Eukaryotic Translation Elongation Factor 1 Delta Inhibits the Nuclear Import of the Nucleoprotein and PA-PB1 Heterodimer of Influenza A Virus

Chicken UFL1 Restricts Avian Influenza Virus Replication by Disrupting the Viral Polymerase Complex and Facilitating Type I IFN Production

During avian influenza virus (AIV) infection, host defensive proteins promote antiviral innate immunity or antagonize viral components to limit viral replication. UFM1-specific ligase 1 (UFL1) is involved in regulating innate immunity and DNA virus replication in mammals, but the molecular mechanism by which chicken (ch)UFL1 regulates AIV replication is unclear. In this study, we first identified chUFL1 as a negative regulator of AIV replication by enhancing innate immunity and disrupting the assembly of the viral polymerase complex. Mechanistically, chUFL1 interacted with chicken stimulator of IFN genes (chSTING) and contributed to chSTING dimerization and the formation of the STING-TBK1-IRF7 complex. We further demonstrated that chUFL1 promoted K63-linked polyubiquitination of chSTING at K308 to facilitate chSTING-mediated type I IFN production independent of UFMylation. Additionally, chUFL1 expression was upregulated in response to AIV infection. Importantly, chUFL1 also interacted with the AIV PA protein to inhibit viral polymerase activity. Furthermore, chUFL1 impeded the nuclear import of the AIV PA protein and the assembly of the viral polymerase complex to suppress AIV replication. Collectively, these findings demonstrate that chUFL1 restricts AIV replication by disrupting the viral polymerase complex and facilitating type I IFN production, which provides new insights into the regulation of AIV replication in chickens.

Host proteins interact with viral elements and affect the life cycle of highly pathogenic avian influenza A virus H7N9

Host-virus interactions can significantly impact the viral life cycle and pathogenesis; however, our understanding of the specific host factors involved in highly pathogenic avian influenza A virus H7N9 (HPAI H7N9) infection is currently restricted. Herein, we designed and synthesized 65 small interfering RNAs targeting host genes potentially associated with various aspects of RNA virus life cycles. Afterward, HPAI H7N9 viruses were isolated and RNA interference was used to screen for host factors likely to be involved in the life cycle of HPAI H7N9. Moreover, the research entailed assessing the associations between host proteins and HPAI H7N9 proteins. Twelve key host proteins were identified: Annexin A (ANXA)2, ANXA5, adaptor related protein complex 2 subunit sigma 1 (AP2S1), adaptor related protein complex 3 subunit sigma 1 (AP3S1), ATP synthase F1 subunit alpha (ATP5A1), COPI coat complex subunit alpha (COP)A, COPG1, heat shock protein family A (Hsp70) member 1A (HSPA)1A, HSPA8, heat shock protein 90 alpha family class A member 1 (HSP90AA1), RAB11B, and RAB18. Co-immunoprecipitation revealed intricate interactions between viral proteins (hemagglutinin, matrix 1 protein, neuraminidase, nucleoprotein, polymerase basic 1, and polymerase basic 2) and these host proteins, presumably playing a crucial role in modulating the life cycle of HPAI H7N9. Notably, ANXA5, AP2S1, AP3S1, ATP5A1, HSP90A1, and RAB18, were identified as novel interactors with HPAI H7N9 proteins rather than other influenza A viruses (IAVs). These findings underscore the significance of host-viral protein interactions in shaping the dynamics of HPAI H7N9 infection, while highlighting subtle variations compared with other IAVs. Deeper understanding of these interactions holds promise to advance disease treatment and prevention strategies.

Influenza Virus Host Restriction Factors: The ISGs and Non-ISGs

Influenza virus has been one of the most prevalent and researched viruses globally. Consequently, there is ample information available about influenza virus lifecycle and pathogenesis. However, there is plenty yet to be known about the determinants of influenza virus pathogenesis and disease severity. Influenza virus exploits host factors to promote each step of its lifecycle. In turn, the host deploys antiviral or restriction factors that inhibit or restrict the influenza virus lifecycle at each of those steps. Two broad categories of host restriction factors can exist in virus-infected cells: (1) encoded by the interferon-stimulated genes (ISGs) and (2) encoded by the constitutively expressed genes that are not stimulated by interferons (non-ISGs). There are hundreds of ISGs known, and many, e.g., Mx, IFITMs, and TRIMs, have been characterized to restrict influenza virus infection at different stages of its lifecycle by (1) blocking viral entry or progeny release, (2) sequestering or degrading viral components and interfering with viral synthesis and assembly, or (3) bolstering host innate defenses. Also, many non-ISGs, e.g., cyclophilins, ncRNAs, and HDACs, have been identified and characterized to restrict influenza virus infection at different lifecycle stages by similar mechanisms. This review provides an overview of those ISGs and non-ISGs and how the influenza virus escapes the restriction imposed by them and aims to improve our understanding of the host restriction mechanisms of the influenza virus.

Whole-Exome Sequencing for Identification of Potential Sex-Biased Variants in Kawasaki Disease Patients

Kawasaki disease (KD) is an autoimmune disease of unknown etiology and has become a main cause of childhood acquired heart disease. KD is more prevalent in males than in females. The reason for this sex bias is unknown. Here, we used whole-exome sequencing (WES) to identify significantly different variants between male and female KD patients. From WES result, a total of 19,500 shared genetic variants in 8421 genes were captured via a series of filters. Further comparisons based on sex were performed to obtain 34 potential sex-biased variants in 34 genes for GO and Reactome Gene Sets enrichment analyses. Moreover, we selected 6 variants associated with immune, cells adhesion, platelet function, homeostasis, and ion channel signaling and expanded the sample size (1247 KD patients containing 713 males and 534 females, 803 healthy population containing 481 males and 322 females) for genotyping validation. From the results, USH2A/rs148135241, LMO7/rs142687160, CEMIP/rs12441101, and EFCC1/rs142391828 presented significant differences of alleles/genotypes frequency distributions between male and female only in KD patients (which were consistent with the result of WES analysis) but not in healthy population. In addition, the result also found that only EFCC1/rs142391828 polymorphism was associated with KD susceptibility. This result suggested that those four variants might play critical roles in sex bias in KD. The study would be in favor of a sex-specific genome atlas establishing and novel sex-specific precision therapies development for KD.

ABTB1 facilitates the replication of influenza A virus by counteracting TRIM4-mediated degradation of viral NP protein

Influenza A viruses (IAVs) continue to cause tremendous economic losses to the global animal industry and respiratory diseases and deaths among humans. The nuclear import of the vRNP complex, composed of polymerase basic protein 1 (PB1), polymerase basic protein 2 (PB2), polymerase acidic protein (PA), nucleoprotein (NP), and viral RNA, is essential for the efficient replication of IAV. Host factors involved in this process can be targeted for the development of countermeasures against IAV infection. Here, we found that Ankyrin Repeat and BTB Domain Containing 1 (ABTB1) promotes the replication of IAV, and positively regulates the nuclear import of the vRNP complex. ABTB1 did not interact directly with NP, indicating that ABTB1 plays an indirect role in facilitating the nuclear import of the vRNP complex. Immunoprecipitation and mass spectrometry revealed that Tripartite Motif Containing 4 (TRIM4) interacts with ABTB1. We found that TRIM4 relies on its E3 ubiquitin ligase activity to inhibit the replication of IAV by targeting and degrading NP within the incoming vRNP complex as well as the newly synthesized NP. ABTB1 interacted with TRIM4, leading to TRIM4 degradation through the proteasome system. Notably, ABTB1-mediated degradation of TRIM4 blocked the effect of TRIM4 on NP stability, and largely counteracted the inhibitory effect of TRIM4 on IAV replication. Our findings define a novel role for ABTB1 in aiding the nuclear import of the vRNP complex of IAV by counteracting the destabilizing effect of TRIM4 on the viral NP protein.

Role of the viral polymerase during adaptation of influenza A viruses to new hosts

As a group, influenza-A viruses (IAV) infect a wide range of animal hosts, however, they are constrained to infecting selected host species by species-specific interactions between the host and virus, that are required for efficient replication of the viral RNA genome. When IAV cross the species barrier, they acquire mutations in the viral genome to enable interactions with the new host factors, or to compensate for their loss. The viral polymerase genes polymerase basic 1, polymerase basic 2, and polymerase-acidic are important sites of host adaptation. In this review, we discuss why the viral polymerase is so vital to the process of host adaptation, look at some of the known viral mutations, and host factors involved in adaptation, particularly of avian IAV to mammalian hosts.

Advances in deciphering the interactions between viral proteins of influenza A virus and host cellular proteins

Influenza A virus (IAV) poses a severe threat to the health of animals and humans. The genome of IAV consists of eight single-stranded negative-sense RNA segments, encoding ten essential proteins as well as certain accessory proteins. In the process of virus replication, amino acid substitutions continuously accumulate, and genetic reassortment between virus strains readily occurs. Due to this high genetic variability, new viruses that threaten animal and human health can emerge at any time. Therefore, the study on IAV has always been a focus of veterinary medicine and public health. The replication, pathogenesis, and transmission of IAV involve intricate interplay between the virus and host. On one hand, the entire replication cycle of IAV relies on numerous proviral host proteins that effectively allow the virus to adapt to its host and support its replication. On the other hand, some host proteins play restricting roles at different stages of the viral replication cycle. The mechanisms of interaction between viral proteins and host cellular proteins are currently receiving particular interest in IAV research. In this review, we briefly summarize the current advances in our understanding of the mechanisms by which host proteins affect virus replication, pathogenesis, or transmission by interacting with viral proteins. Such information about the interplay between IAV and host proteins could provide insights into how IAV causes disease and spreads, and might help support the development of antiviral drugs or therapeutic approaches.

ARIH1 inhibits influenza A virus replication and facilitates RIG-I dependent immune signaling by interacting with SQSTM1/p62

BACKGROUND

Multiple host factors are involved in modulating type I interferon expression induced by viruses; however, the mechanism is not fully elucidated. Influenza A virus infection causes severe respiratory symptoms and triggers a series of signaling cascades and host innate immune responses, including interferon production. The co-IP/MS technology was used to screen several antiviral factors in the early stage. Among these factors, ariadne-1 homolog (ARIH1) caught our attention.

METHODS

Western blot assay was performed to detect the level of proteins and software ImageJ was used to analyze the band intensities. Polymerase activity assay was conducted to evaluate the polymerase activity of influenza A virus. Tissue culture infective dose (TCID₅₀) assay was performed to measure influenza A virus titers, and quantitative RT-PCR assay was applied to test the mRNA level of IFN-β, ISG56, and CXCL10. Luciferase reporter assay was used to confirm the target of ARIH1 in RIG-I signaling. Immunoprecipitation assay was performed to detect the interaction and the ubiquitination of the proteins. All data were analyzed by biostatistical methods and presented as means ± standard deviation from three independent experiments. Statistical significance was determined using two-tailed student's t test. A P value of less than 0.05 was considered statistically significant, and a P value of less than 0.01 was considered highly significant (ns, P ≥ 0.05; *, P < 0.05; and **, P < 0.01).

RESULTS

We found that ARIH1, a member of E3 ubiquitin ligases, enhanced cellular antiviral responses. Subsequent study showed that ARIH1 was up-regulated during influenza A virus infection. Further analysis showed that ARIH1 enhanced IFN-β and downstream gene expression by affecting the degradation of RIG-I through the SQSTM1/p62 signaling pathway.

CONCLUSION

This newly revealed mechanism shows that cellular response increases of ARIH1 and promotes IFN-β expression to boost host survival during viral infection.

Avian Influenza Virus Tropism in Humans

An influenza pandemic happens when a novel influenza A virus is able to infect and transmit efficiently to a new, distinct host species. Although the exact timing of pandemics is uncertain, it is known that both viral and host factors play a role in their emergence. Species-specific interactions between the virus and the host cell determine the virus tropism, including binding and entering cells, replicating the viral RNA genome within the host cell nucleus, assembling, maturing and releasing the virus to neighboring cells, tissues or organs before transmitting it between individuals. The influenza A virus has a vast and antigenically varied reservoir. In wild aquatic birds, the infection is typically asymptomatic. Avian influenza virus (AIV) can cross into new species, and occasionally it can acquire the ability to transmit from human to human. A pandemic might occur if a new influenza virus acquires enough adaptive mutations to maintain transmission between people. This review highlights the key determinants AIV must achieve to initiate a human pandemic and describes how AIV mutates to establish tropism and stable human adaptation. Understanding the tropism of AIV may be crucial in preventing virus transmission in humans and may help the design of vaccines, antivirals and therapeutic agents against the virus.

Nonmuscle myosin IIA promotes the internalization of influenza A virus and regulates viral polymerase activity through interacting with nucleoprotein in human pulmonary cells

Influenza A virus (IAV), responsible for seasonal epidemics and recurring pandemics, represents a global threat to public health. Given the risk of a potential IAV pandemic, it is increasingly important to better understand virus-host interactions and develop new anti-viral strategies. Here, we reported nonmuscle myosin IIA (MYH9)-mediated regulation of IAV infection. MYH9 depletion caused a profound inhibition of IAV infection by reducing viral attachment and internalization in human lung epithelial cells. Surprisingly, overexpression of MYH9 also led to a significant reduction in viral productive infection. Interestingly, overexpression of MYH9 retained viral attachment, internalization, or uncoating, but suppressed the viral ribonucleoprotein (vRNP) activity in a minigenome system. Further analyses found that excess MYH9 might interrupt the formation of vRNP by interacting with the viral nucleoprotein (NP) and result in the reduction of the completed vRNP in the nucleus, thereby inhibiting subsequent viral RNA transcription and replication. Together, we discovered that MYH9 can interact with IAV NP protein and engage in the regulation of vRNP complexes, thereby involving viral replication. These findings enlighten new mechanistic insights into the complicated interface of host-IAV interactions, ultimately making it an attractive target for the generation of antiviral drugs.

Influenza A virus use of BinCARD1 to facilitate the binding of viral NP to importin α7 is counteracted by TBK1-p62 axis-mediated autophagy

As a major component of the viral ribonucleoprotein (vRNP) complex in influenza A virus (IAV), nucleoprotein (NP) interacts with isoforms of importin α family members, leading to the import of itself  and vRNP complex into the nucleus, a process pivotal in the replication cycle of IAV. In this study, we found that BinCARD1, an isoform of Bcl10-interacting protein with CARD (BinCARD), was leveraged by IAV for efficient viral replication. BinCARD1 promoted the nuclear import of the vRNP complex and newly synthesized NP and thus enhanced vRNP complex activity. Moreover, we found that BinCARD1 interacted with NP to promote NP binding to importin α7, an adaptor in the host nuclear import pathway. However, we also found that BinCARD1 promoted RIG-I-mediated innate immune signaling by mediating Lys63-linked polyubiquitination of TRAF3, and that TBK1 appeared to degrade BinCARD1. We showed that BinCARD1 was polyubiquitinated at residue K103 through a Lys63 linkage, which was recognized by the TBK1-p62 axis for autophagic degradation. Overall, our data demonstrate that IAV leverages BinCARD1 as an important host factor that promotes viral replication, and two mechanisms in the host defense system are triggered—innate immune signaling and autophagic degradation—to mitigate the promoting effect of BinCARD1 on the life cycle of IAV.

Nucleoporin 85 interacts with influenza A virus PB1 and PB2 to promote its replication by facilitating nuclear import of ribonucleoprotein

Transcription and replication of the influenza A virus (IAV) genome take place in the nucleus of infected cells, which rely on host factors to aid viral ribonucleoprotein (vRNP) to cross the nuclear pore complex (NPC) and complete the bidirectional nucleocytoplasmic trafficking. Here, we showed that nucleoporin 85 (NUP85), a component of NPC, interacted with RNP subunits polymerase basic 1 (PB1) and polymerase basic 2 (PB2) in an RNA-dependent manner during IAV infection. Knockdown of NUP85 delayed the nuclear import of vRNP, PB1 and PB2, inhibiting polymerase activity and ultimately suppressing viral replication. Further analysis revealed that NUP85 assisted the binding of PB1 to nuclear transport factor Ran-binding protein 5 (RanBP5) and the binding of PB2 to nuclear transport factor importin α1 and importin α7. We also found that NUP85 expression was downregulated upon IAV infection. Together, our study demonstrated that NUP85 positively regulated IAV infection by interacting with viral PB1 and PB2, which may provide new insight into the process of vRNP nuclear import and a novel target for effective antivirals.

ARNT Inhibits H5N1 Influenza A Virus Replication by Interacting with the PA Protein

Increasing evidence suggests that the polymerase acidic (PA) protein of influenza A viruses plays an important role in viral replication and pathogenicity. However, information regarding the interaction(s) of host factors with PA is scarce. By using a yeast two-hybrid screen, we identified a novel host factor, aryl hydrocarbon receptor nuclear translocator (ARNT), that interacts with the PA protein of the H5N1 virus. The interaction between PA and human ARNT was confirmed by co-immunoprecipitation and immunofluorescence microscopy. Moreover, overexpression of ARNT downregulated the polymerase activity and inhibited virus propagation, whereas knockdown of ARNT significantly increased the polymerase activity and virus replication. Mechanistically, overexpression of ARNT resulted in the accumulation of PA protein in the nucleus and inhibited both the replication and transcription of the viral genome. Interaction domain mapping revealed that the bHLH/PAS domain of ARNT mainly interacted with the C-terminal domain of PA. Together, our results demonstrate that ARNT inhibits the replication of the H5N1 virus and could be a target for the development of therapeutic strategies against H5N1 influenza viruses.

G Protein Subunit β1 Facilitates Influenza A Virus Replication by Promoting the Nuclear Import of PB2

G protein subunit β1 (GNB1), the beta subunit of the G protein family, plays an important role in regulating transmembrane signal transduction. Although a recent study has demonstrated that GNB1 can bind the matrix protein 1 (M1) to facilitate M1 transport to budding sites and promote the release of progeny influenza A virus (IAV), whether the GNB1 protein has other functions in IAV replication requires further study. Here, we found that GNB1 promoted IAV replication, as virus yield decreased in GNB1 knockdown or knockout cells. GNB1 interacted with polymerase subunits PB2, PB1, and PA. Overexpressed GNB1 facilitated PB2 binding to importin α3, α5, and α7 promoting the nuclear import of PB2, enhancing viral RNA synthesis and polymerase activity. Altogether, our results demonstrated that GNB1 positively regulates virus replication by interacting with polymerase subunits and facilitating the nuclear import of PB2, which provide novel insights into the molecular mechanism of IAV. IMPORTANCE Until now, there has been only one article on the role of GNB1 in IAV budding. No study has investigated the role of GNB1 in IAV replication. In this study, our research demonstrated that GNB1 could increase the interaction between PB2 and the importin α isoform and mediate the nuclear import of PB2. Therefore, GNB1 could promote viral replication and transcription. Our results provide a better understanding of the molecular mechanisms of viral replication and provide potential antiviral drug targets.

m6A Regulator-Mediated Methylation Modification Patterns and Characteristics of Immunity in Blood Leukocytes of COVID-19 Patients

Both RNA N6-methyladenosine (m⁶A) modification of SARS-CoV-2 and immune characteristics of the human body have been reported to play an important role in COVID-19, but how the m⁶A methylation modification of leukocytes responds to the virus infection remains unknown. Based on the RNA-seq of 126 samples from the GEO database, we disclosed that there is a remarkably higher m⁶A modification level of blood leukocytes in patients with COVID-19 compared to patients without COVID-19, and this difference was related to CD4⁺ T cells. Two clusters were identified by unsupervised clustering, m⁶A cluster A characterized by T cell activation had a higher prognosis than m⁶A cluster B. Elevated metabolism level, blockage of the immune checkpoint, and lower level of m6A score were observed in m⁶A cluster B. A protective model was constructed based on nine selected genes and it exhibited an excellent predictive value in COVID-19. Further analysis revealed that the protective score was positively correlated to HFD45 and ventilator-free days, while negatively correlated to SOFA score, APACHE-II score, and crp. Our works systematically depicted a complicated correlation between m⁶A methylation modification and host lymphocytes in patients infected with SARS-CoV-2 and provided a well-performing model to predict the patients' outcomes.

The role of EEF1D in disease pathogenesis: a narrative review

Objective

The purpose of this paper was to investigate the role and mechanism of EEF1D in various diseases, especially in tumorigenesis and development, and explore the possibility of EEF1D as a biological target.

Background

EEF1D is a part of the EEF1 protein complex, which can produce four protein isoforms, of which three short isoforms are used as translation elongation factors. The three short isoforms play a role in anti-aging, regulating the cell cycle, and promoting the occurrence and development of malignant tumors, and the only long-form isoform plays a role in the development of the nervous system.

Methods

We searched the PubMed and Web of Science databases for literature up to January 2021 using relevant keywords, including “EEF1D”, “eukaryotic translation elongation factor 1 delta”, “translation elongation factor”, “translation elongation factor and cancer”, and “translation elongation factor and nervous system disease”. We then created an overview of the literature and summarized the results of the paper.

Conclusions

Through the review of relevant articles, we found that EEF1D is obviously overexpressed in a variety of tumors, and can regulate the proliferation of tumor cells and tumor growth, as well as play a role in tumor invasion. EEF1D is likely to become a new biological target for tumor therapy and diagnosis.

Construction, Identification and Analysis of the Interaction Network of African Swine Fever Virus MGF360-9L with Host Proteins

African swine fever virus (ASFV) is prevalent in many countries and is a contagious and lethal virus that infects pigs, posing a threat to the global pig industry and public health. The interaction between the virus and the host is key to unlocking the mystery behind viral pathogenesis. A comprehensive understanding of the viral and host protein interaction may provide clues for developing new antiviral strategies. Here, we show a network of ASFV MGF360-9L protein interactions in porcine kidney (PK-15) cells. Overall, 268 proteins that interact with MGF360-9L are identified using immunoprecipitation and liquid chromatography–mass spectrometry (LC-MS). Accordingly, gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses were conducted, and the protein–protein interaction (PPI) network was created. It was speculated that the cellular proteins interacting with MGF360-9L are involved in protein binding, metabolism, and the innate immune response. Proteasome subunit alpha type (PSMA3), 26S protease regulatory subunit 4 (PSMC1), autophagy and beclin 1 regulator 1 (AMBRA1), and DEAD-box helicase 20 (DDX20) could interact with MGF360-9L in vitro. PSMA3 and PSMC1 overexpression significantly promoted ASFV replication, and MGF360-9L maintained the transcriptional level of PSMA3 and PSMC1. Here, we show the interaction between ASFV MGF360-9L and cellular proteins and elucidate the virus–host interaction network, which effectively provides useful protein-related information that can enable further study of the potential mechanism and pathogenesis of ASFV infection.

CMAS and ST3GAL4 Play an Important Role in the Adsorption of Influenza Virus by Affecting the Synthesis of Sialic Acid Receptors

Influenza A viruses (IAVs) initiate infection by attaching Hemagglutinin (HA) on the viral envelope to sialic acid (SA) receptors on the cell surface. Importantly, HA of human IAVs has a higher affinity for α-2,6-linked SA receptors, and avian strains prefer α-2,3-linked SA receptors, whereas swine strains have a strong affinity for both SA receptors. Host gene CMAS and ST3GAL4 were found to be essential for IAV attachment and entry. Loss of CMAS and ST3GAL4 hindered the synthesis of sialic acid receptors, which in turn prevented the adsorption of IAV. Further, the knockout of CMAS had an effect on the adsorption of swine, avian and human IAVs. However, ST3GAL4 knockout prevented the adsorption of swine and avian IAV and the impact on avian IAV was more distinct, whereas it had no effect on the adsorption of human IAV. Collectively, our findings demonstrate that knocking out CMAS and ST3GAL4 negatively regulated IAV replication by inhibiting the synthesis of SA receptors, which also provides new insights into the production of gene-edited animals in the future.

Mammalian and Avian Host Cell Influenza A Restriction Factors

The threat of a new influenza pandemic is real. With past pandemics claiming millions of lives, finding new ways to combat this virus is essential. Host cells have developed a multi-modular system to detect incoming pathogens, a phenomenon called sensing. The signaling cascade triggered by sensing subsequently induces protection for themselves and their surrounding neighbors, termed interferon (IFN) response. This response induces the upregulation of hundreds of interferon-stimulated genes (ISGs), including antiviral effectors, establishing an antiviral state. As well as the antiviral proteins induced through the IFN system, cells also possess a so-called intrinsic immunity, constituted of antiviral proteins that are constitutively expressed, creating a first barrier preceding the induction of the interferon system. All these combined antiviral effectors inhibit the virus at various stages of the viral lifecycle, using a wide array of mechanisms. Here, we provide a review of mammalian and avian influenza A restriction factors, detailing their mechanism of action and in vivo relevance, when known. Understanding their mode of action might help pave the way for the development of new influenza treatments, which are absolutely required if we want to be prepared to face a new pandemic.