Neutralization against Omicron SARS-CoV-2 from previous non-Omicron infection.

The spread of the Omicron SARS-CoV-2 variant underscores the importance of analyzing the cross-protection from previous non-Omicron infection. We have developed a high-throughput neutralization assay for Omicron SARS-CoV-2 by engineering the Omicron spike gene into an mNeonGreen USA-WA1/2020 SARS-CoV-2 (isolated in January 2020). Using this assay, we determine the neutralization titers (defined as the maximal serum dilution that inhibited 50% of infectious virus) of patient sera collected at 1- or 6-months after infection with non-Omicron SARS-CoV-2. From 1- to 6-month post-infection, the neutralization titers against USA-WA1/2020 decrease from 601 to 142 (a 4.2-fold reduction), while the neutralization titers against Omicron-spike SARS-CoV-2 remain low at 38 and 32, respectively. Thus, at 1- and 6-months after non-Omicron SARS-CoV-2 infection, the neutralization titers against Omicron are 15.8- and 4.4-fold lower than those against USA-WA1/2020, respectively. The low cross-neutralization against Omicron from previous non-Omicron infection supports vaccination of formerly infected individuals to mitigate the health impact of the ongoing Omicron surge.

SARS-CoV-2 antibody kinetics in blood donors with a previously positive SARS-CoV-2 antibody test within a seroprevalence survey.

The persistence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibodies is a matter of importance regarding the coronavirus disease 19 (COVID-19) pandemic. To observe antibody dynamics, 105 blood donors, positive for SARS-CoV-2 antibodies by a lateral flow test within a seroprevalence study, were included in this study. Thirty-nine (37%) of 105 the donors were confirmed positive by a total Ig Wantai enzyme-linked immunosorbent assay (ELISA). Three (8%) in this group of 39 reported severe and 26/39 (67%) mild to moderate COVID-19 symptoms. By further ELISA-testing, 33/39 (85%) donors were initially positive for IgG antibodies, 31/39 (79%) for IgA, and 32/39 (82%) for IgM, while 27/39 (69%) were positive for all three isotypes. Persistence of IgG, IgA, and IgM was observed in 73%, 79%, and 32% of donors, respectively, after 6-9 months of observation. For IgM antibodies, the decline in the proportion of positive donors was statistically significant (p = 0.002) during 12 months observation, for IgG only the decline at 3 months was statistically significant (p = 0.042). Four donors exhibited notable increases in antibody levels. In conclusion, persistent SARS-CoV-2 IgA antibodies and IgG antibodies at 6-9 months are present in approximately three of four individuals with previous mild to moderate COVID-19.

Low risk of reinfections and relation with serological response after recovery from the first wave of COVID-19.

The aim of the study was to assess reinfection rates in relation to long-term antibody dynamics against SARS-CoV-2 after the first wave. A prospective longitudinal study with monthly serological follow-up during the first 4 months, and then at 6, 8, and 10 months after the disease onset of all recovered adult in- and outpatients with COVID-19 attending Udine Hospital (Italy) from March to May 2020. During the follow-up, reinfections were collected. A total of 546 unselected individuals with COVID-19 acquired from March to May 2020 were included (292 female, mean age 53 years). After a median follow-up of 10 months (IQR 6.2-10.4), reinfection occurred in 6 (1.1%) patients, median age of 44.5 years (IQR 33‒49). All had a previous history of mild COVID-19 (all were healthcare workers) and reinfection occurred a median of 9 months (IQR 8.2‒10.2) after the onset of the first episode. Patients with reinfection were either seronegative (2/56, n = 3.6%), seroreverted (2/137, 1.5%), or seropositive (2/353, 0.6%) (p = 0.085). All reinfections were mild (n = 5) or asymptomatic (n = 1). After reinfection, none of patients developed IgM response and only two had a transitory boosted IgG immunization response. In an unselected population after the first wave of COVID-19, after a prolonged observation period (mean 10 months), reinfection was very uncommon; occurred in patients with a previous history of mild infection, mostly with weak or absent serological response; and manifested with mild or asymptomatic clinical presentation.

Eosinophil: A Nonnegligible Predictor in COVID-19 Re-Positive Patients.

Although vaccine resources are being distributed worldwide, insufficient vaccine production remains a major obstacle to herd immunity. In such an environment, the cases of re-positive occurred frequently, and there is a big controversy regarding the cause of re-positive episodes and the infectivity of re-positive cases. In this case-control study, we tracked 39 patients diagnosed with COVID-19 from the Jiaodong Peninsula area of China, of which 7 patients tested re-positive. We compared the sex distribution, age, comorbidities, and clinical laboratory results between normal patients and re-positive patients, and analysed the correlation between the significantly different indicators and the re-positive. Re-positive patients displayed a lower level of serum creatinine (63.38 ± 4.94 U/L vs. 86.82 ± 16.98 U/L; P =0.014) and lower albumin (34.70 ± 5.46 g/L vs. 41.24 ± 5.44 g/L, P =0.039) at the time of initial diagnosis. In addition, two positive phases and the middle negative phase in re-positive patients with significantly different eosinophil counts (0.005 ± 0.005 × 109/L; 0.103 ± 0.033 × 109/L; 0.007 ± 0.115 × 109/L; Normal range: 0.02-0.52 × 109/L). The level of eosinophils in peripheral blood can be used as a marker to predict re-positive in patients who once had COVID-19.

Persistence and baseline determinants of seropositivity and reinfection rates in health care workers up to 12.5 months after COVID-19.

We assessed the duration and baseline determinants of antibody responses to SARS-CoV-2 spike antigens and the occurrence of reinfections in a prospective cohort of 173 Spanish primary health care worker patients followed initially for 9 months and subsequently up to 12.5 months after COVID-19 symptoms onset. Seropositivity to SARS-CoV-2 spike and receptor-binding domain antigens up to 149-270 days was 92.49% (90.17% IgG, 76.3% IgA, 60.69% IgM). In a subset of 64 health care workers who had not yet been vaccinated by April 2021, seropositivity was 96.88% (95.31% IgG, 82.81% IgA) up to 322-379 days post symptoms onset. Four suspected reinfections were detected by passive case detection, two among seronegative individuals (5 and 7 months after the first episode), and one low antibody responder. Antibody levels significantly correlated with fever, hospitalization, anosmia/hypogeusia, allergies, smoking, and occupation. Stable sustainment of IgG responses raises hope for long-lasting COVID-19 vaccine immunity.

Favipiravir in the treatment of patients with SARS-CoV-2 RNA recurrent positive after discharge: A multicenter, open-label, randomized trial.

BACKGROUND: The clinical characteristics and treatment of patients who tested positive for COVID-19 after recovery remained elusive. Effective antiviral therapy is important for tackling these patients. We assessed the efficacy and safety of favipiravir for treating these patients. METHODS: This is a multicenter, open-label, randomized controlled trial in SARS-CoV-2 RNA re-positive patients. Patients were randomly assigned in a 2:1 ratio to receive either favipiravir, in addition to standard care, or standard care alone. The primary outcome was time to achieve a consecutive twice (at intervals of more than 24 h) negative RT-PCR result for SARS-CoV-2 RNA in nasopharyngeal swab and sputum sample. RESULTS: Between March 27 and May 9, 2020, 55 patients underwent randomization; 36 were assigned to the favipiravir group and 19 were assigned to the control group. Favipiravir group had a significantly shorter time from start of study treatment to negative nasopharyngeal swab and sputum than control group (median 17 vs. 26 days); hazard ratio 2.1 (95% CI [1.1-4.0], p = 0.038). The proportion of virus shedding in favipiravir group was higher than control group (80.6% [29/36] vs. 52.6% [10/19], p = 0.030, respectively). C-reactive protein decreased significantly after treatment in the favipiravir group (p = 0.016). The adverse events were generally mild and self-limiting. CONCLUSION: Favipiravir was safe and superior to control in shortening the duration of viral shedding in SARS-CoV-2 RNA recurrent positive after discharge. However, a larger scale and randomized, double-blind, placebo-controlled trial is required to confirm our conclusion.

Seasonal coronavirus protective immunity is short-lasting.

A key unsolved question in the current coronavirus disease 2019 (COVID-19) pandemic is the duration of acquired immunity. Insights from infections with the four seasonal human coronaviruses might reveal common characteristics applicable to all human coronaviruses. We monitored healthy individuals for more than 35 years and determined that reinfection with the same seasonal coronavirus occurred frequently at 12 months after infection.

Utility of rapid plasmin reagin titres in assessing treatment response and re-infection for infectious syphilis.

Background The rapid plasma reagin (RPR) assay is commonly used as a surrogate marker of infectious syphilis, but is non-specific, slow to change and variable in its rate of decline post treatment. METHODS: Within an urban sexual health service testing predominantly men who have sex with men, a file review of RPR changes was undertaken in all subjects who had a dilution level of ≥1:4, between January 2015 to the end of December 2018. RESULTS: Overall, 248 cases of infectious syphilis were identified in 215 subjects (165 HIV seropositive, 50 HIV seronegative). Among unique-subject cases with follow-up RPR recorded, seroreversion to a non-reactive titre was achieved in only 42.3% (71/168) cases at a median of 235 days (interquartile range: 138-348 days) and was significantly less likely if patients had HIV infection (P = 0.02), late latent syphilis (P = 0.003) or a subsequent syphilis infection (P < 0.0001). Having HIV infection (P = 0.03) or a subsequent episode of syphilis (P = 0.01) were associated with a lower likelihood of documented cure. CONCLUSIONS: The slow decay in RPR titres post therapy and the inability of a significant number of subjects to achieve a non-reactive result over time makes RPR a poor test for assessing the adequacy of treatment or in diagnosing re-infection, especially in populations having repeated and frequent risk exposures. As the number of syphilis cases continue to climb, better tests that accurately assess pathogen presence are urgently needed.

Elevated CXCL10 Serum Levels in Measles Virus Primary Infection and Reinfection Correlate With the Serological Stage and Hospitalization Status.

We quantified serum concentrations of chemokine CXCL10 in 288 patients with measles virus (MeV) primary infection and 16 patients with reinfection (vaccine failure). CXCL10 peaked with emergence of IgM antibodies and was elevated in hospitalized patients (3233 vs 1930 pg/mL, P < .0001). CXCL10 differed between primary and reinfection (1958 vs 932 pg/mL, P = .0402). In comparison to other viral infections with rash-like symptoms, CXCL10 was highly elevated in MeV infection (area under the curve = 0.935; 95% confidence interval, .905-.965; P < .0001). CXCL10 is a potential marker for diagnosis, stage, and severity of MeV infection.

Inferior Outcomes Associated with the Coexistence of Hepatocellular Carcinoma Recurrence and Hepatic Virus Reinfection After Living Donor Liver Transplantation.

BACKGROUND: Chronic viral hepatitis remains a major etiology of liver cirrhosis and hepatocellular carcinoma. Liver transplantation has been considered an effective treatment for this condition. This study aims to analyze living donor liver transplantation for patients with hepatocellular carcinoma and its relationship with hepatitis virus status. METHODS: A retrospective analysis of 268 patients who received living donor liver transplantation for hepatocellular carcinoma was performed. Patients were analyzed according to their serologic status of hepatitis virus; clinicopathologic features, operative parameters, and outcomes were also assessed and compared. RESULTS: Twenty-three patients (8.6%) had hepatocellular carcinoma recurrence following liver transplantation; the most common pattern of recurrence was systemic spreading (n = 10). Hepatitis B virus relapse was encountered in 41 out of 188 patients (21.8%) with hepatitis B virus-positive, and hepatitis C virus reactivation was noted in 48 (60.8%) patients among 79 hepatitis C virus-positive patients. Incidence of hepatitis C virus reactivation was significantly higher than that of hepatitis B virus relapse (p < 0.0001). Hepatocellular carcinoma recurrence and overall survival were not significantly different in relation to hepatitis virus; however, patients who had hepatocellular carcinoma recurrence combined with hepatitis virus reinfection had the significantly lowest survival rate compared with other groups (p < 0.0001). CONCLUSION: Living donor liver transplantation based on expanded hepatocellular carcinoma criteria achieved a satisfactory result, but reinfection of hepatic virus remains a great concern particularly in patient with hepatitis C. Moreover, hepatocellular carcinoma recurrence accompanied with reinfection of hepatic virus after liver transplantation is associated with inferior outcomes.