ABSTRACT
The management of future booster COVID-19 vaccination requires more and detailed data about the longevity of passive, humoral or cellular, immunity. We investigated the humoral immunogenicity of BNT162b2 mRNA vaccine in healthcare workers (HCW) up to 12 months. This study was designed to evaluate the kinetic of antibody response measuring sequential anti-S IgG levels. Participants were voluntary and SARSCoV- 2 naive HCWs of IRCCS Policlinico San Martino Hospital (Genoa, Italy) that they were immunized with two doses of vaccine at December 2020 and a booster dose 9 months later. Blood was sampled prior to vaccine (T0), at 21 days (T1) and 28 days (T2) after the first dose, at 1 (T3), 3 (T4), 6 (T5) and 9 months (T6) after full vaccination, at 1 (T7) and 3 months (T8) after a booster dose. Serological assays were performed at Laboratory Medicine of our hospital using SARS-CoV-2 IgG panel (Bio-Rad, Marnes-la-Coquette, France). It is a multiplex panel of immunoassays intended for the semiquantitative detection of four different IgG antibodies against the receptor-binding domain (RBD), spike 1 (S1), spike 2 (S2) and nucleocapsid (N) structural proteins of SARS-CoV-2. 51 subjects were enrolled among all HCWs and overall, they showed a seroprevalence of 96% (49/51) for RBD and S1 at T1 and 100% (51/51) from T2 to T6. Median values of RBD [100 (51-188) vs 2945 (1693-5364) U/ mL] and S1[79 (30.7-131) vs 1574 (833-3256) U/mL] increased remarkable from T1 to T2. These parameters reduced gradually from T3 to T6 reaching a fold decrease of -20 times (CI 95%: 18-23) and -19 (CI 95%: 17-22) for RBD and S1, respectively. At T7, it was observed an increase of antibody level in comparison to T2 (RBD 4 times, CI 95%: 2,5-6;S1 3 times, CI 95%: 1,5-5). All subjects were negative for anti-N IgG from T0 until to T8. HCWs experienced SARS-CoV-2 infection documented by a molecular or antigen assay for 39,2% (20/51) after a median time of 165 (69-184) days.Naive and healthy people show a protective humoral response with BNT162b2 that it endures up to 12 months with a booster dose at 9th month. Based on the rapid spread of Omicron variants, humoral decrease and booster breakthrough after less of 6 months, an update of vaccine sera booster may be planned for HCWs and patients with failty.
ABSTRACT
The use of face masks as respiratory protective equipment (RPE) is considered key to maintaining the quality of life during emergency situations, long-term care and working conditions. Face masks can reduce the virus spread and bacterial infections as well as prevent the inhalation of industrial waste gases. Individuals who wear a facial mask over a prolonged time often reported uncomfortable feelings due to breathing resistance, heat, tightness, and overall discomfort. One of the main indicators used to quantify the level of discomfort induced by RPE is the respiratory rate (RR). In fact, RR can be directly associated with RPE-related unease since the presence of facial masks might intuitively modify the breathing pattern of the users. Unfortunately, still little is known about RR and its variability in response to wearing RPE. In the last year, the massive use of face masks due to COVID-19 pandemic fosters the development of sensors to measure RR once mounted into the medical mask. Among other, fiber Bragg grating sensors (FBGs) have gained growing attention since the intrinsic advantages of small size, lightweight, high metrological properties, and safety. In the present study, a single-use FFP2 surgical mask was instrumented by a soft sensor based on FBG to perform a long-term acquisition (i.e., 20 min) of the respiratory signal during ordinary work activities at the video terminal. The promising results confirmed the high accuracy of the proposed system in the estimation of RR with a maximum discrepancy of -0.69 breaths per minute and mean absolute percentage error of 2.88 % when compared to a reference instrument. Moreover, no saturation of the sensor output occurred during the usage time.