Stability of gut microbiome after COVID-19 vaccination in healthy and immuno-compromised individuals.

Bidirectional interactions between the immune system and the gut microbiota are key contributors to various physiological functions. Immune-associated diseases such as cancer and autoimmunity, and efficacy of immunomodulatory therapies, have been linked to microbiome variation. Although COVID-19 infection has been shown to cause microbial dysbiosis, it remains understudied whether the inflammatory response associated with vaccination also impacts the microbiota. Here, we investigate the temporal impact of COVID-19 vaccination on the gut microbiome in healthy and immuno-compromised individuals; the latter included patients with primary immunodeficiency and cancer patients on immunomodulating therapies. We find that the gut microbiome remained remarkably stable post-vaccination irrespective of diverse immune status, vaccine response, and microbial composition spanned by the cohort. The stability is evident at all evaluated levels including diversity, phylum, species, and functional capacity. Our results indicate the resilience of the gut microbiome to host immune changes triggered by COVID-19 vaccination and suggest minimal, if any, impact on microbiome-mediated processes. These findings encourage vaccine acceptance, particularly when contrasted with the significant microbiome shifts observed during COVID-19 infection.

Age-Associated B cells predict impaired humoral immunity after COVID-19 vaccination in patients receiving immune checkpoint blockade

The effect of immune checkpoint blockade on COVID-19 immunity is unclear. In this study, we determine whether immune checkpoint blockade expanded age-associated B cells (ABCs) are similar to those present in other conditions, and whether they enhance or detract from the COVID-19 vaccine responses. First, we use single cell RNA sequencing (scRNAseq) to show that ABCs arising from distinct aetiologies have common transcriptional profiles and may be further subdivided according to expression of genes associated with different immune functions, including the autoimmune regulator (AIRE). Next, we perform detailed longitudinal profiling of the COVID-19 vaccination response in patients. Finally, we show that high pre-vaccination ABC frequency correlates with decreased levels of antigen-specific memory B cells, and reduced magnitude and longevity of neutralising capacity against authentic SARS-CoV-2 virus. Expansion of ABCs is a biomarker for individuals with cancer requiring additional or more frequent booster immunisation against COVID-19.

Evolution of long-term hybrid immunity in healthcare workers after different COVID-19 vaccination regimens: a longitudinal observational cohort study

Both infection and vaccination, alone or in combination, generate antibody and T cell responses against SARSCoV2. However, the maintenance of such responses, and hence protection from disease, requires careful characterisation. In a large prospective study of UK healthcare workers (Protective immunity from T cells in Healthcare workers (PITCH), within the larger SARSCoV2 immunity and reinfection evaluation (SIREN) study) we previously observed that prior infection impacted strongly on subsequent cellular and humoral immunity induced after long and short dosing intervals of BNT162b2 (Pfizer/BioNTech) vaccination. Here, we report longer follow up of 684 HCWs in this cohort over 6-9 months following two doses of BNT162b2 or AZD1222 (Oxford/AstraZeneca) vaccination and up to 6 months following a subsequent mRNA booster vaccination. We make three observations: Firstly, the dynamics of humoral and cellular responses differ; binding and neutralising antibodies declined whereas T and memory B cell responses were maintained after the second vaccine dose. Secondly, vaccine boosting restored IgG levels, broadened neutralising activity against variants of concern including omicron BA.1, BA.2 and BA.5, and boosted T cell responses above the 6 month level post dose 2. Thirdly, prior infection maintained its impact driving larger as well as broader T cell responses compared with never-infected people, a feature maintained until 6 months after the third dose. In conclusion, broadly cross-reactive T cell responses are well maintained over time, especially in those with combined vaccine and infection-induced immunity (hybrid immunity), and may contribute to continued protection against severe disease.

A protease-activatable luminescent biosensor and reporter cell line for authentic SARS-CoV-2 infection.

Efforts to define serological correlates of protection against COVID-19 have been hampered by the lack of a simple, scalable, standardised assay for SARS-CoV-2 infection and antibody neutralisation. Plaque assays remain the gold standard, but are impractical for high-throughput screening. In this study, we show that expression of viral proteases may be used to quantitate infected cells. Our assays exploit the cleavage of specific oligopeptide linkers, leading to the activation of cell-based optical biosensors. First, we characterise these biosensors using recombinant SARS-CoV-2 proteases. Next, we confirm their ability to detect viral protease expression during replication of authentic virus. Finally, we generate reporter cells stably expressing an optimised luciferase-based biosensor, enabling viral infection to be measured within 24 h in a 96- or 384-well plate format, including variants of concern. We have therefore developed a luminescent SARS-CoV-2 reporter cell line, and demonstrated its utility for the relative quantitation of infectious virus and titration of neutralising antibodies.

Inborn errors of IL-6 family cytokine responses.

The IL-6 family of cytokines mediates functions in host protective immunity, development of multiple organs, tissue regeneration and metabolism. Inborn errors in cytokines or cytokine receptor units highlight specific roles for IL-6, IL-11, LIF, OSM, and CLC signaling whereas incomplete loss-of-function variants in the common receptor chain GP130 encoded by IL6ST or the transcription factor STAT3, as well as genes that affect either GP130 glycosylation (PGM3) or STAT3 transcriptional control (ZNF341) lead to complex phenotypes including features of hyper-IgE syndrome. Gain-of-function variants in the GP130-STAT3 signaling pathway cause immune dysregulation disorders. Insights into IL-6 family cytokine signaling inform on therapeutic application in immune-mediated disorders and potential side effects such as infection susceptibility.

Protease-activatable biosensors of SARS-CoV-2 infection for cell-based drug, neutralisation and virological assays

Efforts to define serological correlates of protection against COVID-19 have been hampered by the lack of a simple, scalable, standardised assay for SARS-CoV-2 infection and antibody neutralisation. Plaque assays remain the gold standard, but are impractical for high-throughput screening. In this study, we show that expression of viral proteases may be used to quantitate infected cells. Our assays exploit the cleavage of specific oligopeptide linkers, leading to the activation of cell-based optical biosensors. First, we characterise these biosensors using recombinant SARS-CoV-2 proteases. Next, we confirm their ability to detect viral protease expression during replication of authentic virus. Finally, we generate reporter cells stably expressing an optimised luciferase-based biosensor, enabling viral infection to be measured within 24 h in a 96- or 384-well plate format, including variants of concern. We have therefore developed a luminescent SARS-CoV-2 reporter cell line, and demonstrated its utility for the relative quantitation of infectious virus and titration of neutralising antibodies. Author summaryTechniques for measuring infection with SARS-CoV-2 in the laboratory are laborious and time-consuming, and different laboratories use different approaches. There is therefore no generally agreed way to quantitate neutralising antibodies against SARS-CoV-2, which block infection with the virus and protect people from COVID-19. In this study, we describe a new way to measure SARS-CoV-2 infection, which is much simpler and faster than existing methods. It relies on the production of a specific protease enzyme by the virus, which is able to cleave and activate an engineered protein biosensor in infected cells. This biosensor emits light in the presence of viral infection, and the amount of light released is used as a readout for the amount of infectious SARS-CoV-2 present. The signal is very sensitive, so the number of infected cells required is very small, and the method can be scaled-up to test many samples at once. In particular, we demonstrate how it can be used to detect different variants of SARS-CoV-2, and quantitate neutralising antibodies against these viruses.

Early immune pathology and persistent dysregulation characterise severe COVID-19

In a study of 207 SARS-CoV2-infected individuals with a range of severities followed over 12 weeks from symptom onset, we demonstrate that an early robust bystander CD8 T cell immune response, without systemic inflammation, is characteristic of asymptomatic or mild disease. Those presenting to hospital had delayed bystander responses and systemic inflammation already evident at around symptom onset. Such early evidence of inflammation suggests immunopathology may be inevitable in some individuals, or that preventative intervention might be needed before symptom onset. Viral load does not correlate with the development of this pathological response, but does with its subsequent severity. Immune recovery is complex, with profound persistent cellular abnormalities correlating with a change in the nature of the inflammatory response, where signatures characteristic of increased oxidative phosphorylation and reactive-oxygen species-associated inflammation replace those driven by TNF and IL-6. These late immunometabolic inflammatory changes and unresolved immune defects may have clinical implications.

Tracheal intubation in an urban emergency department in Scotland: a prospective, observational study of 3738 intubations.

AIM: The emergency department (ED) is an area where major airway difficulties can occur, often as complications of rapid sequence induction (RSI). We undertook a prospective, observational study of tracheal intubation performed in a large, urban UK ED to study this further. METHODS: We reviewed data on every intubation attempt made in our ED between January 1999 and December 2011. We recorded techniques and drugs used, intubator details, success rate, and associated complications. Tracheal intubation in our ED is managed jointly by emergency physicians and anaesthetists; an anaesthetist is contacted to attend to support ED staff when RSI is being performed. RESULTS: We included 3738 intubations in analysis. 2749 (74%) were RSIs, 361 (10%) were other drug combinations, and 628 (17%) received no drugs. Emergency physicians performed 78% and anaesthetists 22% of intubations. Tracheal intubation was successful in 3724 patients (99.6%). First time success rate was 85%; 98% of patients were successfully intubated with two or fewer attempts, and three patients (0.1%) had more than three attempts. Intubation failed in 14 patients; five (0.13%) had a surgical airway performed. Associated complications occurred in 286 (8%) patients. The incidence of complications was associated with the number of attempts made; 7% in one attempt, 15% in two attempts, and 32% in three attempts (p<0.001). CONCLUSION: A collaborative approach between emergency physicians and anaesthetists contributed to a high rate of successful intubation and a low rate of complications. Close collaboration in training and delivery of service models is essential to maintain these high standards and achieve further improvement where possible.

Assessment of sleep in children with mucopolysaccharidosis type III.

Sleep disturbances are prevalent in mucopolysaccharidosis Type III (MPS III), yet there is a lack of objective, ecologically valid evidence detailing sleep quantity, quality or circadian system. Eight children with MPS III and eight age-matched typically developing children wore an actigraph for 7-10 days/nights. Saliva samples were collected at three time-points on two separate days, to permit analysis of endogenous melatonin levels. Parents completed a sleep questionnaire and a daily sleep diary. Actigraphic data revealed that children with MPS III had significantly longer sleep onset latencies and greater daytime sleep compared to controls, but night-time sleep duration did not differ between groups. In the MPS III group, sleep efficiency declined, and sleep onset latency increased, with age. Questionnaire responses showed that MPS III patients had significantly more sleep difficulties in all domains compared to controls. Melatonin concentrations showed an alteration in the circadian system in MPS III, which suggests that treatment for sleep problems should attempt to synchronise the sleep-wake cycle to a more regular pattern. Actigraphy was tolerated by children and this monitoring device can be recommended as a measure of treatment success in research and clinical practice.