Social Inequities in the Survival of Liver Cancer: A Nationwide Cohort Study in Korea, 2007-2017.

BACKGROUND: To analyze the effects of socioeconomic status (type of insurance and income level) and cancer stage on the survival of patients with liver cancer in Korea. METHODS: A retrospective cohort study was constructed using data from the Healthcare Big Data Platform project in Korea between January 1, 2007, and December 31, 2017. A total of 143,511 patients in Korea diagnosed with liver cancer (International Classification of Diseases, 10th Revision [ICD-10] codes C22, C220, and C221) were followed for an average of 11 years. Of these, 110,443 died. The patient's insurance type and income level were used as indicators of socioeconomic status. Unadjusted and adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated using a Cox proportional hazards regression model to analyze the relationship between the effects of sex, age, and cancer stage at first diagnosis (Surveillance, Epidemiology, and the End Results; SEER), type of insurance, and income level on the survival of patients with liver cancer. The interactive effects of the type of insurance, income level, and cancer stage on liver cancer death were also analyzed. RESULTS: The lowest income group (medical aid) showed a higher risk for mortality (HR (95% CI); 1.37 (1.27-1.47) for all patients, 1.44 (1.32-1.57) for men, and 1.16 (1.01-1.34) for women) compared to the highest income group (1-6) among liver cancer (ICD-10 code C22) patients. The risk of liver cancer death was also higher in the lowest income group with a distant cancer stage (SEER = 7) diagnosis than for any other group. CONCLUSION: Liver cancer patients with lower socioeconomic status and more severe cancer stages were at greater risk of death. Reducing social inequalities is needed to improve mortality rates among patients in lower social class groups who present with advanced cancer.

Universal versus risk-based strategies for vaccinating children against COVID-19: Japan and Korea.

The global impact of COVID-19 on children emphasises the need for effective vaccination. While most cases are mild, those with underlying conditions face severe risks. Public health agencies promote various paediatric vaccination approaches. Japan universally recommends vaccination, while Korea prioritises high-risk children. Despite similar healthcare systems, Japan's coverage rates (19%-72%) surpass Korea's (2%-55%). Korea's child death rates are higher, indicating increased risk. Both lack methods to address individual risks, hindering prevention. This study advocates universal vaccination to mitigate future pandemics' impact on children systematically.

Assessing the impact and implications of the revised Act on the Aggravated Punishment of Specific Crimes in preventing child traffic injuries in school zones in Korea: an interrupted time series analysis.

In 2019, a child's death in Korea led to legislation that imposed stricter penalties for school zone traffic violations. We assessed the impact of that legislation using 2017-2022 Traffic Accident Analysis System data. Adjusted analyses revealed a significant decline in severe injuries in school zones, decreasing from 11 cases to 8 cases per month (p=0.017). The legislation correlated with a reduced risk of all child traffic injuries (risk ratio, 0.987; 95% confidence interval, 0.977 to 0.997; p=0.002), indicating its efficacy in curbing accidents.

Adverse Events Following COVID-19 Vaccination in Adolescents: Insights From Pharmacovigilance Study of VigiBase.

BACKGROUND: During coronavirus disease 2019 (COVID-19) pandemic, several COVID-19 vaccines were licensed with fast-track procedures. Although these vaccines have demonstrated high immunogenicity, there has been concerns on the serious adverse events (AEs) following COVID-19 vaccination among adolescents. We aimed to analyze comparative safety of COVID-19 vaccination in adolescents. METHODS: In this pharmacovigilance study, we performed a disproportionality analysis using VigiBase, the World Health Organization's global individual case safety report (ICSR) database. To compare serious AEs reported following COVID-19 vaccines vs. all other vaccines in adolescents aged 12-17 years, ICSRs following any vaccines on adolescents aged 12-17 years were included, defining cases as reports with the AEs of interest, with all other AEs as non-cases. The AEs of interest were myocarditis/pericarditis, multisystem inflammatory syndrome/Kawasaki disease (MIS/KD), anaphylaxis, Guillain-Barré syndrome (GBS), and immune thrombocytopenia (ITP). We conducted a disproportionality analysis to estimate reporting odds ratio (ROR) with 95% confidence interval (CI) for each AE of interest, adjusted for sex by using logistic regression. RESULTS: Of 99,735 AE reports after vaccination in adolescents, 80,018 reports were from COVID-19 vaccinated adolescents (52.9% females; 56.3% America). The AEs of interest were predominantly reported as serious AE (76.1%) with mRNA vaccines (99.4%). Generally, higher reporting odds for the AEs were identified following COVID-19 vaccination in adolescents; myocarditis/pericarditis (2,829 reports for the COVID-19 vaccine vs. 35 for all other vaccines, adjusted ROR [aROR], 19.61; 95% CI, 14.05-27.39), and MIS/KD (104 vs. 6, aROR, 4.33; 95% CI, 1.89-9.88). The reporting odds for anaphylaxis (515 vs. 165, aROR, 0.86; 95% CI, 0.72-1.02), GBS (94 vs. 40, aROR, 0.64; 95% CI, 0.44-0.92) and ITP (52 vs. 12, aROR, 1.12; 95% CI, 0.59-2.09) were not significantly higher following COVID-19 vaccination. CONCLUSION: In this study, there were disproportionate reporting of immune-related AEs following COVID-19 vaccination. While awaiting definitive evidence, there is a need to closely monitor for any signs of immune-related AEs following COVID-19 vaccination among adolescents.

Risk of SARS-CoV-2 breakthrough infection following NVX-CoV2373 and BNT162b2 vaccinations in Korean Adults: A population-based observational study.

South Korea experienced a low prevalence of SARS-CoV-2 until the emergence of the omicron in early 2022, triggering a major community epidemic. To evaluate effectiveness of NVX-CoV2373 and BNT162b2 vaccines in Korean population, we conducted an observational study utilizing individual-level case data on laboratory-confirmed SARS-CoV-2 infection, along with vaccination record. A total of 47,078 recipients of NVX-CoV2373 vaccine and 7,561 recipients of BNT162b2 vaccine were eligible for the study. Thirty days post-second doses, COVID-19 rates were 7.9% (595 out of 7561) of NVX-CoV2373 recipients and 8.6 % (647 out of 7561) of BNT162b2 recipients experienced COVID-19. NVX-CoV2373 rates increased to 9.8 % and 11.2 % at 60 and 90 days, while BNT162b2 rates were 10.5 % and 11.3 % at the same intervals. The 22-weeks risk ratios for recipients of the NVX-CoV2373 vaccine as compared with recipients of the BNT162b2 vaccine were 1.11 (95 % CI, 0.99 to 1.25) for laboratory-confirmed SARS-CoV-2 infection. Continued monitoring is essential to evaluate the duration of protection across different vaccine platforms and schedules.

Autoimmune disorders reported following COVID-19 vaccination: A disproportionality analysis using the WHO database.

PURPOSE: Owing to adverse event following immunization (AEFI) related to autoimmune disorders and coronavirus disease 2019 (COVID-19) vaccines sharing common biological mechanisms, identifying the risk of AEFIs associated with COVID-19 vaccines remains a critical unmet need. We aimed to assess the potential safety signals for 16 AEFIs and explore co-reported adverse events (AEs) and drugs using the global database of the World Health Organization, VigiBase. METHODS: We assessed the occurrence of 16 AEFIs following COVID-19 vaccination through the Standardized MedDRA Queries group "Immune-mediated/Autoimmune Disorders" from MedDRA and performed a disproportionality analysis using reporting odds ratio (ROR) and information component (IC) with 95% confidence intervals (CIs). RESULTS: We identified 25,219 events associated with COVID-19 vaccines in VigiBase. Although rare, we detected four potential safety signals related to autoimmune disorders following COVID-19 vaccination, including ankylosing spondylitis or psoriatic arthritis (ROR 1.86; 95% CI 1.53-2.27), inflammatory bowel disease (ROR 1.77; 95% CI 1.60-1.96), polymyalgia rheumatica (ROR 1.42; 95% CI 1.30-1.55), and thyroiditis (ROR 1.40; 95% CI 1.30-1.50), with positive IC025 values. The top co-reported AEs were musculoskeletal disorders, and immunosuppressants were the most representative co-reported drugs. CONCLUSION: In addressing the imperative to comprehend AEFI related to autoimmune disorders following COVID-19 vaccination, our study identified four potential safety signals. Thus, our research underscores the importance of proactive safety monitoring for the identification of the four AEFIs following COVID-19 vaccination, considering the associated advantages.

Safety of COVID-19 Vaccination During Pregnancy and Lactation: A VigiBase Analysis.

BACKGROUND: There is limited evidence on the safety of coronavirus disease 2019 (COVID-19) vaccination during pregnancy and lactation. Thus, we aimed to evaluate the association between COVID-19 vaccination during pregnancy and lactation and reporting risk of adverse pregnancy or lactation outcomes. METHODS: Using VigiBase, we performed a disproportionality analysis with case/non case design. Cases were defined based on the Standardized MedDRA Queries (SMQs) of "pregnancy and neonatal topics" and non-cases were defined as all other adverse events. We included all reports with COVID-19 vaccines as the suspected cause. Using the full database as the comparators, reporting odds ratios (RORs) with 95% confidence intervals (CIs) were estimated by logistic regression while adjusting for maternal age. Infants' age and sex were additionally adjusted in analyzing the risk of COVID-19 vaccination during lactation. RESULTS: We identified 10,266 and 6,474 reports with the SMQ of "pregnancy and neonatal topics" associated with COVID-19 vaccines during pregnancy and lactation, respectively. No significant RORs of adverse pregnancy outcomes associated with COVID-19 vaccines during pregnancy were observed; however, "functional lactation disorders" showed significant disproportionality during lactation with adjusted ROR of 1.48 (95% CI, 1.21-1.79). Further analysis that analyzed "functional lactation disorders" at a preferred term level, showed higher ROR in mastitis (2.76 [95% CI, 1.45-5.27]). CONCLUSION: Overall, we did not observe a positive association between COVID-19 vaccination during pregnancy and risk of reporting adverse pregnancy outcomes. However, we found a significant disproportionate reporting association between COVID-19 vaccination during lactation and "functional lactation disorders", specifically mastitis. Continuous surveillance is warranted to confirm the safety of COVID-19 vaccine during pregnancy and lactation.

Safety of BNT162b2 mRNA COVID-19 vaccine in children with chronic kidney disease: a national population study from South Korea.

BACKGROUND: In South Korea, COVID-19 vaccination has been recommended to adolescents aged 12 - 17 since October, 2021. We aimed to assess the rate of adverse events following COVID-19 vaccination in adolescents with chronic kidney disease (CKD) in South Korea, using national cohort data. METHODS: We retrieved the clinical information of adolescents 12 - 17 years old from the Korea Disease Control and Prevention Agency-COVID19-National Health Insurance Service (K-COV-N) database, to calculate incidence rates of purpura and other hemorrhagic conditions, Guillain-Barré syndrome (GBS), Kawasaki disease/multisystem inflammatory syndrome in children (MIS-C), myocarditis and/or pericarditis, and anaphylaxis in adolescents with CKD, after BNT162b2 vaccination. RESULTS: Among the 2306 adolescents with CKD, 62.7% (n = 1446) had received the BNT-162b2 vaccine. GBS, Kawasaki disease/MIS-C, and anaphylaxis or anaphylactic shock did not occur during the observation period. Purpura and hemorrhagic conditions were more frequent in the unvaccinated group (7/860 vs. 1/1446), while myocarditis/pericarditis was observed only in the vaccinated group (0/860 vs. 1/1446). Adjusted odds ratio for any of the two adverse events was lower in vaccinated adolescents than in the unvaccinated group which did not reach statistical significance (adjusted odds ratio = 0.14, 95% confidence interval: 0.02, 1.16, P = 0.068). CONCLUSIONS: In this national cohort study of adolescents with CKD in South Korea, we observed no evidence of increased risk of adverse events following BNT162b2 vaccination. Our finding offers insights into the safety of COVID-19 vaccines, empowering adolescent patients with CKD and their caregivers to make informed decisions.

Correction: Demographic and Clinico-Epidemiological Features of Dengue Fever in Faisalabad, Pakistan.

[This corrects the article DOI: 10.1371/journal.pone.0267652.].

Effectiveness and Safety of COVID-19 Vaccination During Preconceptional and Preclinical Pregnancy Period: A National Population Study.

BACKGROUND: We aimed to assess the risk of maternal severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and early abortive outcomes after the association between coronavirus disease 2019 (COVID-19) vaccination during the preconceptional period and preclinical pregnancy, which are likely to be inadvertent vaccination. METHODS: We used data from the Korea Disease Control and Prevention Agency-COVID19-National Health Insurance Service cohort from December 2020 to December 2021. The vaccinated pregnant women were matched to unvaccinated pregnant controls at a 1:4 ratio. The risks of SARS-CoV-2 infection and intensive care unit (ICU) admission within 14 days of infection were analyzed to assess its effectiveness. For safety measures, the adjusted relative risks (aRRs) of early abortive outcomes for the first COVID-19 vaccination during the preconceptional and preclinical periods were calculated considering covariates. We compared the risk of early abortion between mRNA and viral vector vaccines. RESULTS: The overall COVID-19 vaccination rates during the preconceptional period and preclinical pregnancy were 3.1% (6,662/215,211) and 2.6% (5,702/215,211), respectively. The cumulative incidence of ICU admission within 14 days of SARS-CoV-2 infection was 6/100,000 in the unvaccinated group, whereas there were no ICU admissions in the vaccinated groups. The risks of early abortive outcomes were not significantly different between the preconceptional vaccination group and the unvaccinated group (aRR, 1.04; 95% confidence interval [CI],0.99-1.10) or between preclinical pregnancy vaccination and their matched controls (1.02; 95% CI, 0.96-1.08). mRNA and viral vector vaccines have shown similar risks for early abortive outcomes and miscarriages. CONCLUSION: Our findings have provided compelling evidence regarding the effectiveness and safety of COVID-19 vaccination prior to and during early pregnancy. Further research is required to extend the safety and efficacy profiles of COVID-19 vaccines to pregnant women and their babies.

Women's Employment in Industries and Risk of Preeclampsia and Gestational Diabetes: A National Population Study of Republic of Korea.

Background: Some working conditions may pose a higher physical or psychological demand to pregnant women leading to increased risks of pregnancy complications. Objectives: We assessed the association of woman's employment status and the industrial classification with obstetric complications. Methods: We conducted a national population study using the National Health Information Service database of Republic of Korea. Our analysis encompassed 1,316,310 women who experienced first-order live births in 2010-2019. We collected data on the employment status and the industrial classification of women, as well as their diagnoses of preeclampsia (PE) and gestational diabetes mellitus (GDM) classified as A1 (well controlled by diet) or A2 (requiring medication). We calculated odds ratios (aORs) of complications per employment, and each industrial classification was adjusted for individual risk factors. Results: Most (64.7%) were in employment during pregnancy. Manufacturing (16.4%) and the health and social (16.2%) work represented the most prevalent industries. The health and social work exhibited a higher risk of PE (aOR = 1.11, 95% confidence interval [CI]: 1.03-1.21), while the manufacturing industry demonstrated a higher risk of class A2 GDM (1.20, 95% CI: 1.03-1.41) than financial intermediation. When analyzing both classes of GDM, women who worked in public administration and defense/social security showed higher risk of class A1 GDM (1.04, 95% CI: 1.01, 1.07). When comparing high-risk industries with nonemployment, the health and social work showed a comparable risk of PE (1.02, 95% CI: 0.97, 1.07). Conclusion: Employment was associated with overall lower risks of obstetric complications. Health and social service work can counteract the healthy worker effect in relation to PE. This highlights the importance of further elucidating specific occupational risk factors within the high-risk industries.

Gender Inequalities in Mental Health During the COVID-19 Pandemic: A Population-based Study in Korea.

OBJECTIVES: This study explored the effect of the coronavirus disease 2019 (COVID-19) pandemic on psychosocial stress in prime working-age individuals in Korea, focusing on gender inequalities. We hypothesized that the impact of COVID-19 on mental health would differ by age and gender, with younger women potentially demonstrating heightened vulnerability relative to men. METHODS: The study involved data from the Korea Community Health Survey and included 319 592 adults aged 30 years to 49 years. We employed log-binomial regression analysis, controlling for variables including age, education, employment status, marital status, and the presence of children. The study period included 3 phases: the period prior to the COVID-19 outbreak (pre-COVID-19), the early pandemic, and the period following the introduction of vaccinations (post-vaccination). RESULTS: The findings indicated that women were at a heightened risk of psychosocial stress during the early pandemic (relative risk [RR], 1.01; 95% confidence interval [CI], 0.98 to 1.05) and post-vaccination period (RR, 1.07; 95% CI, 1.04 to 1.10) compared to men. This pattern was prominent in urban women aged 30-34 years (pre-COVID-19: RR, 1.06; 95% CI, 1.02 to 1.10; early pandemic: RR, 1.16; 95% CI, 1.08 to 1.25; post-vaccination period, RR, 1.22; 95% CI, 1.14 to 1.31). CONCLUSIONS: The COVID-19 pandemic has exerted unequal impacts on psychosocial stress among prime working-age individuals in Korea, with women, particularly those in urban areas, experiencing a heightened risk. The findings highlight the importance of addressing gender-specific needs and implementing appropriate interventions to mitigate the psychosocial consequences of the pandemic.

Socioeconomic Factors and Abortive Outcomes of Clinical Pregnancy After Embryo Transfer in the Setting of Universal Health Insurance Coverage of IVF.

BACKGROUND: In vitro fertilization-embryo transfer (IVF-ET), an expensive option for infertile couples, started to be fully covered by the National Health Insurance (NHI) from October 2017 in South Korea. We investigated the association between woman's socioeconomic status (SES) and abortive outcomes in pregnancies after IVF-ET in the setting of universal coverage of the treatment. METHODS: Using the NHI database in South Korea, we conducted a retrospective cohort study of all women who achieved clinical pregnancy after ET between October 2017 and February 2019. A total of 44,038 clinical pregnancy episodes of 29,847 women who underwent ET were analyzed. We used employment status, income in percentiles, and living in the Seoul capital area as indicators of SES. Relative risks (RRs) for abortive pregnancy outcomes were calculated for each socioeconomic stratum, using log-binomial regression models included woman's age, body mass index, fasting blood glucose, fresh ET, month of ET, and history of smoking. RESULTS: While most pregnancy outcomes were live births (n = 30,783, 69.9%), 11,215 (25.5%) cycles ended with abortion or early pregnancy loss, 1,779 (4.0%) cycles were ectopic pregnancy, 45 (0.1%) were coded as molar pregnancy, and 224 (0.5%) were fetal death in utero or stillbirth. The risk of overall abortive outcomes was higher when a woman was unemployed (adjusted RR, 1.08; 95% confidence interval [CI], 1.05-1.11) or living in a non-Seoul capital area (1.11; 95% CI, 1.08-1.14). The association between relative income level and abortive outcomes was close to null. Living outside Seoul capital area was associated with the greater risk of abortive outcomes especially in younger women. CONCLUSION: Unemployment and living in non-capital areas were associated with a higher risk of abortive outcomes among pregnancies after ET, even in the setting of universal coverage of IVF-ET. This suggests potential impact of socioeconomic position on the IVF-ET pregnancy.

Association of senescence-associated secretory phenotype proteins with ovarian reserve among middle-aged/older women.

OBJECTIVE: This study aimed to examine the association of circulating senescence-associated secretory phenotype proteins, secreted by senescent cells, with indicators of women's ovarian reserve. METHODS: This secondary analysis of cross-sectional baseline survey data was undertaken by the Korean Genome and Epidemiology Study Cardiovascular Disease Association Study. A total of 223 women (aged 40-82 y), without any history of oophorectomy, hysterectomy, or other medical conditions that could lower the ovarian reserve, were enrolled in this analysis. Chronological age (years), menopausal status, and serum anti-müllerian hormone (ng/mL) level were used to assess the associations among biological aging, accelerated menopausal aging, and ovarian reserve. RESULTS: Of the 223 women participants (53.4 ± 11.0 y), 147 (46.4 ± 3.9 y) and 76 (67.0 ± 6.9 y) were premenopausal and postmenopausal, respectively. Serum levels of senescence-associated secretory phenotype proteins were generally higher in postmenopausal, than in premenopausal, women. In the analyses adjusted for chronological age and body mass index, 17 senescence-associated secretory phenotype proteins were associated with menopausal status. However, in premenopausal women, no association trends with the level of anti-müllerian hormone were detected for a total of 28 senescence-associated secretory phenotype proteins. CONCLUSIONS: In a cohort of middle-aged/older women, the level of circulating senescence-associated secretory phenotype proteins indicated chronological age and menopausal status. Yet, serum levels of senescence-associated secretory phenotype protein potentially have limited predictive value for ascertaining ovarian reserve in premenopausal women.

Trend of Women's Health Research in Korea, 2012-2020: Topic and Text Network Analysis.

BACKGROUND: With the epidemiological transition, sociodemographic changes and differential lifetime experiences of women, women's health research improves knowledge of diverse health issues and the impact of policies. To explore the initiatives of women's health research in Korea, the present study examined the trends and topics of research on women's health funded by the government. METHODS: We searched all research projects on women's health funded by the government between 2012 and 2020 in Korea using the National Science & Technology Information Service database. We reviewed all the titles and abstract of the projects and examined the research trends by year. Content analysis was performed using both deductive and inductive approaches. Text network analysis and visualization by topic were conducted for keywords with a minimum of 10 occurrences in the title and abstract. RESULTS: Total number and funding amount of research projects on women's health in 2020 increased by 2.4 and 2.2 times over 2012 levels, respectively. The Ministry of Health and Welfare and the Ministry of Food and Drug Safety funded 20.9% of all projects. The majority of the topics (59.8%) addressed breast and gynecological cancers. Those on sexual and reproductive health accounted for 16.7%, with steep growth in the number (6.1 times) and funding (11.1 times) over 2012 levels. The topic analysis presented a more complex keyword network in 2020 than in 2012; however, the keywords frequently used in 2020 were similar to those of 2012. CONCLUSION: Women's health research projects have been growing in number and funding, with limited diversity in topics. Diversifying the topics and focusing on issues beyond the breast and pregnancy would be needed to reflect the complete life course of women. Institutionalization of diverse communication channels with various interest groups for women's health would be needed to better understand women's health needs from a public health perspective.

Investigation of the abortion-related experience of the providers, women, and advocators in South Korea: The neglected essential healthcare service.

OBJECTIVE: The decriminalization of abortions in South Korea in 2019 has not been followed by the establishment of policies ensuring access to abortion services. This study aimed to explore the current challenges and barriers for quality abortion services in the Korean healthcare system. METHODS: Eleven women, six healthcare providers, and 11 advocates participated in in-depth interviews in 2020. Experiences of abortion were analyzed using the modified Availability, Accessibility, Acceptability, and Quality (AAAQ) framework. RESULTS: While informal, access to surgical abortion services was possible in general. However, accessibility to services and information varied according to women's age, marital status, and physical condition. Considering that the Korean government has been reluctant to adopt proactive measures to ensure access to abortion services, the quality of abortion care in Korea remains questionable, with the mandate of male consent for abortion prevailing. The women interviewed in this study expressed dissatisfaction with their current access to and the quality of abortion services. CONCLUSION: Abortion is an essential service that ensures the sexual and reproductive health and rights of women. Although abortion was decriminalized in Korea in 2019, it remains an informal and stigmatized service. Further research and policy efforts are required to ensure access to abortion in Korea.

Does the father's job matter? Parental occupation and preterm birth in Korea.

OBJECTIVES: Limited evidence is available regarding the impact of paternal occupation and its combined effect with maternal occupation on preterm birth. Therefore, we assessed the association of maternal and paternal occupations with preterm birth. METHODS: We used the national birth data of Korea between 2010 and 2020. Parental occupations were divided into 5 categories: (1) managers; (2) professionals, technicians, and related workers; (3) clerks and support workers; (4) service and sales workers; and (5) manual workers. A multinomial logistic regression model was used to calculate the adjusted odds ratios (aORs) of extremely, very, and moderate-to-late preterm births per occupational category considering individual risk factors. RESULTS: For the 4,004,976 singleton births, 40.2% of mothers and 95.5% of fathers were employed. Compared to non-employment, employment was associated with a lower risk of preterm birth. Among employed mothers, service and sales occupations were associated with a higher risk of preterm birth than managerial occupations (aOR, 1.06; 95% confidence interval [CI], 1.01 to 1.10 for moderate-to-late preterm births). The father's manual occupation was associated with a higher risk of preterm birth (aOR, 1.09; 95% CI, 1.05 to 1.13 for moderate-to-late preterm) than managerial occupations. When both parents had high-risk occupations, the risk of preterm birth was higher than in cases where only the mother or neither of the parents had a high-risk occupation. CONCLUSIONS: Paternal occupation was associated with preterm birth regardless of maternal employment and occupation and modified the effect of maternal occupation. Detailed occupational environment data are needed to identify the paternal exposures that increase the risk.

Differential trend of mild and severe preeclampsia among nulliparous women: a population-based study of South Korea.

We explored the annual risks of mild and severe preeclampsia (PE) among nulliparous women. Using the National Health Information Database of South Korea, 1,317,944 nulliparous women who gave live births were identified. Mild PE increased from 0.9% in 2010 to 1.4% in 2019 (P for trend=0.006), while severe PE decreased from 0.4% in 2010 to 0.3% in 2019 (P=0.049). The incidence of all types of PE (mild and severe) showed no linear change (P=0.514). Adjusted odds ratio (OR) of severe PE decreased in 2013 (0.68; 95% confidence interval [CI]: 0.60, 0.77) and beyond compared to that in 2010, while the OR of mild PE increased in 2017 (1.14; 95% CI: 1.06, 1.22) and beyond. Mild PE was found to be less likely to progress to the severe form since 2010; however, the overall risk of PE among women did not change.

A Nationwide Survey of mRNA COVID-19 Vaccinee's Experiences on Adverse Events and Its Associated Factors.

BACKGROUND: Although coronavirus disease 2019 (COVID-19) vaccines have been distributed worldwide under emergency use authorization, the real-world safety profiles of mRNA vaccines still need to be clearly defined. We aimed to identify the overall incidence and factors associated with adverse events (AEs) following mRNA COVID-19 vaccination. METHODS: We conducted web-based survey from December 2 to 10 in 2021 with a 2,849 nationwide sampled panel. Study participants were individuals who had elapsed at least two-weeks after completing two dosing schedules of COVID-19 vaccination aged between 18-49 years. We weighted the participants to represent the Korean population. The outcome was the overall incidence of AEs following mRNA COVID-19 vaccination and associated factors. We estimated the weighted odds ratios (ORs) using multivariable logistic regression models to identify the factors associated with AEs. RESULTS: Of the 2,849 participants (median [interquartile range] age, 35 [27-42] years; 51.6% male), 90.8% (n = 2,582) for the first dose and 88.7% (n = 2,849) for the second dose reported AEs, and 3.3% and 4.3% reported severe AEs, respectively. Occurrence of AEs was more prevalent in mRNA-1273 (OR, 2.06; 95% confidence interval [CI], 1.59-2.67 vs. BNT162b2), female sex (1.88; 1.52-2.32), and those with dermatologic diseases (2.51; 1.32-4.77). History of serious allergic reactions (1.96; 1.06-3.64) and anticoagulant medication use (4.72; 1.92-11.6) were associated with severe AEs. CONCLUSION: Approximately 90% of participants reported AEs following mRNA COVID-19 vaccination. Substantial factors, including vaccine type (mRNA-1273), female sex, and dermatologic diseases were associated with AEs. Our findings could aid policymakers in establishing vaccination strategies tailored to those potentially susceptible to AEs.

Barriers to COVID-19 vaccine surveillance: the issue of under-reporting adverse events.

OBJECTIVES: This study investigated the reporting rates of adverse events following immunization (AEFIs) to the spontaneous reporting system (SRS) and its predictors among individuals with AEFIs after coronavirus disease 2019 (COVID-19) vaccination. METHODS: A cross-sectional, web-based survey was conducted from December 2, 2021 to December 20, 2021, recruiting participants >14 days after completion of a primary COVID-19 vaccination series. Reporting rates were calculated by dividing the number of participants who reported AEFIs to the SRS by the total number of participants who experienced AEFIs. We estimated adjusted odds ratios (aORs) using multivariate logistic regression to determine factors associated with spontaneous AEFIs reporting. RESULTS: Among 2,993 participants, 90.9% and 88.7% experienced AEFIs after the first and second vaccine doses, respectively (reporting rates, 11.6 and 12.7%). Furthermore, 3.3% and 4.2% suffered moderate to severe AEFIs, respectively (reporting rates, 50.5 and 50.0%). Spontaneous reporting was more prevalent in female (aOR, 1.54; 95% confidence interval [CI], 1.31 to 1.81); those with moderate to severe AEFIs (aOR, 5.47; 95% CI, 4.45 to 6.73), comorbidities (aOR, 1.31; 95% CI, 1.09 to 1.57), a history of severe allergic reactions (aOR, 2.02; 95% CI, 1.47 to 2.77); and those who had received mRNA-1273 (aOR, 1.25; 95% CI, 1.05 to 1.49) or ChAdOx1 (aOR, 1.62; 95% CI, 1.15 to 2.30) vaccines versus BNT162b2. Reporting was less likely in older individuals (aOR, 0.98; 95% CI, 0.98 to 0.99 per 1-year age increment). CONCLUSIONS: Spontaneous reporting of AEFIs after COVID-19 vaccination was associated with younger age, female sex, moderate to severe AEFIs, comorbidities, history of allergic reactions, and vaccine type. AEFIs under-reporting should be considered when delivering information to the community and in public health decision-making.