Mass vaccination is the key element in controlling current COVID-19 pandemic. Studies comparing immunogenicity of different COVID-19 vaccines are largely lacking. We aimed at measuring anti-S ...antibody (Ab) levels in individuals fully vaccinated with BNT162b2, BBIBP-CorV and Gam-COVID-Vac, as well as in COVID-19 convalescents.
In this cross-sectional study, serum was collected from 400 age- and sex-matched participants, 100 fully vaccinated with BNT162b2, 100 with BBIBP-CorV and 100 with Gam-COVID-Vac on the 28th day after the second vaccine dose, and 100 recovered from COVID-19 at least 28 days after symptom(s) resolution. Sera were analyzed using the LIAISON SARS-CoV-2 S1/S2 IgG assay (DiaSorin, Saluggia, Italy). Wilcoxon rank-sum or Kruskal-Wallis tests was used for comparison of Ab levels.
Highest mean value (210.11, SD = 100.42) was measured in the BNT162b2 group, followed by Gam-COVID-Vac (171.11, SD = 120.69) and BBIBP-CorV (68.50, SD = 72.78) AU/mL (p<0.001). Significant differences in antibody levels were found between BNT162b2 and BBIBP-CorV (p<0.001), BNT162b2 and Gam-COVID-Vac (p = 0.001), as well as BBIBP-CorV and Gam-COVID-Vac groups (p<0.001). Percentage of seropositive was 81% in the convalescent group, 83% in BBIBP-CorV vaccinated and 100% in BNT162b2 and Gam-COVID-Vac. When comparing measured antibody levels in vaccinated to those in COVID-19 recovered, significantly higher antibody levels were found for vaccinated with BNT162b2 (p<0.001), and with Gam-COVID-Vac (p<0.001), while for BBIBP-CorV there was no statistically significant difference (p = 0.641).
All three investigated vaccines, BNT162b2, BBIBP-CorV and Gam-COVID-Vac, provide robust immune response 28 days after the second dose of vaccine, in the majority of participants. All individuals vaccinated with BNT162b2 and Gam-COVID-Vac seroconverted, while in vaccinated with BBIBP-CorV and COVID-19 recovered seroconversion rates were lower. Although less potent compared to other two vaccines, immune response after BBIBP-CorV was similar to response measured in convalescents. Challenge still remains to examine dynamics and durability of immunoprotection.
Background
Monitoring changes of seroprevalence over time is important at the beginning and during of COVID-19 outbreak to anticipate its dynamics and plan an adequate public health response.
Methods
...We conducted a repeated cross-sectional investigation among asymptomatic outpatient subjects and covered 0.1% of total population of Northern Serbia (Autonomous Province of Vojvodina). Each participant was tested for anti-SARS-CoV-2 antibodies using an immunochromatographic qualitative test (point-of-care rapid test). In the last round of survey IgG antibodies targeting the S1 subunit of the spike protein and the nucleocapsid protein of SARS-CoV-2 virus were assessed.
Results
During the four rounds of survey (between the end of April and the end of September), anti-SARS-CoV-2 seropositivities based on immunochromatographic test results were 2.60% (95% CI 1.80–3.63), 3.93% (95% CI 2.85–5.28), 6.11% (95% CI 4.72–7.77) and 14.60% (95% 12.51–16.89), respectively. After adjusting with results obtained from the Line immunoassay test, the estimated overall seroprevalence increased to 16.67% (95% CI 14.45–19.08) corresponding to 322,033 infections in total by the end of September 2020 in Vojvodina’s population. Throughout the course of the study, for every RT-PCR confirmed case of COVID-19, there were 39–87 additional infections in Vojvodina. No significant difference (p>0.05) in SARS-CoV-2 seropositivity regarding gender and between age subgroups was observed over the course of the survey.
Conclusions
The population prevalence of SARS-CoV-2 antibodies implies much more widespread infection in Vojvodina than indicated by the number of confirmed cases. However, our results suggest that the population of Vojvodina has not reached a desirable level of protection from SARS-CoV-2 virus by the end of September 2020.
Data related to carriage of Streptococcus pneumoniae (Spn) and antimicrobial resistance patterns in middle-aged and older adults are limited. We assessed the carriage of Spn, and its antibiotic ...resistance patterns, among participants greater than or equal to50 years of age living in the city of Novi Sad during the second year of COVID-19 pandemic. Analysis of prospectively collected data among participants with or without symptoms of upper respiratory tract infection who visited their elected physicians in the Primary Health Care Centre of Novi Sad (outpatient facility) was conducted from May 18, 2021 to December 7, 2021. Both nasopharyngeal (NP) and oropharyngeal (OP) samples from each participant were collected. A total of 1042 samples from 521 study subjects (1 NP and 1 OP sample from each person) were collected. Sixteen samples from the same number of persons (3.1%, 95% confidence interval: 1.76%-4.94%) were culture positive for the presence of Spn. Overall, the median age of study participants was 71 years (range, 50-93 years; 90th percentile, 77 years), and most (197/521, 37.8%) of them were 70-79 years of age. A majority of the study subjects were: females (324/521; 62.2%), sampled during May and June 2021 (376/521, 72.2%), those who did not have contact with children aged 0-10 years in the family (403/521; 77.4%), without smokers in the household (443/521; 85.0%), and those who did not receive vaccine against Spn (519/521; 99.6%). Out of 16 Spn positive samples, for six participants, Spn carriage serotypes were obtained and there were four vaccine (6A, 11A, 15B, and 18C) serotypes, and two (6C and 35F) non-vaccine serotypes. Remaining 10 (62.50%) samples were non-typeable isolates of pneumococci. Among four vaccine serotypes, two (6A and 18C) were represented in PCV13, and 18C along with the other two (11A and 15B) in PPSV23 vaccine. The highest level of resistance of Spn isolates was observed for erythromycin, (10 or 62.50%), and tetracycline, (7 or 43.75%), one isolate showed resistance to penicillin, ampicillin, and amoxicillin/amoxicillin-clavulanic acid, while none of them were resistant to ceftriaxone, trimethoprim/sulfamethoxazole and levofloxacin. There were three multi-drug resistant isolates; one was identified as 6C (non-vaccine serotype), and two other were non-typeable isolates of Spn. In this first study conducted in Serbia on Spn carriage in adults greater than or equal to50 years of age, we found low prevalence of Spn carriage and identified 6 serotypes of Spn, four of which were represented in vaccines. These results may support future Spn colonization studies among middle-aged and older adults.
Modern communication standards, such as 5G new radio (5G NR), require a high speed decoder for highly irregular quasi-cyclic low density parity check (QC-LDPC) codes. A widely used approach in ...QC-LDPC decoders is a layered decoding schedule which processes the parity check matrix in parts, thus providing faster convergence. However, pipelined layered decoding architecture suffers from data hazards that reduce the throughput. This paper presents a novel architecture, which can facilitate any QC-LDPC decoding without stall cycles caused by pipeline hazards. The decoder conveniently incorporates both the layered and the flooding schedules in cases when hazards occur. The paper also presents the genetic algorithm based optimization of the decoding schedule for better signal-to-noise ratio (SNR) performance. The proposed architecture enables insertion of a large number of pipeline stages, thus providing high operating frequency. As a case study, the FPGA implementation for WiMAX, DVB-S2X, and 5G NR provided coded throughput of up to 1.77 Gbps, 4.32 Gbps, and 4.92 Gbps at 10 iterations, respectively. The results show a strong throughput increase of 30%-109% compared with the conventional layered decoder for 5G NR for the same SNR performance. The decoder provides highly efficient utilization of resources when compared with the state-of-the-art solutions.
In sprint disciplines, the start reaction (SR) time affects the final result in the sprint. This research aimed to analyze and examine whether there are significant differences in the SR in the ...semi-final and final groups in the 60 m and 400 m disciplines at the World Indoor Championships in Athletics, held in Belgrade in 2022 in men's and women's competition. The aim was also to determine if there were statistical differences between men and women in the 400 m event. T-test for independent samples showed statistical differences between the SR in the 60 m and 400 m athletics events in men (t=-4.434, p=0.000) and women (t=-3.210, p=0.004). For the 400 m running events, an independent samples t-test was used to examine differences between men and women in SR. No significant differences were obtained between men and women in the 400 m event (t=0.401, p=0.691). SR is part of all running disciplines and affects the time achieved in the race (result). Although it has been known for a long time that training can influence SR, a few studies still examine training's effects on SR. The question can be about how much it is possible to reduce SR with specific training exercises or to apply certain neurophysiological methods.
Many available SARS-CoV-2 vaccines demonstrated good humoral response, but studies directly comparing their immunogenicity in the general population are lacking. We evaluated the medium−term kinetics ...of anti-S SARS-CoV-2 antibodies (Abs) at one and six months after the second dose of BNT162b2, BBIBP-CorV, and Gam-COVID-Vac. Immunogenicity at six months was directly compared between BNT162b2, BBIBP-CorV, Gam-COVID-Vac, and ChAdOx1 nCoV-19. Participants ≥ 20 years old from Novi Sad, Serbia, without prior SARS-CoV-2 infection, were included. Anti S1/S2 IgG antibodies were measured using quantitative LIAISON SARS-CoV-2 assay. A total of 368 participants were included: 231 (62.77%) had sera collected at two time points. Two doses of BNT162b2 were received by 37.50% of participants, followed by BBIBP-CorV (22.01%), Gam-COVID-Vac (21.47%), and ChAdOx1 nCoV-19 (19.02%). Mean Ab levels at the 28th day and 6 months were 216.55 (SD = 105.73) AU/mL and 75.68 (SD = 57.30) for BNT162b2, 194.38 (SD = 140.24) and 90.53 (SD = 111.30) for Gam-COVID-Vac, and 72.74 (SD = 80.04) and 24.43 (SD = 38.43) for BBIBP-CorV group (p < 0.01, between two time points across all three groups), with a significant difference between women and men (p < 0.01, for both sexes). At the sixth month post-vaccination, the highest mean Ab level was detected in Gam-COVID-Vac group (91.28 AU/mL, SD = 95.96), followed by BNT162b2 (85.25 AU/mL, SD = 60.02), ChAdOx1 nCoV-19 (64.22 AU/mL, SD = 65.30), and BBIBP-CorV (25.26 AU/mL, SD = 36.92) (p < 0.01). Anti-spike IgG persistence was demonstrated six months post-vaccination with a significant decline in Ab levels. These results suggest a lower protection against SARS-CoV-2 over time. Our findings support the introduction of additional (booster) doses.
Healthcare workers (HCWs) are a vulnerable and critical population in the ongoing response to the SARS-CoV-2 pandemic. We aimed to estimate the seroprevalence in HCWs considering all of their ...previous contacts with the SARS-CoV-2 virus and/or the immunity acquired through their immunization against COVID-19 before the advent of the Omicron variants BA.4/BA.5. Serum samples were collected from 28 March to 10 June 2022. We covered 25% out of all the people who worked in some of the government healthcare centers (primary, secondary, and tertiary level) across the entire Autonomous Province of Vojvodina (Northern Serbia). Two serological tests (Anti-SARS-CoV-2 QuantiVac ELISA and LIAISON® SARS-CoV-2 TrimericS) were used to detect anti-spike IgG antibodies. The overall prevalence of the SARS-CoV-2 antibody among the 6936 HCWs was 92.96% 95% CI 92.33−93.55. Regarding the type of serological test, there was a statistically significant (p = 0.0079) difference of the seropositivity obtained by the LIAISON® SARS-CoV-2 TrimericS (93.87%, 95% CI 92.97−94.69) and Anti-SARS-CoV-2 QuantiVac ELISA (92.23%, 95% CI 91.34−93.06) tests. Seropositivity to SARS-CoV-2 significantly (p < 0.0001) increased with the number of SARS-CoV-2 infections combined with the number of doses of the SARS-CoV-2 vaccines received. A vast majority of the HCWs in Vojvodina had detectable levels of antibodies to the spike protein of SARS-CoV-2, but despite this high seropositivity, it is unknown whether this herd immunity among HCWs is protective against the new variants of concern. Further research should evaluate the rates of reinfections and the associated severity of COVID-19 caused by the Omicron sublineages and/or new variants of SARS-CoV-2 among HCWs.
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