SARS-CoV-2 has emerged as a human pathogen, causing clinical signs, from fever to pneumonia-COVID-19-but may remain mild or asymptomatic. To understand the continuing spread of the virus, to detect those who are and were infected, and to follow the immune response longitudinally, reliable and robust assays for SARS-CoV-2 detection and immunological monitoring are needed. We quantified IgM, IgG, and IgA antibodies recognizing the SARS-CoV-2 receptor-binding domain (RBD) or the Spike (S) protein over a period of 6 months following COVID-19 onset. We report the detailed setup to monitor the humoral immune response from over 300 COVID-19 hospital patients and healthcare workers, 2500 University staff, and 198 post-COVID-19 volunteers. Anti-SARS-CoV-2 antibody responses follow a classic pattern with a rapid increase within the first three weeks after symptoms. Although titres reduce subsequently, the ability to detect anti-SARS-CoV-2 IgG antibodies remained robust with confirmed neutralization activity for up to 6 months in a large proportion of previously virus-positive screened subjects. Our work provides detailed information for the assays used, facilitating further and longitudinal analysis of protective immunity to SARS-CoV-2. Importantly, it highlights a continued level of circulating neutralising antibodies in most people with confirmed SARS-CoV-2.
Non-injecting drug users are at high-risk for acquiring hepatitis B virus (HBV), although the factors contributing to this increased risk are not known. In the present study, the overall and occult HBV infection prevalence rates were determined in a large population of non-injecting drug users in the Central-West region of Brazil. HBV genotypes and predictors of infection were also identified. A total of 852 individuals in 34 drug treatment centers were interviewed, and their serum samples were tested for the presence of HBV markers by ELISA. HBsAg and anti-HBc-positive samples were tested for HBV DNA by PCR. Samples with HBV DNA were genotyped by restriction fragment length polymorphism (RFLP). The overall prevalence of HBV infection was 14% (95% CI: 11.7-16.5). A multivariate analysis of risk factors showed that age >30 years, non-white race/ethnicity, duration of drug use >10 years, lifetime number of sexual partners >10, non-use of condoms, and HCV and HIV status were associated significantly with HBV infection. Of the 9 (1%) HBsAg-reactive samples, HBV DNA was present in 2/2 of HBeAg-positive and in 5/7 anti-HBe-positive samples. An occult HBV infection rate of 2.7% (3/110) was found among anti-HBc-positive individuals. All HBV DNA-positive samples were genotyped: seven were genotype A, two were genotype D, and one was genotype F. Finally, few individuals (8%) had serological evidence of a previous HBV vaccination. These findings indicate that preventive interventions are needed for both sexual and drug-related high-risk behavior. Additionally, non-injecting drug users should be targeted for HBV vaccination.
The results show a high prevalence of HCV infection and predominance of subtype 1a among drug users in Brazil. In addition, injecting drug use was a major risk factor associated with HCV infection.
Objective: To identify hepatitis B vaccine use and risk behaviors among users of illicit drugs (IDU) in Dourados (Mato Grosso do Sul, Brasil). Methods: A descriptive cross-sectional field study was conducted by questionnaire with 49 users of illicit drugs who were receiving assistance through rehabilitation centers and support programs within the city. Results: A predominance of young men using non-injectable drugs was identified. A history of imprisonment, hepatitis, tattooing, multiple sexual partners and participation in all forms of sexual intercourse were the most common risk factors. Conclusion: These factors, combined with low vaccination rates and lack of completion of the recovery and support programs, confirm the vulnerability of users of IDUs for acquiring hepatitis B. Keywords: Hepatitis B virus; Illicit drugs; Vaccination RESUMOObjetivo: Identificar a cobertura vacinal contra a hepatite B e os comportamentos de risco entre usuários de drogas ilícidas (UDI) em Dourados-MS. Métodos: Trata-se de uma pesquisa de campo, descritiva de corte transversal realizada mediante aplicação de questionário em 49 usuários atendidos pelos centros de recuperação e programas de apoio desse Município. Resultados: Identificou-se predomínio de homens jovens que utilizavam drogas não injetáveis. A história de prisão, e de hepatite na família, tatuagens, múltiplos parceiros sexuais e realização de todas as formas de relação sexual, foram os fatores de risco mais frequentes. Conclusão: Estes fatores combinados com a baixa cobertura vacinal e a falta de término do esquema confirmam a vulnerabilidade do grupo em adquirir a hepatite B. Descritores: Vírus da hepatite B; Drogas ilícitas; Vacinação RESUMEN Objetivo: Identificar la cobertura de vacunas contra la hepatitis B y los comportamientos de riesgo entre usuarios de drogas ilícidas (UDI) en Dourados-MS. Métodos: Se trata de una investigación de campo, descriptiva de corte transversal realizada mediante la aplicación de un cuestionario a 49 usuarios atendidos por los centros de recuperación y programas de apoyo de ese Municipio. Resultados: Se identificó predominio de hombres jóvenes que utilizaban drogas no inyectables. La historia de prisión, y de hepatitis en la familia, tatuajes, parejas sexuales múltiples y realización de todas las formas de relación sexual, fueron los factores de riesgo más frecuentes. Conclusión: Estos factores sumados a la baja cobertura de vacunas y la falta de término del esquema confirman la vulnerabilidad del grupo para adquirir la hepatitis B. Descriptores: Virus de la hepatitis B; Drogas ilícitas; Vacunación
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