Residual risk of mother-to-child transmission of HBV despite timely Hepatitis B vaccination: a major challenge to eliminate hepatitis B infection in Cambodia.

BACKGROUND: In countries with intermediate or high hepatitis B virus (HBV) endemicity, mother-to-child transmission (MTCT) represents the main route of chronic HBV infection. There is a paucity of information on HBV MTCT in Cambodia. This study aimed to investigate the prevalence of HBV infection among pregnant women and its MTCT rate in Siem Reap, Cambodia. METHODS: This longitudinal study included two parts, study-1 to screen HBsAg among pregnant women and study-2 to follow up babies of all HBsAg-positive and one-fourth of HBsAg-negative mothers at their delivery and six-month post-partum. Serum or dried blood spot (DBS) samples were collected to examine HBV sero-markers by chemiluminescent enzyme immunoassay (CLEIA), and molecular analyses were performed on HBsAg-positive samples. Structured questionnaires and medical records were used to examine the risk factors for HBV infection. MTCT rate was calculated by HBsAg positivity of 6-month-old babies born to HBsAg-positive mothers and ascertained by the homology of HBV genomes in mother-child pair at 6-month-old. RESULTS: A total of 1,565 pregnant women were screened, and HBsAg prevalence was 4.28% (67/1565). HBeAg positivity was 41.8% and was significantly associated with high viral load (p < 0.0001). Excluding subjects who dropped out due to restrictions during COVID-19, one out of 35 babies born to HBsAg-positive mothers tested positive for HBsAg at 6 months of age, despite receiving timely HepB birth dose and HBIG, followed by 3 doses of HepB vaccine. Hence the MTCT rate was 2.86%. The mother of the infected baby was positive for HBeAg and had a high HBV viral load (1.2 × 109 copies/mL). HBV genome analysis showed 100% homology between the mother and the child. CONCLUSIONS: Our findings illustrate the intermediate endemicity of HBV infection among pregnant women in Siem Reap, Cambodia. Despite full HepB vaccination, a residual risk of HBV MTCT was observed. This finding supports the recently updated guidelines for the prevention of HBV MTCT in 2021, which integrated screening and antiviral prophylaxis for pregnant women at risk of HBV MTCT. Furthermore, we strongly recommend the urgent implementation of these guidelines nationwide to effectively combat HBV in Cambodia.

Modified ARCHITECT® serologic assays enable plasma-level performance from dried blood spot samples.

Dried blood spots (DBSs) provide an alternative sample input for serologic testing. We evaluated DBSs for the ARCHITECT® hepatitis B surface antigen (HBsAg) NEXT, hepatitis B e-antigen (HBeAg), anti-hepatitis B core antigen (anti-HBc II), HIV antigen/antibody (Ag/Ab) Combo and AdviseDx SARS-CoV-2 IgG II assays. Assay performance with DBSs was assessed with or without assay modification and compared with on-market assay with plasma samples. DBS stability was also determined. HBsAg NEXT and HIV Ag/Ab Combo assays using DBSs showed sensitivity and specificity comparable to that of on-market assays. Modified HBeAg, anti-HBc II and SARS-CoV-2 IgG II DBS assays achieved performance comparable to on-market assays. Use of DBSs as input for high-throughput serologic assays is expected to have significant implications for improving population surveillance and increasing access to diagnostic testing.

Reaction of SARS-CoV-2 antibodies with other pathogens, vaccines, and food antigens.

It has been shown that SARS-CoV-2 shares homology and cross-reacts with vaccines, other viruses, common bacteria and many human tissues. We were inspired by these findings, firstly, to investigate the reaction of SARS-CoV-2 monoclonal antibody with different pathogens and vaccines, particularly DTaP. Additionally, since our earlier studies have shown immune reactivity by antibodies made against pathogens and autoantigens towards different food antigens, we also studied cross-reaction between SARS-CoV-2 and common foods. For this, we reacted monoclonal and polyclonal antibodies against SARS-CoV-2 spike protein and nucleoprotein with 15 different bacterial and viral antigens and 2 different vaccines, BCG and DTaP, as well as with 180 different food peptides and proteins. The strongest reaction by SARS-CoV-2 antibodies were with DTaP vaccine antigen, E. faecalis, roasted almond, broccoli, soy, cashew, α+ß casein and milk, pork, rice endochitinase, pineapple bromelain, and lentil lectin. Because the immune system tends to form immune responses towards the original version of an antigen that it has encountered, this cross-reactivity may have its advantages with regards to immunity against SARS-CoV-2, where the SARS-CoV-2 virus may elicit a "remembered" immune response because of its structural similarity to a pathogen or food antigen to which the immune system was previously exposed. Our findings indicate that cross-reactivity elicited by DTaP vaccines in combination with common herpesviruses, bacteria that are part of our normal flora such as E. faecalis, and foods that we consume on a daily basis should be investigated for possible cross-protection against COVID-19. Additional experiments would be needed to clarify whether or not this cross-protection is due to cross-reactive antibodies or long-term memory T and B cells in the blood.

Acute hepatitis B in pregnancy with surprisingly rapid clearance of serum HBs antigen associated with a favourable outcome.

Acute hepatitis B (AHB) is usually asymptomatic, but it can progress to chronic hepatitis B (HB) defined by HB surface antigen (HBsAg) persisting beyond 6 months. Nevertheless, the delay of HBsAg seroclearance is not well-defined. During pregnancy, the immune system of the pregnant women is altered and delayed HBsAg loss can be observed, leading to chronic infection. Here, we present an uncommon case of AHB in a pregnant woman in whom rapid HBsAg seroclearance (52 days after AHB) was associated with a favourable outcome (no injury to liver). This patient received tenofovir disoproxil fumarate promptly after diagnosis. The case raises questions about the use of antiviral treatment in AHB. This is generally not recommended in AHB, but it would be potentially useful in pregnant women to reduce the risk of chronic HB infection and could also prevent the transmission of the maternal precore mutation, thus reducing the significant risk of fulminant hepatitis in the infant. This case also highlights the impact of the hepatitis B virus (HBV) genotype and precore/core mutations on the clinical course of the disease.

Safety and antibody response to inactivated COVID-19 vaccine in patients with chronic hepatitis B virus infection.

BACKGROUND AND AIMS: The safety and antibody responses of coronavirus disease 2019 (COVID-19) vaccination in patients with chronic hepatitis B (CHB) virus infection is still unclear, and exploration in safety and antibody responses of COVID-19 vaccination in CHB patients is significant in clinical practice. METHODS: 362 adult CHB patients and 87 healthy controls at an interval of at least 21 days after a full-course vaccination (21-105 days) were enrolled. Adverse events (AEs) were collected by questionnaire. The antibody profiles at 1, 2 and 3 months were elucidated by determination of anti-spike IgG, anti-receptor-binding domain (RBD) IgG, and RBD-angiotensin-converting enzyme 2 blocking antibody. SARS-CoV-2 specific B cells were also analysed. RESULTS: All AEs were mild and self-limiting, and the incidence was similar between CHB patients and controls. Seropositivity rates of three antibodies were similar between CHB patients and healthy controls at 1, 2 and 3 months, but CHB patients had lower titers of three antibodies at 1 month. Compared to healthy controls, HBeAg-positive CHB patients had higher titers of three antibodies at 3 months (all P < .05) and a slower decline in antibody titers. Frequency of RBD-specific B cells was positively correlated with titers of anti-RBD IgG (OR = 1.067, P = .004), while liver cirrhosis, antiviral treatment, levels of HBV DNA, alanine aminotransferase (ALT) and aspartate aminotransferase (AST) and total bilirubin (TB) were not correlated with titers of anti-RBD IgG. CONCLUSIONS: Inactivated COVID-19 vaccines were well tolerated, and induced effective antibody response against SARS-CoV-2 in CHB patients.

A case series of COVID-19 patients with chronic hepatitis B virus infection.

Previous studies reported that coronavirus disease 2019 (COVID-19) was likely to result in liver injury. However, few studies reported the impacts of COVID-19 on liver function in patients with chronic liver diseases. We aimed to describe a case series of COVID-19 patients with chronic hepatitis B virus (HBV) infection. Confirmed hospitalized COVID-19 patients from hospitals in 10 cities of Jiangsu province, China, were retrospectively included between 18 January 2020 and 26 February 2020. Demographic information, epidemiologic data, clinical features, and treatment data were extracted from medical records. Seven COVID-19 patients with chronic HBV infection were included. Six (85.7%) patients were male. The patients aged from 33 to 49 years. Two patients had HBV-related cirrhosis. One patient (14.3%) was positive for serum HBV e-antigen. On admission, 1 (14.3%) patient had mildly elevated alanine aminotransferase (ALT) level (>40 U/L) and 1 (14.3%) had elevated aspartate aminotransferase (AST) level (>40 U/L). The serum albumin level and platelet counts were decreased in two patients with HBV-related liver cirrhosis. Three (42.9%) patients had elevated ALT level and 2 (28.6%) patients had elevated AST level in hospitalization. However, the peak ALT and AST level during hospitalization was 51 U/L and 44 U/L, respectively. As of 29 February 2020, all patients were discharged. No patient was admitted to the intensive care units or developed liver failure during hospitalization. The abnormalities of liver function are not uncommon on COVID-19 patients with chronic HBV infection in our case series. However, no patient developed severe liver-related complications during hospitalization.