ABSTRACT
Background: Patients with rheumatic diseases are at an increased risk for community infections (1,2). There still exists lack of data regarding SARS-CoV-2 vaccines' efficacy in vulnerable collectives with a compromised immune system, either due to a chronic pathology or to therapies targeting an autoimmune disease (3). Objectives: To evaluate neutralizing antibodies (nAB) to SARS-CoV-2 vaccine after 3 to 5 months from administration in Systemic Lupus Erythematosus (SLE) patients, as a surrogate of sustained-immunological response. Methods: This cross-sectional study compared nAB titre of 39 SLE patients and 37 Healthy individuals with no previous SARS-CoV-2 infection, who had all received two doses of a mRNA SARS-CoV-2 vaccine within the last 3 to 6 months. SLE patients included 10 Not-treated subjects, 10 patients with Hydroxychloroquine (First-Line), 10 subjects with immunosuppressive drugs (Second-Line) and 9 patients under biological treatment (Third-Line). Glucocorticoids were permitted in all patient groups. Neutralization assay were used to determine nAB titre according previously validated protocol (4). Results: Neutralizing antibody titres were assessed for a total of 76 serum samples from 39 (51%) Lupus patients and 37 (49%) healthy Controls. Healthy individuals showed the highest levels of nAB (1638.0 titre median), which were like not treated SLE subjects (1361.5 titre median). Treated patients presented substantially lower nAB titres compared to Healthy subjects: a 73% decrease for First-Line patients (p-value = 0.0135), 56% for patients received a Second-Line treatment (p-value = 0.2218) and 72% for Third-Line treated patients (p-value = 0.0104). A multivariate analysis pointed to Glucocorticoids as the most associated factor with declining nAB levels (75% decrease, p-value = 0.0037), and the one explaining, to a large extent, the lower acquired response in treated SLE patients. Furthermore, a significant reduction in nAB titres was observed for patients treated with Rituximab compared to Healthy subjects (89% decrease, p-value= 0.0008) (Figure 1). Conclusion: Medium-term response of SLE patients to SARS-CoV-2 vaccination, as measured by the titre of nABs, may be compromised by Glucocorticoids and Rituximab users. This reduced response likely translates into a higher probability of COVID-19 infection These fndings might help to inform recommendations in vaccination protocols for SLE patients.
ABSTRACT
Background: Understanding the determinants of long-term immune responses to SARS-CoV-2 and the concurrent impact of vaccination and emerging variants of concern will guide optimal strategies to achieve global protection against the COVID-19 pandemic. Methods: A prospective cohort of 332 COVID 19 patients was followed beyond one year. Plasma neutralizing activity was evaluated using HIV-based reporter pseudoviruses expressing different SARS-CoV-2 spikes and was longitudinally analyzed using mixed-effects models. Results: Long-term neutralizing activity was stable beyond one year after infection in mild/asymptomatic and hospitalized participants. However, longitudinal models suggest that hospitalized individuals generate both short-and long-lived memory B cells, while responses of non-hospitalized were dominated by long-lived B cells. In both groups, vaccination boosted responses to natural infection. In unvaccinated participants, viral variants, mainly beta, reduced the efficacy of long-term (>300 days from infection) neutralization. Importantly, despite showing higher neutralization titers, hospitalized patients showed lower cross-neutralization of beta variant compared to non-hospitalized. Multivariate analysis identified severity of primary infection as the factor that independently determines both the magnitude and the inferior cross-neutralization activity of long-term neutralizing responses. Conclusion: Neutralizing response induced by SARS-CoV-2 is heterogeneous in magnitude but stable beyond one year after infection. Vaccination boosts these long-lasting natural neutralizing responses and should help counteract the resistance to neutralization of variants of concern such as the beta variant. Severity of primary infection determines higher magnitude but poorer quality of long-term neutralizing responses.
ABSTRACT
Background: SARS-CoV-2 is spread via airborne transmission. Mouthwashes containing virucidal compounds can help reduce viral spread. Here we show that cetylpyridinium chloride (CPC), a quaternary ammonium present in many oral mouthwashes, reduces SARS-CoV-2 infectivity by disrupting viral membranes both in vitro and in vivo. Methods: We tested the capacity of CPC-containing mouthwashes to inhibit SARS-CoV-2 entry into target cells by using a luciferase-based assay with a reporter lentivirus pseudotyped with the SARS-CoV-2 spike protein. The replication-competent SARS-CoV-2 B.1.1.7 and D614G variants were also assayed. Viral envelope disruption by CPC's virucidal effect was measured by dynamic light-scattering analyses (DSL). We confirmed these results by modifying an ELISA that detects the SARS-CoV-2 nucleocapsid (NC), which was used in the absence of its own lysis buffer. The effect of CPC in the saliva of individuals with CoVID-19 was assessed in a double-blind, placebo-controlled, randomized clinical trial. SARS-CoV-2 positive patients were randomized to gargle either water or 0.07% CPC mouthwash. The study outcomes were the SARS-CoV-2 log10 viral RNA load by RT-PCR and the NC protein levels by ELISA, both in saliva at 1h and 3h post-intervention. Results: CPC-containing mouthwashes inhibited SARS-CoV-2 viral fusion in vitro in a dose-dependent manner and decreased more than a 1000 times the viral TCID50 in target cells, regardless of the variant tested. The ELISA and the DSL analyses pointed to the effective disruption of the integrity of viral membranes after treatment with CPC. The clinical study performed with 105 patients showed no significant differences in viral RNA load at 1h and 3h post-treatment in saliva between placebo and CPC-treated groups. However, the levels of SARS-CoV-2 NC protein of lysed viruses were significantly higher in the CPC group at 1h and 3h post-intervention. Conclusion: CPC decreased more than a 1000 times the infectivity of SARS-CoV-2 in vitro and was effective against different SARS-CoV-2 variants. In CoVID-19 patients, the use of a 0.07% CPC mouthwash correlated with a statistically significant increase of NC protein levels in saliva, indicating enhanced disruption of viral particles. CPC-containing mouth rinses can represent a cost-effective measure to reduce SARS-CoV-2 infectivity in saliva, aiding to reduce viral transmission from infected individuals regardless of the variants they are infected with.
ABSTRACT
Oral mouthwashes decrease the infectivity of several respiratory viruses including SARS-CoV-2. However, the precise agents with antiviral activity in these oral rinses and their exact mechanism of action remain unknown. Here we show that cetylpyridinium chloride (CPC), a quaternary ammonium compound in many oral mouthwashes, reduces SARS-CoV-2 infectivity by inhibiting the viral fusion step with target cells after disrupting the integrity of the viral envelope. We also found that CPC-containing mouth rinses decreased more than a thousand times the infectivity of SARS-CoV-2 in vitro, while the corresponding vehicles had no effect. This activity was effective for different SARS-CoV-2 variants, including the B.1.1.7 or Alpha variant originally identified in United Kingdom, and in the presence of sterilized saliva. CPC-containing mouth rinses could therefore represent a cost-effective measure to reduce SARS-CoV-2 infectivity in saliva, aiding to reduce viral transmission from infected individuals regardless of the variants they are infected with.
Subject(s)
COVID-19 , Mouthwashes , Cetylpyridinium/pharmacology , Humans , Mouthwashes/pharmacology , SARS-CoV-2ABSTRACT
Background: Understanding the adaptive immune response to SARS-CoV-2, kinetics, persistence and their relationship with the disease severity would be crucial in order to predict recurrences, reinfections and could serve in the design of vaccination strategies. We sought to characterize IgG and neutralizing antibodies (NAbs) against SARS-CoV-2 in patients who were admitted to hospital with COVID-19 disease. Methods: All patients admitted between March-April 2020 with moderate, severe and critical SARS-CoV-2 pneumonia were prospectively studied. Clinical, laboratory data and IgG against SARS-CoV-2 levels were assessed at baseline (upon admission) and months 1, 3 and 6. NAbs were assessed at month 1, 3 and 6. IgG against the SARS-CoV-2 spike (S) protein was measured in serum by chemiluminescence (LIAISON® SARS-CoV-2 S1/S2, DiaSorin) and results were expressed in arbitrary units (AU)/mL. The neutralizing activity of plasma samples was analyzed in a 293T/hACE2 cell infection test using a surrogate viral inhibition assay that uses human immunodeficiency virus type 1 (HIV-1)-based virus expressing SARS-CoV-2 S protein and Luciferase. For neutralization assays, pseudoviruses were incubated with increasing plasma dilutions (range 1/60-1/14,580) in order to obtain the ID50 values. Results: A total of 110 patients who were discharged from hospital were recruited. Median (range) age was 61 (57-71);61.2% were male and most reported comorbidities were hypertension (39.6%), diabetes (24.3%) and obesity (19.8%). Median time from symptoms onset to admission was 9 days (range 7-11). Median (range) IgG levels (AU/mL) at baseline and months 1, 3 and 6 were 48 (28-81), 168 (134-210), 140 (112-171) and 146 (104-206) respectively. No significant differences were observed in median IgG fold change values up to month 6 among severity groups. Median (range) ID50 values for NAbs at months 1, 3 and 6 were 3938 (1958-6407), 4344 (2335-6752) and 424 (124-1022) respectively. NAb titers presented a significant decrease (overall-10.2-fold change from maximal values) without differences among severity groups (Figure 1 a and b). No reinfections occurred. Conclusion: Specific humoral immune response to SARS CoV-2 in patients requiring hospital admission characterizes for a clear peak between 30 and 90 days after admission followed by a significant decline in titer of NAbs by day 180 regardless of disease severity. Longer follow-up may help to determine the longevity of the specific immune response.
ABSTRACT
Background: One of the fundamental pillars of SARS-CoV-2 pandemic control and vaccine development is understanding mid-and long-term immunity. Early humoral response has been extensively studied, however data on what recovered individuals are still scarce and the most recent studies are based on few time points over time, which limits the comprehension of the longitudinal pattern of the potential changes. In this study we have evaluated the neutralizing activity and IgG antibody titer against SARS-CoV-2 in mild/ asymptomatic and hospitalized COVID-19 individuals, over a 6-month period. Methods: We have evaluated the kinetics of the humoral immune response in 210 individuals infected by SARS-CoV-2 covering the first and second waves of COVID-19 outbreak in Catalonia (Spain). IgG antibody titer was evaluated with an in-house sandwich ELISA against the S2 subunit, the binding domain receptor (RBD) and the nucleoprotein (NP) and the neutralizing activity was evaluated by a neutralization assay with HIV reporter pseudoviruses expressing SARS-CoV-2 S protein. Statistical analyses were carried out using mixed-effects non-linear and linear models. Results: Most study participants developed a neutralizing humoral response against SARS-CoV-2, however the maximum neutralization titer was 10-fold lower in mild/asymptomatic individuals compared to those with a more severe illness. We observed a slow and progressive decay of neutralizing activity in individuals with mild or asymptomatic disease throughout the 6-month period. In hospitalized individuals, half maximal neutralization activity was achieved on day 10 and showed an initial rapid decline that significantly slowed and remained nearly flat after day 80. Despite this, activity at six months remained higher in hospitalized individuals compared to mild symptomatic participants. On the other hand, we observed that IgG antibody titers against S2, RBD and NP had a more marked fall without showing differences in the decay pattern between individuals with different degree of severity of the disease. Conclusion: Our data suggest that the neutralizing activity remains relatively stable for more than 6 months despite the decline in IgG antibodies, suggesting that the quality of immune response evolves and allows maintaining the neutralizing activity despite the decay in antibody titers. Our results provide a more detailed picture of the behavior of the natural humoral immune response over time that complements the current evidence on mid-term immunity.