SARS-CoV-2 transmission in a highly vulnerable population of Brazil: a household cohort study.

Background: Household transmission studies seek to understand the transmission dynamics of a pathogen by estimating the risk of infection from household contacts and community exposures. We estimated within/extra-household SARS-CoV-2 infection risk and associated factors in a household cohort study in one of the most vulnerable neighbourhoods in Rio de Janeiro city. Methods: Individuals ≥1 years-old with suspected or confirmed COVID-19 in the past 30 days (index cases) and household members aged ≥1 year were enrolled and followed at 14 and 28 days (study period November/2020-December/2021). RT-PCR testing, COVID-19 symptoms, and SARS-CoV-2 serologies were ascertained in all visits. Chain binomial household transmission models were fitted using data from 2024 individuals (593 households). Findings: Extra-household infection risk was 74.2% (95% credible interval [CrI] 70.3-77.8), while within-household infection risk was 11.4% (95% CrI 5.7-17.2). Participants reporting having received two doses of a COVID-19 vaccine had lower extra-household (68.9%, 95% CrI 57.3-77.6) and within-household (4.1%, 95% CrI 0.4-16.6) infection risk. Within-household infection risk was higher among participants aged 10-19 years, from overcrowded households, and with low family income. Contrastingly, extra-household infection risk was higher among participants aged 20-29 years, unemployed, and public transportation users. Interpretation: Our study provides important insights into COVID-19 household/community transmission in a vulnerable population that resided in overcrowded households and who struggled to adhere to lockdown policies and social distancing measures. The high extra-household infection risk highlights the extreme social vulnerability of this population. Prioritising vaccination of the most socially vulnerable could protect these individuals and reduce widespread community transmission. Funding: Fundação Oswaldo Cruz, CNPq, FAPERJ, Royal Society, Instituto Serrapilheira, FAPESP.

Prevalence and predictors of anti-SARS-CoV-2 serology in a highly vulnerable population of Rio de Janeiro: A population-based serosurvey.

Background: COVID-19 serosurveys allow for the monitoring of the level of SARS-CoV-2 transmission and support data-driven decisions. We estimated the seroprevalence of anti-SARS-CoV-2 antibodies in a large favela complex in Rio de Janeiro, Brazil. Methods: A population-based panel study was conducted in Complexo de Manguinhos (16 favelas) with a probabilistic sampling of participants aged ≥1 year who were randomly selected from a census of individuals registered in primary health care clinics that serve the area. Participants answered a structured interview and provided blood samples for serology. Multilevel regression models (with random intercepts to account for participants' favela of residence) were used to assess factors associated with having anti-S IgG antibodies. Secondary analyses estimated seroprevalence using an additional anti-N IgG assay. Findings: 4,033 participants were included (from Sep/2020 to Feb/2021, 22 epidemic weeks), the median age was 39·8 years (IQR:21·8-57·7), 61% were female, 41% were mixed-race (Pardo) and 23% Black. Overall prevalence was 49·0% (95%CI:46·8%-51·2%) which varied across favelas (from 68·3% to 31·4%). Lower prevalence estimates were found when using the anti-N IgG assay. Odds of having anti-S IgG antibodies were highest for young adults, and those reporting larger household size, poor adherence to social distancing and use of public transportation. Interpretation: We found a significantly higher prevalence of anti-S IgG antibodies than initially anticipated. Disparities in estimates obtained using different serological assays highlight the need for cautious interpretation of serosurveys estimates given the heterogeneity of exposure in communities, loss of immunological biomarkers, serological antigen target, and variant-specific test affinity. Funding: Fundação Oswaldo Cruz, Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), Fundação de Amparo a Pesquisa do Estado do Rio de Janeiro (FAPERJ), the European Union's Horizon 2020 research and innovation programme, Royal Society, Serrapilheira Institute, and FAPESP.

Persistent platelet activation and apoptosis in virologically suppressed HIV-infected individuals.

Cardiovascular diseases and thrombotic events became major clinical problems in the combined antiretroviral therapy (cART) era. Although the precise mechanisms behind these clinical problems have not been fully elucidated, a persistent pro-inflammatory state plays a central role. As platelets play important roles on both, thrombus formation and inflammatory/immune response, we aimed at investigating platelet function in HIV-infected subjects virologically controlled through cART. We evaluate parameters of activation, mitochondrial function and activation of apoptosis pathways in platelets from 30 HIV-infected individuals under stable cART and 36 healthy volunteers. Despite viral control achieved through cART, HIV-infected individuals exhibited increased platelet activation as indicated by P-selectin expression and platelet spreading when adhered on fibrinogen-coated surfaces. Platelets from HIV-infected subjects also exhibited mitochondrial dysfunction and activation of apoptosis pathways. Finally, thrombin stimuli induced lower levels of P-selectin translocation and RANTES secretion, but not TXA2 synthesis, in platelets from HIV-infected individuals compared to control; and labeling of platelet alpha granules showed reduced granule content in platelets from HIV-infected individuals when compared to healthy subjects. In summary, platelets derived from HIV-infected individuals under stable cART exhibit a phenotype of increased activation, activation of the intrinsic pathway of apoptosis and undermined granule secretion in response to thrombin.

Six-month survival of critically ill patients with HIV-related disease and tuberculosis: a retrospective study.

BACKGROUND: Tuberculosis is one of the leading causes of death from infectious diseases worldwide, mainly after the human immunodeficiency virus (HIV) epidemics. Patient with HIV-related illness are more likely to present with severe TB due to immunosuppression. Very few studies have explored HIV/TB co-infection in critically ill patients. The goal of this study was to analyze factors associated with long-term mortality in critically ill patient with HIV-related disease coinfected with TB. METHODS: We conducted a retrospective study in an infectious disease reference center in Brazil that included all patient with HIV-related illness admitted to the ICU with laboratory-confirmed tuberculosis from March 2007 until June 2012. Clinical and laboratory variables were analyzed based on six-month survival. RESULTS: Forty-four patients with HIV-related illness with a confirmed diagnosis of tuberculosis were analyzed. The six-month mortality was 52 % (23 patients). The main causes of admission were respiratory failure (41 %), severe sepsis/septic shock (32 %) and coma/torpor (14 %). The median time between HIV diagnosis and ICU admission was 5 (1-60) months, and 41 % of patients received their HIV infection diagnosis ≤ 30 days before admission. The median CD4 count was 72 (IQR: 23-136) cells/mm(3). The clinical presentation was pulmonary tuberculosis in 22 patients (50 %) and disseminated TB in 20 patients (45.5 %). No aspect of TB diagnosis or treatment was different between survivors and nonsurvivors. Neurological dysfunction was more prevalent among nonsurvivors (43 % vs. 14 %, p = 0.04). The nadir CD4 cell count lower than 50 cells/mm(3) was independently associated with Six-month mortality (hazard ratio 4.58 [1.64-12.74], p < 0.01), while HIV diagnosis less than three months after positive serology was protective (hazard ratio 0.27, CI 95 % [0.10-0.72], p = 0.01). CONCLUSION: The Six-month mortality of HIV critically ill patients with TB coinfection is high and strongly associated with the nadir CD4 cell count less than 50 cels/mm(3).

Predictors of opportunistic illnesses incidence in post combination antiretroviral therapy era in an urban cohort from Rio de Janeiro, Brazil.

BACKGROUND: Opportunistic illnesses still account for a huge proportion of hospitalizations and deaths among HIV-infected patients in the post combination antiretroviral therapy (cART) era, particularly in middle- and low-income countries. The aim of this study was to assess predictors of the top four most incident opportunistic illnesses (tuberculosis, esophageal candidiasis, cerebral toxoplasmosis and Pneumocystis jiroveci pneumonia) in an HIV clinical cohort from a middle-income country in the post cART era. METHODS: A total of 2835 HIV infected participants aged ≥ 18 years at enrollment were followed from January 2000 to December 2012 until the occurrence of their first opportunistic illness, death or end of study, whichever occurred first. Extended Cox proportional hazards regression models, stratified by use of cART, were fitted to assess predictors of opportunistic illness incidence during follow-up. RESULTS: The incidence rates of tuberculosis, esophageal candidiasis, cerebral toxoplasmosis and Pneumocystis jiroveci pneumonia were 15.3, 8.6, 6.0, 4.8 per 1000 persons-year, respectively. Disease specific adjusted Cox models showed that presence of an opportunistic illness at enrollment significantly increased disease incidence while higher nadir CD4+ T lymphocyte count had a significant protective effect in patients not in use of cART. Duration of cART use also significantly reduced disease incidence. CONCLUSIONS: Our findings show that, still in the post-cART era, prevention of opportunistic infections can be achieved by preventing immune deterioration by instituting early use of cART. Interventions focusing on early diagnosis and linkage to care in addition to the prompt initiation of cART are essential to reduce the incidence of opportunistic illnesses among HIV infected patients in post-cART era.

The innate immune response in HIV/AIDS septic shock patients: a comparative study.

INTRODUCTION: In recent years, the incidence of sepsis has increased in critically ill HIV/AIDS patients, and the presence of severe sepsis emerged as a major determinant of outcomes in this population. The inflammatory response and deregulated cytokine production play key roles in the pathophysiology of sepsis; however, these mechanisms have not been fully characterized in HIV/AIDS septic patients. METHODS: We conducted a prospective cohort study that included HIV/AIDS and non-HIV patients with septic shock. We measured clinical parameters and biomarkers (C-reactive protein and cytokine levels) on the first day of septic shock and compared these parameters between HIV/AIDS and non-HIV patients. RESULTS: We included 30 HIV/AIDS septic shock patients and 30 non-HIV septic shock patients. The HIV/AIDS patients presented low CD4 cell counts (72 [7-268] cells/mm(3)), and 17 (57%) patients were on HAART before hospital admission. Both groups were similar according to the acute severity scores and hospital mortality. The IL-6, IL-10 and G-CSF levels were associated with hospital mortality in the HIV/AIDS septic group; however, the CRP levels and the surrogates of innate immune activation (cytokines) were similar among HIV/AIDS and non-HIV septic patients. Age (odds ratio 1.05, CI 95% 1.02-1.09, p=0.002) and the IL-6 levels (odds ratio 1.00, CI 95% 1.00-1.01, p=0.05) were independent risk factors for hospital mortality. CONCLUSIONS: IL-6, IL-10 and G-CSF are biomarkers that can be used to predict prognosis and outcomes in HIV/AIDS septic patients. Although HIV/AIDS patients are immunocompromised, an innate immune response can be activated in these patients, which is similar to that in the non-HIV septic population. In addition, age and the IL-6 levels are independent risk factors for hospital mortality irrespective of HIV/AIDS disease.

Sepsis is a major determinant of outcome in critically ill HIV/AIDS patients.

INTRODUCTION: New challenges have arisen for the management of critically ill HIV/AIDS patients. Severe sepsis has emerged as a common cause of intensive care unit (ICU) admission for those living with HIV/AIDS. Contrastingly, HIV/AIDS patients have been systematically excluded from sepsis studies, limiting the understanding of the impact of sepsis in this population. We prospectively followed up critically ill HIV/AIDS patients to evaluate the main risk factors for hospital mortality and the impact of severe sepsis on the short- and long-term survival. METHODS: All consecutive HIV-infected patients admitted to the ICU of an infectious diseases research center, from June 2006 to May 2008, were included. Severity of illness, time since AIDS diagnosis, CD4 cell count, antiretroviral treatment, incidence of severe sepsis, and organ dysfunctions were registered. The 28-day, hospital, and 6-month outcomes were obtained for all patients. Cox proportional hazards regression analysis measured the effect of potential factors on 28-day and 6-month mortality. RESULTS: During the 2-year study period, 88 HIV/AIDS critically ill patients were admitted to the ICU. Seventy percent of patients had opportunist infections, median CD4 count was 75 cells/mm3, and 45% were receiving antiretroviral therapy. Location on a ward before ICU admission, cardiovascular and respiratory dysfunctions on the first day after admission, and the presence of severe sepsis/septic shock were associated with reduced 28-day and 6-month survival on a univariate analysis. After a multivariate analysis, severe sepsis determined the highest hazard ratio (HR) for 28-day (adjusted HR, 3.13; 95% CI, 1.21-8.07) and 6-month (adjusted HR, 3.35; 95% CI, 1.42-7.86) mortality. Severe sepsis occurred in 44 (50%) patients, mainly because of lower respiratory tract infections. The survival of septic and nonseptic patients was significantly different at 28-day and 6-month follow-up times (log-rank and Peto test, P < 0.001). CONCLUSIONS: Severe sepsis has emerged as a major cause of admission and mortality for hospitalized HIV/AIDS patients, significantly affecting short- and longer-term survival of critically ill HIV/AIDS patients.

Sepsis induces brain mitochondrial dysfunction.

OBJECTIVE: Mitochondrial dysfunctions have been associated with the pathogenesis of sepsis. A systematic survey of mitochondrial function in brain tissues during sepsis is lacking. In the present work, we investigate brain mitochondrial function in a septic mouse model. DESIGN: Prospective animal study. SETTING: University research laboratory. SUBJECTS: Male Swiss mice, aged 6-8 wks. INTERVENTIONS: Mice were subjected to cecal ligation and perforation (sepsis group) with saline resuscitation or to sham operation (control group). MEASUREMENTS AND MAIN RESULTS: Oxygen consumption was measured polarographically in an oximeter. Brain homogenates from septic animals presented higher oxygen consumption in the absence of adenosine 5'-diphosphate (state 4) compared with control animals. The increase in state 4 respiration in animals in the cecal ligation and perforation group resulted in a drastic decrease in both respiratory control and adenosine 5'-diphosphate/oxygen ratios, indicating a reduction in the oxidative phosphorylation efficiency. Septic animals presented a significant increase in the recovery time of mitochondrial membrane potential on adenosine 5'-diphosphate addition compared with control animals, suggesting a proton leak through the inner mitochondrial membrane. The septic group presented a general reduction in the content of cytochromes. Moreover, the activity of cytochrome c oxidase was specifically and significantly decreased in the brain during sepsis. Hydrogen peroxide generation by brain mitochondria from septic mice did not respond to substrates of electron transport chain or to adenosine 5'-diphosphate, showing that mitochondrial function may be compromised in a critical level in the brain during sepsis. CONCLUSIONS: The mitochondrial dysfunctions demonstrated here indicate that uncoupling of oxidative phosphorylation takes place in the brain of septic mice, compromising tissue bioenergetic efficiency.

Increased susceptibility to septic and endotoxic shock in monocyte chemoattractant protein 1/cc chemokine ligand 2-deficient mice correlates with reduced interleukin 10 and enhanced macrophage migration inhibitory factor production.

The chemokine monocyte chemoattractant protein 1/CC chemokine ligand 2 (MCP-1/CCL2) is a potent chemoattractant of mononuclear cells and a regulatory mediator involved in a variety of inflammatory diseases. In the present study, we demonstrate that mcp-1/ccl2-deficient mice are more susceptible to systemic inflammatory response syndrome induced by lipopolysaccharide and to polymicrobial sepsis induced by cecum ligation and puncture (CLP) when compared with wild-type mice. Interestingly, in the CLP model, mcp-1/ccl2-deficient mice efficiently cleared the bacteria despite an impaired recruitment of leukocytes, especially mononuclear cells. The increased lethality rate in these models correlates with an impaired production of interleukin (IL) 10 in vivo. Furthermore, macrophages from mcp-1/ccl2-deficient mice activated with lipopolysaccharide also produced lower amounts of IL-10 and similar tumor necrosis factor compared with wild-type mice. We observed a drastic increase in the amounts of macrophage migration inhibitory factor at 6 and 24 h after CLP in mcp-1/ccl2-deficient mice. These results indicate that endogenous MCP-1/CCL2 positively regulates IL-10 but negatively controls macrophage migration inhibitory factor during peritoneal sepsis, thus suggesting an important immunomodulatory role for MCP-1/CCL2 in controlling the balance between proinflammatory and anti-inflammatory factors in sepsis.

Exogenous platelet-activating factor acetylhydrolase reduces mortality in mice with systemic inflammatory response syndrome and sepsis.

Current evidence indicates that dysregulation of the host inflammatory response to infectious agents is central to the mortality of patients with sepsis and in those with systemic inflammatory response syndrome. Strategies to block inflammatory mediators, often with complicated outcomes, are currently being investigated as new adjuvant therapies for sepsis. Here, we determined if administration of recombinant platelet-activating factor (rPAF)-acetylhydrolase (rPAF-AH), an enzyme that inactivates PAF and PAF-like lipids, protects mice from inflammatory injury and death after administration of lipopolysaccharide (LPS) or cecal ligation and puncture (CLP). Administration of rPAF-AH increased plasma PAF-AH activity and reduced mortality in both models. Treatment with rPAF-AH increased peritoneal fluid levels of monocyte chemoattractant protein 1/CCL-2 and decreased interleukin 6 and migration inhibitory factor levels after LPS administration or CLP. Administration of a broad-spectrum antibiotic together with rPAF-AH was more protective than single treatment with either of these agents. The combined treatment was associated with reduced interleukin 6 levels in mice subjected to CLP. We observed acute decreases in plasma PAF-AH activity in mice subjected to CLP or challenged with LPS and in human patients with sepsis. We conclude that alterations in the endogenous PAF-AH contribute to the pathophysiology of sepsis and that administration of exogenous rPAF-AH reduces inflammatory injury and mortality in models relevant to the clinical syndrome. Variations in endogenous PAF-AH activity may potentially account for variable responses to exogenous rPAF-AH in previous clinical trials. Serial measurements of plasma PAF-AH activity in murine models demonstrate dynamic regulation of the endogenous enzyme, potentially explaining the variations in human subjects.

Antibiotic treatment in a murine model of sepsis: impact on cytokines and endotoxin release.

Experimental and clinical studies in sepsis indicate that antibiotic therapy may induce the release of endotoxin (LPS) from the outer membrane of gram-negative bacteria and therefore may affect the physiologic response and survival. The aim of this study was to evaluate if antibiotics commonly used to treat secondary peritonitis are capable of changing survival rates, proinflammatory and anti-inflammatory cytokine concentrations, and the release of endotoxin in a murine model of sepsis. Sepsis was induced by cecal ligation and puncture (CLP) in Swiss mice using an 18-gauge needle. The animals received injections of saline solution or imipenem or a combination of ciprofloxacin plus clindamycin every 8 h for 3 days. Antibiotic treatment induced an increase in survival rate and decreased plasma and peritoneal fluid levels of TNF-alpha and IL-6 at 6 and 24 h after CLP as compared with saline-treated animals. Antibiotic-treated animals also showed an early (6 h) decrease and a late (24 h) increase in IL-10 concentration in the peritoneal fluid. LPS concentrations were elevated in all groups, but imipenem-treated animals showed higher levels (2.2 EU/mL) than ciprofloxacin plus clindamycin (1.3 EU/mL) and saline-treated (1.5 EU/mL) groups. We conclude that antibiotic-induced endotoxin release is not a major determinant in the inflammatory response and prognosis in murine models of sepsis.