Three decades of neonatal vaccination has greatly reduced antenatal prevalence of hepatitis B virus infection among gravidae covered by the program

Change in Prevalence of Hepatitis B Virus Infection in Pregnant Women in the Last Two Decades in Thailand

Objectives: In Thailand, there has been a strategy to prevent the mother-to-child transmission of HBV for over 30 years. However, there is still a lack of empirical evidence regarding the effectiveness of this strategy. This study aims to investigate the trends in the prevalence of HBV infection in pregnant women and to identify factors that may be associated with the prevalence of HBV infection in pregnant women. Patients and Methods: A maternal-fetal medicine database was accessed to retrieve the consecutive obstetric records of women giving birth at Chiang Mai University Hospital, Thailand, from January 2003 to December 2022. All women undergoing HBV tests with available results were included for an analysis of the trends and changes in the prevalence of maternal HBV infection. Also, the rates of infection in different age cohorts were compared. Results: During the study period, a total of 36,958 women were eligible for analysis. Overall, the prevalence of HBV infection in pregnant women was found to be 5.3% (1970 cases). Overall, HBV prevalence fell from 6.11% in 2003 to 3.15% in 2022. There was a significant reduction, especially in the adolescent group, decreasing from 8.26% in 2003 to 0% in 2022. In the reproductive age group, the prevalence significantly decreased from 6.41% to 2.01%. However, the prevalence in the elderly group was unchanged. The only significant risk factor was the years in the early timeline of the study period, presumably associated with previous HBV vaccination. Other factors, such as socioeconomic status, residential area, and being a private case, were not correlated with the prevalence of HBV. Conclusion: The prevalence of HBV infection in pregnant women has significantly decreased in the past two decades from 6.11% in 2003 to 3.15% in 2022. The percentage of reduction was very striking in the adolescent group, dropping from 8.6% in 2003 to 0.0% in 2022 or being nearly eradicated in the most recent years. Our results suggest that the overall prevalence of HBV infection among our pregnant women will probably be less than 1.0% in the near future.

Possible Association between Genetic Diversity of Hepatitis B Virus and Its Effect on the Detection Rate of Hepatitis B Virus DNA in the Placenta and Fetus

Background: The prevalence of HBV infection and HBV genotypes varies from country to country, and the role of HBV genotypes in the presence of HBV in the placenta and fetus has never been explored. This study was conducted to (1) identify HBV genotypes, and their frequencies, that infected Northern Thai pregnant women; (2) evaluate the association between HBV genotypes and the detection rate of HBV DNA in the placenta and fetus; (3) evaluate the association between specific mutations of the HBV genome and HBV DNA detection in placental tissue; and (4) identify the mutation of the HBV genome that might occur between maternal blood, placenta, and cord blood. Methods: Stored samples of the maternal blood, placental tissue, and cord blood that were collected from 145 HBsAg-positive pregnant Thai women were analyzed to identify HBV DNA. Results: Approximately 25% of infected mothers had fetal HBV DNA detection, including cases with concomitant HBV DNA detection in the placenta (77.3%). A total of 11.7% of cases with placental detection had no HBV DNA detection in the maternal blood, indicating that the placenta could be a site of HBV accumulation. Of the 31 HBV-positive blood samples detected by nested PCR, the detected strains were subgenotype C1 (77.4%), subgenotype B9 (9.7%), and subgenotype C2, B2, B4, and recombinant B4/C2 (3.2% for each). Genotype B had a trend in increased risk of placental HBV DNA detection compared to genotype C, with a relative risk of 1.40 (95% CI: 1.07-1.84). No specific point mutation had a significant effect on HBV DNA detection in placental tissue. Mutation of C454T tended to enhance HBV DNA detection in placental tissue, whereas T400A tended to have a lower detection rate. No mutation was detected in different sample types collected from the same cases. Conclusions: HBV DNA detection in the fetus was identified in approximately 25% of HBV-positive mothers, associated with the presence of HBV in the placenta in most cases. The placenta could possibly be a site of HBV accumulation. Subgenotype C1 was the most common subgenotype, followed by subgenotype B9. HBV genotype B possibly had a higher trend in intrauterine detection than HBV genotype C. Mutation is unlikely to occur during intrauterine exposure.

Correlations between maternal hepatitis B virus carrier status and Down's syndrome prenatal screening indicators and their effects on the screening results

The aim of this study was to determine the correlation between maternal hepatitis B virus (HBV) carrier status and pregnancy-associated serum screening indicators, as well as their implications on the prenatal screening results of Down's syndrome (DS). This retrospective cohort study included two groups, namely the healthy gravidas group (n = 19804) and the maternal HBV carrier group (n = 792). Serum pregnancy-associated plasma protein A (PAPP-A), alpha-fetoprotein (AFP), and free beta subunit of human chorionic gonadotropin (free β-hCG) levels, as well as the foetal nuchal translucency (NT) thickness, were measured. Multivariatebinary logistic regression analysis was used to evaluate the association between the HBV carrier status and prenatal screening biomarkers. The PAPP-A multiple of the medium (MoM) and free β-hCG MoM in the first trimester were significantly higher in the HBV carrier group than in the control group (both P < .05). Multivariate binary logistic regression analysis showed that HBV carrier status was identified as a risk factor for PAPP-A and the intrahepatic cholestasis of pregnancy (ICP), with adjusted odds ratios (aOR) of 1.363 (1.216-1.527) and 3.255 (2.356-4.499), respectively. Pregnant women with HBV carrier status had higher influence on serum PAPP-A level and ICP, and the risk calculation algorithm for DS in HBV carriers should be corrected in the first trimester of pregnancy. IMPACT STATEMENTWhat is already known on this subject? The maternal serum levels of pregnancy-associated plasma protein A (PAPP-A), alpha-fetoprotein (AFP), and free beta subunit of human chorionic gonadotropin (free β-hCG), as well as the foetal nuchal translucency (NT) thickness, have been collectively used in the prenatal screening of Down's syndrome (DS), Edward's syndrome (ES), and open neural tube defects (ONTD). However, many factors, including the maternal age; maternal weight; gestational age; race; history of smoking and so on can affect those serum biomarker levels. Our aim is to know whether there is a difference for HBV status to pregnancy-associated serum screening indicators hoes.What the results of this study add? The PAPP-A multiple of the medium (MoM) and free β-hCG MoM in the first trimester were significantly higher in the HBV carrier group than in the control group (both p < .05). Multivariate binary logistic regression analysis showed that the PAPP-A and intrahepatic cholestasis of pregnancy (ICP) were risk factors for HBV carriers, with aORs of 1.363 (1.216-1.527) and 3.255 (2.356-4.499), respectively.What the implications are of these findings for clinical practice and/or further research? The PAPP-A MoM in maternal HBV carriers was significantly higher than that in healthy gravidas, and the risk calculation algorithm for DS in maternal HBV carriers should be corrected in the first trimester of pregnancy.

Maternal hepatitis B surface antigen Carrier Status and Pregnancy Outcome: A Retrospective Cohort Study

To investigate the effect of maternal hepatitis B surface antigen (HBsAg) carrier status during pregnancy on pregnancy outcomes in a population of patients in Hangzhou, China. A retrospective cohort study was conducted to analyse data from 20 753 pregnant women who delivered at Hangzhou Women's Hospital between January 2015 and March 2020. Of these, 18 693 were normal pregnant women (the non-exposed group) and 735 were HBsAg carriers (the exposed group). We then analysed by binary multivariate logistic regression to determine the association between maternal HBsAg-positive and adverse pregnancy outcomes. The prevalence of HBsAg carriers was 3.78% and the odds ratio (OR) for maternal age in the exposed group was 1.081. Pregnant women who are HBsAg-positive in Hangzhou, China, are at higher risk of a range of adverse pregnancy outcomes, including intrahepatic cholestasis of pregnancy (ICP) (adjusted OR (aOR) 3.169), low birth weight (aOR 2.337), thrombocytopenia (aOR 2.226), fallopian cysts (aOR 1.610), caesarean scar pregnancy (aOR 1.283), foetal distress (aOR 1.414). Therefore, the obstetricians should pay particular attention to ICP, low birth weight, thrombocytopenia, fallopian cysts, caesarean scar, foetal distress in HBsAg-positive pregnant women.

Pakistan Ranks Third Globally With the Most Unvaccinated Children: Is the Impact of Parental Perception and Attitude on Immunization an Essential Contributing Factor to an Unsuccessful Vaccination Coverage?

Introduction

Having the third-highest burden of child mortality and ranking third globally for the most under-vaccinated children, Pakistan contains 15% of its population under the age of five, which accounts for 50% of the mortality rate in this country. Every year, almost three million children miss out on an entire course of the most readily available vaccines, leaving them vulnerable to life-threatening diseases. The Expanded Program of Immunization (EPI) was launched in 1978 to protect children from vaccine-preventable childhood diseases. It is the main program through which routine immunization is provided to the public. However, since its inception within Pakistan, it has encountered many problems, including a lack of parental awareness and education. Low literacy rate, socio-economic disparities, cultural and religious beliefs have made parents doubtful about vaccinations. This term is known as vaccine hesitancy. Belief in conspiracy theories has also led to reduced vaccination coverage in Pakistan.

Methods 

A cross-sectional study was conducted on 300 parents with children under five, chosen from Karachi, Pakistan, through a convenience sampling technique. The data was collected via 300 self-administered or researcher administered questionnaires. Associations were evaluated using the chi-square test with the level of significance taken as p < 0.05 and Cramer's V to determine the strength of these associations. Data analysis was done using Statistical Package for the Social Sciences (SPSS) version 20.0. 

Results 

Strong associations were found between parental knowledge of immunization, vaccines, and willingness to get their children immunized. Associations were greater and significant in parents with a higher level of education compared to lower. However, lack of knowledge about certain essential vaccines like Pentavalent, Pneumococcal, and IPV was an important aspect to consider. Also, it was noted that their inability to access these free vaccines was due to their own firm beliefs. It was also about the lack of awareness and facilities for a better and beneficial program. 22.3% of parents said that administering multiple vaccines at a time would be harmful to their child, and 21.7% believed it would cause the disease it's supposed to prevent. However, the majority of the parents said they would strongly recommend others to get vaccinated. In this study, religions included and investigated mostly encouraged vaccination to their relatives (p value= 0.079). Occupation and Monthly income had little to no effect on the immunization regime of young children. 

Conclusion

An impact of higher levels of education on the perceptions and attitudes of parents regarding the immunization of children was noted. Consequently, as religion, gender, occupation, and monthly income do not affect parents' perceptions regarding immunizations, the problem lies within their knowledge and understanding of basic medical science and easily communicable diseases. Oblivious to the consequences of contracting a lethal disease, it has developed a laid-back attitude amongst parents. Hence, awareness and education of parents regarding vaccine-preventable diseases by the healthcare system and the governing bodies can lead to a higher successful immunization rate.

Hepatitis B virus infection seromarkers among college freshmen and their immune responses to different vaccination policies of hepatitis B vaccine

BACKGROUND

College students are one of the susceptible population of Hepatitis B virus (HBV) infection. We aim to delineate HBV infection seromarkers among college freshmen and to evaluate immunological response of vaccination immunization for hepatitis B vaccine (HepB).

METHODS

A simple random sampling method was adopted to select subjects and who met the "inclusion and exclusion criteria" and who with history of vaccination were selected as the observation objects. HBsAg and anti-HBs levels were detected before revaccination. Subjects with negative anti-HBs before immunization were inoculated with 20 ug HepB according to the 0-1-6 procedure and those with weak positive anti-HBs before immunization were inoculated with 1-dose 20 ug HepB. Anti-HBs levels were detected after HepB booster. Combined with the results of anti-HBs, their immune response to HepB and influencing factors in freshmen were investigated. Anti-HBs before immunization was negative and ≥10 m IU/ml after immunization was considered positive conversion; anti-HBs before immunization was weak positive and anti-HBs≥100 m IU/ml after immunization was also considered positive conversion.

RESULTS

A total of 10645 freshmen were included. The total rate of HBsAg carriers was 0.6% (63/10645), and the strong positive rate of anti-HBs was 16.1% (1706/10645), the weak positive rate was 14.4% (1526/10645).1286 freshmen were vaccinated with HepB and completed the questionnaire survey. About 79.0% (154/195) of freshmen's anti-HBs turned strong positive after receiving 1-dose HepB and 100.0% (1091/1091) turned positive after receiving 3-doses HepB. The Geometrical Mean Titer (GMT) of anti-HBs was significantly influenced by gender, registration and the immunization doses of HepB.

CONCLUSION

The HBsAg carrying rate and anti-HBs positive rate of college freshmen were low, and the HepB has a good effect on the immunity of college freshmen. Increasing the immunization rate of HepB is very important for the prevention and control of hepatitis B.

Hepatitis B surface antigen and antibody positivity among women of childbearing age after three decades of universal vaccination in South Korea

OBJECTIVES

We estimated the impact of universal hepatitis B immunization using 18-year data of women who are of childbearing age in South Korea.

METHODS

We used hepatitis B surface antigen (HBsAg) and antibody (anti-HBs) data of 145,993 women aged 20-49 years during 2001-2018 at the Gangnam CHA Medical Center. Annual prevalences of HBsAg and anti-HBs positivity were calculated and tested for linear trend. We conducted age-period-cohort (APC) analysis to obtain period and cohort effect.

RESULTS

Overall proportion of HBsAg positivity was 3.5% (n = 5050) and anti-HBs positivity was 75.3% (n = 109,907) during the study period. HBsAg positivity percentage decreased from 5.1% in 2001 to 2.5% in 2018 (P < 0.001) while anti-HBs positivity increased from 59.9% to 75.8% (P = 0.002). Average annual percent change of HBsAg positivity was -5.9% (95% confidence interval (CI): -6.9%, -4.8%). The period and cohort RR curve identified a consistent decrease in HBsAg positivity over time and across generations.

CONCLUSIONS

We observed a concurrent decrease in HBsAg and an increase in anti-HBs seropositivity among Korean women of childbearing age, implicating success in preventing vertical transmission.

The Importance of Hepatitis B Antigen Screening in Pregnancy

In the United States, pregnant women are screened for hepatitis B antigen because of the significant risk of perinatal vertical transmission of hepatitis to the fetus. It is important that the maternal hepatitis B antigen screen is documented in the medical record to ensure appropriate prophylaxis for the neonate. The purpose of this column is to discuss the pathophysiology of hepatitis B, as well as the screening process and prophylaxis for the neonate.

Hepatitis B vaccine development and implementation

Vaccination against hepatitis B is the most effective strategy to control HBV infection. The first licensed hepatitis B vaccine was developed by the purification of hepatitis B surface antigen (HBsAg) from plasma of asymptomatic HBsAg carriers. Then, the recombinant DNA technology enabled the development of recombinant hepatitis B vaccine. A series of three doses vaccine can elicit long-term protection more than 30 y. Concurrent use of hepatitis B immunoglobulin and hepatitis B vaccine has substantially reduced the mother-to-child transmission of HBV, nearly zero infection in children of carrier mother with negative hepatitis B e antigen (HBeAg) and 5-10% infection in children of HBeAg-positive mothers. By the end of 2018, 189 countries adopted universal hepatitis B vaccination program, which has dramatically reduced the global prevalence of HBsAg in children <5 y of age, from 4.7% in the prevaccine era to 1.3% in 2015. However, the implementation of universal hepatitis B vaccination in some regions is suboptimal and timely birth dose vaccine is not routinely administered in more than half of newborn infants. Optimal worldwide universal hepatitis B vaccination requires more efforts to overcome the social and economic challenges.

Prevention of perinatal hepatitis B virus transmission

PURPOSE

Chronic hepatitis B virus (HBV) infection remains endemic and continues to cause significant morbidity and mortality. It is a global health issue and the World Health Organization aims to eradicate HBV by 2030. Since vertical transmission accounts for the majority of chronic HBV infection, pregnancy offers an excellent opportunity to achieve complete HBV eradication by providing effective immunization of the offspring.

METHODS

We reviewed recent publications identified from PubMed database using a combination of the relevant keywords for HBV, pregnancy, vertical transmission, immunoprophylaxis failure and antiviral treatment.

RESULTS

We summarized the evidence of factors associated with, and measures to reduce and prevent maternal to child transmission, including the use of antiviral treatment during pregnancy to prevent immunoprophylaxis failure. Evidence suggested that highly viremia mother can be offered antenatal antiviral treatment to prevent immunoprophylaxis failure. We elaborated the viral load threshold to start maternal antiviral treatment and the importance of timely neonatal vaccination. A clinical algorithm to manage HBV carriers during pregnancy was proposed.

CONCLUSION

Eradication of HBV is achievable with optimal management of HBV carriers, especially during pregnancy by interruption of vertical transmission. Routine antenatal screening and neonatal immunoprophylaxis remain the key measures to reduce the global HBV burden, and additional antenatal antiviral treatment could further minimize the chance of persistent infection in newborns.