Discrepancy in impact of maternal milk on vertical transmission between Hepatitis B virus and Human cytomegalovirus

Viruses and Human Milk: Transmission or Protection?

Human milk (HM) is considered the best source of nutrition for infant growth and health. This nourishment is unique and changes constantly during lactation to adapt to the physiological needs of the developing infant. It is also recognized as a potential route of transmission of some viral pathogens although the presence of a virus in HM rarely leads to a disease in an infant. This intriguing paradox can be explained by considering the intrinsic antiviral properties of HM. In this comprehensive and schematically presented review, we have described what viruses have been detected in HM so far and what their potential transmission risk through breastfeeding is. We have provided a description of all the antiviral compounds of HM, along with an analysis of their demonstrated and hypothesized mechanisms of action. Finally, we have also analyzed the impact of HM pasteurization and storage methods on the detection and transmission of viruses, and on the antiviral compounds of HM. We have highlighted that there is currently a deep knowledge on the potential transmission of viral pathogens through breastfeeding and on the antiviral properties of HM. The current evidence suggests that, in most cases, it is unnecessarily to deprive an infant of this high-quality nourishment and that the continuation of breastfeeding is in the best interest of the infant and the mother.

Altered expression of endosomal Toll-like receptors and HBeAg seropositivity may act synergistically towards the vertical transmission of HBV

PROBLEM

Hepatitis B is one of the leading causes of mortality in India. Despite the mass vaccination programme, the burden of the infection is still increasing due to its vertical transmission. Asymptomatic nature of hepatitis B virus (HBV) infection owing to immune tolerance among pregnant women is a major issue in this regard.

METHOD OF STUDY

As such, this study aims to investigate the potential role of altered Toll-like receptor (TLR) expression (TLR-3, 7 and 9) along with peripheral blood HBeAg status in attaining differential cord blood (CB) HBV DNA status.

RESULT

Expression analysis reveals an overall downregulation of expression with mean ± SD value 1.14 ± 1.05, 0.86 ± 0.5 and 0.71 ± 0.4 (TLR 3, 7 and 9, respectively) upon comparison with healthy women. Further stratification based on CB HBV DNA status; the downregulation of expression was found to be significantly (p < .05) associated with positive CB HBV DNA status apart from peripheral HBeAg status. One hundred percent HBeAg positive parturiting women exhibit positive CB HBV DNA. Pearson's correlation analysis reveals a positive correlation between CB HBV DNA status and altered TLR expression, HBeAg status and mother HBV DNA status and as such can be associated with the potential risk of HBV vertical transmission.

CONCLUSION

This study suggests that the downregulation of TLR 3, 7 and 9 may be a risk factor for potential vertical transmission of HBV.

Pharmacological approaches to prevent vertical transmission of HIV and HBV

INTRODUCTION

Mother-to-child transmission (MTCT) is mainly responsible for the global pediatric HIV and HBV epidemic. Vertical transmission can be prevented and reduced through a series of interventions at the primary healthcare level, including extensive screening of pregnant women, administration of antivirals or immune-based treatments, counselling on type of delivery and breastfeeding.

AREAS COVERED

In this narrative review, approved therapeutic options for the treatment of pregnant women living with HIV or HBV are discussed with special focus on efficacy and safety profiles of each agent or drug class examined. The search was performed using Medline (via PubMed), Web of Science, and Google Scholar to identify studies assessing vertical transmission of both HIV and HBV.

EXPERT OPINION

Elimination of MTCT of both infections is firmly endorsed by major global commitments and the integration of tailored preventive interventions into maternal and newborn health services is of strategical importance to achieve this critical target. However, further research centered on antiviral-based and immunization trials among pregnant women is urgently needed to mitigate the risk of maternal and neonatal adverse outcomes, effectively prevent transmission to the offspring and finally eliminate the pediatric HIV and HBV epidemic, one of the key global health challenges of our time.

Clinical presentation and transmission of postnatal cytomegalovirus infection in preterm infants

BACKGROUND

Preterm infants are at greater risk of developing postnatal cytomegalovirus (CMV) infection with serious symptoms. Breast milk is the main route of CMV transmission in populations with a high seroprevalence.

OBJECTIVES

This study aimed to investigate the clinical presentation and transmission of postnatal CMV (pCMV) infection via breast milk in preterm infants under the specific setting of our neonatal intensive care unit (NICU).

METHODS

The medical records of 147 preterm infants were reviewed retrospectively, and their clinical characteristics and outcomes were analyzed. Breast milk and infant urine samples were collected every two weeks until discharge, and the kinetics of CMV loads were evaluated using a polymerase chain reaction assay.

RESULTS

Seventeen infants (11.6%) were diagnosed with pCMV infection during the study period. In comparison between the pCMV and control groups, the mean birth weight was significantly lower in the pCMV group than in the control group (1084.1 ± 404.8 g vs. 1362.5 ± 553.8 g, P = 0.047). Four (23.5%) patients had leukocytopenia, six (35.3%) had neutropenia, three (17.6%) had thrombocytopenia, and two (11.8%) had hyperbilirubinemia in the pCMV group. Five patients were treated with antiviral agents, and their CMV load in the urine decreased after treatment. CMV loads peaked at 3-5 weeks in breast milk, whereas they peaked at 8-12 weeks of postnatal age in infants' urine. A comparison between the median CMV load in breast milk from the pCMV and control groups revealed a significant difference (P = 0.043).

CONCLUSION

Most preterm infants with pCMV infection present a favorable clinical course and outcomes. A high CMV viral load in breast milk is associated with transmission. Further studies are warranted to prevent transmission and severe pCMV infections in preterm infants.

Incidence of Postnatal CMV Infection among Breastfed Preterm Infants: a Systematic Review and Meta-analysis

BACKGROUND

We performed a systematic review and meta-analysis to evaluate the incidence of breast milk-acquired cytomegalovirus (CMV) infection in preterm infants born to CMV-seropositive mothers.

METHODS

PubMed, Embase, and Cochrane Library databases were searched using the terms: ("breast feeding" or "breast milk" or "human milk" or "breast") and ("HCMV" or "cytomegalovirus") and ("infant, extremely premature" or "premature birth" or "newborn" or "neonate" or "low birth weight" or "very low birth weight" or "premature" or "preterm infant"). Studies that had information on CMV status and breast feeding were included in the meta-analysis.

RESULTS

A total of 2,502 newborns from 19 studies were included in this meta-analysis. The rate of postnatally acquired CMV infection among breastfed infants with CMV-seropositive mothers was 16.5% (95% confidence interval [CI], 0.10-0.26; P < 0.001). The infection rate was 26% with fresh breast milk, 8% with a combined diet of fresh and freeze-thawed breast milk, and 11% with freeze-thawed breast milk. Among cases where the CMV status of breast milk was determined, CMV shedding into breast milk occurred in 80.5% (95% CI, 0.71-0.87; P < 0.001) of CMV seropositive mothers. The breast milk-acquired CMV infection rate among infants fed CMV-positive breast milk was 20.7% (95% CI, 0.14-0.30; P < 0.001).

CONCLUSION

This meta-analysis examined the rate of breast milk-acquired CMV infections in preterm infants with CMV-seropositive mothers; the CMV infection rate was higher in preterm infants fed fresh breast milk. Until further data are available, we cautiously suggest the use of freeze-thawed breast milk, rather than fresh breast milk, for preterm infants or very low birth weight infants.

Epidemiological trends and virological traits of hepatitis B virus infection in pregnant women and neonates

In infants, hepatitis B virus (HBV) infections are mainly acquired by mother-to-child transmission (MTCT). Current tests for the presence of HBV markers at birth can neither confirm nor exclude MTCT. The aim of this study was to find an early diagnostic marker of HBV MTCT. From 2011 to 2016, we studied a total of 5999 pregnant women who gave birth at our hospital in Shenzhen City, China. HBsAg-positive mothers and their offspring (n=386 pairs) were tested at birth for HBV markers, and 207 infants were followed up at 7-12 months after birth. The HBsAg-seropositive rate of the pregnant women was 12.5%. Additionally, 28.0%, 36.0%, 98.5% and 6.6% of umbilical cord (UC) blood samples of neonates were found to be positive for HBsAg, HBeAg, anti-HBc and HBV-DNA, respectively, whereas for neonatal femoral venous (FV) blood, the percentages were 16.2%, 38.0%, 98.8% and 2.6%, respectively. Mothers with high HBV DNA loads and those who were HBeAg positive were the most likely to have HBV-positive offspring. Immunoprophylaxis failed in five infants: the difference in median HBV DNA titer between UC blood from infants with and without HBV MTCT was statistically significant, and there was no significant difference in HBV DNA titer between UC blood and in peripheral blood of infants with HBV MTCT. In conclusion, we found that HBeAg positivity and high HBV loads are strong risk factors for MTCT of HBV and that the HBV DNA titer in the UC is a good predictor for HBV MTCT.

Mechanisms and Prevention of Vertical Transmission in Chronic Viral Hepatitis

Vertical transmission (VT) is the primary route of transmission of viral hepatitis in children. The rate of VT ranges from 1-28% with hepatitis B virus (HBV) and 3-15% with hepatitis C virus (HCV). VT for both viruses can occur during the intrauterine or peripartum period. VT of HBV primarily occurs by intrauterine transmission (IUT). Hepatitis B surface antigen is unable to cross the placenta and, therefore, relies on processes like transplacental leakage, placental infection, cellular transmission by peripheral blood mononuclear cells, and germline transmission. HCV can also infect the fetus by IUT. Both viruses also have the potential for transmission during delivery, when there is increase chance of maternal-fetal blood exposure. HBV and HCV share some common risk factors for VT, including maternal viral load, human immunodeficiency virus co-infection and neonatal sex. Prevention of VT differs greatly between HBV and HCV. There are several alternatives for prevention of HBV VT, including antiviral medications during the third trimester of pregnancy and HBV vaccine, as well as hepatitis B immunoglobulin administration to infants post-partum. In contrast, there are no preventative interventions available for HCV. Despite these differences, the key to prevention with both viruses is screening women prior to and during pregnancy.