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The global experience with COVID-19 holds important lessons for preparing for, and responding to, future emergences of pathogens with pandemic potential.

Anti–SARS-CoV-2 antibodies have been used in health care and clinical settings to prevent and treat COVID-19. The National Institutes of Health convened a virtual summit on 15 June 2021 to summarize existing knowledge and to identify key unanswered scientific questions to catalyze future development of these antibodies., As the fourth wave of the SARS-CoV-2 pandemic encircles the globe, there remains an urgent challenge to identify safe and effective treatment and prevention strategies that can be implemented in a range of health care and clinical settings. Substantial advances have been made in the use of anti–SARS-CoV-2 antibodies to mitigate the morbidity and mortality associated with COVID-19. On 15 June 2021, the National Institutes of Health, in collaboration with the U.S. Food and Drug Administration, convened a virtual summit to summarize existing knowledge on anti–SARS-CoV-2 antibodies and to identify key unanswered scientific questions to further catalyze the clinical development and implementation of antibodies.

Severe COVID-19 is characterized by a prothrombotic state associated with thrombocytopenia, with microvascular thrombosis being almost invariably present in the lung and other organs at postmortem examination. We evaluated the presence of antibodies to platelet factor 4 (PF4)–polyanion complexes using a clinically validated immunoassay in 100 hospitalized patients with COVID-19 with moderate or severe disease (World Health Organization score, 4 to 10), 25 patients with acute COVID-19 visiting the emergency department, and 65 convalescent individuals. Anti-PF4 antibodies were detected in 95 of 100 hospitalized patients with COVID-19 (95.0%) irrespective of prior heparin treatment, with a mean optical density value of 0.871 ± 0.405 SD (range, 0.177 to 2.706). In contrast, patients hospitalized for severe acute respiratory disease unrelated to COVID-19 had markedly lower levels of the antibodies. In a high proportion of patients with COVID-19, levels of all three immunoglobulin (Ig) isotypes tested (IgG, IgM, and IgA) were simultaneously elevated. Antibody levels were higher in male than in female patients and higher in African Americans and Hispanics than in White patients. Anti-PF4 antibody levels were correlated with the maximum disease severity score and with significant reductions in circulating platelet counts during hospitalization. In individuals convalescent from COVID-19, the antibody levels returned to near-normal values. Sera from patients with COVID-19 induced higher levels of platelet activation than did sera from healthy blood donors, but the results were not correlated with the levels of anti-PF4 antibodies. These results demonstrate that the vast majority of patients with severe COVID-19 develop anti-PF4 antibodies, which may play a role in the clinical complications of COVID-19.

Both the 1918 influenza pandemic and the 2019‒2021 COVID-19 pandemic are among the most disastrous infectious disease emergences of modern times. In addition to similarities in their clinical, pathological, and epidemiological features, the two pandemics, separated by more than a century, were each met with essentially the same, or very similar, public health responses, and elicited research efforts to control them with vaccines, therapeutics, and other medical approaches. Both pandemics had lasting, if at times invisible, psychosocial effects related to loss and hardship. In considering these two deadly pandemics, we ask: what lessons have we learned over the span of a century, and how are we applying those lessons to the challenges of COVID-19?

SUMMARYSARS-CoV-2 mRNA booster vaccines provide protection from severe disease, eliciting strong immunity that is further boosted by previous infection. However, it is unclear whether these immune responses are affected by the interval between infection and vaccination. Over a two-month period, we evaluated antibody and B-cell responses to a third dose mRNA vaccine in 66 individuals with different infection histories. Uninfected and post-boost but not previously infected individuals mounted robust ancestral and variant spike-binding and neutralizing antibodies, and memory B cells. Spike-specific B-cell responses from recent infection were elevated at pre-boost but comparatively less so at 60 days post-boost compared to uninfected individuals, and these differences were linked to baseline frequencies of CD27lo B cells. Day 60 to baseline ratio of BCR signaling measured by phosphorylation of Syk was inversely correlated to days between infection and vaccination. Thus, B-cell responses to booster vaccines are impeded by recent infection.

Severe acute respiratory syndrome coronavirus 1 (SARS-CoV-1) emerged 20 years ago, presaging a series of subsequent infectious disease epidemics of international concern. The recent emergence of SARS-CoV-2 has underscored the importance of targeted preparedness research to enable rapid countermeasure development during a crisis. In December 2021 the National Institute of Allergy and Infectious Diseases (NIAID), building upon the successful strategies developed during the SARS-CoV-2 response and to prepare for future pandemics, published a pandemic preparedness plan that outlined a research strategy focused on priority pathogens, technology platforms, and prototype pathogens. To accelerate the discovery, development, and evaluation of medical countermeasures against new or previously unknown pathogens of pandemic potential, we present here a strategy of research directed at select prototype pathogens. In this manner, leveraging a prototype pathogen approach may serve as a powerful cornerstone in biomedical research preparedness to protect public health from newly emerging and reemerging infectious diseases.

Separated by a century, the influenza pandemic of 1918 and the COVID-19 pandemic of 2019–2021 are among the most disastrous infectious disease emergences of modern times. Although caused by unrelated viruses, the two pandemics are nevertheless similar in their clinical, pathological, and epidemiological features, and in the civic, public health, and medical responses to combat them. Comparing and contrasting the two pandemics, we consider what lessons we have learned over the span of a century and how we are applying those lessons to the challenges of COVID-19.

The coronavirus disease 2019 (COVID-19) pandemic has significantly impacted persons with human immunodeficiency virus (HIV), interfering with critical health services for HIV prevention, treatment, and care. While there are multiple profiles of persons living with HIV and the impact of COVID-19 may differ for each, the severity of COVID-19 in persons with HIV is related strongly to the presence of comorbidities that increase the risk of severe disease in COVID-19 patients in the absence of HIV. An effective response to the juxtaposition of the HIV and COVID-19 pandemics requires a novel coordinated and collaborative global effort of scientists, industry, and community partners to accelerate basic and clinical research, as well as implementation science to operationalize evidence-based interventions expeditiously in real-world settings. Accelerated development and clinical evaluation of prevention and treatment countermeasures are urgently needed to mitigate the juxtaposition of the HIV and COVID-19 pandemics.

Messenger RNA (mRNA) vaccines against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are highly effective at inducing protective immunity. However, weak antibody responses are seen in some individuals, and cellular correlates of immunity remain poorly defined, especially for B cells. Here we used unbiased approaches to longitudinally dissect primary antibody, plasmablast, and memory B cell (MBC) responses to the two-dose mRNA-1273 vaccine in SARS-CoV-2–naive adults. Coordinated immunoglobulin A (IgA) and IgG antibody responses were preceded by bursts of spike-specific plasmablasts after both doses but earlier and more intensely after dose 2. While antibody and B cell cellular responses were generally robust, they also varied within the cohort and decreased over time after a dose-2 peak. Both antigen-nonspecific postvaccination plasmablast frequency after dose 1 and their spike-specific counterparts early after dose 2 correlated with subsequent antibody levels. This correlation between early plasmablasts and antibodies remained for titers measured at 6 months after vaccination. Several distinct antigen-specific MBC populations emerged postvaccination with varying kinetics, including two MBC populations that correlated with 2- and 6-month antibody titers. Both were IgG-expressing MBCs: one less mature, appearing as a correlate after the first dose, while the other MBC correlate showed a more mature and resting phenotype, emerging as a correlate later after dose 2. This latter MBC was also a major contributor to the sustained spike-specific MBC response observed at month 6. Thus, these plasmablasts and MBCs that emerged after both the first and second doses with distinct kinetics are potential determinants of the magnitude and durability of antibodies in response to mRNA-based vaccination.

Acute HIV infection is characterized by rapid viral seeding of immunologic inductive sites in the gut followed by the severe depletion of gut CD4(+) T cells. Trafficking of α(4)β(7)-expressing lymphocytes to the gut is mediated by MAdCAM, the natural ligand of α(4)β(7) that is expressed on gut endothelial cells. MAdCAM signaling through α(4)β(7) costimulates CD4(+) T cells and promotes HIV replication. Similar to MAdCAM, the V2 domain of the gp120 HIV envelope protein binds to α(4)β(7). In this study, we report that gp120 V2 shares with MAdCAM the capacity to signal through α(4)β(7) resulting in CD4(+) T cell activation and proliferation. As with MAdCAM-mediated costimulation, cellular activation induced by gp120 V2 is inhibited by anti-α(4)β(7) monoclonal antibodies (mAbs). It is also inhibited by anti-V2 domain antibodies including nonneutralizing mAbs that recognize an epitope in V2 that has been linked to reduced risk of acquisition in the RV144 vaccine trial. The capacity of the V2 domain of gp120 to mediate signaling through α(4)β(7) likely impacts early events in HIV infection. The capacity of nonneutralizing V2 antibodies to block this activity reveals a previously unrecognized mechanism whereby such antibodies might impact HIV transmission and pathogenesis.

Four Decades of HIV/AIDS Considering the spectacular scientific advances that have been made over nearly four decades, it is conceivable that with optimal implementation of available prevention str...

Historical data regarding time to viral rebound following analytical treatment interruption (ATI) have been used to determine therapeutic efficacy in HIV cure trials; however, such data were collected from studies conducted a decade or more ago and included participants receiving older antiretroviral therapy (ART) regimens with infrequent virologic monitoring. We conducted a study of 22 HIV-infected participants receiving modern ART to determine the kinetics of plasma viral rebound following ATI. Our data suggest that modern ART does not alter kinetics of viral rebound when compared to previous regimens and that immunologic interventions may be necessary to achieve ART-free virologic remission. Clinical Trials Registration ClinicaTrials.gov identifier: NCT03225118.

This article outlines the significant scientific progress reported in 2019 that has led to the development of new drugs and therapeutic regimens, vaccine candidates, and diagnostics for the prevention and treatment of tuberculosis. In 2020, it will be important to build on this momentum and continue to advance basic and clinical research to develop improved tools and interventions, simultaneously optimizing their implementation in national control programs. To successfully achieve the goal to end tuberculosis within a generation, a concerted, collective, and collaborative effort is required, involving government, academia, industry and civil society at all levels.

Significance In HIV-infected patients on combination antiretroviral therapy (cART), greater than 95% of proviruses in the peripheral blood are “defective.” Historically, these defective proviruses have been thought to be dead-end products with no real pathophysiological significance, as they do not encode replication-competent viruses. Contrary to this view, we have identified cells in tissue culture and from cART-treated patients that harbor defective proviruses and produce viral proteins. Features found in these translationally competent yet defective proviruses suggest that HIV-1 infection results in modification of the CD4+ T cell genome analogous to human endogenous retroviruses. We propose that these defective HIV-1 proviruses are biologically significant, despite being “replication incompetent,” have the potential to elicit immune activation, and may serve as a barrier to HIV-1 cure., HIV-1 proviruses persist in the CD4+ T cells of HIV-infected individuals despite years of combination antiretroviral therapy (cART) with suppression of HIV-1 RNA levels

Eastern Equine Encephalitis Virus In the summer and fall of 2019, nine U.S. states reported 36 human cases (14 of them fatal) of EEE, an arthropod-borne viral (arboviral) disease transmitted by mos...

Anthony Fauci on four decades of progress against HIV, and what’s needed for the future. Anthony Fauci on four decades of progress against HIV, and what’s needed for the future.

The 2005 Immunity paper by Kariko et al. has been hailed as a cornerstone insight that directly led to the design and delivery of the mRNA vaccines against COVID-19. We asked experts in pathogen sensing, vaccine development, and public health to provide their perspective on the study and its implications.

International audience; No abstract available

SARS-CoV-2 mRNA booster vaccines provide protection from severe disease, eliciting strong immunity that is further boosted by previous infection. However, it is unclear whether these immune responses are affected by the interval between infection and vaccination. Over a 2-month period, we evaluated antibody and B cell responses to a third-dose mRNA vaccine in 66 individuals with different infection histories. Uninfected and post-boost but not previously infected individuals mounted robust ancestral and variant spike-binding and neutralizing antibodies and memory B cells. Spike-specific B cell responses from recent infection (180 days) were elevated at pre-boost but comparatively less so at 60 days post-boost compared with uninfected individuals, and these differences were linked to baseline frequencies of CD27

Research in the Context of a Pandemic Clifford Lane and Anthony Fauci comment on the findings of the RECOVERY trial of dexamethasone to treat Covid-19, noting that scientifically robust and ethical...

Anti-HIV broadly neutralizing antibodies (bNAbs) may favor development of antiviral immunity by engaging the immune system during immunotherapy. Targeting integrin α4β7 with an anti-α4β7 monoclonal antibody (Rh-α4β7) affects immune responses in SIV/SHIV-infected macaques. To explore the therapeutic potential of combining bNAbs with α4β7 integrin blockade, SHIVSF162P3-infected, viremic rhesus macaques were treated with bNAbs only (VRC07-523LS and PGT128 anti-HIV antibodies) or a combination of bNAbs and Rh-α4β7 or were left untreated as a control. Treatment with bNAbs alone decreased viremia below 200 copies/ml in all macaques, but seven of eight macaques (87.5%) in the bNAbs-only group rebounded within a median of 3 weeks (95% CI: 2 to 9). In contrast, three of six macaques treated with a combination of Rh-α4β7 and bNAbs (50%) maintained a viremia below 200 copies/ml until the end of the follow-up period; viremia in the other three macaques rebounded within a median of 6 weeks (95% CI: 5 to 11). Thus, there was a modest delay in viral rebound in the macaques treated with the combination antibody therapy compared to bNAbs alone. Our study suggests that α4β7 integrin blockade may prolong virologic control by bNAbs in SHIVSF162P3-infected macaques.

Messenger RNA (mRNA) vaccines against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are highly effective at inducing protective immunity. However, weak antibody responses are seen in some individuals, and cellular correlates of immunity remain poorly defined, especially for B cells. Here we used unbiased approaches to longitudinally dissect primary antibody, plasmablast, and memory B cell (MBC) responses to the two-dose mRNA-1273 vaccine in SARS-CoV-2-naive adults. Coordinated immunoglobulin A (IgA) and IgG antibody responses were preceded by bursts of spike-specific plasmablasts after both doses but earlier and more intensely after dose 2. While antibody and B cell cellular responses were generally robust, they also varied within the cohort and decreased over time after a dose-2 peak. Both antigen-nonspecific postvaccination plasmablast frequency after dose 1 and their spike-specific counterparts early after dose 2 correlated with subsequent antibody levels. This correlation between early plasmablasts and antibodies remained for titers measured at 6 months after vaccination. Several distinct antigen-specific MBC populations emerged postvaccination with varying kinetics, including two MBC populations that correlated with 2- and 6-month antibody titers. Both were IgG-expressing MBCs: one less mature, appearing as a correlate after the first dose, while the other MBC correlate showed a more mature and resting phenotype, emerging as a correlate later after dose 2. This latter MBC was also a major contributor to the sustained spike-specific MBC response observed at month 6. Thus, these plasmablasts and MBCs that emerged after both the first and second doses with distinct kinetics are potential determinants of the magnitude and durability of antibodies in response to mRNA-based vaccination.

The development of a protective vaccine remains a top priority for the control of the HIV/AIDS pandemic. Here, we show that a messenger RNA (mRNA) vaccine co-expressing membrane-anchored HIV-1 envelope (Env) and simian immunodeficiency virus (SIV) Gag proteins to generate virus-like particles (VLPs) induces antibodies capable of broad neutralization and reduces the risk of infection in rhesus macaques. In mice, immunization with co-formulated env and gag mRNAs was superior to env mRNA alone in inducing neutralizing antibodies. Macaques were primed with a transmitted-founder clade-B env mRNA lacking the N276 glycan, followed by multiple booster immunizations with glycan-repaired autologous and subsequently bivalent heterologous envs (clades A and C). This regimen was highly immunogenic and elicited neutralizing antibodies against the most prevalent (tier-2) HIV-1 strains accompanied by robust anti-Env CD4

Therapeutics for hospitalized COVID-19 patients were identified through a robust research response with several lessons learned: clinical trial data should guide therapeutic use, results should not be extrapolated between disease stages, and robust studies should be designed to give clinically relevant data. These lessons should be applied to the outpatient research response.

Certain infected individuals suppress human immunodeficiency virus (HIV) in the absence of anti-retroviral therapy (ART). Elucidating the underlying mechanism(s) is of high interest. Here we present two contrasting case reports of HIV-infected individuals who controlled plasma viremia for extended periods after undergoing analytical treatment interruption (ATI). In Participant 04, who experienced viral blips and initiated undisclosed self-administration of suboptimal ART detected shortly before day 1,250, phylogenetic analyses of plasma HIV env sequences suggested continuous viral evolution and/or reactivation of pre-existing viral reservoirs over time. Antiviral CD8

Amid the staggering amount of suffering and death during this historic pandemic of COVID-19, a remarkable success story stands out. The development of several highly efficacious vaccines against a previously unknown viral pathogen, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), in less than 1 year from the identification of the virus is unprecedented in the history of vaccinology. A frequently asked question is how such an extraordinary accomplishment could have been realized in such a short time frame, when timelines for other vaccines are measured in years if not decades. In fact, concern about this truncated timeline has contributed in part to the hesitancy in accepting these vaccines. What is not fully appreciated is that the starting point of the timeline for SARS-CoV-2 vaccines was not 10 January 2020, when the Chinese published the genetic sequence of the virus. Rather, it began decades earlier, out of the spotlight. Two activities predate the successful COVID-19 vaccines: the utilization of highly adaptable vaccine platforms such as RNA (among others) and the adaptation of structural biology tools to design agents (immunogens) that powerfully stimulate the immune system. The RNA approach evolved over several years owing to the ingenuity of individual scientists, including Drew Weissman and Katalin Kariko, and the concentrated efforts of several biotech and pharmaceutical companies. The discovery of an immunogen adaptable to the multiple platforms (messenger RNA and others) used for COVID-19 vaccines resulted from collaboration across different scientific subspecialities. At the Vaccine Research Center (VRC) of the U.S. National Institute of Allergy and Infectious Diseases, a group led by Peter Kwong had for several years used tools of structure-based vaccine design to determine the optimal structural conformation of a trimeric protein on the surface of the virus (the envelope protein) that allows HIV to bind to cells and ultimately trigger the production of antibodies that neutralize many HIV viral strains. Although this sophisticated approach has not yet led to a successful HIV vaccine, it caught the attention of another VRC investigator, Barney Graham, who was interested in generating a vaccine for respiratory syncytial virus (RSV). Graham joined Jason McLellan (of Kwong's team) to adapt a structure-based approach to an RSV vaccine. They identified the prefusion conformation of the viral spike protein as highly immunogenic and created mutations to stabilize that conformation for successful use as an immunogen. This was a huge step toward the creation of a successful RSV vaccine. VRC researchers and colleagues then built on the RSV advances. Graham's team, including Kizzmekia Corbett, and collaborators in the laboratories of McLellan and Andrew Ward adopted this approach of mutational stabilization of prefusion proteins in their work on the spike protein of the coronaviruses that cause Middle East respiratory syndrome (MERS) and severe acute respiratory syndrome (SARS). So, when the genetic sequence of the SARS-CoV-2 became available, Graham's team lost no time in joining their long-time collaborators at Moderna to develop an RNA vaccine using a stabilized, prefusion spike protein as the immunogen. Pfizer and BioNTech, where Kariko was working, also used the RNA platform that she and Weissman had perfected and the immunogen designed by Graham to develop an RNA vaccine. Additional companies also used Graham's immunogen in other vaccine platforms that had been evolving for years, to make SARS-CoV-2 vaccines. SARS-CoV-2 vaccines based on the new immunogen rapidly moved to clinical trials. Several of these vaccines were tested in phase 3 efficacy trials at a time when the level of community spread of SARS-CoV-2 was extremely high, allowing vaccine efficacy endpoints of greater than 90% to be reached in a timely fashion. The speed and efficiency with which these highly efficacious vaccines were developed and their potential for saving millions of lives are due to an extraordinary multidisciplinary effort involving basic, preclinical, and clinical science that had been under way—out of the spotlight—for decades before the unfolding of the COVID-19 pandemic. When the stories and recounting of this pandemic are written, it is important that this history not be forgotten, as we are reminded once again of the societal value of a sustained and robust support of our scientific enterprise.