Nevertheless, the predominant cohort comprises individuals primarily undergoing treatment with dimethyl fumarate (DMF), glatiramer acetate (GA), or beta-interferon (INF) [12]. that antibody levels more accurately reflect the serological status and exhibit a stronger correlation with vaccination than just the presence of antibodies. Keywords: COVID-19, SARS-CoV-2, receptor binding domain name, spike protein, nucleocapsid protein, multiple sclerosis, disease-modifying therapies, antibodies, vaccines, serology 1. Introduction Coronavirus 2019 (COVID-19) is usually a disease caused by the severe respiratory syndrome coronavirus 2 (SARS-CoV-2) computer virus, which is responsible for the pandemic that started in 2019 [1]. The genetic material of the computer virus comprises a single-stranded RNA that encodes 16 non-structural proteins and four structural proteins: spike (S), nucleocapsid (N), envelope (E), and membrane (M) [2]. In a clinical context, the pivotal protein is the S protein, which was found to be accountable for facilitating computer virus entrance into the host cell via binding to the ACE2 (angiotensin-converting enzyme 2) receptor [3]. The spike protein was selected as a therapeutic target in the design of vaccines against the SARS-CoV-2 computer virus [4]. In addition, the antibodies against the S protein, which are produced as a result of active immunization (natural contamination) and passive immunization (vaccination), are the only ones that have a neutralizing capability, thereby conferring protection against contamination or reinfection [5]. It is also known that antibodies directed against the receptor binding domain name (RBD) within the S1 subunit (anti-S1RBD antibodies) have the highest AF 12198 neutralizing capacity [6]. Moreover, the S1-RBD subunit exhibits minimal amino acid sequence homology AF 12198 compared to other coronaviruses [4]. The second clinically significant protein of the SARS-CoV-2 computer virus is the nucleocapsid (N) protein, which is responsible for the replication and transcription of viral RNA [7]. The N protein, as with the S protein, induces a humoral response. However, antibodies directed against the N protein are solely generated after natural contamination but not after vaccination [8]. As in most European countries, in Poland, in December 2020, a mass vaccination program against COVID-19 began, initially available to selected risk groups (including healthcare workers). From May 2021, all adult Poles could receive the first dose of the vaccine. Registration for the second dose of the vaccine opened in November 2021. From April 2022, the second booster dose of the vaccine could be administered to people over 80 years of age, and from September 2022, all people over 12 years of age. The first available vaccine was the Comirnaty mRNA vaccine (Pfizer-BioNTech; Marburg, Germany). Subsequently, another mRNA vaccine, Spikevax (Moderna Biotech Spain, S.L, Madrit, Spain), was approved. Other vaccines approved in EU countries (including those used en masse in Poland) were vector vaccines: Vaxzeveria AF 12198 (AstraZeneca; Cambridge, UK) FLJ25987 and Janssen Vaccine (Janssen-Cilag International NV; Beerse, Belgium) and a protein vaccine (Nouvaxovid Novavax; Gaithersburg, MD, USA). In May 2021, the Polish Neurological Society published an official position recommending COVID-19 vaccination for AF 12198 patients suffering from multiple sclerosis. Patients treated with beta interferons (INF), glatiramer acetate (GA), teriflunomide (TFN), dimethyl fumarate (DMF), and natalizumab (NTZ) should consider vaccination at every stage of treatment (no switch in the therapy schedule is necessary). The guidelines specify groups of patients treated with fingolimod, ocrelizumab, cladribine, and alemtuzumab, where vaccination techniques are proposed depending on the time of DMT administration [9]. Insubsequent stages of the pandemic, the Polish Neurological Society updated its position on additional doses and booster doses [10]. Multiple sclerosis (MS) is usually a demyelinating autoimmune disease that impacts individuals across numerous age groups. The disease is usually predominantly diagnosed during the third decade of life [11]. MS is usually treated with immunomodulating and immunosuppressive drugs, termed disease-modifying therapies (DMTs). In Poland, 15 DMTs are currently available and financed by the National Health Fund. Nevertheless, the predominant cohort comprises individuals primarily undergoing treatment with dimethyl fumarate (DMF),.