Efficacité de la sérovaccination chez des nouveau-nés de mères antigènes HBs positif : à propos de 60 observations

Immunoprophylaxis failure and vaccine response in infants born to mothers with chronic hepatitis B infection in Djibouti

BACKGROUND

In endemic areas, vertical transmission of hepatitis B virus (HBV) remains a major source of the global reservoir of infected people. Eliminating mother-to-child transmission (MTCT) of HBV is at the heart of World Health Organization's goal of reducing the incidence of HBV in children to less than 0.1% by 2030. Universal screening for hepatitis B during pregnancy and neonatal vaccination are the main preventive measures.

AIM

To evaluate the efficacy of HBV vaccination combined with one dose of immunoglobulin in children born to hepatitis B surface antigen (HBsAg)-positive mothers in Djibouti city.

METHODS

We conducted a study in a prospective cohort of HBsAg-positive pregnant women and their infants. The study ran from January 2021 to May 2022, and infants were followed up to 7 mo of age. HBV serological markers and viral load in pregnant women were measured using aVidas microparticle enzyme-linked immunosorbent assay (Biomérieux, Paris, France) and the automated Amplix platform (Biosynex, Strasbourg, France). All infants received hepatitis B immunoglobulin and were vaccinated against HBV at birth. These infants were closely monitored to assess their seroprotective response and for failure of immunoprophylaxis. Simple logistic regression was also used to identify risk factors associated with immunoprophylaxis failure and poor vaccine response. All statistical analyses were performed with version 4.0.1 of the R software.

RESULTS

Of the 50 pregnant women recruited, the median age was 31 years, ranging from 18 years to 41 years. The MTCT rate in this cohort was 4% (2/50) in HBsAg-positive women and 67% (2/3) in hepatitis B e antigen-positive women with a viral load > 200000 IU/mL. Of the 48 infants who did not fail immunoprophylaxis, 8 (16%) became poor responders (anti-HB < 100 mIU/mL) after HBV vaccination and hepatitis B immunoglobulin, while 40 (84%) infants achieved a good level of seroprotection (anti-HB > 100 mIU/mL). Factors associated with this failure of immunoprophylaxis were maternal HBV DNA levels (> 200000 IU/mL) and hepatitis B e antigen-positive status (odds ratio = 158, 95% confidence interval: 5.05-4958, P < 0.01). Birth weight < 2500 g was associated with a poor immune response to vaccination (odds ratio = 34, 95% confidence interval: 3.01-383.86, P < 0.01).

CONCLUSION

Despite a failure rate of immunoprophylaxis higher than the World Health Organization target, this study showed that the combination of immunoglobulin and HBV vaccine was effective in preventing MTCT of HBV. Therefore, further studies are needed to better understand the challenges associated with immunoprophylaxis failure in infants in Djibouti city.

[Seroprevalence of HBsAg in pregnant women in central Morocco]

Maternal-fetal transmission of hepatitis B virus (HBV) is a global public health problem leading to the implementation of strengthened prevention measures. Viral replication in HIV-positive mother, assessed based on HBeAg positivity and the rate of viral load, determines the contamination risk which is very important during perinatal period. Mothers with chronic HBV are a real reservoir of vertical transmission of this infection. This is a prospective investigation of 1120 pregnant Moroccan women aiming to study the seroprevalence of HBsAg which was 2.35%, in order to supply the national evidence on this topic. Among these HIV-positive women who were HBsAg positive, 79.1% were HBeAg negative and underwent molecular research that was positive in 89.4% of cases. Immunization of women of childbearing age is one of the major pillars of prevention of HBV vertical transmission. Only 2.4% of our patients were vaccinated. This highlights the role of screening during pregnancy, which should focus on raising awareness about the importance of immunization in HIV-negative women and of monitoring using molecular biology tools in HIV-positive mothers in order to establish an appropriate prophylactic treatment.

Efficacy of hepatitis B sero-vaccination in newborns of African HBsAg positive mothers

BACKGROUND

Maternal-infant transmission of hepatitis B virus (HBV) during birth carries a high risk of chronic HBV infection in infants. Appropriate neonatal prophylaxis is effective in preventing perinatal transmission of HBV. The purpose of this study was to evaluate the protective efficacy of anti-HBV sero-vaccination in newborns of HBsAg positive mothers from Mayotte, French island in the Mozambican canal.

PATIENTS AND METHODS

One-hundred newborns of HBsAg positive mothers were identified retrospectively on the basis of hospital medical record and hepatitis B immune globulin (HBIG) prescriptions review from 1994 to 2007. To determine the rate of protective efficacy of neonatal prophylaxis defined by anti HBs antibodies >10 IU/mL with negative HBsAg, anti HBc and HBV DNA testing, HBV serological markers were performed in vaccinated children.

RESULTS

Eighty-three of 100 newborns (83%) were given a complete sero-vaccination. Maternal HBe Ag status at delivery (available in 93%) was positive in 56 (60%) of cases and HBV viral load (available in 57%) was <5 logIU/mL, between 5 and 7 logsIU/mL and >7 logsIU/mL in 23 (40.4%), 12 (21%) and 22 (38.6%), respectively. HBV markers in all children at a median age of 5 years [IQR 2-8] showed that 76% were protected with anti HBs >10 IU/mL, despite incomplete sero-vaccination in 12 infants; 6% of infants had anti-HBs and anti-HBc positivity with undetectable HBV DNA, 1% had isolated anti HBc while 14% were seronegative. Only 3% had evidence of immunoprophylaxis failure: 1 infant was HBsAg carrier and 2 had detectable HBV DNA without HBsAg (occult HBV infection). The only factor associated with sustained protective efficacy was on time serological control performed within one year of life, whereas maternal age, HBeAg status and HBV viral load on delivery were not.

CONCLUSION

The anti-HBV sero-vaccination of newborns of HBsAg-positive mothers is fairly done in Mayotte and allows a high protection of mother-to-child transmission in a mean endemic area with fair safety. Screening of sero-vaccination failures has to be reinforced in order either to revaccinate or to treat infected children.