1.Maternal Exposures to COVID-19 Vaccine and Adverse Birth Outcomes:National Population Study in Korea
Kyuwon KIM ; Erdenetuya BOLORMAA ; Eunseon GWAK ; Ju-Young SHIN ; Nam-Kyong CHOI ; Young June CHOE ; Seung-Ah CHOE
Journal of Korean Medical Science 2025;40(17):e63-
Background:
This study aimed to estimate the association between mRNA coronavirus disease 2019 (COVID-19) vaccine exposure during pregnancy and the risks of preterm birth and congenital malformations leveraging a national population data.
Methods:
This retrospective cohort study utilized national data from the National Health Insurance System, linking maternal and infant records with COVID-19 vaccination registries.Newborns with congenital malformations were identified using diagnosis codes. The analysis included women aged 20–49 who gave live births between February 2022 and December 2022. Odds ratios (ORs) for preterm birth and any congenital malformation per COVID-19 vaccination during pregnancy compared to 1:4 matched unvaccinated controls, adjusted for maternal age, residential area, employment, income, disability, month of conception, prepregnancy obesity, smoking, and severe acute respiratory syndrome coronavirus 2 infection prior to pregnancy, were calculated. We compared the risk of two outcomes between BNT162b2 and mRNA-1273.
Results:
Among 106,692 women who gave birth during the study period, 8,966 (8.4%) received a COVID-19 vaccination during pregnancy. Of the newborns, 7,039 (6.6%) were preterm births and 7,658 (7.2%) had congenital malformations. COVID-19 vaccination during pregnancy was associated with a comparable risk of preterm birth (OR, 1.03; 95% confidence interval [CI], 0.77–1.36) and a similar risk of congenital malformations (0.90; 95% CI, 0.72–1.12) compared to non-vaccinees. The ORs of preterm birth (1.02; 95% CI, 0.77–1.36) and congenital malformation (0.91; 95% CI, 0.73–1.14) for mRNA-1273 were comparable to those for BNT162b2.
Conclusion
COVID-19 vaccines during pregnancy poses no increased risk of preterm birth and congenital malformations compared to those not exposed to the vaccine, with similar risk levels observed between the two mRNA vaccines. This finding provides additional evidence supporting the safety of COVID-19 vaccines.
2.Maternal Exposures to COVID-19 Vaccine and Adverse Birth Outcomes:National Population Study in Korea
Kyuwon KIM ; Erdenetuya BOLORMAA ; Eunseon GWAK ; Ju-Young SHIN ; Nam-Kyong CHOI ; Young June CHOE ; Seung-Ah CHOE
Journal of Korean Medical Science 2025;40(17):e63-
Background:
This study aimed to estimate the association between mRNA coronavirus disease 2019 (COVID-19) vaccine exposure during pregnancy and the risks of preterm birth and congenital malformations leveraging a national population data.
Methods:
This retrospective cohort study utilized national data from the National Health Insurance System, linking maternal and infant records with COVID-19 vaccination registries.Newborns with congenital malformations were identified using diagnosis codes. The analysis included women aged 20–49 who gave live births between February 2022 and December 2022. Odds ratios (ORs) for preterm birth and any congenital malformation per COVID-19 vaccination during pregnancy compared to 1:4 matched unvaccinated controls, adjusted for maternal age, residential area, employment, income, disability, month of conception, prepregnancy obesity, smoking, and severe acute respiratory syndrome coronavirus 2 infection prior to pregnancy, were calculated. We compared the risk of two outcomes between BNT162b2 and mRNA-1273.
Results:
Among 106,692 women who gave birth during the study period, 8,966 (8.4%) received a COVID-19 vaccination during pregnancy. Of the newborns, 7,039 (6.6%) were preterm births and 7,658 (7.2%) had congenital malformations. COVID-19 vaccination during pregnancy was associated with a comparable risk of preterm birth (OR, 1.03; 95% confidence interval [CI], 0.77–1.36) and a similar risk of congenital malformations (0.90; 95% CI, 0.72–1.12) compared to non-vaccinees. The ORs of preterm birth (1.02; 95% CI, 0.77–1.36) and congenital malformation (0.91; 95% CI, 0.73–1.14) for mRNA-1273 were comparable to those for BNT162b2.
Conclusion
COVID-19 vaccines during pregnancy poses no increased risk of preterm birth and congenital malformations compared to those not exposed to the vaccine, with similar risk levels observed between the two mRNA vaccines. This finding provides additional evidence supporting the safety of COVID-19 vaccines.
3.Maternal Exposures to COVID-19 Vaccine and Adverse Birth Outcomes:National Population Study in Korea
Kyuwon KIM ; Erdenetuya BOLORMAA ; Eunseon GWAK ; Ju-Young SHIN ; Nam-Kyong CHOI ; Young June CHOE ; Seung-Ah CHOE
Journal of Korean Medical Science 2025;40(17):e63-
Background:
This study aimed to estimate the association between mRNA coronavirus disease 2019 (COVID-19) vaccine exposure during pregnancy and the risks of preterm birth and congenital malformations leveraging a national population data.
Methods:
This retrospective cohort study utilized national data from the National Health Insurance System, linking maternal and infant records with COVID-19 vaccination registries.Newborns with congenital malformations were identified using diagnosis codes. The analysis included women aged 20–49 who gave live births between February 2022 and December 2022. Odds ratios (ORs) for preterm birth and any congenital malformation per COVID-19 vaccination during pregnancy compared to 1:4 matched unvaccinated controls, adjusted for maternal age, residential area, employment, income, disability, month of conception, prepregnancy obesity, smoking, and severe acute respiratory syndrome coronavirus 2 infection prior to pregnancy, were calculated. We compared the risk of two outcomes between BNT162b2 and mRNA-1273.
Results:
Among 106,692 women who gave birth during the study period, 8,966 (8.4%) received a COVID-19 vaccination during pregnancy. Of the newborns, 7,039 (6.6%) were preterm births and 7,658 (7.2%) had congenital malformations. COVID-19 vaccination during pregnancy was associated with a comparable risk of preterm birth (OR, 1.03; 95% confidence interval [CI], 0.77–1.36) and a similar risk of congenital malformations (0.90; 95% CI, 0.72–1.12) compared to non-vaccinees. The ORs of preterm birth (1.02; 95% CI, 0.77–1.36) and congenital malformation (0.91; 95% CI, 0.73–1.14) for mRNA-1273 were comparable to those for BNT162b2.
Conclusion
COVID-19 vaccines during pregnancy poses no increased risk of preterm birth and congenital malformations compared to those not exposed to the vaccine, with similar risk levels observed between the two mRNA vaccines. This finding provides additional evidence supporting the safety of COVID-19 vaccines.
4.Maternal Exposures to COVID-19 Vaccine and Adverse Birth Outcomes:National Population Study in Korea
Kyuwon KIM ; Erdenetuya BOLORMAA ; Eunseon GWAK ; Ju-Young SHIN ; Nam-Kyong CHOI ; Young June CHOE ; Seung-Ah CHOE
Journal of Korean Medical Science 2025;40(17):e63-
Background:
This study aimed to estimate the association between mRNA coronavirus disease 2019 (COVID-19) vaccine exposure during pregnancy and the risks of preterm birth and congenital malformations leveraging a national population data.
Methods:
This retrospective cohort study utilized national data from the National Health Insurance System, linking maternal and infant records with COVID-19 vaccination registries.Newborns with congenital malformations were identified using diagnosis codes. The analysis included women aged 20–49 who gave live births between February 2022 and December 2022. Odds ratios (ORs) for preterm birth and any congenital malformation per COVID-19 vaccination during pregnancy compared to 1:4 matched unvaccinated controls, adjusted for maternal age, residential area, employment, income, disability, month of conception, prepregnancy obesity, smoking, and severe acute respiratory syndrome coronavirus 2 infection prior to pregnancy, were calculated. We compared the risk of two outcomes between BNT162b2 and mRNA-1273.
Results:
Among 106,692 women who gave birth during the study period, 8,966 (8.4%) received a COVID-19 vaccination during pregnancy. Of the newborns, 7,039 (6.6%) were preterm births and 7,658 (7.2%) had congenital malformations. COVID-19 vaccination during pregnancy was associated with a comparable risk of preterm birth (OR, 1.03; 95% confidence interval [CI], 0.77–1.36) and a similar risk of congenital malformations (0.90; 95% CI, 0.72–1.12) compared to non-vaccinees. The ORs of preterm birth (1.02; 95% CI, 0.77–1.36) and congenital malformation (0.91; 95% CI, 0.73–1.14) for mRNA-1273 were comparable to those for BNT162b2.
Conclusion
COVID-19 vaccines during pregnancy poses no increased risk of preterm birth and congenital malformations compared to those not exposed to the vaccine, with similar risk levels observed between the two mRNA vaccines. This finding provides additional evidence supporting the safety of COVID-19 vaccines.
5.A result of the detection of homozygous deletion of SMN1 gene in the spinal muscular atrophy
Esukhei E ; Khandsuren B ; Erdenetuya D ; Bolormaa D ; Mandakhnar M ; Oyungerel B ; Sarantsetseg S ; Yundendash D ; Nyam-Erdene N ; Batchimeg B ; Altansukh Ts ; Munkhbayar S ; Chimeglkham B
Mongolian Medical Sciences 2024;207(1):20-29
Background:
Spinal muscular atrophy (SMA) is a degenerative neuromuscular disease that causes progressive
muscle weakness and atrophy due to the loss of the motor neurons. Approximately 95% of patients
with SMA are homozygous for the deletion of SMN1 exon 7. With an incidence of 1/10.000 and a carrier
frequency of 1/40 to 1/50, SMA is the most common genetic cause of death in infants.
Purpose:
To detect homozygous deletion of SMN1 exon 7 and to analyse the SMN1 copy number by molecular
genetic analysis.
Materials and Methods:
In this study, 3 SMA patients with SMN1 gene homozygous deletion and 17 people of their relatives were
included. Molecular genetic analysis was performed in the Central Scientific Research Laboratory of the
Institute of Medical Sciences. DNA was extracted from peripheral blood, and its purity was assessed by
spectrophotometer. Homozygous deletion of SMN1 gene was analyzed with allele-specific PCR, and
the SMN1 gene copy number was evaluated by real-time PCR.
Results:
Among the five participants diagnosed with SMA by clinical symptom and electromyographic test, three
cases were found to have homozygous deletion of exon 7 of the SMN1 gene, while two cases did not
exhibit such mutation by the allele specific PCR analysis.
The mean age of study participants was 27.76±16.07 (ranging from 8 months to 52 years).
Six of the 7 relatives of the first proband had 1 copy number of SMN1 (0.75±0.29) or were carriers
of SMA, while one had 3 copy numbers (2.99) or no deletion of SMN1 gene. Additionally, 6 of the 7
individuals of the second proband had 1 copy number of the SMN1 gene (0.72±0.14), and 1 person
had 2 copy numbers. All 3 relatives of the third proband had 1 copy number of SMN1 gene (0.96±0.37).
Conclusion
We consider that determination of SMN1 gene homozygous deletion and carrier testing
can be performed by the PCR method locally. Further, it is necessary to implement the molecular
genetic testing method into practice and to study the requirements and needs of early detection of SMA
in the newborn screening program of Mongolia.
6.Methodology of comparative studies on the relative effectiveness of COVID-19 vaccines: a systematic review
Erdenetuya BOLORMAA ; Jiae SHIM ; Young-Sook CHOI ; Donghyok KWON ; Young June CHOE ; Seung-Ah CHOE
Osong Public Health and Research Perspectives 2024;15(5):395-408
Objectives:
This study aimed to comprehensively outline the methodological approaches used in published research comparing the vaccine effectiveness (VE) of coronavirus disease 2019 (COVID-19) vaccines.
Methods:
A systematic search was conducted on June 13, 2024, to identify comparative studies evaluating the effectiveness of mRNA versus non-mRNA and monovalent versus bivalent COVID-19 vaccines. We screened titles, abstracts, and full texts, collecting data on publication year, country, sample size, study population composition, study design, VE estimates, outcomes, and covariates. Studies that reported relative VE (rVE) were analyzed separately from those that did not.
Results:
We identified 25 articles comparing rVE between mRNA and non-mRNA COVID-19 vaccines, as well as between monovalent and bivalent formulations. Among the studies assessing VE by vaccine type, 126 did not provide rVE estimates. Comparative VE studies frequently employed retrospective cohort designs. Among the definitions of rVE used, the most common were hazard ratio and absolute VE, calculated as (1−odds ratio)×100. Studies were most frequently conducted in the United Kingdom and the United States, and the most common outcome was infection. Most targeted the general population and assessed the VE of mRNA vaccines using the AstraZeneca vaccine as a reference. A small proportion, 7.3% (n=11), did not adjust for any variables. Only 3 studies (2.0%) adjusted for all core confounding variables recommended by the World Health Organization.
Conclusion
Few comparative studies of COVID-19 vaccines have incorporated rVE methodologies. Reporting rVE and employing a consistent set of covariates can broaden our understanding of COVID-19 vaccines.
7.Methodology of comparative studies on the relative effectiveness of COVID-19 vaccines: a systematic review
Erdenetuya BOLORMAA ; Jiae SHIM ; Young-Sook CHOI ; Donghyok KWON ; Young June CHOE ; Seung-Ah CHOE
Osong Public Health and Research Perspectives 2024;15(5):395-408
Objectives:
This study aimed to comprehensively outline the methodological approaches used in published research comparing the vaccine effectiveness (VE) of coronavirus disease 2019 (COVID-19) vaccines.
Methods:
A systematic search was conducted on June 13, 2024, to identify comparative studies evaluating the effectiveness of mRNA versus non-mRNA and monovalent versus bivalent COVID-19 vaccines. We screened titles, abstracts, and full texts, collecting data on publication year, country, sample size, study population composition, study design, VE estimates, outcomes, and covariates. Studies that reported relative VE (rVE) were analyzed separately from those that did not.
Results:
We identified 25 articles comparing rVE between mRNA and non-mRNA COVID-19 vaccines, as well as between monovalent and bivalent formulations. Among the studies assessing VE by vaccine type, 126 did not provide rVE estimates. Comparative VE studies frequently employed retrospective cohort designs. Among the definitions of rVE used, the most common were hazard ratio and absolute VE, calculated as (1−odds ratio)×100. Studies were most frequently conducted in the United Kingdom and the United States, and the most common outcome was infection. Most targeted the general population and assessed the VE of mRNA vaccines using the AstraZeneca vaccine as a reference. A small proportion, 7.3% (n=11), did not adjust for any variables. Only 3 studies (2.0%) adjusted for all core confounding variables recommended by the World Health Organization.
Conclusion
Few comparative studies of COVID-19 vaccines have incorporated rVE methodologies. Reporting rVE and employing a consistent set of covariates can broaden our understanding of COVID-19 vaccines.
8.Methodology of comparative studies on the relative effectiveness of COVID-19 vaccines: a systematic review
Erdenetuya BOLORMAA ; Jiae SHIM ; Young-Sook CHOI ; Donghyok KWON ; Young June CHOE ; Seung-Ah CHOE
Osong Public Health and Research Perspectives 2024;15(5):395-408
Objectives:
This study aimed to comprehensively outline the methodological approaches used in published research comparing the vaccine effectiveness (VE) of coronavirus disease 2019 (COVID-19) vaccines.
Methods:
A systematic search was conducted on June 13, 2024, to identify comparative studies evaluating the effectiveness of mRNA versus non-mRNA and monovalent versus bivalent COVID-19 vaccines. We screened titles, abstracts, and full texts, collecting data on publication year, country, sample size, study population composition, study design, VE estimates, outcomes, and covariates. Studies that reported relative VE (rVE) were analyzed separately from those that did not.
Results:
We identified 25 articles comparing rVE between mRNA and non-mRNA COVID-19 vaccines, as well as between monovalent and bivalent formulations. Among the studies assessing VE by vaccine type, 126 did not provide rVE estimates. Comparative VE studies frequently employed retrospective cohort designs. Among the definitions of rVE used, the most common were hazard ratio and absolute VE, calculated as (1−odds ratio)×100. Studies were most frequently conducted in the United Kingdom and the United States, and the most common outcome was infection. Most targeted the general population and assessed the VE of mRNA vaccines using the AstraZeneca vaccine as a reference. A small proportion, 7.3% (n=11), did not adjust for any variables. Only 3 studies (2.0%) adjusted for all core confounding variables recommended by the World Health Organization.
Conclusion
Few comparative studies of COVID-19 vaccines have incorporated rVE methodologies. Reporting rVE and employing a consistent set of covariates can broaden our understanding of COVID-19 vaccines.
9.Methodology of comparative studies on the relative effectiveness of COVID-19 vaccines: a systematic review
Erdenetuya BOLORMAA ; Jiae SHIM ; Young-Sook CHOI ; Donghyok KWON ; Young June CHOE ; Seung-Ah CHOE
Osong Public Health and Research Perspectives 2024;15(5):395-408
Objectives:
This study aimed to comprehensively outline the methodological approaches used in published research comparing the vaccine effectiveness (VE) of coronavirus disease 2019 (COVID-19) vaccines.
Methods:
A systematic search was conducted on June 13, 2024, to identify comparative studies evaluating the effectiveness of mRNA versus non-mRNA and monovalent versus bivalent COVID-19 vaccines. We screened titles, abstracts, and full texts, collecting data on publication year, country, sample size, study population composition, study design, VE estimates, outcomes, and covariates. Studies that reported relative VE (rVE) were analyzed separately from those that did not.
Results:
We identified 25 articles comparing rVE between mRNA and non-mRNA COVID-19 vaccines, as well as between monovalent and bivalent formulations. Among the studies assessing VE by vaccine type, 126 did not provide rVE estimates. Comparative VE studies frequently employed retrospective cohort designs. Among the definitions of rVE used, the most common were hazard ratio and absolute VE, calculated as (1−odds ratio)×100. Studies were most frequently conducted in the United Kingdom and the United States, and the most common outcome was infection. Most targeted the general population and assessed the VE of mRNA vaccines using the AstraZeneca vaccine as a reference. A small proportion, 7.3% (n=11), did not adjust for any variables. Only 3 studies (2.0%) adjusted for all core confounding variables recommended by the World Health Organization.
Conclusion
Few comparative studies of COVID-19 vaccines have incorporated rVE methodologies. Reporting rVE and employing a consistent set of covariates can broaden our understanding of COVID-19 vaccines.
10.Methodology of comparative studies on the relative effectiveness of COVID-19 vaccines: a systematic review
Erdenetuya BOLORMAA ; Jiae SHIM ; Young-Sook CHOI ; Donghyok KWON ; Young June CHOE ; Seung-Ah CHOE
Osong Public Health and Research Perspectives 2024;15(5):395-408
Objectives:
This study aimed to comprehensively outline the methodological approaches used in published research comparing the vaccine effectiveness (VE) of coronavirus disease 2019 (COVID-19) vaccines.
Methods:
A systematic search was conducted on June 13, 2024, to identify comparative studies evaluating the effectiveness of mRNA versus non-mRNA and monovalent versus bivalent COVID-19 vaccines. We screened titles, abstracts, and full texts, collecting data on publication year, country, sample size, study population composition, study design, VE estimates, outcomes, and covariates. Studies that reported relative VE (rVE) were analyzed separately from those that did not.
Results:
We identified 25 articles comparing rVE between mRNA and non-mRNA COVID-19 vaccines, as well as between monovalent and bivalent formulations. Among the studies assessing VE by vaccine type, 126 did not provide rVE estimates. Comparative VE studies frequently employed retrospective cohort designs. Among the definitions of rVE used, the most common were hazard ratio and absolute VE, calculated as (1−odds ratio)×100. Studies were most frequently conducted in the United Kingdom and the United States, and the most common outcome was infection. Most targeted the general population and assessed the VE of mRNA vaccines using the AstraZeneca vaccine as a reference. A small proportion, 7.3% (n=11), did not adjust for any variables. Only 3 studies (2.0%) adjusted for all core confounding variables recommended by the World Health Organization.
Conclusion
Few comparative studies of COVID-19 vaccines have incorporated rVE methodologies. Reporting rVE and employing a consistent set of covariates can broaden our understanding of COVID-19 vaccines.

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