Estimating the burden of hepatitis B virus infection in Laos between 2020 and 2021: A cross-sectional seroprevalence survey.

Background: Laos is considered highly endemic for persistent infection with hepatitis B virus (HBV). To eliminate this burden, it has gradually implemented universal anti-hepatitis B immunisation of newborns over the past two decades. Methods: Using VIKIA® HBsAg, a rapid test for the qualitative detection of the HBV surface antigen, we conducted between Sep 1st, 2020 and Aug 31st, 2021 the largest prospective prevalence survey ever in Laos. This survey included blood donors (BD, n = 42,277), patients attending care in capital and provincial hospitals (n = 37,347) including attending mothers (n = 20,548), HIV-infected patients (n = 7439, recruited from 2009 to 2020), students from the Health Sciences University (n = 609), and outpatients (n = 350) coming for diagnosis at the Center Infectiology Lao-Christophe Mérieux in Vientiane. In total, 88,022 persons were tested, representing approximately 1.22% of the national population. To reach a reasonable estimate of HBsAg prevalence in Laos, we segmented the population according to three variables, age (≤20 years as a cut-off), sex, and geographical origin. BD values were used to estimate HBsAg prevalence in patients aged <20 while hospital survey prevalence was used to estimate the prevalence in those aged older than 20 years. Findings: We observed an HBsAg seroprevalence ranging from 2.6% in blood donors to 8.0% in HIV-infected patients. In BD, men were significantly more at risk to be carriers than women (RR = 1.2, P = 0.00063). For BD, attending mothers, or HIV-infected patients, HBsAg was significantly more prevalent in northern Laos (5.1-8.4%) than in central (2.0-8.1%) or southern parts of the country (2.2-6.9%), thereby delineating a North-to-South gradient. Interpretation: We considered that HBsAg prevalence probably ranges between 5.0% and 6.0% of the total population. Thus, we consider that Laos may no longer be highly endemic for chronic HBV infection but rather a country with intermediate endemicity. Funding: The funding sources were the Agence Universitaire de la Francophonie, the French Government, the French Institute for Sustainable Development (IRD), and European Union's Horizon 2020 Marie Sklodowska-Curie Actions (MSCA) - Research and Innovation Staff Exchange - (RISE) under grant agreement N° 823935.

Perinatal hepatitis B virus transmission in Lao PDR: A prospective cohort study.

BACKGROUND: Mother-to-child transmission of hepatitis B virus (HBV) is the main cause of new infections worldwide. We aimed at assessing the percentage of infants successfully immunized in two major hospitals in Vientiane, Lao PDR where HB immune globulin (HBIg) is not available. METHODS: We studied a prospective cohort of chronically HBV infected pregnant women and their infants until 6 months post-partum from January 2015 to March 2017. All infants received HB vaccine at birth and 6, 10 and 14 weeks thereafter, and HBV status was assessed at 6 months of age. HBV surface gene sequencing was performed in infected mother-infant pairs. RESULTS: Of 153 mothers with HB surface antigen (HBsAg), 60 (39%) had detectable serum HBe antigen (HBeAg). HBeAg positive pregnant women were younger than those negative (median age 26 versus 28 years; p = 0.02) and had a significantly higher HBV viral load at delivery (median 8.0 versus 4.0 log10 IU/mL, p <0.001). Among the 120 infants assessed at 6 months of age, 5 (4%) were positive for HBsAg and had detectable HBV viral load by polymerase chain reaction. All were born to mothers with HBeAg and viral load >8.5 log10 IU/mL. However, only four (3.3%, 95% CI 0.5% to 7.0%) had a virus strain closely related to their mother's strain. HBV surface gene mutations were detected in 4 of the 5 infected infants. Anti-HBs antibody levels were below 10 IU/L in 10 (9%) uninfected infants at 6 months of age. CONCLUSIONS: Mother-to-child transmission occurred less frequently than expected without the use of HBIg. Adding HBIg and/or maternal antiviral prophylaxis may have prevented some of these infections. The observation of unsatisfactory levels of anti-HBs antibodies in 9% of the uninfected infants at 6 months highlights the need for improvement of the universal immunization procedures.

Prevalence of Hepatitis B Virus Infection among Pregnant Women Attending Antenatal Clinics in Vientiane, Laos, 2008-2014.

The Lao People's Democratic Republic (PDR) is still considered a highly endemic country for hepatitis B, mainly due to perinatal transmission of hepatitis B virus (HBV), despite efforts made since 2004 for universal immunization of newborns. The prevalence of HBV surface antigen (HBsAg) carriage in pregnant women is a relevant marker for the risk of mother-to-child HBV transmission. This study aimed to assess the changes in prevalence of HBV infection among pregnant women attending the Mahosot Prenatal Clinic (Vientiane Capital). Methods. A retrospective study was performed in the Mahosot Hospital Laboratory to collect and analyze all the results of HBsAg testing in pregnant women from 2008 to 2014. Results. Of a total of 13,238 tested women of mean age of 26 years, 720 women (5,44% [95 CI: 5.1-5.8%]) were found HBsAg positive, the annual prevalence ranging from 4.6% to 6.2%. A slight but steady and significant decrease in prevalence over the 7 years of the study could be documented. Conclusion. Although below the 8% hyperendemic threshold, the HBsAg prevalence observed in pregnant women in Vientiane reflects a high risk of HBV perinatal transmission and call for a widespread infant immunization with an HBV vaccine birth dose.

Vaccination status, knowledge and awareness towards hepatitis B among students of health professions in Vientiane, Lao PDR.

Health care workers (HCW) are a population at high risk of hepatitis B virus (HBV) infection, especially in endemic countries such as Lao PDR. Effective vaccines are available since over 10 years, but many HCWs are not aware of the risk of infection and are still not immunized against hepatitis B. This study aimed to assess immunization coverage against hepatitis B among the students of the University of Health Sciences (UHS) of Lao PDR in 2013 and to look for the causes of non-vaccination. A cross-sectional survey was conducted by self-administered questionnaire on a representative stratified sample of each academic year in each faculty. In total, 961 questionnaires were collected, Basic Sciences: 143, Medicine: 167, Pharmacy: 148, Dentistry: 139, Nursing Sciences: 159, Medical Technology: 99, and Postgraduate Studies: 106. Respondents were predominantly female (59.1%), mean age 25.1±7.0 years, single (76.3%), from the provinces (68.0%), of the Lao Loum ethnic group (84.4%). Among them, 21% were fully vaccinated against hepatitis B and 9.5% partially. Immunization coverage rates were significantly higher among women (p=0.01), students aged over 25 years, married or belonging to the post-graduate faculty (p<0.001). The most common reason (38.6%) given for non-vaccination was not knowing where to get vaccinated. Knowledge about hepatitis B, scored from 0 to 5, was poor (0-1) for 86.5% of the students, but 77.5% were aware of the hepatitis B vaccine. The knowledge scores were significantly higher for students aged over 25 years, married or post-graduated (p<0.001). Vaccination coverage against hepatitis B is dramatically low among students of health professions in Laos, largely because of their lack of knowledge and awareness. Upon admission to the University, all future HCWs should receive information about the occupational risks of blood-borne viruses transmission and be encouraged to get vaccinated against hepatitis B.

Knowledge, awareness and attitudes about cervical cancer among women attending or not an HIV treatment center in Lao PDR.

BACKGROUND: Cervical cancer is the first female cancer in Lao PDR, a low-income country with no national screening and prevention programs for this human papillomavirus (HPV) associated pathology. HIV-infected women have a higher risk of persistent oncogenic HPV infection.The purpose of this study was to determine the knowledge, awareness and attitudes about cervical cancer among Lao women attending or not an HIV treatment center, in order to understand if this attendance had offered an opportunity for information and prevention. METHODS: A cross-sectional case-control survey was conducted in three provinces of Lao PDR, Vientiane, Luang Prabang and Savannakhet. Cases were 320 women aged 25 to 65, living with HIV and followed in an HIV treatment center. Controls were 320 women matched for age and place of residence, not attending an HIV treatment center. RESULTS: Cases had a greater number of sexual partners and used condoms more often than controls. Only 36.6% of women had consulted a gynecologist (47.5% among cases and 25.6% among controls, p < 0.001) and 3.9% had benefited from at least one Pap smear screening (5.6% cases and 2.2% controls, p = 0.02). The average knowledge score was 3.5 on a 0 to 13 scale, significantly higher in cases than in controls (p < 0.0001). Despite having a lower education level and economic status, the women living with HIV had a better knowledge about cervical cancer and were more aware than the controls of the risk of developing such a cancer (35.9% vs. 8.4%, p = 0.0001). The main source of information was healthcare professionals. The main reasons for not undergoing Pap smear were the absence of symptoms and the default of medical injunction for cases, the lack of information and ignorance of screening usefulness for controls. CONCLUSION: In Lao PDR, routine consultation in HIV treatment centers is not enough harnessed to inform women of their high risk of developing cervical cancer, and to perform screening testing and treatment of precancerous lesions. Implementing this cost-effective strategy could be the first step toward a national prevention program for cervical cancer.

Antiretroviral therapy initiation in France: adherence to national guidelines and outcome.

OBJECTIVES AND METHODS: Retrospective study of all patients who started antiretroviral therapy (ART) in 2007 in a single center in Paris, with baseline characteristics and 1-year outcome, to assess adherence to national guidelines. RESULTS: We analyzed 118 patients. Time of ART initiation was in agreement with the guidelines for only 64 (54.2%) patients. Fifty patients (42%) started ART with AIDS or a CD4 count <200 cells/mm(3). In all, 62 (52%) and 47 patients (40%) received a combination of 2 nucleoside analogues with efavirenz (EFV) and 1 ritonavir-boosted protease inhibitor (PI/r), respectively. Treatment regimens were in accordance with the guidelines for 114 patients (97%). At 1 year, 16 patients (13.5%) were lost to follow-up, only 5 (4.9%) experienced HIV disease progression or death, but 19 (18.6%) required hospitalization. Antiretroviral therapy was changed in 21 patients (21%). Ten patients (8.4%) experienced virologic failure. CONCLUSION: Antiretroviral therapy was in agreement with guidelines for the choice of combination but was often initiated too late.