COVID-19

Vaccines and targeted therapeutics for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are currently lacking. Here, the authors report a human monoclonal antibody capable of neutralizing both authentic SARS-CoV and SARS-CoV-2 by targeting a common epitope.

There is currently no licensed SARS-CoV-2 vaccine. Here, the authors generate an optimized DNA vaccine candidate encoding the SARS-CoV-2 spike antigen, demonstrating induction of specific T cells and neutralizing antibody responses in mice and guinea pigs. These initial results support further development of this vaccine candidate.

Antibody mediated immunity to SARS-CoV-2 will affect future transmission and disease severity. This systematic review on antibody response to coronaviruses, including SARS-CoV-2, SARS-CoV, MERS-CoV and endemic coronaviruses provides insights into kinetics, correlates of protection, and association with disease severity.

Here, the authors develop a self-amplifying RNA encoding the SARS-CoV-2 spike protein encapsulated within a lipid nanoparticle as a vaccine candidate and show induction of neutralization antibody titers in mice that are comparable to titers in convalescent sera of patients.

SARS-CoV-2 variants with spike (S)-protein D614G mutations currently predominate globally. Here, Zhang et al. hypothesize that D614G variant may increase infectivity by increasing S protein abundance on the virion since pseudoviruses carrying S-G614 incorporate higher amounts of S protein and enter cells more efficiently than those carrying S-D614.

COVID-19 is a serious pandemic threat to public health, but insights on the pathophysiological and immunological conditions are only emerging. Here the authors use multi-color flow cytometry to characterize CD4⁺ and CD8⁺ T cells in peripheral blood from 39 COVID-19 patients in Italy to report altered T cell activation, function and polarization.

Children with SARS-CoV-2 infection are more likely to have mild symptoms and may be asymptomatic, but underlying reasons remain unclear. Here, the authors show cellular, cytokine and antibody response to SARS-CoV-2 infection in three children who repeatedly tested negative for the virus by PCR, despite high exposure in the household.

Here, Ejemel et al. report the identification and characterization of a cross-neutralizing human IgA monoclonal antibody, named MAb362, that binds the receptor-binding domain of SARS-CoV-2 Spike, blocking its interaction with the ACE2 host receptor.

SARS-CoV-2 uses ACE2 as the entry receptor. Here, the authors show that an ACE2-Ig fusion protein inhibits entry of virus pseudotyped with the SARS-CoV-2 spike protein, show differential binding kinetics of SARS-CoV and SARSCoV-2 spike proteins to ACE2, and determine pharmakocinetic parameters of ACE2-Ig in mice.

A vaccine preventing infection and transmission of SARS-CoV-2 is needed. Here, Wu et al. generate an adenovirus-vector vaccine expressing SARS-CoV-2 spike protein and show that a single dose of mucosal vaccination protects mice and ferrets from infection and inhibits virus replication in the upper respiratory tract.

Here, the authors characterize a SARS-CoV-2 subunit vaccine candidate that contains full-length spike protein stabilized in its prefusion conformation, and show immunogenicity in baboons and protection in mice with Matrix-M adjuvanted vaccine.

Emerging SARS-CoV-2 variants contain mutations in the spike protein that may affect vaccine efficacy. Here, Jalkanen et al. show, using sera from 180 BNT162b2-vaccinated health care workers, that neutralization of SARS-CoV2 variant B.1.1.7 is not affected, while neutralization of B.1.351 variant is five-fold reduced.

Here, the authors perform plaque reduction neutralization (PRNT) assays quantitating SARS-CoV-2 specific neutralizing antibodies from 195 patients in different disease states and find that patients with severe disease exhibit higher peaks of neutralizing antibody titres than patients with mild or asymptomatic infections and that serum neutralizing antibody persists for over 6 months in most people.

T cells compose a critical component of the immune response to coronavirus infection with SARS-CoV-2. Here the authors characterise the T cell response to SARS CoV-2 in patients and their close contacts, and show the presence of SARS-CoV-2 specific T cells in the absence of detectable virus infection.

Antibody responses are critical for protection from developing severe COVID-19 following SARS-CoV-2 infection. Here the authors show that antibody responses against SARS-CoV-2 spike protein correlate with neutralizing capacity and protection, are not affected by heterologous boosting of influenza or common cold immunity, and can last up to 8 months.

Pre-existing immune responses between antigenically related viruses can influence responses in viral infections or vaccinations. Here the authors assess and characterize the presence of antibody and memory B cell populations specific to SARS-CoV2 and endemic human coronaviruses.

The humoral immune response to SARS-CoV-2 infection is not yet fully understood. Here, Marot et al. monitor the longitudinal profile and neutralizing activity of IgG, IgA, and IgM among 26 healthcare workers and provide evidence for a short-lasting humoral immune protection due to a decrease of neutralizing antibody titers within 3 months.

A better understanding of longitudinal changes in antibody responses in COVID-19 patients is needed. Here the authors analyze anti-spike and anti-nucleocapsid antibody responses to Sars-CoV-2 over a course of 6 months in a large cohort of patients with COVID-19, showing that IgM is mostly not detectable after 3 months, whereas IgG responses contract, yet remain at high levels at 6 months.

Infection with SARS-CoV2 and the development of Coronavirus disease 2019 (COVID-19) has been linked to induction of autoimmunity and autoantibody production. Here the authors characterise the new-onset IgG autoantibody response in hospitalised patients with COVID-19 which they correlate to the magnitude of the SARS-CoV2 response.

The extent of antibody protection against SARS-CoV-2 remains unclear. Here, using a cohort of 120 seroconverted individuals, the authors longitudinally characterize neutralization, Fc-function, and SARS-CoV-2 specific T cell responses, which they show to be prominent only in those subjects that elicited receptor-binding domain (RBD)-specific antibody titers above a certain threshold, suggesting that development of T cell responses to be related to anti-RBD Ab production.

While cross-reactive immunity between human coronavirus and SARS-CoV-2 may contribute to host protection, validating evidences are still scarce. Here the authors assess a cohort of 52 donors with immediate-early contact with SARS-CoV-2 to correlate higher frequency of cross-reactive T cells with lower infection rate.

Pregnant women have been disproportionately under-vaccinated against COVID-19, partly because they were excluded from initial trials. This systematic review and meta-analysis supports efficacy of vaccination in pregnancy, and finds no evidence of adverse maternal or perinatal outcomes.

In this prospective cohort study, authors follow 328 households in Germany with at least one confirmed SARS-CoV-2 infection and find that children are more likely to seroconvert without symptoms and have higher specific antibody levels that persist longer than in adults.

Emerging SARS-CoV-2 variants of concern (VOCs) raises concerns regarding vaccine efficacy. Here, the authors evaluate the neutralizing antibody, and cellular response elicited following inactivated vaccine immunization, and mRNA booster, against the Omicron variant.

Waning immunity to SARS-CoV-2 is of concern. Here the authors follow spike- and nucleocapsid specific immunity in convalescent individuals for 9 months observing a decline in antibody levels but persisting T cell response. Vaccination approximately 11 months after infection boosts antibody and T cell immunity.

Remdesivir (RDV) is a broad-spectrum antiviral drug with activity against MERS coronavirus, but in vivo efficacy has not been evaluated. Here, the authors show that RDV has superior anti-MERS activity in vitro and in vivo compared to combination therapy with lopinavir, ritonavir and interferon beta and reduces severe lung pathology.

SARS-CoV-2 has rapidly spread globally and animal models to study transmission are needed. Here, Richard et al. show efficient transmission of SARS-CoV-2 between ferrets via direct contact and via the air, through respiratory droplets and/or aerosols.

In this study, Massachusetts Consortium for Pathogen Readiness (MassCPR) investigators assess the relationship between SARS-CoV-2 viral load and COVID-19 disease severity and report that the levels of detectable viral RNA, especially in plasma, correlates with severity of respiratory disease, inflammatory markers and predicted risk of death.

Coronavirus main protease is essential for viral polyprotein processing and replication. Here Vuong et al. report efficient inhibition of SARS-CoV-2 replication by the dipeptide-based protease inhibitor GC376 and its parent GC373, which were originally used to treat feline coronavirus infection.

Here, Hanke et al. immunize an alpaca with SARS-CoV-2 spike protein domains and identify a nanobody that binds the receptor binding domain of spike in both the up and down conformations and sterically hinders ACE2 engagement.

SARS-CoV-2 spike protein binds host ACE2 for virus entry. Here, the authors determine kinetic and thermodynamic properties of this interaction using atomic force microscopy, develop peptides that inhibit binding and suggest existence of additional attachment factors.

Recent evidence has suggested that blood type may be associated with severe COVID-19. Here, the authors use data from ~14,000 individuals tested for SARS-CoV-2 at a New York City hospital, and find that certain ABO and Rh blood types are associated with infection, intubation, and death.

Here, the authors isolate several nanobodies from a synthetic library that bind the receptor-binding domain (RBD) of SARS-CoV-2 spike protein (S) and neutralize S pseudotyped viruses. Cryo-EM structure of Spike with one nanobody and further biophysical analysis shows competition with ACE2 binding.

Duration of infectious SARS-CoV-2 shedding is an important measure for improved disease control. Here, the authors use virus cultures of respiratory tract samples from COVID-19 patients and observe a median shedding duration of 8 days and a drop below 5% after 15,2 days post onset of symptoms.

Hydroxychloroquine and chloroquine have been investigated as a potential treatment for Covid-19 in several clinical trials. Here the authors report a meta-analysis of published and unpublished trials, and show that treatment with hydroxychloroquine for patients with Covid-19 was associated with increased mortality, and there was no benefit from chloroquine.

SARS-CoV-2 D614G spike protein mutation is one of the predominant circulating vital mutants. Here, Ozono et al. demonstrate that D614G mutation increases in vitro cell entry by acquiring higher affinity to ACE2.

Remdesivir is a nucleoside analog that inhibits the SARS-CoV-2 RNA dependent RNA polymerase (RdRp) and is used as a drug to treat COVID19 patients. Here, the authors provide insights into the mechanism of remdesivir-induced RdRp stalling by determining the cryo-EM structures of SARS-CoV-2 RdRp with bound RNA molecules that contain remdesivir at defined positions and observe that addition of the fourth nucleotide following remdesivir incorporation into the RNA product is impaired by a barrier to further RNA translocation.

Statins, which have anti-inflammatory and antithrombotic properties, could have effects in COVID-19 patients. Here, the authors find in a retrospective analysis of patients hospitalized with COVID-19 that antecedent statin use is associated with lower inpatient mortality.

Emerging SARS-CoV-2 mutants may escape neutralization by antibodies. Here, the authors use deep mutational scanning to identify mutations in the RBD that escape human monoclonal antibodies or convalescent plasmas.

Some epidemiological data suggests that SARS-CoV-2 can be transmitted through the air over longer distances. Here, Kutter et al. show in the ferret model that SARS-CoV-2 and SARS-CoV can be transmitted through the air over more than a meter distance, however, data should be interpreted with care, as ferrets are likely more susceptible to coronavirus infections.

Viruses manipulate host cell pathways to support infection. Here the authors show that SARS-CoV-2 infection modulates cellular metabolism and limits autophagy, and identify druggable host pathways for virus inhibition.

While vaccines protecting against SARS-CoV-2 infection are approved, currently, there are no drugs suitable for high-risk exposure use against SARS-CoV-2. Here, Rosenke et al. provide evidence that orally delivered MK-4482, a nucleoside analog, inhibits SARS-CoV-2 replication in the Syrian hamster model.

Cell surface attachment factors, such as glycans, play an important role in viral infection. Here, Petitjean et al. show that SARS-CoV-2 specifically binds to 9-Oacetylated sialic acid and have designed novel inhibitors based on multivalent derivatives.

Here, the authors isolate and characterize a bispecific monomeric nanobody that induces dimerization of SARS-CoV-2 spike trimers, neutralizes variants of concerns as well as SARS-CoV, and inhibits SARS-CoV-2 infection in mice.

Severe COVID-19 requires immediate and targeted intervention that is efficient against SARS-CoV-2 and its variants. Authors show here the therapeutic potential of engineered natural killer cells that simultaneously express a chimeric antigen receptor targeting the spike protein of SARS-CoV-2, and IL-15, a cytokine that enhances the function and survival of their own.

The immune response to SARS-CoV-2 infection is variable but has been linked to prognosis and the development of severe immunopathology. Here the authors assess a range of immune parameters in both peripheral blood and respiratory samples, providing a comparative assessment of the immune response between these compartments and their potential impact on immune-pathogenesis.

There is an urgent need for anti-virals targeting SARS-CoV-2. One of the most promising viral targets is the main protease of SARS-CoV-2, which is essential for viral replication and has no human analogue. Here, Abdelnabi et al. show that one of the most promising anti-virals (PF-07321332), currently in clinical trials, protects against SARS-CoV-2 alpha, beta and delta variant infection and provide evidence of reduced transmission.

Congenital infection of SARS-CoV-2 has been described, but the transmission routes remain unclear. Here, the authors report evidence of transplacental transmission of SARS-CoV-2 in a neonate born to a mother infected in the last trimester and presenting with neurological compromise.

Anecdotal reports suggest potential severity and outcome differences between sexes following infection by SARS-CoV-2. Here, the authors perform meta-analyses of more than 3 million cases collected from global public data to demonstrate that male patients with COVID-19 are 3 times more likely to require intensive care, and have ~40% higher death rate.

SARS-CoV-2 has emerged recently and may still adapt to the human host. Here the authors show that none of the so far identified recurrent mutations in SARS-CoV-2 are significantly associated with increased viral transmission.

Estimating the extent of SARS-CoV-2 infection in a population is challenging due to the limitations of testing. Here, the authors estimate that the true number of infections in the United States in mid-April was up to 20 times higher than the number of confirmed cases.

Fine-grained studies of epidemic spread and of the effect of nonpharmaceutical interventions are still needed to underpin demographic and socio-economic effects. Here, the authors study the spatial and temporal spread of SARS-CoV-2 in Santiago de Chile using anonymized mobile phone data.

Recommendations regarding the use of face masks as a preventive measure for COVID-19 are inconsistent. Here, the authors show that optimal distribution of surgical-standard face masks in the population, or universal coverage of homemade face coverings, could reduce total infections and deaths.

Large-scale population screening can provide insights to levels of ongoing SARS-CoV-2 transmission. Here, the authors report a citywide screening of ~10,000,000 residents of Wuhan and show that SARS-CoV-2 infection prevalence was very low five to eight weeks after the end of lockdown.

Better understanding of who is at highest risk of death from COVID-19 is important for public health planning. Here, the authors demonstrate an unequal mortality burden associated with socially disadvantaged groups in Sweden.

SARS-CoV-2 infection is widely diagnosed by RT-PCR, but RNA extraction is a bottleneck for fast and cheap diagnosis. Here, the authors develop protocols to perform RT-PCR directly on heat-inactivated subject samples or samples lysed with readily available detergents and benchmark performance against 597 clinically diagnosed patient samples.

Hesitancy and resistance towards vaccination is a challenge for public health. Here the authors determine psychological characteristics associated with COVID-19 vaccine hesitancy or resistance attitudes in the UK and Ireland.

New Zealand has been relatively successful in controlling COVID-19 due to implementation of strict non-pharmaceutical interventions. Here, the authors demonstrate a striking decline in reports of influenza and other non-influenza respiratory pathogens over winter months in which the interventions have been in place.

Test, trace, and isolate programmes are central to COVID-19 control. Here, Viola Priesemann and colleagues evaluate how to allocate scarce resources to keep numbers low, and find that if case numbers exceed test, trace and isolate capacity, there will be a self-accelerating spread.

The duration of effectiveness of SARS-CoV-2 vaccination is not yet known. Here, the authors present preliminary evidence of BNT162b2 vaccine waning across all age groups above 16, with a higher incidence of infection in people who received their second dose early in 2021 compared to later in the year.

Social distancing policies aiming to reduce COVID-19 transmission have been reflected in reductions in human mobility. Here, the authors show that reduced mobility is correlated with decreased transmission, but that this relationship weakened over time as social distancing measures were relaxed.

Common mitigation measures gradually inhibit the spread of infectious diseases, yielding smooth transitions to large-scale epidemics. As Scarselli et al. show, limited testing may radically change the transition to include jumps, potentially resulting in unforseen, accelerated growth of case numbers.

While Digital contact tracing (DCT) has been argued to be a valuable complement to manual tracing in the containment of COVID-19, no empirical evidence of its effectiveness is available to date. Here, the authors report the results of a 4-week population-based controlled experiment, where they assessed the impact of the Spanish DCT app.

The role of meteorological factors in SARS-COV-2 transmission is not well understood. Here, the authors use county-level data from the United States to the end of 2020 and find evidence of a moderate association between increased transmissibility and cold, dry weather and low ultraviolet radiation.

Vo’, Italy, is a unique setting for studying SARS-CoV-2 antibody dynamics because mass testing was conducted there early in the pandemic. Here, the authors perform two follow-up serological surveys and estimate seroprevalence, the extent of within-household transmission, and the impact of contact tracing.

COVID-19 diagnosis is commonly performed by PCR testing, however, serologic methods are more accurate and versatile for monitoring disease burden and epidemiology. Here the authors report a protein microarray with antigens from SARS-CoV-2, SARS-CoV, MERS-CoV as well as common human respiratory viruses.

Understanding collective behaviour is an important aspect of managing the pandemic response. Here the authors show in a large global study that participants that reported identifying more strongly with their nation reported greater engagement in public health behaviours and support for public health policies in the context of the pandemic.

Here, using genomic approaches, Rockett et al. identify Omicron and Delta SARS-CoV-2 co-infections in two adults, highlighting the usefulness of genomic surveillance for the timely recognition of co-infections in situations when different variants of the virus are circulating in the community.

To monitor the presence of novel SARS-CoV-2 variants in New York City, Smyth et al. perform deep-sequencing of the receptor binding domain of S protein in wastewater samples and find novel cryptic lineages containing mutations affecting ACE2-tropism and showing decreased neutralization by antibodies.

Hong Kong has used an elimination strategy to control SARS-CoV-2 with stringent measures including traveller quarantine. Here, the authors show that the majority of community-acquired cases until January 2021 resulted from three importations, and that increased transmission followed prolonged periods of restrictions, likely due to adherence fatigue.

Here, the authors simulate COVID-19 outbreaks on an empirical contact network derived from digital contact data collected on cruise ships. They model impacts of different control measures and find that combinations of measures, particularly vaccination and rapid antigen testing, are important for mitigating outbreaks.

It has been suggested that pangolin coronaviruses may be the origin of SARS-CoV-2. Here the authors show that the Pangolin-CoV spike is structurally closely related to the closed form of SARS-CoV-2 spike and exhibits similar binding properties to human and pangolin ACE2; although neither spike binds bat ACE2.

SARS-CoV-2 has spread globally. Here, the authors characterize the entry pathway of SARS-CoV-2, show that the SARS-CoV-2 spike protein is less stable than that of SARS-CoV, and show limited cross-neutralization activities between SARS-CoV and SARS-CoV-2 sera.

In this study, Delaune et al., isolate and characterise a SARS-CoV-2-related coronavirus from two bats sampled in Cambodia. Their findings suggest that the geographic distribution of SARS-CoV-2-related viruses is wider than previously reported.

Specific non-structural proteins (nsp) of SARS coronaviruses are involved in methylation of virally encoded mRNAs to mimic cellular mRNAs for protection against host innate immune restriction. Here, the authors present a high resolution structure of SARS-CoV-2 nsp16/nsp10 ternary complex in the presence of cognate RNA substrate analogue and methyl donor, S-adenosyl methionine, revealing unique ligand-binding sites that may represent alternative targets for antiviral development.

Characterisation of the human antibody response to SARS-CoV-2 can help the design of serological tests and vaccines. Here, the authors identify two linear epitopes in SARS-CoV-2 spike protein that elicit neutralising antibodies in several patients and could thus be useful for serology and vaccine development.

The SARS-CoV-2 3CL main protease (3CL M^pro) is a chymotrypsin-like protease that facilitates the production of non-structural proteins, which are essential for viral replication and is therefore of great interest as a drug target. Here, the authors present the 2.30 Å room temperature crystal structure of ligand-free 3CL M^pro and compare it with the earlier determined low-temperature ligand-free and inhibitor-bound crystal structures.

Chest CT is emerging as a valuable diagnostic tool for clinical management of COVID-19 associated lung disease. Here, the authors present a multinational study on the application of deep learning algorithms for COVID-19 diagnosis against multiple lung conditions as controls.

The SARS-CoV-2 viral genome is encapsulated by the nucleocapsid protein (N^SARS-CoV-2) that is essential for viral replication. Here, the authors show that RNA induces liquid-liquid phase separation of N^SARS-CoV-2 and how N^SARS-CoV-2 phosphorylation modulates RNA-binding and phase separation and that these RNA/N^SARS-CoV-2-droplets recruit and concentrate the SARS-CoV-2 RNA-dependent RNA polymerase complex in vitro, which would enable high initiation and elongation rates during viral transcription.

Comparing and contrasting structural ensembles of different protein variants helps connect specific structural features to a protein’s biochemical properties. Here, the authors propose DiffNets, a self-supervised, deep learning method that streamlines this process.

Here the authors visualize SARS-CoV-2 infected cells by in situ cryo-electron tomography, delineating the structural organization and conformational changes that occur during virus replication and budding; and provide insight into vRNP architecture and RNA networks in double membrane vesicles.

Currently very little is known about how our immune system responds to SARS-CoV-2 infection. Here the authors generate a SARS-CoV-2 proteome microarray for profiling of IgG and IgM responses to COVID-19 in patients and find significant responses to ORF9b and NSP5, as well as the S1 and N proteins.

A bat origin for SARS-CoV-2 has been proposed. Here, by sampling wild Rhinolophus acuminatus bats from Thailand, the authors identified a SARS-CoV-2-related coronavirus (SC2r-CoV), designated as RacCS203, with 91.5% genome similarity to SARS-CoV-2, and show that sera obtained from bats and Malayan pangolin neutralize SARS-CoV-2.

Therapies and vaccines for COVID-19, caused by the SARS-CoV-2 viral pandemic, are urgently needed. Here the authors establish and screen an antibody library from a convalescent COVID-19 patient to isolate a neutralizing antibody with the ability to reduce viral titer and alleviate symptoms in ferret, hamster, and rhesus monkey infection models.

The SARS-CoV-2 gene set remains unresolved, hindering dissection of COVID-19 biology. Comparing 44 Sarbecovirus genomes provides a high-confidence protein-coding gene set. The study characterizes protein-level and nucleotide-level evolutionary constraints, and prioritizes functional mutations from the ongoing COVID-19 pandemic.

Homologous recombination between co-infecting coronaviruses can produce novel pathogens. Here, Wardeh et al. develop a machine learning approach to predict associations between mammals and multiple coronaviruses and hence estimate the potential for generation of novel coronaviruses by recombination.

SARS-CoV-2 S protein prematurely refolds to the post-fusion conformation, compromising immunogenic properties and prefusion trimer yield. Here, Juraszek et al. present a stable SARS-CoV-2 S-closed protein variant with increased expression and correct folding, predominantly in closed prefusion conformation.

SARS-CoV-2 nucleocapsid (N) protein is responsible for viral genome packaging. Here the authors employ single-molecule spectroscopy with all-atom simulations to provide the molecular details of N protein and show that it undergoes phase separation with RNA.

COVID-19 is a critical public health threat, but molecular characterizations of patients’ immunity is still lacking. Here the authors collected blood from patients with various disease severity, and prefiltered to exclude selected comorbidity, to obtain genomic, transcriptomic, proteomic, metabolomic and lipidomic profiles to report a trans-omics landscape.

Variants of concerns arise from SARS-CoV-2 mutations poise as severe public health threats. Here the authors chronicle SARS-CoV-2 mutations onset and immune parameters in an immunocompromised patient with continuous virus-shedding, thereby hinting potential intra-host viral evolution and escape facilitated by ineffective T cell immunity.

Structural immunology is critical in understanding the interplay between the immune response and the infective agent but such studies in T cells and SARS-CoV-2 lag behind those of antibodies and B-cell receptors. Here the authors assess recognition of SARS-CoV-2 spike epitopes and their natural variants by public and private T cell receptors.

BriSΔ, a SARS-CoV-2 variant from clinical isolate hCoV/England/02/2020, comprises a deletion in a spike cleavage site. The structure and molecular dynamics of this spike provides mechanistic insights into how the deletion modulates virus infectivity.

The SARS-CoV-2 spike has been evolving in the human population. The variants of concern alpha and beta evolved to optimise spike openness and so ability to bind its receptor ACE2, the affinity towards the receptor, and stability upon receptor binding.

This study determined the structure of the spike protein of the SARS-CoV-2 omicron variant, revealing a predominantly open conformation of the molecule that may help omicron infect cells more efficiently than do previous variants.