10A (6.8%), and 11A (6.8%). Serotypes 10A, 15B, 19A, and 12F were more common in patients ≤5 years old, while serotype 3 was more common in patients ≥65 years old compared with the other age groups. The coverage rates of pneumococcal conjugate vaccine (PCV)7, PCV10, PCV13, and pneumococcal polysaccharide vaccine 23 were 11.8%, 12.12%, 33.3%, and 53.6%, respectively. Of the 1,855 isolates, 857 (46.2%) were multi-drug resistant (MDR), with serotypes 11A and 19A predominant among the MDR strains. The resistance rates against penicillin, cefotaxime, and levofloxacin were 22.8%, 12.5%, and 9.4%, respectively.

Conclusions

There were significant changes in the major S. pneumoniae serotypes in the community. Non-PCV13 serotypes increased in patients ≤5 years old following the introduction of national immunization programs with the 10- and 13-polyvalent vaccines.

Invasive Pneumococcal Disease Caused by Non-Vaccine Type Multidrug-Resistant Streptococcus pneumoniae Transmitted by Close Contact in a Healthy Adult

The incidence of vaccine-type Streptococcus pneumoniae carriage and disease have declined in vaccinated children as well as in unvaccinated children and adults. However, diseases caused by non-vaccine type (NVT) S. pneumoniae are increasing. In this study, we report an invasive pneumococcal disease (IPD) caused by NVT multidrug-resistant (MDR) S. pneumoniae transmitted from a vaccinated infant to an unvaccinated healthy woman, and the clinical characteristics of this serotype. A 29-year-old previously healthy woman visited our hospital with fever and headache. She had been breastfeeding her baby for 8 months. She was diagnosed with brain abscess and sinusitis caused by S. pneumoniae. Although the patient had no previous exposure to antibiotics, antibiotic susceptibility test identified the pathogen as MDR. The patient's family members were examined using nasopharyngeal swabs for bacterial culture. The serotype of S. pneumoniae identified from the blood, abscess, and sputum of the patient was 15B/C. After investing the patient's family members, we found that the serotype from nasopharyngeal specimen of her baby was the same. We described an invasive MDR pneumococcal disease in an immunocompetent young adult in the community. IPD likely spread to the patient by close contact with her baby, who harbored S. pneumoniae of NVT. The spread of NVT S. pneumoniae in the post-vaccine era has increased in the community, and resistance pattern for S. pneumoniae of 15B/C changed compared to the pre-pneumococcal conjugate vaccine era. The spread of MDR pathogens causing IPD among family members should be monitored.

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.

Trends in varicella and herpes zoster epidemiology before and after the implementation of universal one-dose varicella vaccination over one decade in South Korea, 2003-2015

Background: In South Korea, the one-dose varicella vaccine was included in the National Immunization Program for children aged 12-15 months in 2005, and the vaccine coverage reached >95%. The impact of varicella vaccination on varicella and herpes zoster (HZ) was investigated, accounting for demographic changes over time.Methods: We calculated the crude and age-sex standardized incidence rates (IRs) and age-specific IRs of varicella and HZ from 2003 to 2015, using the National Health Information Database including approximately 50 million Koreans. The annual incidence rate ratios (IRRs) were calculated using a negative binomial regression analysis, adjusting for age and sex.Results: The crude varicella IR steadily declined by 67%, from 5.70/1000 to 1.87/1000 person years (IRR per year: 0.91; 95% CI 0.89-0.93), but the adjusted IRs showed a significant decline only during 2010-2015 (adjusted IRR per year: 0.90; 95% CI 0.88-0.93). The greatest decline was found in children ≤4 years of age, whereas the IR increased until 2011 and then declined afterward in children aged 5-9 years, who represented the highest incidence age group in 2013-2015. The crude HZ IR increased from 2.67/1000 to 9.80/1000 person years (IRR per year: 1.12; 95% CI 1.10-1.15), and the adjusted IR also followed the same trend. A similar increasing trend was observed before and after universal vaccination.Conclusions: One-dose varicella vaccination was moderately effective in preventing varicella, but this strategy was insufficient to interrupt varicella transmission in children. Furthermore, the HZ incidence dramatically increased over this decade. The current vaccination strategy against varicella-zoster disease should be reconsidered.

Changes in Serotype of Streptococcus pneumoniae After the Introduction of the 13-Valent Pneumococcal Vaccine in a Homogenous Population on Jeju Island

We compared the serotypes of Streptococcus pneumoniae between the pre-pneumococcal conjugate vaccine (PCV)13 era and post-PCV13 era among homogenous inhabitants of an isolated South Korean island. A total of 325 S. pneumoniae strains were isolated. In the pre-PCV13 era, 19A/F, 15A/F, 19B, and 23A serotypes were identified. In the post-PCV13 era, 15 serotypes were identified. The 19F and 23A serotypes showed the highest prevalence in the pre- and post-PCV13 era, respectively. After PCV13 introduction, the PCV 13 serotype coverage rate was decreased (80.0% and 30.5% in the pre- and post-PCV13 eras, respectively), while the proportion of non-PCV 13 serotypes increased.

Immunogenicity and safety of a tetanus-diphtheria vaccine and a 13-valent pneumococcal conjugate vaccine after concomitant vaccination in ≥ 50-year-old adults

BACKGROUND

When two or more vaccines are administered concurrently, there is concern about safety and immunogenicity from vaccine interaction.

METHODS

Subjects aged ≥50 years were randomized 1:1:1 to receive tetanus-diphtheria (Td) + 13-valent pneumococcal conjugate vaccine (PCV13; Group 1), PCV13 alone (Group 2), or Td alone (Group 3). After single or concomitant vaccination, enzyme-linked immunosorbent assay and opsonophagocytic assay (OPA) were performed to compare immunogenicity for Td and PCV13, respectively.

RESULTS

A total of 448 subjects were available for the assessment. After concomitant administration, the non-inferiority criteria of geometric mean titer (GMT) ratios were met for tetanus, diphtheria, and all four pneumococcal serotypes (1, 5, 18C, and 19A). However, subjects in Group 3 (Td alone) were more likely to have a high IgG anti-tetanus antibody titer (≥ 0.5 U/mL) than those in Group 1 (Td + PCV13) (p <  0.01). As for the pneumococcal serotype 1, the OPA GMT was significantly higher in Group 1 (PCV13 + Td) compared to Group 2 (PCV13 alone) (p = 0.02). No serious adverse event occurred.

CONCLUSIONS

Concomitant Td and PCV13 administration induced sufficient immunity without significant interference and showed good safety profiles.

TRIALS REGISTRATION

NCT03552445 registered at http://www.clinicaltrials.gov on June 11, 2018 (retrospectively registered).

Tetanus-diphtheria-acellular pertussis vaccination for adults: an update

Although tetanus and diphtheria have become rare in developed countries, pertussis is still endemic in some developed countries. These are vaccine-preventable diseases and vaccination for adults is important to prevent the outbreak of disease. Strategies for tetanus, diphtheria, and pertussis vaccines vary from country to country. Each country needs to monitor consistently epidemiology of the diseases and changes vaccination policies accordingly. Recent studies showed that tetanus–diphtheria–acellular pertussis vaccine for adults is effective and safe to prevent pertussis disease in infants. However, vaccine coverage still remains low than expected and seroprevalence of protective antibodies levels for tetanus, diphtheria, and pertussis decline with aging. The importance of tetanus–diphtheria–acellular pertussis vaccine administration should be emphasized for the protection of young adult and elderly people also, not limited to children.

Serotype 6B from a pneumococcal polysaccharide vaccine induces cross-functional antibody responses in adults to serotypes 6A, 6C, and 6D

Cross-reactivity of pneumococcal capsular polysaccharides is a key element for formulating pneumococcal vaccines and evaluating vaccine efficacy. This study examined whether 23-valent pneumococcal polysaccharide vaccine (PPSV23), which only contains 6B, can elicit cross-functional immune responses against recently discovered serotypes (6C and 6D), as well as against 6A, in 2 adult age groups.Young adults (25-51 years; N = 28) and elderly subjects (over 65 years; N = 60) were immunized with PPSV23. Functional antibody responses were determined in pre- and postimmune sera via multiplexed opsonophagocytic killing assay against serotypes 6A/B/C/D.At postimmunization, the geometric mean opsonic indices (OIs) for 6B and nonvaccine serotypes (6A, 6C, and 6D) significantly increased in both age groups. The geometric fold increases of OIs for 6B/A/C/D significantly differed (18.2, 24.8, 3.1, and 7.1, respectively). Proportions of subjects with 4-fold increases in OIs for 6B/A/C/D were 73%, 70%, 31%, and 49%, respectively. Correlations of fold increases in OIs were highest between 6B and 6A, followed by 6B and 6D, then by 6B and 6C. Comparisons of young adults and the elderly revealed that most immunogenicity variables were higher in the former group.Our data demonstrated that 6B in PPSV23 induced cross-functional immune responses against serotypes 6A, 6C, and 6D, according to the degree of similarity in their capsular polysaccharide structures. In addition, we found significant age-related differences in PPSV23-induced cross-reactivity.

Indirect Effects of Pneumococcal Conjugate Vaccines in National Immunization Programs for Children on Adult Pneumococcal Disease

The pneumococcal conjugate vaccine (PCV) was developed to overcome the limitations of the pneumococcal polysaccharide vaccine, which produces poor immunogenicity in infants younger than 2 years. As many countries have included PCVs in national immunization programs for children, the incidence of invasive pneumococcal disease caused by vaccine type Streptococcus pneumoniae has declined markedly, not only among the vaccinated pediatric population, but also among unvaccinated adults. In this review, we present a concise overview of the indirect effects of mass pediatric PCV immunization on unvaccinated adults.

Functional immune responses to twelve serotypes after immunization with a 23-valent pneumococcal polysaccharide vaccine in older adults

BACKGROUND

The 23-valent pneumococcal polysaccharide vaccine (PPSV23) was introduced as part of the national immunization program for the elderly (≥65 years of age) in Korea on 2013. To evaluate immune responses in this population, serotype-specific anti-pneumococcal antibodies were studied with opsonophagocytic assay (OPA).

METHODS

Pneumococcal vaccine-naïve participants ≥65 years of age were enrolled. They were divided into two groups according to their age: 30 in (65-74 years) and 32 in group (≥75 years). The functional antibody response was determined by multiplexed OPA (MOPA) for 12 serotypes (1, 3, 4, 5, 6B, 7F, 9V, 14, 18C, 19A, 19F, and 23F) before and 4 weeks after vaccination with PPSV23.

RESULTS

Geometric mean titers (GMTs) to all tested serotypes significantly increased in both groups after vaccination compared to those before vaccination. There were no significant differences in either the fold rise (post-vaccination to pre-vaccination) or the percentage of participants with a ≥4-fold increase in OPA titers between two groups for any of the 12 serotypes. Following vaccination, GMT for serotype 9V was higher in group 1 than in group 2 (P=0.011).

CONCLUSIONS

PPSV23 induces functional immune response for 12 vaccine serotypes in both age groups. Further analysis is needed for the remaining 11 serotypes in the PPSV23, in order to develop a better understanding of the immune responses induced by PPV23 in older adults.