Résumé
Background. Variant-adaptated vaccines against coronavirus disease 2019 (COVID-19) as boosters are needed to increase a broader protection against SARS CoV-2 variants. New adjuvanted recombinant protein vaccines as heterologous boosters could maximize the response. Methods. In this randomized, single-blinded, multicenter trial, adults who had received two doses of Pfizer-BioNTech mRNA vaccine (BNT162b2) 3 to7 months before were randomly assigned to receive a boost of BNT162b2, Sanofi/GSK SARS-CoV-2 adjuvanted recombinant protein MV D614 (monovalent parental formulation) or SARS-CoV-2 adjuvanted recombinant protein MV B.1.351 vaccine (monovalent Beta formulation). The primary endpoint was the percentage of subjects with a [≥] 10-fold increase in neutralizing antibody titers for the Wuhan (D614) and B.1.351 (Beta) SARS-CoV-2 viral strains between day 0 and day 15. Findings. The percentages of participants whose neutralizing antibody titers against the Wuhan (D614) SARS-CoV-2 strain increased by a factor [≥]10 between day 0 and day 15 was 55.3% (95% CI 43.4-66.7) in MV D614 group (n=76), 76.1% (64.5-85.4) in MV B.1.351 (Beta) group (n=71) and 63.2% (51.3-73.9) in BNT162b2 group (n=76). These percentages were 44.7% (33.3-56.6), 84.5% (74.0-92.0) and 51.3% (39.6-63.0) for the B.1.351 (Beta) viral strain, respectively. Higher neutralizing antibodies rates against Delta and Omicron BA.1 variants were also elicited after Sanofi/GSK MV Beta vaccine compared to the other vaccines. Comparable reactogenicity profile was observed with the three vaccines. Interpretation. Heterologous boosting with the Sanofi/GSK Beta formulation vaccine resulted in a higher neutralizing antibody response against Beta variant but also the original strain and Delta and Omicron BA.1 variants, compared with mRNA BNT162b2 vaccine or the Sanofi/GSK MVD614 formulation. New vaccines containing Beta spike protein may represent an interesting strategy for broader protection against SARS CoV-2 variants.
Sujets)
COVID-19Résumé
The replacement of the Omicron BA.1 variant of SARS-CoV-2 by the BA.2 and the rapid growth of the BA.5 sub lineage, which have both different sets of mutations in the spike glycoprotein, alters the spectrum of activity of therapeutic antibodies currently licensed in the European Union. Using clinical strains of the Omicron BA.2 and BA.5 variants, we compared the neutralising power of monoclonal antibodies against the Omicron BA.1, BA.2 and BA.5 variants, using an ancestral strain (lineage B.1, D614G) and a Delta variant strain as reference. Sotrovimab/Vir-7831 is less active against BA.2 than against BA.1 (fold change reduction ~1,4) and even less active against BA.5 (fold change reduction ~2.7). Within the Evusheld /AZD7442 cocktail, Cilgavimab/AZD1061 is more active against BA.2 and BA.5 than against BA.1 (fold change increase ~32), whilst the very low activity of Tixagevimab/AZD8895 against BA.1 is not enhanced against BA.2 nor BA.5. In total, compared to BA.1, the activity of the Evusheld/AZD7442 is significantly improved against BA.2 and that against BA.5 is intermediate but closer to that against BA.2.
Résumé
Background: Studies showed high prevalence of SARs-CoV-2 among homeless people in shelters, but no longitudinal studies confirmed these findings, put them into perspective, or considered homeless populations beyond shelters. Methods: All homeless adults sleeping rough, in slums or squats, in emergency shelters or transitional accommodation in Marseille were eligible. There were two testing sessions, 3 months apart, during which each participant was tested for anti-SARS-CoV-2 antibodies and completed a face-to-face surveys. The primary outcome was the occurrence of a seroconversion event defined as a biologically confirmed SARS-CoV-2 infection. Cox proportional hazards regression models and Kaplan-Meier survival analysis with log-rank test were performed to evaluate risk factors associated with seroconversion. Local data from a national seroprevalence survey were used for comparison between homeless people and the general population.Findings: A total of 1249 people were included. SARS-CoV-2 seroprevalence increased from 6.0% [4.7-7.3] during the first session to 18.9% [16.0-21.7] during the second one, compared to 3.0% [1.9-4.2] and 6.5% [4.5-8.7] in the general population. Factors significantly associated with an increased risk of COVID-19 infection were: having stayed in emergency shelters (1.93 [1.18 – 3.15]), being an isolated parent (1.64 [1.07-2.52]) and having contact with more than 5-15 people per day (1.84 [1.27 – 2.67]). By contrast, smoking (0.46 (0.32 – 0.65)), having financial resources (0.70 (0.51 – 0.97)) and psychiatric or addictive comorbidities (0.52 (0.32 – 0.85)) were associated with a lower risk.Interpretation: We confirm that homeless people have higher infection rates than the general population, with increased risk in emergency shelters.Funding Information: French Directorate of Health care facilities (DGOS) – research grant PHRC COVID-19 (COVID-homeless 0047)Declaration of Interests: The authors declare that they have no competing interests. Ethics Approval Statement: All participants provided a written informed consent. The COVIDHomeless study was designed and carried out in compliance with the Declaration of Helsinki and with legal and regulatory provisions. It was approved by the ethics committee on May 28, 2020 (CPP IDF VI - number 44-20; ID: 2020-AO1398-31). The database was anonymized and declared to the French data protection commission (Commission Nationale de l’Informatique et des Libertés, CNIL, n°2018172v0).
Sujets)
COVID-19Résumé
Background: Overcrowded housing, as well as inadequate sanitary conditions, contribute to making homeless people particularly vulnerable to the SARS-CoV-2 infection. We aimed to assess the seroprevalence of the SARS-CoV-2 infection among people experiencing homelessness on a large city-wide scale in France, taking into account different community settings. Methods: A consortium of outreach teams in 48 different locations including streets, slums, squats, emergency or transitional shelters and drop-in centres participated in the inclusion process. All participants consented to receive a validated rapid assay for immunoglobulins M (IgM) and G (IgG) antibodies and to answer a questionnaire on medical health conditions, comorbidities, historic of symptoms compatible with COVID-19, with a retrospective calendar of types of accommodation since COVID-19 crisis. Results: From June 01 to August 05, 2020, 1,156 homeless participants were enrolled in the study and tested. Seroprevalence of SARS-CoV-2 IgG/IgM antibodies was 5.6% (95%CI 2.3–7.0), with a range of 2.2% in people living on the streets to 8.1% in people living in emergency shelters (P=0.009). Around one third of the seropositive participants reported symptoms with COVID-19. Compared to the general population in Marseille (3.6%), the homeless population living in the same urban area experienced an significant increased risk of SARS-CoV-2 infection (|z|=3.65 > 1.96). Conclusion: These results highlight the need for organizing regular screening to prevent clusters forming in homeless accommodations and for providing basic resources for health maintenance.
Sujets)
COVID-19Résumé
The SARS-CoV-2 pandemic has led to an unprecedented daily use of molecular RT-PCR tests. These tests are interpreted qualitatively for diagnosis, and the relevance of the test result intensity, i.e. the number of amplification cycles (Ct), is debated because of strong potential biases. We analyze a national database of tests performed on more than 2 million individuals between January and November 2020. Although we find Ct values to vary depending on the testing laboratory or the assay used, we detect strong significant trends with patient age, number of days after symptoms onset, or the state of the epidemic (the temporal reproduction number) at the time of the test. These results suggest that Ct values can be used to improve short-term predictions for epidemic surveillance.