ABSTRACT
BackgroundOmicron variant questioned the efficacy of the approved therapies for the early COVID-19. I In vitro data show retained neutralizing activity against BA.1 and BA.2 for remdesivir (RDV), molnupiravir (MLN), and nirmatrelvir/ritonavir (NRM/r), while poor efficacy for Sotrovimab (STR) against BA.2. No data about the risk of clinical failure and in vivo antiviral activity are available. Material and methodsSingle-center observational comparison study enrolling all consecutive patients with a confirmed SARS-CoV-2 Omicron (BA.1 or BA.2) diagnosis and who met eligibility criteria for treatment with RDV, MLN, NRM/r, or STR. Treatment allocation was subject to drug availability, time from symptoms onset, and comorbidities. Patients were followed through day 30. Nasopharyngeal swab (NPS) VL was measured on day 1 (D1) and D7 and was expressed by log2 cycle threshold (CT) scale. Comparisons between groups were made by Chi-square and Wilcoxon paired-test. Primary endpoint was D1-D7 VL variation. Potential decrease in VL and average treatment effect (ATE) were calculated from fitting marginal linear regression models weighted for calendar month of infusion, duration of symptoms, and immunodeficiency. Secondary endpoints were the proportion of D7 undetectable VL in NPS and clinical outcomes compared by treatment groups using a Chi-square test. ResultsA total of 521 pts received treatments (STR 202, MLN 117, NRM/r 84, and RDV 118): female 250 (48%), median age 66 yrs (IQR 55-76), 90% vaccinated; 15% with negative baseline serology. At D1, median time from symptoms onset was 3 days (2,4). 378 (73%) pts were infected with BA.1 and 143 (27%) with BA.2. D1 mean viral load was 4.12 log2 (4.16 for BA.1 and 4.01 for BA.2). The adjusted analysis showed that NRM/r significantly reduced VL compared to all the other drugs in pts infected with BA.1 while no evidence for a difference vs. MLP was seen in those infected with BA.2. MLN had comparable activity to STR against BA.1 and to NRM/r against BA.2. There was no significant difference between STR and RDV for BA.2. At D7, 35/521 (6.7%) pts had undetectable VL. Of these, 31 were infected with BA.1 [9 (9%) MLN, 7 (14%) NRM/r, 7 (8%) RDV, and 8 (5%) STR)], and only 4 with BA.2, all treated with NRM/r. After 30 days of follow-up, 9/568 pts experienced COVID-19-related clinical failure [7/226 STR (5 BA.1) and 2/87 NRM /r (2 BA.1)]. ConclusionsIn this analysis of in vivo early VL reductions, NRM/r appears to be the drug showing the greatest antiviral activity regardless of the VoC, together with MLN, although the latter limited to people with BA.2. In the Omicron era, due to the high prevalence of vaccinated people and the lower probability of hospital admission, VL decrease can be a valuable surrogate of drug activity.
ABSTRACT
ObjectivesComparative analysis between different monoclonal antibodies (mAbs) against SARS-CoV-2 are lacking. We present an emulation trial from observational data to compare effectiveness of Bamlanivimab/Etesevimab (BAM/ETE) and Casirivimab/Imdevimab (CAS/IMD) in outpatients with early mild-to-moderate COVID-19 in a real-world scenario of variants of concern (VoCs) from Alpha to Delta. MethodsAllocation to treatment was subject to mAbs availability, and the measured factors were not used to determine which combination to use. Patients were followed through day 30. Viral load was measured by cycle threshold (CT) on D1 (baseline) and D7. Primary outcome was time to COVID-19-related hospitalization or death from any cause over days 0-30. Weighted pooled logistic regression and marginal structural Cox model by inverse probability weights were used to compare BAM/ETE vs. CAS/IMD. ANCOVA was used to compare mean D7 CT values by intervention. Models were adjusted for calendar month, MASS score and VoCs. We evaluated effect measure modification by VoCs, vaccination, D1 CT levels and enrolment period. ResultsCOVID19-related hospitalization or death from any cause occurred in 15 of 237 patients in the BAM/ETE group (6.3%) and in 4 of 196 patients in the CAS/IMD group (2.0%) (relative risk reduction [1 minus the relative risk] 72%; p=0.024). Subset analysis carried no evidence that the effect of the intervention was different across stratification factors. There was no evidence in viral load reduction from baseline through day 7 across the two groups (+0.17, 95% -1.41;+1.74, p=0.83). Among patients who experienced primary outcome, none showed a negative RT-PCR test in nasopharingeal swab (p=0.009) and 82.4% showed still high viral load (p<0.001) on D7. ConclusionsIn a pre-Omicron epidemiologic scenario, CAS/IMD reduced risk of clinical progression of COVID-19 compared to BAM/ETE. This effect was not associated with a concomitant difference in virological response.
ABSTRACT
Coronavirus disease 2019 (COVID-19) vaccines are proving to be very effective in preventing severe illness; however, although rare, post-vaccine infections have been reported. The present study describes 94 infections (47.9% symptomatic, 52.1% asymptomatic), occurred in Lazio Region (Central Italy) in the first trimester 2021, after first or second dose of mRNA BNT162b2 vaccine. Median viral load at diagnosis was independent from number and time of vaccine dose administration, despite the higher proportion of samples with low viral load observed in fully vaccinated individuals. More importantly, infectious virus was cultured from NPS collected from both asymptomatic and symptomatic vaccinated individuals, suggesting that, at least in principle, they can transmit the infection to susceptible people. The majority of the post-vaccine infections here reported, showed pauci/asymptomatic clinical course, confirming the impact of vaccination on COVID-19 disease. Most cases (78%) showed infection in presence of neutralizing antibodies at the time of infection diagnosis, presumably attributable to vaccination, due to the concomitant absence of anti-N IgG in most cases. The proportion of post-vaccine infections attributed either to Alpha and Gamma VOCs was similar to the proportion observed in the contemporary unvaccinated population in Lazio region. In addition, mutational analysis did not suggest enrichment of a defined set of Spike protein substitutions depending on the vaccination status. Characterization of host and virus factors associated with vaccine breakthrough, coupled with intensive and continuous monitoring of involved viral strains, is crucial to adopt informed vaccination strategies.
ABSTRACT
Compared to RT-PCR, lower performance of antigen detection assays, including the Lumipulse G SARS-CoV-2 Ag assay, may depend on specific testing scenarios. We tested 594 nasopharyngeal swab samples from individuals with COVID-19 (RT-PCR cycle threshold [Ct] values [≤]40) or non-COVID-19 (Ct values [≤]40) diagnoses. RT-PCR positive samples were assigned to diagnostic, screening, or monitoring groups of testing. With a limit of detection of 1.2 x 104 SARS-CoV-2 RNA copies/ml, Lumipulse showed positive percent agreement (PPA) of 79.9% (155/194) and negative percent agreement of 99.3% (397/400), whereas PPAs were 100% for samples with Ct values of <18 or 18-<25 and 92.5% for samples with Ct values of 25-<30. By three groups, Lumipulse showed PPA of 87.0% (60/69), 81.1% (43/53), or 72.2% (52/72), respectively, whereas PPA was 100% for samples with Ct values of <18 or 18-<25, and was 94.4%, 80.0%, or 100% for samples with Ct values of 25-<30, respectively. RT-PCR positive samples were also tested for SARS-CoV-2 subgenomic RNA and, by three groups, testing showed that PPA was 63.8% (44/69), 62.3% (33/53), or 33.3% (24/72), respectively. PPAs dropped to 55.6%, 20.0%, or 41.7% for samples with Ct values of 25-<30, respectively. All 101 samples with a subgenomic RNA positive result had a Lumipulse assays antigen positive result, whereas only 54 (58.1%) of remaining 93 samples had a Lumipulse assays antigen positive result. In conclusion, Lumipulse assay was highly sensitive in samples with low RT-PCR Ct values, implying repeated testing to reduce consequences of false-negative results.
ABSTRACT
COVID-19 pandemic is becoming one of the most dramatic health, social and economic global challenges in recent history. Testing is one of the main components of the public health response to contain the virus spreading. There is an urgent need to expand testing capacity and antigen rapid tests (Ag RDT) represent good candidates for point-of-care and mass surveillance testing to rapidly identify people with SARS-CoV-2 infection, counterbalancing lower sensitivity as compared to the gold standard molecular tests with timeliness of results and possibility of recurred testing. Here, we report preliminary data of the testing algorithm implemented at the points-of-entry (airports and port) in Lazio Region (Central Italy) on travelers arriving between 17th of August to 15th of October, 2020, using the STANDARD F COVID-19 Antigen Fluorescence ImmunoAssay. Our findings show that the probability of molecular confirmation of Ag RDT positive results is directly dependent from the semi-quantitative results of this Ag RDT, and that the molecularly confirmed samples actually harbor infectious virus. These results support the public health strategies based on early screening campaigns in settings where molecular testing is not feasible or easily accessible, using rapid and simple point of care tests, able to rapidly identify those subjects who are at highest risk of spreading SARS-CoV-2 infection.
