Hepatitis B Virus (HBV) Infection in Patients at Pasteur Institute of Dakar in Senegal from 2016 to 2020: Prevalence and Seroprotection Level

Hepatitis B virus (HBV) infection is highly endemic in Senegal. Vaccination of all children against HBV was introduced in 1999 and included in Expanded Programme on Immunisation in 2005. The aim of this study was to assess the prevalence and immune status against HBV in patients received at Pasteur Institut in Dakar, Senegal. Methods: Between January 2016 and December 2020, patients aged between 1 and 96 years received laboratory were included in the study. Serum samples were analysed for HBV serology (HBs antigen: HBsAg, HBs antibody: HBsAb and HBc antibody: HBcAb) using ARCHITECT? analyser. Patients with anti-HBs antibody levels (HBsAb ≥ 10 IU/l) were considered seroprotected against HBV. Results: A total of 5629 patients were analysed with a mean age of 39 years and extremes from 1 to 96 years. The most represented age group was 31 - 45 years with 38.4%. HBsAg was present in 520 patients (9.2%) and was signed by sex and age group. Anti-HBc antibodies were found in 52.7% of patients and 1603 (28.48%) had isolated anti-HBs antibodies reflecting proportion of people vaccinated at the time of the study. However, 2143 patients (41.9%) had no seroprotection (HBsAb 10 IU/L) and 640 (12.6%) had strong seroprotection defined as HBsAb > 1000 IU/L. Conclusion: Our results show a significant presence of virus in Senegalese population and low vaccination coverage, especially in adults. Evaluation of HBsAb levels and provision of HBV booster shots should be considered for children in Senegal.

Effectiveness of hepatitis B virus vaccination program in Egypt:Multicenter national project

AIM:To assess the effectiveness of hepatitis B virus(HBV) vaccination program among fully vaccinated children.METHODS:A national community based crosssectional study was carried out in 6 governorates representing Egypt. A total of 3600 children aged from 9 mo to 16 years who were fully vaccinated with HBV vaccine during infancy were recruited. Face to face interviews were carried out and sera were evaluated for hepatitis B surface antigen(HBsA g),anti-HBV core antibodies(total) and quantitative detection of hepatitis B surface antibody using enzyme linked immunoassays techniques. Samples positive to HBs Ag/anti-HBV core antibodies were subjected to quantitative HBV-DNA detection by real time polymerase chain reaction with 3.8 IU/L detection limit. RESULTS:Sero-protection was detected among 2059 children(57.2%) with geometric mean titers 75.4 ± 3.6 IU/L compared to 3.1 ± 2.1 IU/L among nonseroprotected children. Multivariate logistic analysis revealed that older age and female gender were the significant predicting variables for having non seroprotective level,with adjusted odds ratio 3.3,9.1and 14.2 among children aged 5 to < 10,10 to < 15 and ≥ 15 years respectively compared to those < 5 years and 1.1 among girls compared to boys with P < 0.01. HBs Ag was positive in 0.11% and breakthrough infection was 0.36% and 0.39% depending on positivity of anti-HBc and DNA detection respectively. The prevalence of HBV infection was significantly higher among children aged ≥ 7 years(0.59%) compared to 0.07% among younger children with odds ratio equal to 8.4(95%CI:1.1-64.2) and P < 0.01.The prevalence was higher among girls(0.48%) than boys(0.29%) with P > 0.05. C ON C LU S I ON :T he E gy pt ian c ompuls or y H B V vaccination program provides adequate protection. Occult HBV infection exists among apparently healthy vaccinated children. Adherence to infection control measures is mandatory.

Efficacy of Shanvac-B recombinant DNA hepatitis B vaccine in health care workers of Northern India

BACKGROUND: Health care workers (HCWs) constitute a high-risk population of HBV infection. There are limited data on the efficacy of vaccination in HCWs in India. This study was to evaluate the efficacy of indigenous recombinant hepatitis B vaccine, Shanvac-B, in HCWs. METHODS: In 597 HCWs screened before the vaccination, 216 (36.2%) showed the presence of at least one of the markers of HBV/HCV infection. Of the remaining 381 (63.8%) HCWs who were considered for vaccination, only 153 (age 18-45 years; 48 males and 105 females) were available for final assessment. These HCWs received 20 μg of vaccine at 0, 1 and 6 months. They were asked for the reactogenicity and monitored for the seroprotective efficacy of the vaccination. Anti-HBs titres were measured after vaccination at 1, 2 and 7 months. The presence of anti-HBs titers equal to 1 MIU/ml was considered as seroconversion and that of titres greater than 10 MIU/ml as seroprotection. RESULTS: After vaccination, 32 males (67%) and 76 females (72%) showed seroconvertion; finally 12 (25%) of the males and 47 (45%) of the females were seroprotected. Seroprotection at 2 and 7 months was more dominant in the females than in the males (96% vs. 56%, P=0.001, 100% vs. 85%, P=0.0001), respectively. Geometric mean titres of anti-HBs after vaccination were also higher in the females than in the males (257±19.7 vs. 29±1.88 MIU/ml, P=0.01, 1802±35.2 vs. 306±13.6 MIU/ml, P≤0.05, 6465±72 vs. 2142±73.6 MIU/ml, P<0.05). Seven male HCWs showed unsatisfactory response, non-response (n=3, 6%) and hypo-response (≤10 MIU/ml, n=4, 8%) at the end of vaccination. Smoking and alcoholism were significantly correlated with unsatisfactory response. No significant adverse effects of vaccination were observed in any HCW.CONCLUSIONS: The presence of HBsAg in HCWs indicates that a high proportion of HCWs are infected with HBV and HCV in India. Recombinant indigenous vaccine Shanvac-B is highly efficacious in HCWs, and its immunogenicity is significantly higher in females than in males. However, prevaccination screening of HCWs is strongly recommended in India.

Prevaccination Antibody Confers Additional Immune Responses to Repeated Yearly Influenza Vaccination in an Elderly Population

Annual vaccination is necessary to maintain humoral immunity in the elderly population. However, the factors influencing the response to influenza vaccination have not been completely identified. The aim of this study was to explore the factors that influenced antibody responses to repeated vaccination using measures that were both objective and quantitative. A total of 111 volunteers aged > 61 years were vaccinated subcutaneously with one dose of influenza vaccine from the 2005-2006 season through the 2009-2010 season. The factors that influenced antibody responses after vaccination were evaluated. The seroprotection rates (PRs) were significantly higher in responders (subjects with a higher antibody titer in the 2005-2006 season) than in nonresponders only in the 2006-2007 and 2007-2008 seasons. PRs after vaccination were significantly higher in seropositive individuals (subjects with a higher prevaccination antibody titer in the 2006-2007 season) than in seronegative individuals for all three virus strains in almost all of the 5 years. Age, gender, and vaccination in the 2004-2005 season did not influence the response. These results suggest that an immune response at a certain time point would predict immune responses only in the near future. However, prevaccination antibody titer in the following season is the ideal predictor for future responses that last over several influenza seasons.