South Korea’s current vaccination policies leave a surveillance gap for non-National Immunization Program (NIP) vaccines. In this study, we proposed a sentinel surveillance approach for monitoring the safety of non-NIP vaccines. Vaccination data were collected retrospectively among patients hospitalized with pre-defined adverse events of special interest (AESI) by reviewing electronic medical records in five university hospitals. This approach incorporates expert assessment to determine the causal relationship. We confirmed that 16 patients had received non-NIP vaccines among 860 patients diagnosed with AESI.We concluded one case of preeclampsia was possibly related to tetanus-diphtheria-pertussis vaccination. We propose a multi-hospital-based, retrospective assessment system for predefined AESIs as an alternative to active vaccine safety monitoring method. These efforts are expected to enhance both the accuracy and timeliness of safety monitoring in South Korea.

South Korea’s current vaccination policies leave a surveillance gap for non-National Immunization Program (NIP) vaccines. In this study, we proposed a sentinel surveillance approach for monitoring the safety of non-NIP vaccines. Vaccination data were collected retrospectively among patients hospitalized with pre-defined adverse events of special interest (AESI) by reviewing electronic medical records in five university hospitals. This approach incorporates expert assessment to determine the causal relationship. We confirmed that 16 patients had received non-NIP vaccines among 860 patients diagnosed with AESI.We concluded one case of preeclampsia was possibly related to tetanus-diphtheria-pertussis vaccination. We propose a multi-hospital-based, retrospective assessment system for predefined AESIs as an alternative to active vaccine safety monitoring method. These efforts are expected to enhance both the accuracy and timeliness of safety monitoring in South Korea.

South Korea’s current vaccination policies leave a surveillance gap for non-National Immunization Program (NIP) vaccines. In this study, we proposed a sentinel surveillance approach for monitoring the safety of non-NIP vaccines. Vaccination data were collected retrospectively among patients hospitalized with pre-defined adverse events of special interest (AESI) by reviewing electronic medical records in five university hospitals. This approach incorporates expert assessment to determine the causal relationship. We confirmed that 16 patients had received non-NIP vaccines among 860 patients diagnosed with AESI.We concluded one case of preeclampsia was possibly related to tetanus-diphtheria-pertussis vaccination. We propose a multi-hospital-based, retrospective assessment system for predefined AESIs as an alternative to active vaccine safety monitoring method. These efforts are expected to enhance both the accuracy and timeliness of safety monitoring in South Korea.

South Korea’s current vaccination policies leave a surveillance gap for non-National Immunization Program (NIP) vaccines. In this study, we proposed a sentinel surveillance approach for monitoring the safety of non-NIP vaccines. Vaccination data were collected retrospectively among patients hospitalized with pre-defined adverse events of special interest (AESI) by reviewing electronic medical records in five university hospitals. This approach incorporates expert assessment to determine the causal relationship. We confirmed that 16 patients had received non-NIP vaccines among 860 patients diagnosed with AESI.We concluded one case of preeclampsia was possibly related to tetanus-diphtheria-pertussis vaccination. We propose a multi-hospital-based, retrospective assessment system for predefined AESIs as an alternative to active vaccine safety monitoring method. These efforts are expected to enhance both the accuracy and timeliness of safety monitoring in South Korea.

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.

Background: A healthcare system’s collapse due to a pandemic, such as the coronavirus disease 2019 (COVID-19), can expose healthcare workers (HCWs) to various mental health problems. This study aimed to investigate the impact of the COVID-19 pandemic on the depression and anxiety of HCWs. Methods: A nationwide questionnaire-based survey was conducted on HCWs who worked in healthcare facilities and public health centers in Korea in December 2020. Patient Health Questionnaire-9 (PHQ-9) and Generalized Anxiety Disorder-7 (GAD-7) were used to measure depression and anxiety. To investigate factors associated with depression and anxiety, stepwise multiple logistic regression analysis was performed. Results: A total of 1,425 participating HCWs were included. The mean depression score (PHQ-9) of HCWs before and after COVID-19 increased from 2.37 to 5.39, and the mean anxiety score (GAD-7) increased from 1.41 to 3.41. The proportion of HCWs with moderate to severe depression (PHQ-9 ≥ 10) increased from 3.8% before COVID-19 to 19.5% after COVID-19, whereas that of HCWs with moderate to severe anxiety (GAD-7 ≥ 10) increased from 2.0% to 10.1%. In our study, insomnia, chronic fatigue symptoms and physical symptoms after COVID-19, anxiety score (GAD-7) after COVID-19, living alone, and exhaustion were positively correlated with depression. Furthermore, post-traumatic stress symptoms, stress score (Global Assessment of Recent Stress), depression score (PHQ-9) after COVID-19, and exhaustion were positively correlated with anxiety. Conclusion In Korea, during the COVID-19 pandemic, HCWs commonly suffered from mental health problems, including depression and anxiety. Regularly checking the physical and mental health problems of HCWs during the COVID-19 pandemic is crucial, and social support and strategy are needed to reduce the heavy workload and psychological distress of HCWs.

In the 2023–2024 season, the influenza epidemic in South Korea peaked earlier than in recent years. In this study, we aimed to estimate the interim vaccine effectiveness (VE) of the influenza vaccination to prevent influenza during the early season. From November 1, 2023, to December 31, 2023, we enrolled 2,632 subjects with influenza-like illness from eight hospitals participating in hospital-based influenza morbidity and mortality surveillance. A retrospective test-negative case-control study was conducted to estimate the VE. The results showed an adjusted VE of 22.5% (95% confidence interval [CI], 6.6 to 35.8) for the total population. The adjusted VE was 22.3% (95% CI, 6.1 to 35.7) for influenza A and 9.4% (95% CI, −51.3 to 45.7) for influenza A/H1N1. Full results of the analysis will be reported.

Background: In Korea, there are no surveillance programs for vaccines that are not included in the national immunization program (NIP), and vaccine safety monitoring in the adult population is inadequate. This study aimed to establish a safety monitoring system for nonNIP vaccines in adults. Methods: Frequently administered non-NIP vaccines were selected. Individuals were included if they received at least one of the selected vaccines at a participating institution and provided informed consent. Solicited and unsolicited adverse events were monitored using questionnaires sent through text messages on days 1, 3, 7, 28, and 90 post-vaccination.Selected adverse events of special interest (AESIs) were monitored monthly by retrospective review of electronic medical records. Causality was assessed according to the Korea Disease Control and Prevention Agency guidelines. Results: Four vaccines (tetanus-diphtheria-pertussis [Tdap], pneumococcal conjugate 13-valent [PCV13], live zoster vaccine [ZVL], and recombinant zoster vaccine [RZV]) were selected, and their safety profiles were monitored at four tertiary hospitals and 10 primary care clinics. The response rates of the questionnaires on post-vaccination days 1, 7, 28, and 90 were 99.2%, 93.6%, 81.0%, and 48.7%, respectively. Of 555 AESI identified over 10 months, 10 cases received one of the selected non-NIP vaccines within 90 days of the event. Conclusion We are establishing the first safety monitoring system for selected non-NIP vaccines in Korea since September 2022 and report its progress as of July 2023. However, continuous government support is essential for its maintenance and improvement.

Background: Bivalent booster mRNA vaccines containing the omicron-variant strains have been introduced worldwide in the autumn of 2022. Nevertheless, the omicron subvariants evoked another large coronavirus disease 2019 (COVID-19) pandemic wave in late 2022 and early 2023. Methods: A retrospective, test-negative, case-control study was conducted to estimate the vaccine effectiveness (VE) of bivalent COVID-19 vaccines in 8 university hospitals between January and February 2023. The case and control groups were divided based on nasopharyngeal COVID-19 real-time polymerase chain reaction results and matched based on age, sex, hospital, and date (week) of the test performed. The VE of the BA.1- or BA.4/BA.5-based mRNA vaccines were estimated. VE was calculated using the 1−adjusted odds ratio from multivariable logistic regression. Results: In total, 949 patients and 947 controls were enrolled in this study. VE for the BA.4/ BA.5-based bivalent mRNA vaccine was 43% (95% confidence interval [CI], 17, 61%). In subgroup analysis based on age and underlying medical conditions, BA.4/BA.5-based bivalent mRNA vaccine was effective against old adults aged ≥ 65-years (VE, 55%; 95% CI, 23, 73%) and individuals with comorbidities (VE, 54%; 95% CI, 23, 73%). In comparison, the BA.1-based bivalent mRNA vaccine did not demonstrate statistically significant effectiveness (VE, 25%; 95% CI, −8, 49%). Conclusion The BA.4/BA.5-based bivalent mRNA booster vaccine provided significant protection against COVID-19 in the Korean adults, especially in the older adults aged ≥ 65 years and in individuals with underlying medical conditions.

Objective: To assess the influence of advanced maternal age on congenital malformations, short- and long-term outcomes in offspring of nulligravida. Methods: A retrospective study was conducted using the Korean National Health Insurance Service database spanning from January 2005 to December 2019. All live-born offspring of nulligravida (n=3,685,817) were included. The maternal age was subdivided into the following subgroups: <25 years (n=153,818), 25-29 years (n=845,355), 30-34 years (n=1,738,299), 35-39 years (n=787,530), 40-44 years (n=151,519), and >44 years (n=9,296). Outcomes were assessed based on International Classification of Diseases-10 codes. Adjusted odds ratios (aOR) were calculated with the group of 25-29 years as a reference.Result Most congenital malformations showed an age dependent increase, but cleft lip and abdominal wall defect exhibited a U-shape curve, indicating an increase even in those <25 years old. Similarly, various disorders included in the neonatal composite outcomes from short-term outcomes showed aged dependent escalation. However, the preterm birth from the short-term outcome and most of the long-term developmental outcomes, except for motor developmental delay and Tics, showed a U-shaped pattern. The aOR of autism and cerebral palsy, showing the most obvious U-shaped curved in the long-term outcomes, was 1.50 (95% confidence interval [CI], 1.24-1.82) and 1.54 (95% CI, 1.17-2.03), respectively in the group >44 years old and 1.18 (95% CI, 1.11-1.25) and 1.19 (95% CI, 1.09-1.30) in <25 years old group. Conclusion Overall, an advanced maternal age has an age-dependent correlation with most congenital malformations and shortand long-term outcomes of neonates.