Likelihood Of Suppression Research Articles

Reduction in time to viral suppression among persons living with HIV in Jamaica between 2017-2019.

HIV viral suppression is important for effective treatment and for reducing new infections. In 2019, only 66% of persons on antiretroviral treatment (ART) in Jamaica were virally suppressed. We aim to compare time to viral suppression by ART initiation year and type of treatment site to understand the implications for programming. We assessed time to viral suppression among 4560 persons who received viral load testing either pre or post ART initiation from 2017-2019. We used descriptive statistics and Kaplan-Meier estimates to compare survival curves by ART year (2017, 2018, 2019), sex and type of treatment site (public and non-governmental organizations). Persons were censored if suppression was not achieved. Mixed effects Cox regression was used to determine the effect of covariates on the likelihood of viral suppression. We report hazard ratios and 95% confidence intervals. Pre-ART viral load testing decreased from 36% in 2017 to 30% in 2019. For post-ART viral load tests, approximately 78% (n = 1589) of persons achieved suppression, 51% (n = 809) were female and 86% (n = 1341) used a public treatment site. The median time to suppression decreased by 3 months from 2017 to 2019. The likelihood of suppression was almost 2 times greater in 2018 (HR = 1.56, CI = 1.39-1.75) and 3 times greater in 2019 (HR = 3.17, CI = 2.76-3.64) compared to 2017. NGO treatment sites were also significantly associated with the likelihood of viral suppression compared to public sites. Pre-ART viral load testing and the time to viral suppression decreased over three years. Initiating ART after 2017 and early use of NGO treatment sites were found to significantly increase the likelihood of achieving suppression. This demonstrates improvements in the national HIV response but there is need to increase the number of persons on ART and achieving viral suppression.

Neutralization of SARS-CoV-2 requires antibodies against conformational receptor-binding domain epitopes.

BackgroundThe determinants of successful humoral immune response to the severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) are of critical importance for the design of effective vaccines and the evaluation of the degree of protective immunity conferred by exposure to the virus. As novel variants emerge, understanding their likelihood of suppression by population antibody repertoires has become increasingly important.MethodsIn this study, we analyzed the SARS‐CoV‐2 polyclonal antibody response in a large population of clinically well‐characterized patients after mild and severe COVID‐19 using a panel of microarrayed structurally folded and unfolded SARS‐CoV‐2 proteins, as well as sequential peptides, spanning the surface spike protein (S) and the receptor‐binding domain (RBD) of the virus.ResultsS‐ and RBD‐specific antibody responses were dominated by immunoglobulin G (IgG), mainly IgG1, and directed against structurally folded S and RBD and three distinct peptide epitopes in S2. The virus neutralization activity of patients´ sera was highly correlated with IgG antibodies specific for conformational but not sequential RBD epitopes and their ability to prevent RBD binding to its human receptor angiotensin‐converting enzyme 2 (ACE2). Twenty percent of patients selectively lacked RBD‐specific IgG. Only immunization with folded, but not with unfolded RBD, induced antibodies against conformational epitopes with high virus‐neutralizing activity. Conformational RBD epitopes required for protection do not seem to be altered in the currently emerging virus variants.ConclusionThese results are fundamental for estimating the protective activity of antibody responses after natural infection or vaccination and for the design of vaccines, which can induce high levels of SARS‐CoV‐2–neutralizing antibodies conferring sterilizing immunity.

Poor Vertical Root Development May Contribute to Suppression in a Red Pine Plantation

Initial stem and root growth of trees that became suppressed within 30 years in a red pine (Pinus resinosa Ait.) plantation were poorer than those that became codominants. Stem and horizontal root extension improved later but then declined. The likelihood of suppression may have been initiated at or before planting. Inadequate development, perhaps through chance, of vertical roots that could tap moisture-holding layers at the 2.8 m depth in the well-drained loamy sand soil contributed to the suppression process.