109 Corresponding author: Eugenia-Andreea Marcu E-mail: busuandreea01@gmail.com Romanian JouRnal of infectious Diseases – Vol. XXIV, No. 2, Y eaR 2021 Risk of mother-to-child transmission in HIV-hepatitis B virus coinfection CASE PRESENTATIONS ABSTRACT Introduction. Human immunodeficiency virus (HIV) and hepatitis B virus (HBV) are two major causes of death worldwide. These two viruses share routes of transmission, and therefore, HIV–HBV coinfection is common and is associated with low plasma levels of CD4 T lymphocytes and accelerated liver disease progression. Maternal HIV and HBV infections have been individually associated with preterm birth and low birth weight. Case presentation. We describe the case of a 28-year-old patient, 14 weeks pregnant, asymptomatic, who performed Elisa-HIV 1,2 test within prenatal screening, with a positive result, in 2018. From the medical his- tory, we mention that the patient is known for about 5 years with HBV-hepatitis D virus coinfection, for which she underwent interferon treatment for a year. ART was initiated after one month with lamivudine / zidovu- dine + lopinavir / ritonavir. The patient was adherent to ART (adherence ≥ 95%) during pregnancy. Before birth, the immunovirological evaluation revealed the suppression of maternal HIV viral load, a moderate degree of immunosuppression and undetectable HBV-DNA. The patient gave birth by caesarean section to a female child, with a gestational age of 36 weeks, birth weight of 1730 g, lenght = 43 cm, head circumfer- ence = 30 cm, APGAR score = 8 points. The child received antiretroviral prophylaxis with retrovir+epivir, human hepatitis B immunoglobulin and was vaccinated against hepatitis B. The newborn was not vertically infected with HIV and HBV. Conclusions. Good adherence to ART during pregnancy has been associated with HIV viral load and HBV-DNA suppression and it led to the birth of a child who has not been infected with HIV or HBV. Maternal HIV-HBV coinfection was a significant risk factor for preterm birth and low birth weight. Keywords: HIV, hepatitis B virus, coinfection, maternal-fetal Ref: Ro J Infect Dis. 2021;24(2) DOI: 10.37897/RJID.2021.2.8 Article History: Received: 11 June 2021 Accepted: 22 June 2021 INTRODUCTION Human immunodeficiency virus (HIV) and hepa- titis B virus (HBV) are two major causes of death worldwide. These two viruses share routes of trans- mission, and therefore, HIV–HBV coinfection is common and is associated with low plasma levels of CD4 T lymphocytes and accelerated liver disease progression [1]. HIV-HBV coinfection has become a major public health issue. According to the World Health Organi- zation (WHO), there are 2.6 million HIV-HBV coin- fected people worldwide and chronic HBV infection affects an estimated of 5-20% of people living with HIV [2]. Among HIV-positive pregnant women, an Euro- pean study reported an incidence of HBV coinfection of 4.9%. According to the European Center for Disease Prevention and Control, Romania has an es- timated prevalence of HBV infection of 4.4% [3]. In the USA and Western Europe, sexual transmis- sion accounts for the majority of HBV infections, most infections occuring in adolescents and young adults. In Asia and Sub-Saharan Africa perinatal transmission of HBV infection is more common, oc- curring in 90% of exposed infants [4]. Maternal HIV and HBV infections have been in- dividually associated with preterm birth and low birth weight. Most studies on HBV coinfection in Florentina Dumitrescu 1,2 , Eugenia-Andreea Marcu 1,2 1 University of Medicine and Pharmacy, Craiova, Romania 2 “Victor Babeş” Clinical Hospital of Infectious Diseases and Pneumoftiziology, Craiova, Romania