Association Between Human Immunodeficiency Virus Viremia and Compromised Neutralization of Severe Acute Respiratory Syndrome Coronavirus 2 Beta Variant

BACKGROUND

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection may be associated with worse clinical outcomes in people with human immunodeficiency virus (HIV) (PWH). We report anti-SARS-CoV-2 antibody responses in patients hospitalized with coronavirus disease 2019 in Durban, South Africa, during the second SARS-CoV-2 infection wave dominated by the Beta (B.1.351) variant.

METHODS

Thirty-four participants with confirmed SARS-CoV-2 infection were followed up with weekly blood sampling to examine antibody levels and neutralization potency against SARS-CoV-2 variants. Participants included 18 PWH, of whom 11 were HIV viremic.

RESULTS

SARS-CoV-2-specific antibody concentrations were generally lower in viremic PWH than in virologically suppressed PWH and HIV-negative participants, and neutralization of the Beta variant was 4.9-fold lower in viremic PWH. Most HIV-negative participants and antiretroviral therapy-suppressed PWH also neutralized the Delta (B.1.617.2) variant, whereas the majority of viremic PWH did not. CD4 cell counts <500/μL were associated with lower frequencies of immunoglobulin G and A seroconversion. In addition, there was a high correlation between a surrogate virus neutralization test and live virus neutralization against ancestral SARS-CoV-2 virus in both PWH and HIV-negative individuals, but correlation decreased for the Beta variant neutralization in PWH.

CONCLUSIONS

HIV viremia was associated with reduced Beta variant neutralization. This highlights the importance of HIV suppression in maintaining an effective SARS-CoV-2 neutralization response.

Omicron BA.4/BA.5 escape neutralizing immunity elicited by BA.1 infection

SARS-CoV-2 Omicron (B.1.1.529) BA.4 and BA.5 sub-lineages, first detected in South Africa, have changes relative to Omicron BA.1 including substitutions in the spike receptor binding domain. Here we isolated live BA.4 and BA.5 viruses and measured BA.4/BA.5 neutralization elicited by BA.1 infection either in the absence or presence of previous vaccination as well as from vaccination without BA.1 infection. In BA.1-infected unvaccinated individuals, neutralization relative to BA.1 declines 7.6-fold for BA.4 and 7.5-fold for BA.5. In vaccinated individuals with subsequent BA.1 infection, neutralization relative to BA.1 decreases 3.2-fold for BA.4 and 2.6-fold for BA.5. The fold-drop versus ancestral virus neutralization in this group is 4.0-fold for BA.1, 12.9-fold for BA.4, and 10.3-fold for BA.5. In contrast, BA.4/BA.5 escape is similar to BA.1 in the absence of BA.1 elicited immunity: fold-drop relative to ancestral virus neutralization is 19.8-fold for BA.1, 19.6-fold for BA.4, and 20.9-fold for BA.5. These results show considerable escape of BA.4/BA.5 from BA.1 elicited immunity which is moderated with vaccination and may indicate that BA.4/BA.5 may have the strongest selective advantage in evading neutralization relative to BA.1 in unvaccinated, BA.1 infected individuals.

Immunohistopathological changes in the placenta of malaria-infected women in unstable transmission setting of Aligarh

INTRODUCTION

Pregnant women are more susceptible to malaria due to a combination of physiological and immunological changes. The infection may even affect the growth and survival of the foetus, which mainly occur when parasite enters the placenta. The sequestration of infected erythrocytes may trigger the host response, leading to placental inflammation and altered development, affecting the structure and nutrient transport of placenta. These factors collectively impair placental functions and affect foetal growth.

METHODS

Pregnant women with peripheral parasitaemia for P. falciparum and P. vivax (20 each) were included in the present study, along with 15 age-matched uninfected healthy pregnant women. Placentae were analysed for the presence of local parasitaemia along with pathological lesions caused due to the parasite. Immunohistochemical staining for CD20, CD45 and CD68 cells was performed for examining the specific leucocytes in the intervillous space of the placenta.

RESULTS

Of the 20 individuals with P. falciparum, only seven placentae showed parasitaemia, whereas individuals with P. vivax showed no placental infection. The pathological changes observed in the P. falciparum-infected placenta include syncytial knotting, excess fibrinoid deposition, syncytiotrophoblast necrosis, syncytial rupture, thickening of trophoblast basement membrane and increased collagen deposition. Immunohistochemical staining showed a significant increase in B cells (CD20), leucocytes (CD45) and monocytes and macrophages (CD68) in the P. falciparum-infected placenta (p < 0.0001).

DISCUSSION

The result implies that P. falciparum is responsible for pathological alterations in placenta, affecting the nutrient transport across placenta and foetal growth. The immune cells also migrate to the placenta and accumulate in the intervillous space to show humoral and cell-mediated immunity against the parasite.

Microgravity-induced stress mechanisms in human stem cell-derived cardiomyocytes

Exposure to outer space microgravity poses a risk for the development of various pathologies including cardiovascular disease. To study this, we derived cardiomyocytes (CMs) from human-induced pluripotent stem cells and exposed them to simulated microgravity (SMG). We combined different “omics” and chromosome conformation capture technologies with live-cell imaging of various transgenic lines to discover that SMG impacts on the contractile velocity and function of CMs via the induction of senescence processes. This is linked to SMG-induced changes of reactive oxygen species (ROS) generation and energy metabolism by mitochondria. Taken together, we uncover a microgravity-controlled axis causing contractile dysfunctions to CMs. Our findings can contribute to the design of preventive and therapeutic strategies against senescence-associated disease.

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Simulated microgravity (SMG) causes ROS production in human cardiomyocytes (CMs)

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SMG inhibits mitochondria function and energy metabolism and induces senescence of CMs

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SMG attenuates contractile velocity, beating frequency and Ca²⁺ influx in CMs

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SMG induces chromosomal changes and modifies the chromosomal architecture in CMs

System resilience and neighbourhood action on social determinants of health inequalities: an English Case Study

AIMS

This article seeks to make the case for a new approach to understanding and nurturing resilience as a foundation for effective place-based co-produced local action on social and health inequalities.

METHODS

A narrative review of literature on community resilience from a public health perspective was conducted and a new concept of neighbourhood system resilience was developed. This then shaped the development of a practical programme of action research implemented in nine socio-economically disadvantaged neighbourhoods in North West England between 2014 and 2019. This Neighbourhood Resilience Programme (NRP) was evaluated using a mixed-method design comprising: (1) a longitudinal household survey, conducted in each of the Neighbourhoods For Learning (NFLs) and in nine comparator areas in two waves (2015/2016 and 2018/2019) and completed in each phase by approximately 3000 households; (2) reflexive journals kept by the academic team; and (3) semi-structured interviews on perceptions about the impacts of the programme with 41 participants in 2019.

RESULTS

A difference-in-difference analysis of household survey data showed a statistically significant increase of 7.5% (95% confidence interval (CI), 1.6 to 13.5) in the percentage of residents reporting that they felt able to influence local decision-making in the NFLs relative to the residents in comparator areas, but no effect attributable to the NRP in other evaluative measures. The analysis of participant interviews identified beneficial impacts of the NRP in five resilience domains: social connectivity, cultural coherence, local decision-making, economic activity, and the local environment.

CONCLUSION

Our findings support the need for a shift away from interventions that seek solely to enhance the resilience of lay communities to interventions that recognise resilience as a whole systems phenomenon. Systemic approaches to resilience can provide the underpinning foundation for effective co-produced local action on social and health inequalities, but they require intensive relational work by all participating system players.

Omicron infection enhances Delta antibody immunity in vaccinated persons

The extent to which Omicron infection1-9, with or without previous vaccination, elicits protection against the previously dominant Delta (B.1.617.2) variant is unclear. Here we measured the neutralization capacity against variants of severe acute respiratory syndrome coronavirus 2 in 39 individuals in South Africa infected with the Omicron sublineage BA.1 starting at a median of 6 (interquartile range 3-9) days post symptom onset and continuing until last follow-up sample available, a median of 23 (interquartile range 19-27) days post symptoms to allow BA.1-elicited neutralizing immunity time to develop. Fifteen participants were vaccinated with Pfizer's BNT162b2 or Johnson & Johnson's Ad26.CoV2.S and had BA.1 breakthrough infections, and 24 were unvaccinated. BA.1 neutralization increased from a geometric mean 50% focus reduction neutralization test titre of 42 at enrolment to 575 at the last follow-up time point (13.6-fold) in vaccinated participants and from 46 to 272 (6.0-fold) in unvaccinated participants. Delta virus neutralization also increased, from 192 to 1,091 (5.7-fold) in vaccinated participants and from 28 to 91 (3.0-fold) in unvaccinated participants. At the last time point, unvaccinated individuals infected with BA.1 had low absolute levels of neutralization for the non-BA.1 viruses and 2.2-fold lower BA.1 neutralization, 12.0-fold lower Delta neutralization, 9.6-fold lower Beta variant neutralization, 17.9-fold lower ancestral virus neutralization and 4.8-fold lower Omicron sublineage BA.2 neutralization relative to vaccinated individuals infected with BA.1. These results indicate that hybrid immunity formed by vaccination and Omicron BA.1 infection should be protective against Delta and other variants. By contrast, infection with Omicron BA.1 alone offers limited cross-protection despite moderate enhancement.

A preliminary study of patient-specific differences in induced pluripotent stem cell-derived cardiomyocytes following hypoxia-induced injury

Funding Acknowledgements

Type of funding sources: Foundation. Main funding source(s): Courtois Cardiovascular Signature Program

The increasing rate of cardiovascular disease (CVD) contributes to a worsening morbidity in the general population and a socioeconomic burden on the healthcare system. Newly approved therapies present unforeseen side effects and occasionally entail adverse cardiovascular responses in patients - this issue significantly stalls efficacious pharmacological development. Indeed, modern cardiovascular treatments do not account for the variability of individual patient reactions, due to a lack of a representative in vitro cardiac model. While the use of induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs) has gained traction as a superior model for drug screening when compared to cardiac biopsies and immortalized cell lines, cardiovascular patient-specific differences remain poorly understood and understudied.

We hypothesized that 1) cardiomyopathic patient-derived iPSC-CMs have differing baselines of beating rate, contractility, viability, metabolic activity and protein expression, when compared to healthy controls, and that 2) cell lines have patient-specific responses to hypoxia-induced injury. As such, the purpose of this preliminary study was two-fold: 1) to perform a characterization of patient iPSC-CM function, and 2) to study patient-specific cellular responses to hypoxia.

First, we generated iPSC-CMs from the peripheral blood of donors (n=6 patients with cardiomyopathies, n=2 healthy donors). We then confirmed the expression of prominent cardiac markers connexin 43 (CXN43), sarcoendoplasmic reticulum Ca2+ ATPase (SERCA2a), GATA4 and cardiac Troponin T, as well as a lack of pluripotency markers Octamer-binding transcription factor 4 (OCT4), Nanog, Stage-specific embryonic antigen-4 (SSEA-4) and TRA-1-60 in the iPSC-CM lines, via immunocytochemistry. Preliminary assessment of iPSC-CMs (days 1-30 post-differentiation) revealed significant baseline differences in beating rate (p&lt;0.01) and contractility amplitude (p&lt;0.01) between iPSC-CMs derived from cardiomyopathic patients and healthy donors.

We then subjected iPSC-CM lines to hypoxic conditions (24 hours), to mimic ischaemic injury. Diseased patient-derived lines had significantly decreased viability and metabolic activity when compared to the controls, under normoxic (p&lt;0.01) and hypoxic conditions (p&lt;0.001). Immunoblotting revealed differential expression of cardiac markers and factors implicated in cardiac function, cardioprotection and pathology. Taken together, these results suggest that the detected differences at the cellular level after hypoxia-induced injury might be translatable to the inter-individual variability currently observed in the CVD patient population. The data gathered will prove to be instrumental in future studies of iPSC-CM responses to treatment. With this preliminary study, we hope to shift the focus towards these patient-specific differences at the cellular level, in the search for tailored therapies and a higher standard of care for CVD patients.

The SARS-CoV-2 Delta variant induces an antibody response largely focused on class 1 and 2 antibody epitopes

Exposure histories to SARS-CoV-2 variants and vaccinations will shape the specificity of antibody responses. To understand the specificity of Delta-elicited antibody immunity, we characterize the polyclonal antibody response elicited by primary or mRNA vaccine-breakthrough Delta infections. Both types of infection elicit a neutralizing antibody response focused heavily on the receptor-binding domain (RBD). We use deep mutational scanning to show that mutations to the RBD's class 1 and class 2 epitopes, including sites 417, 478, and 484-486 often reduce binding of these Delta-elicited antibodies. The anti-Delta antibody response is more similar to that elicited by early 2020 viruses than the Beta variant, with mutations to the class 1 and 2, but not class 3 epitopes, having the largest effects on polyclonal antibody binding. In addition, mutations to the class 1 epitope (e.g., K417N) tend to have larger effects on antibody binding and neutralization in the Delta spike than in the D614G spike, both for vaccine- and Delta-infection-elicited antibodies. These results help elucidate how the antigenic impacts of SARS-CoV-2 mutations depend on exposure history.

Live-Cell Imaging of the Contractile Velocity and Transient Intracellular Ca2+ Fluctuations in Human Stem Cell-Derived Cardiomyocytes

Live-cell imaging techniques are essential for acquiring vital physiological and pathophysiological knowledge to understand and treat heart disease. For live-cell imaging of transient alterations of [Ca2+]i in human cardiomyocytes, we engineered human-induced pluripotent stem cells carrying a genetically-encoded Ca2+-indicator (GECI). To monitor sarcomere shortening and relaxation in cardiomyocytes in real-time, we generated a α-cardiac actinin (ACTN2)-copepod (cop) green fluorescent protein (GFP+)-human-induced pluripotent stem cell line by using the CRISPR-Cas9 and a homology directed recombination approach. The engineered human-induced pluripotent stem cells were differentiated in transgenic GECI-enhanced GFP+-cardiomyocytes and ACTN2-copGFP+-cardiomyocytes, allowing real-time imaging of [Ca2+]i transients and live recordings of the sarcomere shortening velocity of ACTN2-copGFP+-cardiomyocytes. We developed a video analysis software tool to quantify various parameters of sarcoplasmic Ca2+ fluctuations recorded during contraction of cardiomyocytes and to calculate the contraction velocity of cardiomyocytes in the presence and absence of different drugs affecting cardiac function. Our cellular and software tool not only proved the positive and negative inotropic and lusitropic effects of the tested cardioactive drugs but also quantified the expected effects precisely. Our platform will offer a human-relevant in vitro alternative for high-throughput drug screenings, as well as a model to explore the underlying mechanisms of cardiac diseases.

The SARS-CoV-2 Delta variant induces an antibody response largely focused on class 1 and 2 antibody epitopes

Exposure histories to SARS-CoV-2 variants and vaccinations will shape the specificity of antibody responses. To understand the specificity of Delta-elicited antibody immunity, we characterize the polyclonal antibody response elicited by primary or mRNA vaccine-breakthrough Delta infections. Both types of infection elicit a neutralizing antibody response focused heavily on the receptor-binding domain (RBD). We use deep mutational scanning to show that mutations to the RBD's class 1 and class 2 epitopes, including sites 417, 478, and 484-486 often reduce binding of these Delta-elicited antibodies. The anti-Delta antibody response is more similar to that elicited by early 2020 viruses than the Beta variant, with mutations to the class 1 and 2, but not class 3 epitopes, having the largest effects on polyclonal antibody binding. In addition, mutations to the class 1 epitope (e.g., K417N) tend to have larger effects on antibody binding and neutralization in the Delta spike than in the D614G spike, both for vaccine- and Delta-infection-elicited antibodies. These results help elucidate how the antigenic impacts of SARS-CoV-2 mutations depend on exposure history.

T cell responses to SARS-CoV-2 spike cross-recognize Omicron

The SARS-CoV-2 Omicron variant (B.1.1.529) has multiple spike protein mutations1,2 that contribute to viral escape from antibody neutralization3-6 and reduce vaccine protection from infection7,8. The extent to which other components of the adaptive response such as T cells may still target Omicron and contribute to protection from severe outcomes is unknown. Here we assessed the ability of T cells to react to Omicron spike protein in participants who were vaccinated with Ad26.CoV2.S or BNT162b2, or unvaccinated convalescent COVID-19 patients (n = 70). Between 70% and 80% of the CD4+ and CD8+ T cell response to spike was maintained across study groups. Moreover, the magnitude of Omicron cross-reactive T cells was similar for Beta (B.1.351) and Delta (B.1.617.2) variants, despite Omicron harbouring considerably more mutations. In patients who were hospitalized with Omicron infections (n = 19), there were comparable T cell responses to ancestral spike, nucleocapsid and membrane proteins to those in patients hospitalized in previous waves dominated by the ancestral, Beta or Delta variants (n = 49). Thus, despite extensive mutations and reduced susceptibility to neutralizing antibodies of Omicron, the majority of T cell responses induced by vaccination or infection cross-recognize the variant. It remains to be determined whether well-preserved T cell immunity to Omicron contributes to protection from severe COVID-19 and is linked to early clinical observations from South Africa and elsewhere9-12.

207 An Assessment of Outcome in Patients with Anaemia (Iron Deficient and Non-Iron Deficient) Who Have Colon Cancer - Effect of Treatment with Oral/ IV Iron

Aim

Treatment of iron deficiency anaemia in patients undergoing colon cancer resection improves outcome defined by length of stay, recurrence, and requirement for blood transfusions.

Method

Retrospective analysis of patients with anaemia and colonic cancer between January 2018 - August 2019. Anaemia categorised as – Iron Deficiency Anaemia and non- Iron Deficiency anaemia. IDA was defined as hypochromic microcytic anaemia. Patient demographics, tumour location, pre- and post-operative haemoglobin, length of stay, recurrence and requirement for blood transfusions were collected plus treatment for anaemia. Comparisons made between IDA and non-IDA groups in relation to treatment for anaemia with iron (oral/IV). Non-parametric statistical tests used (median, 2-way ANOVA, Kruskal-Wallis) with significance at P &lt;0.05.

Results

150 patients with colonic cancer identified: 77 in IDA group, 46 treated (42 oral, 4 iv iron). 11 in non- IDA group, 8 treated (oral iron).

IDA oral and IV treatment versus non-IDA:

Median age 74, 80 and 78 years (P = 0.814),

Pre- and post op Hb IDA vs non-IDA: 107, 97; 109, 101 (P 0.007 significant),

Requirement for blood transfusion (units) 0.77, 0.50;0.90 (P 0.596)

Length of Stay (days) 6, 5; 7 (P 0.113),

Tumour location: mean of right colon and transverse colon 24.33, 3.667 (P &gt;0.1), and

Recurrence P &gt;0.1.

Conclusions

In our series, iron treatment does not influence recurrence, length of stay, requirement for blood transfusions. Tumour location is not significantly different between IDA and non-IDA group. Patients treated with oral iron therapy are seen to have a larger drop in haemoglobin post operatively than the other groups.

SARS-CoV-2 prolonged infection during advanced HIV disease evolves extensive immune escape

Characterizing SARS-CoV-2 evolution in specific geographies may help predict properties of the variants that come from these regions. We mapped neutralization of a SARS-CoV-2 strain that evolved over 6 months from ancestral virus in a person with advanced HIV disease in South Africa; this person was infected prior to emergence of the Beta and Delta variants. We longitudinally tracked the evolved virus and tested it against self-plasma and convalescent plasma from ancestral, Beta, and Delta infections. Early virus was similar to ancestral, but it evolved a multitude of mutations found in Omicron and other variants. It showed substantial but incomplete Pfizer BNT162b2 escape, weak neutralization by self-plasma, and despite pre-dating Delta, it also showed extensive escape of Delta infection-elicited neutralization. This example is consistent with the notion that SARS-CoV-2 evolving in individual immune-compromised hosts, including those with advanced HIV disease, may gain immune escape of vaccines and enhanced escape of Delta immunity, and this has implications for vaccine breakthrough and reinfections.

A SARS-CoV-2 variant elicits an antibody response with a shifted immunodominance hierarchy

Many SARS-CoV-2 variants have mutations at key sites targeted by antibodies. However, it is unknown if antibodies elicited by infection with these variants target the same or different regions of the viral spike as antibodies elicited by earlier viral isolates. Here we compare the specificities of polyclonal antibodies produced by humans infected with early 2020 isolates versus the B.1.351 variant of concern (also known as Beta or 20H/501Y.V2), which contains mutations in multiple key spike epitopes. The serum neutralizing activity of antibodies elicited by infection with both early 2020 viruses and B.1.351 is heavily focused on the spike receptor-binding domain (RBD). However, within the RBD, B.1.351-elicited antibodies are more focused on the "class 3" epitope spanning sites 443 to 452, and neutralization by these antibodies is notably less affected by mutations at residue 484. Our results show that SARS-CoV-2 variants can elicit polyclonal antibodies with different immunodominance hierarchies.

Omicron extensively but incompletely escapes Pfizer BNT162b2 neutralization

The emergence of the SARS-CoV-2 variant of concern Omicron (Pango lineage B.1.1.529), first identified in Botswana and South Africa, may compromise vaccine effectiveness and lead to re-infections1. Here we investigated Omicron escape from neutralization by antibodies from South African individuals vaccinated with Pfizer BNT162b2. We used blood samples taken soon after vaccination from individuals who were vaccinated and previously infected with SARS-CoV-2 or vaccinated with no evidence of previous infection. We isolated and sequence-confirmed live Omicron virus from an infected person and observed that Omicron requires the angiotensin-converting enzyme 2 (ACE2) receptor to infect cells. We compared plasma neutralization of Omicron relative to an ancestral SARS-CoV-2 strain and found that neutralization of ancestral virus was much higher in infected and vaccinated individuals compared with the vaccinated-only participants. However, both groups showed a 22-fold reduction in vaccine-elicited neutralization by the Omicron variant. Participants who were vaccinated and had previously been infected exhibited residual neutralization of Omicron similar to the level of neutralization of the ancestral virus observed in the vaccination-only group. These data support the notion that reasonable protection against Omicron may be maintained using vaccination approaches.

Omicron infection of vaccinated individuals enhances neutralizing immunity against the Delta variant

Omicron variant (B.1.1.529) infections are rapidly expanding worldwide, often in settings where the Delta variant (B.1.617.2) was dominant. We investigated whether neutralizing immunity elicited by Omicron infection would also neutralize the Delta variant and the role of prior vaccination. We enrolled 23 South African participants infected with Omicron a median of 5 days post-symptoms onset (study baseline) with a last follow-up sample taken a median of 23 days post-symptoms onset. Ten participants were breakthrough cases vaccinated with Pfizer BNT162b2 or Johnson and Johnson Ad26.CoV2.S. In vaccinated participants, neutralization of Omicron increased from a geometric mean titer (GMT) FRNT50 of 28 to 378 (13.7-fold). Unvaccinated participants had similar Omicron neutralization at baseline but increased from 26 to only 113 (4.4-fold) at follow-up. Delta virus neutralization increased from 129 to 790, (6.1-fold) in vaccinated but only 18 to 46 (2.5-fold, not statistically significant) in unvaccinated participants. Therefore, in Omicron infected vaccinated individuals, Delta neutralization was 2.1-fold higher at follow-up relative to Omicron. In a separate group previously infected with Delta, neutralization of Delta was 22.5-fold higher than Omicron. Based on relative neutralization levels, Omicron re-infection would be expected to be more likely than Delta in Delta infected individuals, and in Omicron infected individuals who are vaccinated. This may give Omicron an advantage over Delta which may lead to decreasing Delta infections in regions with high infection frequencies and high vaccine coverage.

Omicron infection of vaccinated individuals enhances neutralizing immunity against the Delta variant

Omicron variant (B.1.1.529) infections are rapidly expanding worldwide, often in settings where the Delta variant (B.1.617.2) was dominant. We investigated whether neutralizing immunity elicited by Omicron infection would also neutralize the Delta variant and the role of prior vaccination. We enrolled 23 South African participants infected with Omicron a median of 5 days post-symptoms onset (study baseline) with a last follow-up sample taken a median of 23 days post-symptoms onset. Ten participants were breakthrough cases vaccinated with Pfizer BNT162b2 or Johnson and Johnson Ad26.CoV2.S. In vaccinated participants, neutralization of Omicron increased from a geometric mean titer (GMT) FRNT50 of 28 to 378 (13.7-fold). Unvaccinated participants had similar Omicron neutralization at baseline but increased from 26 to only 113 (4.4-fold) at follow-up. Delta virus neutralization increased from 129 to 790, (6.1-fold) in vaccinated but only 18 to 46 (2.5-fold, not statistically significant) in unvaccinated participants. Therefore, in Omicron infected vaccinated individuals, Delta neutralization was 2.1-fold higher at follow-up relative to Omicron. In a separate group previously infected with Delta, neutralization of Delta was 22.5-fold higher than Omicron. Based on relative neutralization levels, Omicron re-infection would be expected to be more likely than Delta in Delta infected individuals, and in Omicron infected individuals who are vaccinated. This may give Omicron an advantage over Delta which may lead to decreasing Delta infections in regions with high infection frequencies and high vaccine coverage.

OUP accepted manuscript

Current methods for tuberculosis treatment monitoring are suboptimal. We evaluated plasma matrix metalloproteinase (MMP) and procollagen III N-terminal propeptide concentrations before and during tuberculosis treatment as biomarkers. Plasma MMP-1, MMP-8, and MMP-10 concentrations significantly decreased during treatment. Plasma MMP-8 was increased in sputum Mycobacterium tuberculosis culture–positive relative to culture-negative participants, before (median, 4993 pg/mL [interquartile range, 2542–9188] vs 698 [218–4060] pg/mL, respectively; P = .004) and after (3650 [1214–3888] vs 720 [551–1321] pg/mL; P = .008) 6 months of tuberculosis treatment. Consequently, plasma MMP-8 is a potential biomarker to enhance tuberculosis treatment monitoring and screen for possible culture positivity.