(2020) and Long et al

(2020) and Long et al. humoral response regardless of sex, disease severity and BMI. Subject terms:Immunology, Infectious diseases == Introduction == At the end of 2019, patients with viral infection symptoms and pneumonia were found in Wuhan, China, leading to the discovery of 5-O-Methylvisammioside a novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). More than 169 million cases and 3.5 million deaths were reported from SARS-CoV-2disease up to May 28, 2021. Apprehending the immune responses and the features of antibody production after SARS-CoV-2 are key points in developing an effective treatment. Hence, the significance of improved understanding of immune response to SARS-CoV-2 virus is indisputable. There are confirmed facts that all arms of the immune responses to SARS-CoV-2, although many questions remain uncertain1. One of the Rabbit Polyclonal to CPZ central issues of 5-O-Methylvisammioside the disease is the probability of reinfection and long-term immunity. A limited number of documented and confirmed cases of re-infections are registered in immunocompetent individuals24. The resistance to re-infection may be less a function of the durability of the immune response, than the peculiarities of the individual response or the breadth of immunity. During reinfection, high avidity IgG and elevated titers of neutralizing antibody were discovered. This indicates that the first infections priming of immunity made for a more robust antibody response in the second infection4. As it is well known, during the common human coronaviruses neutralizing antibodies are induced and last for years, providing protection from reinfection or attenuated disease, even if individuals get re-infected5. Long-term follow-up studies of SARS-COV showed the decline of antibody titers over 2 to 3 3 years, although in some patients neutralizing antibodies were detected 12 years after infection6. Thus, the decay in antibody production after SARS-CoV-2 infection cannot be extrapolated from early time points, demonstrating the need for longer-term follow-up studies7. Seroconversion and virus neutralization between 5 and 14 days after symptom onset have been well-documented, but scarce data are available about the durability of antibody production and immunity after a long period of SARS-CoV-2 infections. Contraindicating conclusions exist regarding the duration of immunity, with a rapid decay of protective antibodies within a 34 months811and in opposite persistence of antibodies more than 56 months. Several factors have been evaluated and correlated with a higher or lower antibody response against SARS-CoV-2, such as disease severity1214, BMI12,15,16, sex1214,17and age1215,18,19, but factors associated with long term serological response are not fully evaluated. Therefore, in this study, we aimed to describe the seroprevalence and kinetics of IgG antibodies against SARS-CoV-2 nucleocapsid (N) protein (anti-SARS-CoV-2 (N) IgG) in convalescent immunocompetent patients and analyzed the factors associated with the seropositivity and the humoral response persistence (Fig.1). == Figure 1. == Design of the prospective study. (a) SARS-CoV-2 convalescent patients were involved in the study after maximum of a month of positive PCR testing, and then sampled monthly up to 19 months (subsequent detailed analysis of antibodies titer was performed for 15 months follow-up). Two groups of 5-O-Methylvisammioside healthy donors were also included in the study: pre-pandemic control grouphealthy 5-O-Methylvisammioside donors before SARS-CoV-2 pandemic 5-O-Methylvisammioside period (from 2017 up to February 2020), and SARS-CoV-2 pandemic group -healthy donors throughout the SARS-CoV-2 pandemic period (started from March 2 of 2020). (b) Number of patients inclusion per months. (c) The distribution of patients with different number of samplings for anti-SARS-Cov2 antibodies. == Results == == Patients general characteristics == The study group included 1441 SARS-CoV-2 convalescent patients, out of which 74.1% were female (n = 1004 patients) with mean age 47 15 years and BMI 27 5.2 kg/m2. SARS-CoV-2 infection was asymptomatic in 104 cases (7.2%), mild in 846 cases (58.7%), moderate in 429 cases (29.8%) and severe in 62 cases (4.3%). The most common symptoms of SARS-CoV-2 infection were fever (n = 1089; 80.4%), fatigue (n = 924; 68.2%), headache (n = 626; 46.2%), myalgia (n = 531; 42.1%), cough (n = 467; 34.5%), loss of taste (428; 31.6%) and olfactory impairment (n = 537; 39.6%) (Table1). The most common comorbidities were arterial hypertension (18.9%), autoimmune thyroiditis (6.3%) and diabetes mellitus (5.6%) without any cases of neoplasia or hematological disease or any immunosuppressive therapies.During the median follow-up of 44 weeks, only 1 1 (1.9%) convalescent patient developed a reinfection 12 months after of the first positive PCR.