Immune correlates analysis of the PREVENT-19 COVID-19 vaccine efficacy clinical trial.

In the PREVENT-19 phase 3 trial of the NVX-CoV2373 vaccine (NCT04611802), anti-spike binding IgG concentration (spike IgG), anti-RBD binding IgG concentration (RBD IgG), and pseudovirus 50% neutralizing antibody titer (nAb ID50) measured two weeks post-dose two are assessed as correlates of risk and as correlates of protection against COVID-19. Analyses are conducted in the U.S. cohort of baseline SARS-CoV-2 negative per-protocol participants using a case-cohort design that measures the markers from all 12 vaccine recipient breakthrough COVID-19 cases starting 7 days post antibody measurement and from 639 vaccine recipient non-cases. All markers are inversely associated with COVID-19 risk and directly associated with vaccine efficacy. In vaccine recipients with nAb ID50 titers of 50, 100, and 7230 international units (IU50)/ml, vaccine efficacy estimates are 75.7% (49.8%, 93.2%), 81.7% (66.3%, 93.2%), and 96.8% (88.3%, 99.3%). The results support potential cross-vaccine platform applications of these markers for guiding decisions about vaccine approval and use.

Coronavirus Antibody Responses before COVID-19 Pandemic, Africa and Thailand.

Prior immune responses to coronaviruses might affect human SARS-CoV-2 response. We screened 2,565 serum and plasma samples collected from 2013 through early 2020, before the COVID-19 pandemic began, from 2,250 persons in 4 countries in Africa (Kenya, Nigeria, Tanzania, and Uganda) and in Thailand, including persons living with HIV-1. We detected IgG responses to SARS-CoV-2 spike (S) subunit 2 protein in 1.8% of participants. Profiling against 23 coronavirus antigens revealed that responses to S, subunit 2, or subunit 1 proteins were significantly more frequent than responses to the receptor-binding domain, S-Trimer, or nucleocapsid proteins (p<0.0001). We observed similar responses in persons with or without HIV-1. Among all coronavirus antigens tested, SARS-CoV-2, SARS-CoV-1, and Middle East respiratory syndrome coronavirus antibody responses were much higher in participants from Africa than in participants from Thailand (p<0.01). We noted less pronounced differences for endemic coronaviruses. Serosurveys could affect vaccine and monoclonal antibody distribution across global populations.

Prevalence and predictors of food insecurity among people living with and without HIV in the African Cohort Study.

OBJECTIVE: We determined the prevalence and identified predictors of food insecurity in four African countries. DESIGN: Cross-sectional analyses at study enrolment. SETTING: From January 2013 to March 2020, people living with HIV (PLWH) and without HIV were enrolled at twelve clinics in Kenya, Uganda, Tanzania and Nigeria. PARTICIPANTS: Participants reporting not having enough food to eat over the past 12 months or receiving <3 meals/d were defined as food insecure. Robust Poisson regression models were used to estimate unadjusted and adjusted prevalence ratios (aPR) and 95 % CI for predictors of food insecurity among all participants and separately among PLWH. RESULTS: 1694/3496 participants (48·5 %) reported food insecurity at enrolment, with no difference by HIV status. Food insecurity was more common among older participants (50+ v. 18-24 years aPR 1·35, 95 % CI 1·15, 1·59). Having 2-5 (aPR 1·14, 95 % CI 1·01, 1·30) or >5 dependents (aPR 1·17, 95 % CI 1·02, 1·35), and residing in Kisumu West, Kenya (aPR 1·63, 95 % CI 1·42, 1·87) or Nigeria (aPR 1·20, 95 % CI 1·01, 1·41) was associated with food insecurity. Residing in Tanzania (aPR 0·65, 95 % CI 0·53, 0·80) and increasing education (secondary/above education v. none/some primary education aPR 0·73, 95 % CI 0·66, 0·81) was protective against food insecurity. Antiretroviral therapy (ART)-experienced PLWH were more likely to be food secure irrespective of viral load. CONCLUSION: Food insecurity was highly prevalent in our cohort though not significantly associated with HIV. Policies aimed at promoting education, elderly care, ART access in PLWH and financial independence could potentially improve food security in Africa.

PEPFAR's Role in Protecting and Leveraging HIV Services in the COVID-19 Response in Africa.

PURPOSE OF REVIEW: We describe the impact of COVID-19 on PEPFAR programs in Africa and how PEPFAR adapted and leveraged its interventions to the changing landscape of the COVID-19 pandemic. RECENT FINDINGS: To mitigate the potential impact of COVID-19 on the HIV response and protect the gains, continuity of treatment was the guiding principle regarding the provision of services in PEPFAR-supported countries. As the COVID-19 pandemic matured, PEPFAR's approach evolved from a strictly "protect and salvage" approach to a "restore and accelerate" approach that embraced innovative adaptations in service and "person-centered" care. The impact of service delivery interruptions caused by COVID-19 on progress towards HIV epidemic control in PEPFAR-supported African countries remains undetermined. With COVID vaccine coverage many months away and more transmissible variants being reported, Africa may experience more pandemic surges. HIV programs will depend on nimble and innovative adaptations in prevention and treatment services in order to advance epidemic control objectives.

Efficacy and Safety of NVX-CoV2373 in Adults in the United States and Mexico.

BACKGROUND: NVX-CoV2373 is an adjuvanted, recombinant spike protein nanoparticle vaccine that was shown to have clinical efficacy for the prevention of coronavirus disease 2019 (Covid-19) in phase 2b-3 trials in the United Kingdom and South Africa, but its efficacy had not yet been tested in North America. METHODS: We conducted a phase 3, randomized, observer-blinded, placebo-controlled trial in the United States and Mexico during the first half of 2021 to evaluate the efficacy and safety of NVX-CoV2373 in adults (≥18 years of age) who had not had severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Participants were randomly assigned in a 2:1 ratio to receive two doses of NVX-CoV2373 or placebo 21 days apart. The primary objective was to determine vaccine efficacy against reverse-transcriptase-polymerase-chain-reaction-confirmed Covid-19 occurring at least 7 days after the second dose. Vaccine efficacy against moderate-to-severe disease and against different variants was also assessed. RESULTS: Of the 29,949 participants who underwent randomization between December 27, 2020, and February 18, 2021, a total of 29,582 (median age, 47 years; 12.6% ≥65 years of age) received at least one dose: 19,714 received vaccine and 9868 placebo. Over a period of 3 months, 77 cases of Covid-19 were noted - 14 among vaccine recipients and 63 among placebo recipients (vaccine efficacy, 90.4%; 95% confidence interval [CI], 82.9 to 94.6; P<0.001). Ten moderate and 4 severe cases occurred, all in placebo recipients, yielding vaccine efficacy against moderate-to-severe disease of 100% (95% CI, 87.0 to 100). Most sequenced viral genomes (48 of 61, 79%) were variants of concern or interest - largely B.1.1.7 (alpha) (31 of the 35 genomes for variants of concern, 89%). Vaccine efficacy against any variant of concern or interest was 92.6% (95% CI, 83.6 to 96.7). Reactogenicity was mostly mild to moderate and transient but was more frequent among NVX-CoV2373 recipients than among placebo recipients and was more frequent after the second dose than after the first dose. CONCLUSIONS: NVX-CoV2373 was safe and effective for the prevention of Covid-19. Most breakthrough cases were caused by contemporary variant strains. (Funded by Novavax and others; PREVENT-19 ClinicalTrials.gov number, NCT04611802.).

Severe acute respiratory syndrome coronavirus-2 antibody prevalence in people with and without HIV in rural Western Kenya, January to March 2020.

Among 582 participants in Western Kenya who were retrospectively tested from January through March 2020, 19 (3.3%) had detectable SARS-CoV-2 antibodies. The prevalence of detectable SARS-CoV-2 antibodies was similar between participants with and without HIV (3.1% vs. 4%, P = 0.68). One participant reported a cough in the preceding week but others denied symptoms. These may represent cross-reactivity or asymptomatic infections that predated the first reported COVID-19 cases in Kenya.

Current approaches to HIV vaccine development: a narrative review.

INTRODUCTION: The development of an effective vaccine to protect against HIV is a longstanding global health need complicated by challenges inherent to HIV biology and to the execution of vaccine efficacy testing in the context of evolving biomedical prevention interventions. This review describes lessons learnt from previous efficacy trials, highlights unanswered questions, and surveys new approaches in vaccine development addressing these gaps. METHODS: We conducted a targeted peer-reviewed literature search of articles and conference abstracts from 1989 through 2021 for HIV vaccine studies and clinical trials. The US National Library of Medicine's Clinical Trials database was accessed to further identify clinical trials involving HIV vaccines. The content of the review was also informed by the authors' own experience and engagement with collaborators in HIV vaccine research. DISCUSSION: The HIV vaccine field has successfully developed multiple vaccine platforms through advanced clinical studies; however, the modest efficacy signal of the RV144 Thai trial remains the only demonstration of HIV vaccine protection in humans. Current vaccine strategies include prime-boost strategies to improve elicitation of immune correlates derived from RV144, combination mosaic antigens, novel viral vectors, antigens designed to elicit broadly neutralizing antibody, new nucleic acid platforms and potent adjuvants to enhance immunogenicity across multiple classes of emerging vaccine candidates. CONCLUSIONS: HIV vaccine developers have applied lessons learnt from previous successes and failures to innovative vaccine design approaches. These strategies have yielded novel mosaic antigen constructs now in efficacy testing, produced a diverse pipeline of early-stage immunogens and novel adjuvants, and advanced the field towards a globally effective HIV vaccine.

Transient Reductions in Human Immunodeficiency Virus (HIV) Clinic Attendance and Food Security During the Coronavirus Disease 2019 (COVID-19) Pandemic for People Living With HIV in 4 African Countries.

The coronavirus disease 2019 (COVID-19) pandemic and associated public health responses have disrupted daily living activities with economic and health consequences globally. We observed transient decreases in human immunodeficiency virus (HIV) clinic visit adherence and food security among persons living with HIV early in the pandemic, and an increase in viral suppression later in the pandemic.

PEPFAR's response to the convergence of the HIV and COVID-19 pandemics in Sub-Saharan Africa.

INTRODUCTION: The COVID-19 pandemic reached the African continent in less than three months from when the first cases were reported from mainland China. As COVID-19 preparedness and response plans were rapidly instituted across sub-Saharan Africa, many governments and donor organizations braced themselves for the unknown impact the COVID-19 pandemic would have in under-resourced settings with high burdens of PLHIV. The potential negative impact of COVID-19 in these countries is uncertain, but is estimated to contribute both directly and indirectly to the morbidity and mortality of PLHIV, requiring countries to leverage existing HIV care systems to propel COVID-19 responses, while safeguarding PLHIV and HIV programme gains. In anticipation of COVID-19-related disruptions, PEPFAR promptly established guidance to rapidly adapt HIV programmes to maintain essential HIV services while protecting recipients of care and staff from COVID-19. This commentary reviews PEPFAR's COVID-19 technical guidance and provides country-specific examples of programme adaptions in sub-Saharan Africa. DISCUSSION: The COVID-19 pandemic may pose significant risks to the continuity of HIV services, especially in countries with high HIV prevalence and weak and over-burdened health systems. Although there is currently limited understanding of how COVID-19 affects PLHIV, it is imperative that public health systems and academic centres monitor the impact of COVID-19 on PLHIV. The general principles of the HIV programme adaptation guidance from PEPFAR prioritize protecting the gains in the HIV response while minimizing in-person home and facility visits and other direct contact when COVID-19 control measures are in effect. PEPFAR-supported clinical, laboratory, supply chain, community and data reporting systems can play an important role in mitigating the impact of COVID-19 in sub-Saharan Africa. CONCLUSIONS: As community transmission of COVID-19 continues and the number of country cases rise, fragile health systems may be strained. Utilizing the adaptive, data-driven programme approaches in facilities and communities established and supported by PEPFAR provides the opportunity to strengthen the COVID-19 response while protecting the immense gains spanning HIV prevention, testing and treatment reached thus far.