Current status of pertussis vaccination during pregnancy and influencing factors in Korea

Effectiveness of maternal pertussis vaccination in Singapore: A test-negative case-control study

Pertussis vaccination (Tdap -Tetanus-diphtheria-acellular pertussis) for pregnant women has been recommended since November 2017 in Singapore. In this prospective test-negative case-control study from 2018 to 2019, we aimed to evaluate vaccine effectiveness (VE) against pertussis infection and pertussis-related intensive care unit (ICU) admission according to Tdap (Tetanus-diphtheria-acellular pertussis) during pregnancy and/or infant pertussis vaccination. A total of 58 children (26 cases, 32 controls) were recruited with 4 ICU admissions. The median age was 3 months (interquartile range [IQR] 1.50-4.56 months). Overall, 25.9 % of mothers had received antenatal Tdap vaccination and 43.1 % of infants received pertussis vaccination, majority only 1 dose. Tdap in pregnancy alone without infant vaccine or with 0-1 infant dose had a VE of 97.62 % (95 % confidence interval [CI] 53.25-99.88 %), 98.17 % (95 %CI 66.61-99.9 %) respectively, against pertussis infection and 71.9 % (95 %CI 0.0-98.64), 75.86 % (95 % CI 0.0-98.78) respectively, against ICU admissions. Conclusion: Maternal Tdap vaccination was highly protective against infant pertussis and should be routinely recommended for all pregnant women.

A systematic review to determine the anti-vaccination thoughts of pregnant women and the reasons for not getting vaccinated

The aim of this study was to determine the anti-vaccination thoughts of pregnant women and the reasons for not getting vaccinated. In this study, data was obtained by retrospectively scanning the cross-sectional and qualitative studies published in the databases of 'PubMed, Cochrane, EBSCOhost, ULAKBİM and Google Scholar' in Turkish and English languages between 2011-2021. The PRISMA method was used in the preparation of the systematic review. In the studies reviewed, it was determined that the rate of pregnant women who were against the vaccine ranged from 6.2% to 98.6%, and the opinions of pregnant women against vaccination and the reasons for not getting vaccinated are presented under seven themes. The results of the study were considered important in terms of showing that quality and important studies were carried out in the literature on the subject and that the data were presented.IMPACT STATEMENTWhat is already known on this subject? Today, with the global coronavirus pandemic, vaccines and their effects are on the agenda again. Especially in pregnant women, opposition to vaccination and not getting vaccinated have emerged for various reasons.What do the results of this study add? The anti-vaccine thoughts of the pregnant women and the reasons for not getting vaccinated were mostly as follows: insufficient level of knowledge, mistrust of vaccines, perception of low infection risk, misconceptions and beliefs about the safety, content, side effects and efficacy of vaccines, worry and fear about the side effects of vaccines, the thought that the vaccine will harm herself and the baby, causes arising from healthcare professionals, financial, temporal and logistical barriers.What the implications are of these findings for clinical practice and/or further research? Scientific studies that can provide comprehensive and strong evidence about vaccine hesitancy and its causes, methods of increasing social approval in vaccination, and solutions should be proposed in the light of these researches in the fight against vaccine rejection.

COVID-19 Vaccine Acceptance during Pregnancy and Influencing Factors in South Korea

Pregnant women were excluded from vaccination against Coronavirus 2019 (COVID-19) until September 2021 in South Korea. Although vaccination for pregnant women started in October 2021, vaccine acceptance in pregnant women is yet unknown. This cross-sectional study aimed to investigate COVID-19 vaccine acceptance during pregnancy and influencing factors. An anonymous survey was distributed in obstetrics departments to all pregnant or postpartum women, during the prenatal or postpartum visit. The proportion of self-reported COVID-19 vaccination during pregnancy among 436 women was 26.6%. Pregnancy-related independent factors influencing maternal COVID-19 vaccination were “received vaccine information about from obstetrics and gynecology (OBGYN) doctors” (OR 3.41, 95% CI 2.05–5.65), “cohabitant COVID-19 vaccination” (OR 2.43, 95% CI 1.06–5.59), and “second trimester” (OR 7.35, 95% CI 1.54–35.15). In women who did not want to get vaccinated, the most common reason for COVID-19 vaccination hesitancy was concern that COVID-19 vaccine might affect the fetus (91.7%, 243/266), followed by distrust in COVID-19 vaccine effectiveness (42.6%, 113/266). This study showed that providing information about maternal COVID-19 vaccination, especially by OBGYN doctors, is crucial for increasing vaccination coverage in pregnant women. Providing updated evidence of COVID-19 vaccine efficacy and safety in pregnant women may be also helpful for increasing vaccine acceptance.

Post-Marketing Surveillance of Tetravalent Diphtheria-Tetanus-Acellular Pertussis and Inactivated Poliovirus (DTaP-IPV) Vaccine in South Korea, 2009 to 2015

Introduction

TETRAXIM™ (Sanofi), a combined diphtheria, tetanus, acellular pertussis, and inactivated poliovirus (DTaP-IPV) vaccine, has been licensed in South Korea since 2009. In accordance with the Ministry of Food and Drug Safety regulations, this post-marketing surveillance (PMS) study evaluated the safety of the DTaP-IPV vaccine in real-world clinical practice in infants and children who received it as either a part of the three-dose primary series dose at 2, 4, and 6 months or school entry booster between 4 and 6 years of age.

Methods

This multicenter, observational, PMS study was conducted in real-world practice in South Korea for 6 years (2009–2015) in participants aged between 2 months and 6 years. The study outcomes included solicited reactions, unsolicited adverse events (AEs)/adverse drug reactions (ADRs), unexpected AEs/ADRs, and serious AEs (SAEs)/ADRs.

Results

Data from 647 participants was included in the safety analysis. Overall, 268 AEs were reported by 181 (28%) participants: 47 (17.5%) solicited reactions, 220 (82.1%) unsolicited AEs, and 1 (0.4%) unsolicited ADR. A total of 48 AEs (including 47 solicited reactions) were reported to have a causal relationship with the DTaP-IPV vaccine and were reported by 36 (5.6%) participants. A total of 212 unexpected AEs were reported by 152 (23.5%) participants, none of which had a causal relationship with the DTaP-IPV vaccine. Neither immediate AEs nor SAEs were reported during the study. Among the participants who reported AEs, 220 (34%) were on concomitant medications. Most AEs were of mild intensity, and all participants recovered.

Conclusion

No safety concerns related to the DTaP-IPV vaccine in a real-world setting were raised in participants aged 2–6 months for the primary series and 4–6 years for the school-entry booster dose in the Korean population. The DTaP-IPV vaccine was well tolerated and can be continued as part of routine immunization programs in infants and children.

Trial Registration: NCT01437423.

The impact of COVID-19 in pregnancy: Part II. Vaccination to pregnant women

Effective strategies are urgently needed to decrease the risk of untoward outcomes of pregnant women with severe acute respiratory syndrome coronavirus 2 (coronavirus disease 2019 [COVID-19]) infection. Pregnant women are a vulnerable population to infectious disease pandemics with dramatically increased infectious diseases-related serious complications, such as the need of hospitalizations, the need of admission to intensive care unit, and the final disease-related death compared with those nonpregnant counterparts or those pregnant women without infection. Several studies have shown that vaccinations in pregnancy are a safe and highly effective strategy, not only for pregnant women but also for fetus and/or newborn because of the passive transplacental transfer of antibodies to the offspring. Active and passive prevention of infectious diseases is approved as effective strategies for women who attempt to become pregnant or during pregnancy. Despite the large and proven scientific evidence, pregnant women still puzzle over whether they should get vaccinated. The question therefore arises: Why are pregnant women so reluctant to receive vaccination? The explanation is more likely in the way that the benefits of vaccination have been communicated "confusedly." In fact, like virtually all clinical trials, all the COVID-19 vaccine trials have excluded pregnant and lactating women from participating, contributing to uncertainty of safety and efficacy in COVID-19 vaccines that have been well prepared and available for the general adult population worldwide. Moreover, messenger RNA vaccine is a relatively brand-new vaccine, and experience with this type of vaccine is still scarce. It is hard to overcome this innovation deadlock. The knowledge and awareness of pregnant women who are at risk, and full information on the knowledge of vaccines and related preventable diseases in pregnant women may avoid hesitancy and increase vaccine acceptance. The current review is a part two addressing the impact of COVID-19 on pregnant women. We focus on the up-to-date information about the application of vaccination on pregnant women, especially during this COVID-19 pandemic.

Infectious Respiratory Diseases Decreased during the COVID-19 Pandemic in South Korea

Infectious respiratory diseases are highly contagious and very common, and thus can be considered as one of the leading causes of morbidity and mortality worldwide. We followed up the incidence rates (IRs) of eight infectious respiratory diseases, including chickenpox, measles, pertussis, mumps, invasive pneumococcal disease, scarlet fever, rubella, and meningococcal disease, after COVID-19 mitigation measures were implemented in South Korea, and then compared those with the IRs in the corresponding periods in the previous 3 years. Overall, the IRs of these diseases before and after age- or sex-standardization significantly decreased in the intervention period compared with the pre-intervention periods (p < 0.05 for all eight diseases). However, the difference in the IRs of all eight diseases between the IRs before and after age-standardization was significant (p < 0.05 for all periods), while it was not significant with regard to sex-standardization. The incidence rate ratios for eight diseases in the pre-intervention period compared with the intervention period ranged from 3.1 to 4.1. These results showed the positive effects of the mitigation measures on preventing the development of respiratory infectious diseases, regardless of age or sex, but we need to consider the age-structure of the population to calculate the effect size. In the future, some of these measures could be applied nationwide to prevent the occurrence or to reduce the transmission during outbreaks of these infections. This study provides evidence for strengthening the infectious disease management policies in South Korea.