Regional variation in weight change after the transition to dolutegravir: a prospective cohort study in Uganda and South Africa.

BACKGROUND: People with HIV (PWH) on integrase inhibitor-based regimens may be at risk of excess weight gain, but it is unclear if this risk is consistent across settings. We assessed weight change over 48 weeks among PWH who were transitioned to tenofovir disoproxil fumarate/lamivudine/dolutegravir (TLD). DESIGN: We conducted a prospective cohort study at public-sector HIV clinics in Uganda and South Africa. METHODS: Eligible participants were adults who were transitioned to TLD. Weight was measured at enrollment, 24-, and 48-weeks post TLD transition. Our outcomes were (1) weight change, (2) change in waist circumference, and (3) clinically significant weight gain, defined as ≥10% increase in weight from baseline, over 48 weeks. We used linear mixed-effects regression models, adjusted for demographic factors, to estimate weight gain and identify risk factors. RESULTS: Weight data were available for 428 participants in Uganda and 367 in South Africa. The mean weight change was 0.6 kg [95%CI: 0.1-1.0] in Uganda and 2.9 kg [2.3-3.4] in South Africa (p < 0.001). The mean change in waist circumference was 0.8 cm [95%CI: 0.0-1.5]) in Uganda and 2.3 cm [95%CI: 1.4-3.2] in South Africa (p = 0.012). Clinically significant weight gain occurred in 9.8% [7.0-12.6] of participants in Uganda and 18.0% [14.1-21.9] in South Africa (p < 0.001). After adjustment, PWH gained significantly less weight in Uganda than in South Africa. CONCLUSIONS: PWH in South Africa experienced significantly greater weight gain and increases in waist circumference compared to Uganda. Strategies to address weight gain in PWH should be carefully considered and may vary by region.

Clearance of persistent SARS-CoV-2 associates with increased neutralizing antibodies in advanced HIV disease post-ART initiation.

SARS-CoV-2 clearance requires adaptive immunity but the contribution of neutralizing antibodies and T cells in different immune states is unclear. Here we ask which adaptive immune responses associate with clearance of long-term SARS-CoV-2 infection in HIV-mediated immunosuppression after suppressive antiretroviral therapy (ART) initiation. We assembled a cohort of SARS-CoV-2 infected people in South Africa (n = 994) including participants with advanced HIV disease characterized by immunosuppression due to T cell depletion. Fifty-four percent of participants with advanced HIV disease had prolonged SARS-CoV-2 infection (>1 month). In the five vaccinated participants with advanced HIV disease tested, SARS-CoV-2 clearance associates with emergence of neutralizing antibodies but not SARS-CoV-2 specific CD8 T cells, while CD4 T cell responses were not determined due to low cell numbers. Further, complete HIV suppression is not required for clearance, although it is necessary for an effective vaccine response. Persistent SARS-CoV-2 infection led to SARS-CoV-2 evolution, including virus with extensive neutralization escape in a Delta variant infected participant. The results provide evidence that neutralizing antibodies are required for SARS-CoV-2 clearance in HIV-mediated immunosuppression recovery, and that suppressive ART is necessary to curtail evolution of co-infecting pathogens to reduce individual health consequences as well as public health risk linked with generation of escape mutants.

SARS-CoV-2 infection in immunosuppression evolves sub-lineages which independently accumulate neutralization escape mutations.

One mechanism of variant formation may be evolution during long-term infection in immunosuppressed people. To understand the viral phenotypes evolved during such infection, we tested SARS-CoV-2 viruses evolved from an ancestral B.1 lineage infection lasting over 190 days post-diagnosis in an advanced HIV disease immunosuppressed individual. Sequence and phylogenetic analysis showed two evolving sub-lineages, with the second sub-lineage replacing the first sub-lineage in a seeming evolutionary sweep. Each sub-lineage independently evolved escape from neutralizing antibodies. The most evolved virus for the first sub-lineage (isolated day 34) and the second sub-lineage (isolated day 190) showed similar escape from ancestral SARS-CoV-2 and Delta-variant infection elicited neutralizing immunity despite having no spike mutations in common relative to the B.1 lineage. The day 190 isolate also evolved higher cell-cell fusion and faster viral replication and caused more cell death relative to virus isolated soon after diagnosis, though cell death was similar to day 34 first sub-lineage virus. These data show that SARS-CoV-2 strains in prolonged infection in a single individual can follow independent evolutionary trajectories which lead to neutralization escape and other changes in viral properties.

Evolution and neutralization escape of the SARS-CoV-2 BA.2.86 subvariant.

Omicron BA.2.86 subvariant differs from Omicron BA.2 as well as recently circulating variants by over 30 mutations in the spike protein alone. Here we report on the isolation of the live BA.2.86 subvariant from a diagnostic swab collected in South Africa which we tested for escape from neutralizing antibodies and viral replication properties in cell culture. We found that BA.2.86 does not have significantly more escape relative to Omicron XBB.1.5 from neutralizing immunity elicited by either Omicron XBB-family subvariant infection or from residual neutralizing immunity of recently collected sera from the South African population. BA.2.86 does have extensive escape relative to ancestral virus with the D614G substitution (B.1 lineage) when neutralized by sera from pre-Omicron vaccinated individuals and relative to Omicron BA.1 when neutralized by sera from Omicron BA.1 infected individuals. BA.2.86 and XBB.1.5 show similar viral infection dynamics in the VeroE6-TMPRSS2 and H1299-ACE2 cell lines. We also investigate the relationship of BA.2.86 to BA.2 sequences. The closest BA.2 sequences are BA.2 samples from Southern Africa circulating in early 2022. Similarly, many basal BA.2.86 sequences were sampled in Southern Africa. This suggests that BA.2.86 potentially evolved in this region, and that unobserved evolution led to escape from neutralizing antibodies similar in scale to recently circulating strains of SARS-CoV-2.

Determinants of health-related quality of life in people with Human Immunodeficiency Virus, failing first-line treatment in Africa.

BACKGROUND: Antiretroviral treatment improves health related quality of life (HRQoL) of people with human immunodeficiency virus (PWH). However, one third initiating first-line treatment experience virological failure and the determinants of HRQoL in this key population are unknown. Our study aims to identify determinants of among PWH failing antiretroviral treatment in sub-Saharan Africa. METHODS: We analysed data from a cohort of PWH having virological failure (> 1,000 copies/mL) on first-line ART in South Africa and Uganda. We measured HRQoL using the EuroQOL EQ-5D-3L and used a two-part regression model to obtain by-country analyses for South Africa and Uganda. The first part identifies risk factors that were associated with the likelihood of participants reporting perfect health (utility = 1) versus non-perfect health (utility < 1). The second part identifies risk factors that were associated with the EQ-5 L-3L utility scores for participants reporting non-perfect health. We performed sensitivity analyses to compare the results between the two-part model using tobit models and ordinary least squares regression. RESULTS: In both countries, males were more likely to report perfect health and participants with at least one comorbidity were less likely to report perfect health. In South Africa, participants with side effects and in Uganda those with opportunistic infections were also less likely to report perfect health. In Uganda, participants with 100% ART adherence were more likely to report perfect health. In South Africa, high HIV viral load, experiencing ART side effects, and the presence of opportunistic infections were each associated with lower HRQoL, whereas participants with 100% ART adherence reported higher HRQoL. In Uganda participants with lower CD4 count had lower HRQoL. CONCLUSION: Markers of advanced disease (opportunistic infection, high viral load, low CD4), side effects, comorbidities and lack of ART adherence negatively impacted HRQoL for PWH experiencing virological failure. TRIAL REGISTRATION: ClinicalTrials.gov: NCT02787499.

Food Insecurity Is Associated With Low Tenofovir Diphosphate in Dried Blood Spots in South African Persons With HIV.

Background: Food insecurity has been linked to suboptimal antiretroviral therapy (ART) adherence in persons with HIV (PWH). This association has not been evaluated using tenofovir diphosphate (TFV-DP) in dried blood spots (DBSs), a biomarker of cumulative ART adherence and exposure. Methods: Within a prospective South African cohort of treatment-naive PWH initiating ART, a subset of participants with measured TFV-DP in DBS values was assessed for food insecurity status. Bivariate and multivariate median-based regression analysis compared the association between food insecurity and TFV-DP concentrations in DBSs adjusting for age, sex, ethnicity, medication possession ratio (MPR), and estimated glomerular filtration rate. Results: Drug concentrations were available for 285 study participants. Overall, 62 (22%) PWH reported worrying about food insecurity and 44 (15%) reported not having enough food to eat in the last month. The crude median concentrations of TFV-DP in DBSs differed significantly between those who expressed food insecurity worry versus those who did not (599 [interquartile range {IQR}, 417-783] fmol/punch vs 716 [IQR, 453-957] fmol/punch; P = .032). In adjusted median-based regression, those with food insecurity worry had concentrations of TFV-DP that were 155 (95% confidence interval, -275 to -35; P = .012) fmol/punch lower than those who did not report food insecurity worry. Age and MPR remained significantly associated with TFV-DP. Conclusions: In this study, food insecurity worry is associated with lower TFV-DP concentrations in South African PWH. This highlights the role of food insecurity as a social determinant of HIV outcomes including ART failure and resistance.

Seemingly Unrelated Regression Analysis of the Cost and Health-Related Quality of Life Outcomes of the REVAMP Randomized Clinical Trial.

OBJECTIVE: This study aimed to evaluate the 9-month cost and health-related quality of life (HRQOL) outcomes of resistance versus viral load testing strategies to manage virological failure in low-middle income countries. METHODS: We analyzed secondary outcomes from the REVAMP clinical trial: a pragmatic, open label, parallel-arm randomized trial investigating resistance versus viral load testing for individuals failing first-line treatment in South Africa and Uganda. We collected resource data, valued according to local cost data and used the 3-level version of EQ-5D to measure HRQOL at baseline and 9 months. We applied seemingly unrelated regression equations to account for the correlation between cost and HRQOL. We conducted intention-to-treat analyses with multiple imputation using chained equations for missing data and performed sensitivity analyses using complete cases. RESULTS: For South Africa, resistance testing and opportunistic infections were associated with statistically significantly higher total costs, and virological suppression was associated with lower total cost. Higher baseline utility, higher cluster of differentiation 4 (CD4) count, and virological suppression were associated with better HRQOL. For Uganda, resistance testing and switching to second-line treatment were associated with higher total cost, and higher CD4 was associated with lower total cost. Higher baseline utility, higher CD4 count, and virological suppression were associated with better HRQOL. Sensitivity analyses of the complete-case analysis confirmed the overall results. CONCLUSION: Resistance testing showed no cost or HRQOL advantage in South Africa or Uganda over the 9-month REVAMP clinical trial.

SARS-CoV-2 evolves increased infection elicited cell death and fusion in an immunosuppressed individual.

The milder clinical manifestations of Omicron infection relative to pre-Omicron SARS CoV-2 raises the possibility that extensive evolution results in reduced pathogenicity. To test this hypothesis, we quantified induction of cell fusion and cell death in SARS CoV-2 evolved from ancestral virus during long-term infection. Both cell fusion and death were reduced in Omicron BA.1 infection relative to ancestral virus. Evolved virus was isolated at different times during a 6-month infection in an immunosuppressed individual with advanced HIV disease. The virus isolated 16 days post-reported symptom onset induced fusogenicity and cell death at levels similar to BA.1. However, fusogenicity was increased in virus isolated at 6 months post-symptoms to levels intermediate between BA.1 and ancestral SARS-CoV-2. Similarly, infected cell death showed a graded increase from earlier to later isolates. These results may indicate that, at least by the cellular measures used here, evolution in long-term infection does not necessarily attenuate the virus.

A comprehensive overview of pneumococcal vaccination recommendations for adults in South Africa, 2022.

Pneumococcal infections remain a common global cause of significant morbidity and mortality. The first recommendations for adult pneumococcal vaccination, published in South Africa in 1999, contained information only on the 23-valent polysaccharide vaccine (PPV23). With the introduction of the 13-valent pneumococcal conjugate vaccine (PCV13) for use in adults and the perceived uncertainty that most clinicians had regarding use of these vaccines in adults, these vaccine recommendations were updated in 2022. A Working Group, which consisted of individuals in various fields of medical practice in South Africa, who were from different areas of the country, and included clinicians from both the public and private sectors, was assembled to revise the recommendations. The expertise of the participants varied widely, dependent on their training and specialty, and encompassed different organ systems, disease conditions, and/or practice types. Each participant was allocated a different section, based on their expertise, for which they were required to do an extensive review of the current literature and write their section. The entire working group then reviewed the complete document several times, following additional comments and recommendations. This update contains recommendations for the use of both PPV23 and PCV13, either alone, or in sequence, both in vaccine naïve and in previously vaccinated individuals. It includes both age and risk categories, and encompasses the elderly (≥65 years), as well as younger adults (<65 years) with comorbid conditions or with high-risk conditions and/or immunocompromise. It is hoped that this review and its associated vaccine recommendations will clarify for clinicians, from all spheres of practice in South Africa, how, where, and when pneumococcal vaccines should be used in adults, with the ultimate goal of significantly increasing the appropriate use of these vaccines, in order to decrease the substantial morbidity and mortality associated with pneumococcal infections in adults in South Africa. Furthermore, it is hoped that this review of local epidemiological data and the manner in which this information was interpreted in the development of these local vaccine recommendations, could be used as an example for other regions of the world, to tailor their recommendations to locally available epidemiological data.

Prognostic variables and 4-year survival outcomes in CD20 Positive AIDS-Related Lymphoma in the Anti-retroviral treatment era: A Retrospective Review from a Single Centre in KwaZulu-Natal, South Africa.

OBJECTIVE: To describe 4-year survival outcomes and assess the value of established and additional relevant variables to predict complete response (CR), four-year progression-free survival (PFS) and overall survival (OS) of CD20 positive AIDS-Related Lymphoma (ARL) treated with standard combination chemotherapy. METHOD: We performed a retrospective review of patients diagnosed with CD20 positive ARL between 2006 and 2016. All patients over 12 years of age who received at least one cycle of combination chemotherapy with curative intent were included in the analysis. Variables assessed included the International Prognostic Index (IPI), age-adjusted-IPI, age, gender, B symptoms, extent of disease, functional performance status, CD4 cell count, viral load, concurrent ART with chemotherapy, rituximab inclusion, and number of chemotherapy cycles used. Kaplan-Meier survival curves for OS and PFS at 4 years were compared for IPI and aaIPI using the log-rank test. A Cox proportional hazards model was used to investigate the effects of prognostic variables for patients achieving OS and PFS at 4 years and logistic regression for patients achieving CR. RESULTS: A total of 102 patients were included in the analysis. At year four of follow-up, the OS was 50% (n = 51) and PFS was 43% (n = 44). Attaining a CR and male gender were significantly associated with improved 4-year OS (p<0.001 and p = 0.028 respectively) and PFS (p<0.001 and 0.048 respectively). A viral load of < 50 copies/ml was associated with a higher complete response rate (aOR 6.10 [95% CI 1.15, 24.04], p = 0.01). Six or more cycles of chemotherapy was superior to fewer cycles for both PFS (aHR 0.17 [95% CI 0.10, 0.29]) and OS (aHR 0.12 [95% CI 0.07, 0.22]) with p-value < 0.001 for both PFS and OS. The Kaplan-Meier survival estimates demonstrated the prognostic utility of the IPI and aaIP for OS (p = 0.002 and 0.030 respectively) and the IPI for PFS (p = 0.002). CONCLUSION: This study is a first from a high prevalence HIV area in KwaZulu-Natal, South Africa, and confirms the utility of the internationally accepted prognostic scoring systems in predicting survival in CD20 positive ARL in the local population.

Omicron BA.4/BA.5 escape neutralizing immunity elicited by BA.1 infection.

SARS-CoV-2 Omicron (B.1.1.529) BA.4 and BA.5 sub-lineages, first detected in South Africa, have changes relative to Omicron BA.1 including substitutions in the spike receptor binding domain. Here we isolated live BA.4 and BA.5 viruses and measured BA.4/BA.5 neutralization elicited by BA.1 infection either in the absence or presence of previous vaccination as well as from vaccination without BA.1 infection. In BA.1-infected unvaccinated individuals, neutralization relative to BA.1 declines 7.6-fold for BA.4 and 7.5-fold for BA.5. In vaccinated individuals with subsequent BA.1 infection, neutralization relative to BA.1 decreases 3.2-fold for BA.4 and 2.6-fold for BA.5. The fold-drop versus ancestral virus neutralization in this group is 4.0-fold for BA.1, 12.9-fold for BA.4, and 10.3-fold for BA.5. In contrast, BA.4/BA.5 escape is similar to BA.1 in the absence of BA.1 elicited immunity: fold-drop relative to ancestral virus neutralization is 19.8-fold for BA.1, 19.6-fold for BA.4, and 20.9-fold for BA.5. These results show considerable escape of BA.4/BA.5 from BA.1 elicited immunity which is moderated with vaccination and may indicate that BA.4/BA.5 may have the strongest selective advantage in evading neutralization relative to BA.1 in unvaccinated, BA.1 infected individuals.

Effect of Dysglycemia on Urinary Lipid Mediator Profiles in Persons With Pulmonary Tuberculosis.

Background: Oxidized lipid mediators such as eicosanoids play a central role in the inflammatory response associated with tuberculosis (TB) pathogenesis. Diabetes mellitus (DM) leads to marked changes in lipid mediators in persons with TB. However, the associations between diabetes-related changes in lipid mediators and clearance of M. tuberculosis (Mtb) among persons on anti-TB treatment (ATT) are unknown. Quantification of urinary eicosanoid metabolites can provide insights into the circulating lipid mediators involved in Mtb immune responses. Methods: We conducted a multi-site prospective observational study among adults with drug-sensitive pulmonary TB and controls without active TB; both groups had sub-groups with or without dysglycemia at baseline. Participants were enrolled from RePORT-Brazil (Salvador site) and RePORT-South Africa (Durban site) and stratified according to TB status and baseline glycated hemoglobin levels: a) TB-dysglycemia (n=69); b) TB-normoglycemia (n=64); c) non-TB/dysglycemia (n=31); d) non-TB/non-dysglycemia (n=29). We evaluated the following urinary eicosanoid metabolites: 11α-hydroxy-9,15-dioxo-2,3,4,5-tetranor-prostane-1,20-dioic acid (major urinary metabolite of prostaglandin E2, PGE-M), tetranor-PGE1 (metabolite of PGE2, TN-E), 9α-hydroxy-11,15-dioxo-2,3,4,5-tetranor-prostane-1,20-dioic acid (metabolite of PGD2, PGD-M), 11-dehydro-thromboxane B2 (11dTxB2), 2,3-dinor-6-keto-PGF1α (prostaglandin I metabolite, PGI-M), and leukotriene E4 (LTE4). Comparisons between the study groups were performed at three time points: before ATT and 2 and 6 months after initiating therapy. Results: PGE-M and LTE4 values were consistently higher at all three time-points in the TB-dysglycemia group compared to the other groups (p<0.001). In addition, there was a significant decrease in PGI-M and LTE4 levels from baseline to month 6 in the TB-dysglycemia and TB-normoglycemia groups. Finally, TB-dysglycemia was independently associated with increased concentrations of PGD-M, PGI-M, and LTE4 at baseline in a multivariable model adjusting for age, sex, BMI, and study site. These associations were not affected by HIV status. Conclusion: The urinary eicosanoid metabolite profile was associated with TB-dysglycemia before and during ATT. These observations can help identify the mechanisms involved in the pathogenesis of TB-dysglycemia, and potential biomarkers of TB treatment outcomes, including among persons with dysglycemia.

Unsuppressed HIV infection impairs T cell responses to SARS-CoV-2 infection and abrogates T cell cross-recognition.

In some instances, unsuppressed HIV has been associated with severe COVID-19 disease, but the mechanisms underpinning this susceptibility are still unclear. Here, we assessed the impact of HIV infection on the quality and epitope specificity of SARS-CoV-2 T cell responses in the first wave and second wave of the COVID-19 epidemic in South Africa. Flow cytometry was used to measure T cell responses following peripheral blood mononuclear cell stimulation with SARS-CoV-2 peptide pools. Culture expansion was used to determine T cell immunodominance hierarchies and to assess potential SARS-CoV-2 escape from T cell recognition. HIV-seronegative individuals had significantly greater CD4+ T cell responses against the Spike protein compared to the viremic people living with HIV (PLWH). Absolute CD4 count correlated positively with SARS-CoV-2-specific CD4+ and CD8+ T cell responses (CD4 r=0.5, p=0.03; CD8 r=0.5, p=0.001), whereas T cell activation was negatively correlated with CD4+ T cell responses (CD4 r=-0.7, p=0.04). There was diminished T cell cross-recognition between the two waves, which was more pronounced in individuals with unsuppressed HIV infection. Importantly, we identify four mutations in the Beta variant that resulted in abrogation of T cell recognition. Taken together, we show that unsuppressed HIV infection markedly impairs T cell responses to SARS-Cov-2 infection and diminishes T cell cross-recognition. These findings may partly explain the increased susceptibility of PLWH to severe COVID-19 and also highlights their vulnerability to emerging SARS-CoV-2 variants of concern.

Omicron infection enhances Delta antibody immunity in vaccinated persons.

The extent to which Omicron infection1-9, with or without previous vaccination, elicits protection against the previously dominant Delta (B.1.617.2) variant is unclear. Here we measured the neutralization capacity against variants of severe acute respiratory syndrome coronavirus 2 in 39 individuals in South Africa infected with the Omicron sublineage BA.1 starting at a median of 6 (interquartile range 3-9) days post symptom onset and continuing until last follow-up sample available, a median of 23 (interquartile range 19-27) days post symptoms to allow BA.1-elicited neutralizing immunity time to develop. Fifteen participants were vaccinated with Pfizer's BNT162b2 or Johnson & Johnson's Ad26.CoV2.S and had BA.1 breakthrough infections, and 24 were unvaccinated. BA.1 neutralization increased from a geometric mean 50% focus reduction neutralization test titre of 42 at enrolment to 575 at the last follow-up time point (13.6-fold) in vaccinated participants and from 46 to 272 (6.0-fold) in unvaccinated participants. Delta virus neutralization also increased, from 192 to 1,091 (5.7-fold) in vaccinated participants and from 28 to 91 (3.0-fold) in unvaccinated participants. At the last time point, unvaccinated individuals infected with BA.1 had low absolute levels of neutralization for the non-BA.1 viruses and 2.2-fold lower BA.1 neutralization, 12.0-fold lower Delta neutralization, 9.6-fold lower Beta variant neutralization, 17.9-fold lower ancestral virus neutralization and 4.8-fold lower Omicron sublineage BA.2 neutralization relative to vaccinated individuals infected with BA.1. These results indicate that hybrid immunity formed by vaccination and Omicron BA.1 infection should be protective against Delta and other variants. By contrast, infection with Omicron BA.1 alone offers limited cross-protection despite moderate enhancement.

SARS-CoV-2 prolonged infection during advanced HIV disease evolves extensive immune escape.

Characterizing SARS-CoV-2 evolution in specific geographies may help predict properties of the variants that come from these regions. We mapped neutralization of a SARS-CoV-2 strain that evolved over 6 months from ancestral virus in a person with advanced HIV disease in South Africa; this person was infected prior to emergence of the Beta and Delta variants. We longitudinally tracked the evolved virus and tested it against self-plasma and convalescent plasma from ancestral, Beta, and Delta infections. Early virus was similar to ancestral, but it evolved a multitude of mutations found in Omicron and other variants. It showed substantial but incomplete Pfizer BNT162b2 escape, weak neutralization by self-plasma, and despite pre-dating Delta, it also showed extensive escape of Delta infection-elicited neutralization. This example is consistent with the notion that SARS-CoV-2 evolving in individual immune-compromised hosts, including those with advanced HIV disease, may gain immune escape of vaccines and enhanced escape of Delta immunity, and this has implications for vaccine breakthrough and reinfections.

Omicron extensively but incompletely escapes Pfizer BNT162b2 neutralization.

The emergence of the SARS-CoV-2 variant of concern Omicron (Pango lineage B.1.1.529), first identified in Botswana and South Africa, may compromise vaccine effectiveness and lead to re-infections1. Here we investigated Omicron escape from neutralization by antibodies from South African individuals vaccinated with Pfizer BNT162b2. We used blood samples taken soon after vaccination from individuals who were vaccinated and previously infected with SARS-CoV-2 or vaccinated with no evidence of previous infection. We isolated and sequence-confirmed live Omicron virus from an infected person and observed that Omicron requires the angiotensin-converting enzyme 2 (ACE2) receptor to infect cells. We compared plasma neutralization of Omicron relative to an ancestral SARS-CoV-2 strain and found that neutralization of ancestral virus was much higher in infected and vaccinated individuals compared with the vaccinated-only participants. However, both groups showed a 22-fold reduction in vaccine-elicited neutralization by the Omicron variant. Participants who were vaccinated and had previously been infected exhibited residual neutralization of Omicron similar to the level of neutralization of the ancestral virus observed in the vaccination-only group. These data support the notion that reasonable protection against Omicron may be maintained using vaccination approaches.

Omicron infection of vaccinated individuals enhances neutralizing immunity against the Delta variant.

Omicron variant (B.1.1.529) infections are rapidly expanding worldwide, often in settings where the Delta variant (B.1.617.2) was dominant. We investigated whether neutralizing immunity elicited by Omicron infection would also neutralize the Delta variant and the role of prior vaccination. We enrolled 23 South African participants infected with Omicron a median of 5 days post-symptoms onset (study baseline) with a last follow-up sample taken a median of 23 days post-symptoms onset. Ten participants were breakthrough cases vaccinated with Pfizer BNT162b2 or Johnson and Johnson Ad26.CoV2.S. In vaccinated participants, neutralization of Omicron increased from a geometric mean titer (GMT) FRNT50 of 28 to 378 (13.7-fold). Unvaccinated participants had similar Omicron neutralization at baseline but increased from 26 to only 113 (4.4-fold) at follow-up. Delta virus neutralization increased from 129 to 790, (6.1-fold) in vaccinated but only 18 to 46 (2.5-fold, not statistically significant) in unvaccinated participants. Therefore, in Omicron infected vaccinated individuals, Delta neutralization was 2.1-fold higher at follow-up relative to Omicron. In a separate group previously infected with Delta, neutralization of Delta was 22.5-fold higher than Omicron. Based on relative neutralization levels, Omicron re-infection would be expected to be more likely than Delta in Delta infected individuals, and in Omicron infected individuals who are vaccinated. This may give Omicron an advantage over Delta which may lead to decreasing Delta infections in regions with high infection frequencies and high vaccine coverage.

Who's slipping through the cracks? A comprehensive individual, clinical and health system characterization of people with virological failure on first-line HIV treatment in Uganda and South Africa.

OBJECTIVES: HIV virological failure remains a major threat to programme success in sub-Saharan Africa. While HIV drug resistance (HIVDR) and inadequate adherence are the main drivers of virological failure, the individual, clinical and health system characteristics that lead to poor outcomes are not well understood. The objective of this paper is to identify those characteristics among people failing first-line antiretroviral therapy (ART). METHODS: We enrolled a cohort of adults in HIV care experiencing virological failure on first-line ART at five sites and used standard statistical methods to characterize them with a focus on three domains: individual/demographic, clinical, and health system, and compared each by country of enrolment. RESULTS: Of 840 participants, 51% were women, the median duration on ART was 3.2 years [interquartile range (IQR) 1.1, 6.4 years] and the median CD4 cell count prior to failure was 281 cells/µL (IQR 121, 457 cells/µL). More than half of participants [53%; 95% confidence interval (CI) 49-56%] stated that they had > 90% adherence and 75% (95% CI 72-77%) took their ART on time all or most of the time. Conversely, the vast majority (90%; 95% CI 86-92%) with a completed genotypic drug resistance test had any HIV drug resistance. This population had high health system use, reporting a median of 3 (IQR 2.6) health care visits and a median of 1 (IQR 1.1) hospitalization in the preceding 6 months. CONCLUSIONS: Patients failing first-line ART in sub-Saharan Africa generally report high rates of adherence to ART, have extremely high rates of HIV drug resistance and utilize significant health care resources. Health systems interventions to promptly detect and manage treatment failure will be a prerequisite to establishing control of the HIV epidemic.