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We aimed to review the existing literature on the different types of neutralization assays and international standards for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). We comprehensively summarized the serological assays for detecting neutralizing antibodies against SARS-CoV-2 and demonstrated the importance of an international standard for calibrating the measurement of neutralizing antibodies. Following the coronavirus disease outbreak in December 2019, there was an urgent demand to detect neutralizing antibodies in patients or vaccinated people to monitor disease outcomes and determine vaccine efficacy. Therefore, many approaches were developed to detect neutralizing antibodies against SARS-CoV-2, such as microneutralization assay, SARS-CoV-2 pseudotype virus assay, enzyme-linked immunosorbent assay (ELISA), and rapid lateral flow assay. Given the many types of serological assays for quantifying the neutralizing antibody titer, the comparison of different assay results is a challenge. In 2020, the World Health Organization proposed the first international standard as a common unit to define neutralizing antibody titer and antibody responses against SARS-CoV-2. These standards are useful for comparing the results of different assays and laboratories.

Non-pharmaceutical interventions were used widely in care homes for older people during the COVID-19 pandemic, but there have been few randomised trials to support policy decisions. We aimed to evaluate the effect of biweekly asymptomatic staff testing with support funding for sick pay and agency staffing on the clinical outcomes of residents. We conducted a cluster randomised unblinded superiority trial, aiming to recruit up to 280 residential and/or nursing homes in England providing care to adults aged >65 years. Homes were randomised 1:1 to the control arm, which followed national testing policy (comprising symptomatic plus outbreak testing at trial initiation) or intervention (additional twice weekly asymptomatic staff testing for SARS-CoV-2, staff sick pay and agency backfill). Outcomes were evaluated using health data from routine national datasets in combination with aggregate data from participating homes. The primary outcome was the incidence of COVID-19-related hospital admissions in residents. The trial was conducted from January to August 2023, with 41 care homes randomised to intervention and 40 randomised to control included in the analysis. The trial was stopped early as it was not adequately powered for the primary outcome due to site recruitment and primary outcome events being substantially lower than expected. There was no significant difference in the primary outcome of resident COVID-linked hospital admission incidence between intervention and control arms (22.7/1000 person-years vs 15.0/1000 person-years, incidence rate ratio 1.19, 95%CI 0.55-2.58, P = 0.66; incidence rate difference 4.0, 95%CI -14.3 to 22.2). Trial set up took less than three months. Most trial outcomes were derived from routinely collected data. Recorded uptake of staff testing in the intervention arm was low (mean per home each week 14.4%). This trial was not well-powered to evaluate the impact of the intervention on the primary outcome, and recorded uptake of staff testing was low. However, our pre-existing care home network underpinned by linked routinely collected data provides a model for more agile interventional studies in the care home setting. NCT05639205.

In April, 2020, in a joint effort, the Coalition for Epidemic Preparedness Innovations (CEPI), the National Institute for Biological Standards and Control (NIBSC), and WHO provided vaccine developers and the entire scientific community with a research reagent for an anti-SARS-CoV-2 antibody. Initiatives have been launched for the harmonisation of immune response assessment across COVID-19 vaccine candidates, including the CEPI Global Centralised Laboratory Network.3 CEPI centralised laboratories will achieve harmonisation of the results from different vaccine clinical trials with the use of common standard operating procedures and the same crucial reagents, including a working standard calibrated to the international standard. [...]the results from clinical trials expressed in IU would allow for the comparison of the immune responses after natural infection and induced by various vaccine candidates.

Abstract Rationale The International Health Regulations (IHR) have been the governing framework for global health security since 2007. Declaring public health emergencies of international concern (PHEIC) is a cornerstone of the IHR. Here we review how PHEIC are formally declared, the diseases for which such declarations have been made from 2007 to 2020 and justifications for such declarations. Key findings Six events were declared PHEIC between 2007 and 2020: the 2009 H1N1 influenza pandemic, Ebola (West African outbreak 2013–2015, outbreak in Democratic Republic of Congo 2018–2020), poliomyelitis (2014 to present), Zika (2016) and COVID-19 (2020 to present). Poliomyelitis is the longest PHEIC. Zika was the first PHEIC for an arboviral disease. For several other emerging diseases a PHEIC was not declared despite the fact that the public health impact of the event was considered serious and associated with potential for international spread. Recommendations The binary nature of a PHEIC declaration is often not helpful for events where a tiered or graded approach is needed. The strength of PHEIC declarations is the ability to rapidly mobilize international coordination, streamline funding and accelerate the advancement of the development of vaccines, therapeutics and diagnostics under emergency use authorization. The ultimate purpose of such declaration is to catalyse timely evidence-based action, to limit the public health and societal impacts of emerging and re-emerging disease risks while preventing unwarranted travel and trade restrictions.

Policy Points Equitable access to a COVID‐19 vaccine in all countries remains a key policy objective, but experience of previous pandemics suggests access will be limited in developing countries, despite the rapid development of three successful vaccine candidates. The COVAX Facility seeks to address this important issue, but the prevalence of vaccine nationalism threatens to limit the ability of the facility to meet both its funding targets and its ambitious goals for vaccine procurement. A failure to adequately address the underlying lack of infrastructure in developing countries threatens to further limit the success of the COVAX Facility. Context Significant effort has been directed toward developing a COVID‐19 vaccine, which is viewed as the route out of the pandemic. Much of this effort has coalesced around COVAX, the multilateral initiative aimed at accelerating the development of COVID‐19 vaccines, and ensuring they are equitably available in low‐ and middle‐income countries (LMICs). This paper represents the first significant analysis of COVAX, and the extent to which it can be said to have successfully met these aims. Methods This paper draws on the publicly available policy documents made available by the COVAX initiatives, as well as position papers and public statements from governments around the world with respect to COVID‐19 vaccines and equitable access. We analyze the academic literature regarding access to vaccines during the H1N1 pandemic. Finally, we consider the WHO Global Allocation System, and its principles, which are intended to guide COVAX vaccine deployment. Findings We argue that the funding mechanism deployed by the COVAX Pillar appears to be effective at fostering at‐risk investments in research and development and the production of doses in advance of confirmation of clinical efficacy, but caution that this represents a win‐win situation for vaccine manufacturers, providing them with opportunity to benefit regardless of whether their vaccine candidate ever goes on to gain regulatory approval. We also argue that the success of the COVAX Facility with respect to equitable access to vaccine is likely to be limited, primarily as a result of the prevalence of vaccine nationalism, whereby countries adopt policies which heavily prioritize their own public health needs at the expense of others. Conclusions Current efforts through COVAX have greatly accelerated the development of vaccines against COVID‐19, but these benefits are unlikely to flow to LMICs, largely due to the threat of vaccine nationalism.

International collaboration is key for the fair and efficient distribution of covid-19 vaccines. Lisa Herzog and colleagues’ Fair Priority Model, with its focus on allocating vaccine based on limiting covid-19 harms, realises ethical principles better than Covax’s proposal of proportional allocation based on population

The SARS-CoV-2 omicron (B.1.1.529) variant, which was first identified in November, 2021, spread rapidly in many countries, with a spike protein highly diverged from previously known variants, and raised concerns that this variant might evade neutralising antibody responses. We therefore aimed to characterise the sensitivity of the omicron variant to neutralisation. For this cross-sectional study, we cloned the sequence encoding the omicron spike protein from a diagnostic sample to establish an omicron pseudotyped virus neutralisation assay. We quantified the neutralising antibody ID50 (the reciprocal dilution that produces 50% inhibition) against the omicron spike protein, and the fold-change in ID50 relative to the spike of wild-type SARS-CoV-2 (ie, the pandemic founder variant), for one convalescent reference plasma pool (WHO International Standard for anti-SARS-CoV-2 immunoglobulin [20/136]), three reference serum pools from vaccinated individuals, and two cohorts from Stockholm, Sweden: one comprising previously infected hospital workers (17 sampled in November, 2021, after vaccine rollout and nine in June or July, 2020, before vaccination) and one comprising serum from 40 randomly sampled blood donors donated during week 48 (Nov 29–Dec 5) of 2021. Furthermore, we assessed the neutralisation of omicron by five clinically relevant monoclonal antibodies (mAbs). Neutralising antibody responses in reference sample pools sampled shortly after infection or vaccination were substantially less potent against the omicron variant than against wild-type SARS-CoV-2 (seven-fold to 42-fold reduction in ID50 titres). Similarly, for sera obtained before vaccination in 2020 from a cohort of convalescent hospital workers, neutralisation of the omicron variant was low to undetectable (all ID50 titres <20). However, in serum samples obtained in 2021 from two cohorts in Stockholm, substantial cross-neutralisation of the omicron variant was observed. Sera from 17 hospital workers after infection and subsequent vaccination had a reduction in average potency of only five-fold relative to wild-type SARS-CoV-2 (geometric mean ID50 titre 495 vs 105), and two donors had no reduction in potency. A similar pattern was observed in randomly sampled blood donors (n=40), who had an eight-fold reduction in average potency against the omicron variant compared with wild-type SARS-CoV-2 (geometric mean ID50 titre 369 vs 45). We found that the omicron variant was resistant to neutralisation (50% inhibitory concentration [IC50] >10 μg/mL) by mAbs casirivimab (REGN-10933), imdevimab (REGN-10987), etesevimab (Ly-CoV016), and bamlanivimab (Ly-CoV555), which form part of antibody combinations used in the clinic to treat COVID-19. However, S309, the parent of sotrovimab, retained most of its activity, with only an approximately two-fold reduction in potency against the omicron variant compared with ancestral D614G SARS-CoV-2 (IC50 0·1–0·2 μg/mL). These data highlight the extensive, but incomplete, evasion of neutralising antibody responses by the omicron variant, and suggest that boosting with licensed vaccines might be sufficient to raise neutralising antibody titres to protective levels. European Union Horizon 2020 research and innovation programme, European and Developing Countries Clinical Trials Partnership, SciLifeLab, and the Erling-Persson Foundation.

OBJECTIVE: This study aimed to construct a job-exposure matrix (JEM) for the risk of being infected by infectious agents through airborne or droplet transmission in an occupational setting, which might lead to a respiratory disease. METHODS: An established COVID-19-JEM formed the basis for the development of the general airborne infectious agents JEM. Nine researchers in occupational epidemiology from three European countries (Denmark, The Netherlands and the United Kingdom) discussed and agreed on which factors from the COVID-19-JEM were relevant and whether new factors or adjustments of risk levels were needed. Adjustments to the COVID-19 JEM were made in a structured iterative. based on an expert assessment, a JEM on solar ultraviolet radiation (UVR) exposure including information on hours per day working inside, and national data on hours per week on site. Finally, a risk score was assigned to all factors for each job title within the International Standard Classification of Occupations system 2008 (ISCO-08). RESULTS: This airborne infectious agents JEM contains five factors: (i) hours spent per week on site, (ii) hours spent per day working inside, (iii) number and (iv) nature of contacts, and (v) being in close physical contact to others. Per occupation, a risk score ranging from 1 (low risk) to 3 (high risk) was provided for all five factors separately. CONCLUSION: This newly developed infectious agents JEM assesses the risk at population level using five factors. Following validation, this JEM could serve as a valuable tool in future studies investigating the role of work in the occurrence of a respiratory disease.

COVID-19 has caused great devastation in the past year. Multi-organ point-of-care ultrasound (PoCUS) including lung ultrasound (LUS) and focused cardiac ultrasound (FoCUS) as a clinical adjunct has played a significant role in triaging, diagnosis and medical management of COVID-19 patients. The expert panel from 27 countries and 6 continents with considerable experience of direct application of PoCUS on COVID-19 patients presents evidence-based consensus using GRADE methodology for the quality of evidence and an expedited, modified-Delphi process for the strength of expert consensus. The use of ultrasound is suggested in many clinical situations related to respiratory, cardiovascular and thromboembolic aspects of COVID-19, comparing well with other imaging modalities. The limitations due to insufficient data are highlighted as opportunities for future research.