First and second doses of Covishield vaccine provided high level of protection against SARS-CoV-2 infection in highly transmissible settings: results from a prospective cohort of participants residing in congregate facilities in India.

OBJECTIVES: This study aimed to determine the effectiveness of Covishield vaccine among residents of congregate residential facilities. DESIGN: A prospective cohort study in congregate residential facilities. SETTING: Dharamshala, Himachal Pradesh, India, from December 2020 to July 2021. PARTICIPANTS: Residents of all ages in seven facilities-three monasteries, two old age homes and two learning centres-were enrolled. EXPOSURES: First and second doses of Covishield vaccine against SARS-CoV-2 infection. MAIN OUTCOMES MEASURES: Primary outcome was development of COVID-19. Secondary outcome was unfavourable outcomes, defined as a composite of shortness of breath, hospitalisation or death. Vaccine effectiveness (%) was calculated as (1-HR)×100. RESULTS: There were 1114 residents (median age 31 years) participating in the study, 82% males. Twenty-eight per cent (n=308/1114) were unvaccinated, 50% (n=554/1114) had received one dose and 23% (n=252/1114) had received two doses of Covishield. The point prevalence of COVID-19 for the facilities ranged from 11% to 57%. Incidence rates (95% CI) of COVID-19 were 76 (63 to 90)/1000 person-months in the unvaccinated, 25 (18 to 35)/1000 person-months in recipients of one dose and 9 (4 to 19)/1000 person-months in recipients of two doses. The effectiveness of first and second doses of Covishield were 71% (adjusted HR (aHR) 0.29; 95% CI 0.18 to 0.46; p<0.001) and 80% (aHR 0.20; 95% CI 0.09 to 0.44; p<0.001), respectively, against SARS-CoV-2 infection and 86% (aHR 0.24; 95% CI 0.07 to 0.82; p=0.023) and 99% (aHR 0.01; 95% CI 0.002 to 0.10; p<0.001), respectively, against unfavourable outcome. The effectiveness was higher after 14 days of receiving the first and second doses, 93% and 98%, respectively. Risk of infection was higher in persons with chronic hepatitis B (aHR 1.78; p=0.034) and previous history of tuberculosis (aHR 1.62; p=0.047). CONCLUSION: Covishield was effective in preventing SARS-CoV-2 infection and reducing disease severity in highly transmissible settings during the second wave of the pandemic driven by the Delta variant.

Tuberculosis screening among ambulatory people living with HIV: a systematic review and individual participant data meta-analysis.

BACKGROUND: The WHO-recommended tuberculosis screening and diagnostic algorithm in ambulatory people living with HIV is a four-symptom screen (known as the WHO-recommended four symptom screen [W4SS]) followed by a WHO-recommended molecular rapid diagnostic test (eg Xpert MTB/RIF [hereafter referred to as Xpert]) if W4SS is positive. To inform updated WHO guidelines, we aimed to assess the diagnostic accuracy of alternative screening tests and strategies for tuberculosis in this population. METHODS: In this systematic review and individual participant data meta-analysis, we updated a search of PubMed (MEDLINE), Embase, the Cochrane Library, and conference abstracts for publications from Jan 1, 2011, to March 12, 2018, done in a previous systematic review to include the period up to Aug 2, 2019. We screened the reference lists of identified pieces and contacted experts in the field. We included prospective cross-sectional, observational studies and randomised trials among adult and adolescent (age ≥10 years) ambulatory people living with HIV, irrespective of signs and symptoms of tuberculosis. We extracted study-level data using a standardised data extraction form, and we requested individual participant data from study authors. We aimed to compare the W4SS with alternative screening tests and strategies and the WHO-recommended algorithm (ie, W4SS followed by Xpert) with Xpert for all in terms of diagnostic accuracy (sensitivity and specificity), overall and in key subgroups (eg, by antiretroviral therapy [ART] status). The reference standard was culture. This study is registered with PROSPERO, CRD42020155895. FINDINGS: We identified 25 studies, and obtained data from 22 studies (including 15 666 participants; 4347 [27·7%] of 15 663 participants with data were on ART). W4SS sensitivity was 82% (95% CI 72-89) and specificity was 42% (29-57). C-reactive protein (≥10 mg/L) had similar sensitivity to (77% [61-88]), but higher specificity (74% [61-83]; n=3571) than, W4SS. Cough (lasting ≥2 weeks), haemoglobin (<10 g/dL), body-mass index (<18·5 kg/m2), and lymphadenopathy had high specificities (80-90%) but low sensitivities (29-43%). The WHO-recommended algorithm had a sensitivity of 58% (50-66) and a specificity of 99% (98-100); Xpert for all had a sensitivity of 68% (57-76) and a specificity of 99% (98-99). In the one study that assessed both, the sensitivity of sputum Xpert Ultra was higher than sputum Xpert (73% [62-81] vs 57% [47-67]) and specificities were similar (98% [96-98] vs 99% [98-100]). Among outpatients on ART (4309 [99·1%] of 4347 people on ART), W4SS sensitivity was 53% (35-71) and specificity was 71% (51-85). In this population, a parallel strategy (two tests done at the same time) of W4SS with any chest x-ray abnormality had higher sensitivity (89% [70-97]) and lower specificity (33% [17-54]; n=2670) than W4SS alone; at a tuberculosis prevalence of 5%, this strategy would require 379 more rapid diagnostic tests per 1000 people living with HIV than W4SS but detect 18 more tuberculosis cases. Among outpatients not on ART (11 160 [71·8%] of 15 541 outpatients), W4SS sensitivity was 85% (76-91) and specificity was 37% (25-51). C-reactive protein (≥10 mg/L) alone had a similar sensitivity to (83% [79-86]), but higher specificity (67% [60-73]; n=3187) than, W4SS and a sequential strategy (both test positive) of W4SS then C-reactive protein (≥5 mg/L) had a similar sensitivity to (84% [75-90]), but higher specificity than (64% [57-71]; n=3187), W4SS alone; at 10% tuberculosis prevalence, these strategies would require 272 and 244 fewer rapid diagnostic tests per 1000 people living with HIV than W4SS but miss two and one more tuberculosis cases, respectively. INTERPRETATION: C-reactive protein reduces the need for further rapid diagnostic tests without compromising sensitivity and has been included in the updated WHO tuberculosis screening guidelines. However, C-reactive protein data were scarce for outpatients on ART, necessitating future research regarding the utility of C-reactive protein in this group. Chest x-ray can be useful in outpatients on ART when combined with W4SS. The WHO-recommended algorithm has suboptimal sensitivity; Xpert for all offers slight sensitivity gains and would have major resource implications. FUNDING: World Health Organization.

Systemic DPP4/CD26 is associated with natural HIV-1 control: Implications for COVID-19 susceptibility.

The current intersection of the COVID-19 and HIV-1 pandemics, has raised concerns about the risk for poor COVID-19 outcomes particularly in regions like sub-Saharan Africa, disproportionally affected by HIV. DPP4/CD26 has been suggested to be a potential therapeutic target and a biomarker for risk in COVID-19 patients with high risk co-morbidities. We therefore evaluated soluble DPP4 (sDPP4) levels and activity in plasma of 131 HIV-infected and 20 HIV-uninfected South African individuals. Flow cytometry was performed to compare cell surface expression of DPP4/CD26 and activation markers on peripheral blood mononuclear cells of extreme clinical phenotypes. Progressors had lower specific DPP4 activity and lower frequency of CD3+ T-cells expressing CD26 than HIV-1 controllers, but more activated CD3+CD26+ T-cells. The frequency of CD26-expressing T-cells negatively correlated with HLA-DR+ and CD38+ T-cells. Divergent DPP4/CD26 expression between HIV-1 controllers and progressors may have implications for risk and treatment of COVID-19 in people living with HIV.