Durability of humoral immune responses to rubella following MMR vaccination

BackgroundWhile administration of the measles-mumps-rubella (MMR-II®) vaccine has been effective at preventing rubella infection in the United States, the durability of humoral immunity to the rubella component of MMR vaccine has not been widely studied among older adolescents and adults.MethodsIn this longitudinal study, we sought to assess the durability of rubella virus (RV)-specific humoral immunity in a healthy population (n = 98) of adolescents and young adults at two timepoints: ~7 and ~17 years after two doses of MMR-II® vaccination. Levels of circulating antibodies specific to RV were measured by ELISA and an immune-colorimetric neutralization assay. RV-specific memory B cell responses were also measured by ELISpot.ResultsRubella-specific IgG antibody titers, neutralizing antibody titers, and memory B cell responses declined with increasing time since vaccination; however, these decreases were relatively moderate. Memory B cell responses exhibited a greater decline in men compared to women.ConclusionsCollectively, rubella-specific humoral immunity declines following vaccination, although subjects’ antibody titers remain well above the currently recognized threshold for protective immunity. Clinical correlates of protection based on neutralizing antibody titer and memory B cell ELISpot response should be defined.     

Immunogenicity of the hepatitis A vaccine 20 years after infant immunization

To determine the duration of immunity provided by the Hepatitis A vaccination (HepA), we evaluated a cohort of participants in Alaska 20 years after being immunized as infants. At recruitment, participants received two doses of inactivated HepA vaccine on one of three schedules. We conducted hepatitis A antibody (anti-HAV) testing for participants at the 20-year time-point. Seventy-five of the original 183 participants (41%) were available for follow-up. The overall anti-HAV geometric mean concentration was 29.9 mIU/mL (95% CI 22.4 mIU/mL, 39.7 mIU/mL) and 50 participants (68%) remained seropositive (titer ≥ 20 mIU/mL). Using a fractional polynomial model, the predicted percent seropositive at 25 years was 55.3%, 49.8% at 30 years and 45.7% at 35 years, suggesting that the percent sero-positive could drop below 50% earlier than previously expected. Further research is necessary to understand if protection continues after seropositivity diminishes or if a HepA booster dose may become necessary.     

Current State of Hypertrophic Cardiomyopathy Clinical Trials

BackgroundHypertrophic cardiomyopathy (HCM) is a genetic disorder with a very large global burden for which more therapeutic management regimens are required.ObjectivesIn this study, the authors explore HCM-related clinical trials, determine the shortcomings leading to the lack of development of new HCM therapies, and attempt to shed light on potential areas for improvement.MethodsIn January 2019, the authors completed a search on ClinicalTrials.gov for all therapeutic and interventional clinical trials involving HCM, without any limits for location or date. Information on trial characteristics such as phase, start and end dates, sample size, experimental intervention, publications, study design, selection criteria, and results were collected and analyzed.ResultsSixty-three trials met the selection criteria. The average trial duration across phases was around 3 years. Around one-half of the trials were conducted in North America (United States and Canada) and 44% of the trials were in their early phases (I and II). Approximately one-third of the trials were completed. Only 14 publications were produced from all the clinical trials studied.ConclusionsThe study revealed a low number of trials, lack of geographic diversity, and scarcity of published results concerning HCM clinical trials. Proper management of HCM trials is of vast importance to achieve effective therapies.     

“Being seen” at the clinic: Zambian and South African health worker reflections on the relationship between health facility spatial organisation and items and HIV stigma in 21 health facilities,the HPTN 071 (PopART) study

Health workers in 21 government health facilities in Zambia and South Africa linked spatial organisation of HIV services and material items signifying HIV-status (for example, coloured client cards) to the risk of People Living with HIV (PLHIV) ‘being seen’ or identified by others. Demarcated HIV services, distinctive client flow and associated-items were considered especially distinguishing. Strategies to circumvent any resulting stigma mostly involved PLHIV avoiding and/or reducing contact with services and health workers reducing visibility of PLHIV through alterations to structures, items and systems. HIV spatial organisation and item adjustments, enacting PLHIV-friendly policies and wider stigma reduction initiatives could combined reduce risks of identification and enhance the privacy of health facility space and diminish stigma.