Several SARS-CoV-2 lineages with spike receptor binding domain (RBD) N501Y mutation have spread globally. We evaluated the impact of N501Y on neutralizing activity of COVID-19 convalescent sera and ...on anti-RBD IgG assays.
The susceptibility to neutralization by COVID-19 patients’ convalescent sera from Hong Kong were compared between two SARS-CoV-2 isolates (B117-1/B117-2) from the α variant with N501Y and 4 non-N501Y isolates. The effect of N501Y on antibody binding was assessed. The performance of commercially-available IgG assays was determined for patients infected with N501Y variants.
The microneutralization antibody (MN) titers of convalescent sera from 9 recovered COVID-19 patients against B117-1 (geometric mean titerGMT,80; 95% CI, 47–136) were similar to those against the non-N501Y viruses. However, MN titer of these serum against B117-2 (GMT, 20; 95% CI, 11–36) was statistically significantly reduced when compared with non-N501Y viruses (P < 0.01; one-way ANOVA). The difference between B117-1 and B117-2 was confirmed by testing 60 additional convalescent sera. B117-1 and B117-2 differ by only 3 amino acids (nsp2-S512Y, nsp13-K460R, spike-A1056V). Enzyme immunoassay using 272 convalescent sera showed reduced binding of anti-RBD IgG to N501Y or N501Y-E484K-K417N when compared with that of wild-type RBD (mean difference: 0.1116 and 0.5613, respectively; one-way ANOVA). Of 7 anti-N-IgG positive sera from patients infected with N501Y variants (collected 9-14 days post symptom onset), 6 (85.7%) tested negative for a commercially-available anti-S1-IgG assay.
Richard and Carol Yu, Michael Tong, and the Government Consultancy Service (see acknowledgments for full list).
We highlighted the importance of using a panel of viruses within the same lineage to determine the impact of virus variants on neutralization. Furthermore, clinicians should be aware of the potential reduced sensitivity of anti-RBD IgG assays.
The SARS-CoV-2 Omicron variant has led to a major wave of COVID-19 in Hong Kong between January and May 2022. Here, we used seroprevalence to estimate the combined incidence of vaccination and ...SARS-CoV-2 infection, including subclinical infection which were not diagnosed at the acute stage. The overall seropositive rate of IgG against receptor binding domain (anti-RBD IgG) increased from 52.2% in December 2021 to 89.3% in May 2022. The level of anti-RBD IgG was lowest in the 0-9 and ≥80 year-old age groups in May 2022. The seropositive rate of antibody against ORF8, which reflects the rate of prior infection, was 23.4% in May 2022. Our data suggest that although most individuals were either vaccinated or infected after the fifth wave, children and older adults remain most vulnerable. Public health measures should target these age groups in order to ameliorate the healthcare consequences of upcoming waves.
SARS-CoV-2 RT-PCR with pooled specimens has been implemented during the COVID-19 pandemic as a cost- and manpower-saving strategy for large-scale testing. However, there is a paucity of data on the ...efficiency of different nucleic acid extraction platforms on pooled specimens. This study compared a novel automated high-throughput liquid-based RNA extraction (LRE) platform (PHASIFY™) with a widely used magnetic bead-based total nucleic acid extraction (MBTE) platform (NucliSENS
easyMAG
). A total of 60 pools of nasopharyngeal swab and 60 pools of posterior oropharyngeal saliva specimens, each consisting of 1 SARS-CoV-2 positive and 9 SARS-CoV-2 negative specimens, were included for the comparison. Real-time RT-PCR targeting the SARS-CoV-2 RdRp/Hel gene was performed, and GAPDH RT-PCR was used to detect RT-PCR inhibitors. No significant differences were observed in the Ct values and overall RT-PCR positive rates between LRE and MBTE platforms (92.5% (111/120 vs. 90% (108/120), but there was a slightly higher positive rate for LRE (88.3% (53/60) than MBTE (81.7% (49/60) among pooled saliva. The automated LRE method is comparable to a standard MBTE method for the detection of SAR-CoV-2 in pooled specimens, providing a suitable alternative automated extraction platform. Furthermore, LRE may be better suited for pooled saliva specimens due to more efficient removal of RT-PCR inhibitors.
Background
Conventional freehand immediate placement of dental implants is technically challenging in the jaw reconstructive surgery. Computer‐aided surgery might be the best solution, however, there ...has not been any standard approach to ensure the accuracy and efficiency of simultaneous dental implants in fibula flap jaw reconstruction.
Purpose
We aim to evaluate the clinical outcome of simultaneous dental implant in fibula flap using the “three‐in‐one” patient‐specific surgical guide (3‐in‐1‐PSSG) in an open‐label, prospective, single‐arm, and single‐center clinical trial.
Materials and Methods
A novel computer‐aided designed and three‐dimensional (3D) printed 3‐in‐1‐PSSG, which contains functions of fibula segmentation, surgical plate positioning and implant placement, was used to facilitate the reconstructive surgery and simultaneous dental implant placement. The intraoperative success of dental implant placement, implant survival rate and accuracy of dental implant placement were reported.
Results
From November 2018 to June 2020, 15 consecutive patients with 48 dental implants were enrolled in this study. Fifteen 3‐in‐1‐PSSGs were fabricated with a mean number of dental implants per guide of 3.2 ± 1.5. The intraoperative success rate of this approach was 14 out of 15. With an average follow‐up period of 40 weeks, the overall implant survival rate was 83.3% (40/48). Eight implants were removed due to two fibula flap failures. The mean deviation at the implant platform and implant apex were 2.8 mm (interquartile range IQR: 1.9‐3.4) and 3.2 mm (IQR: 2.0‐4.6), and the angular deviation was 2.5° (IQR: 1.1‐6.8).
Conclusions
Our preliminary data indicated that the 3D printed 3‐in‐1‐PSSG facilitated simultaneous dental implant in fibula flap jaw reconstruction with a favorable intraoperative success and short‐term clinical outcome. It might be a viable alternative to allow one‐step immediate oral rehabilitation in patients underwent jaw reconstruction with free flaps. Long‐term results with a larger sample size are warranted.
Vaccination reduces COVID-19-related hospitalization among older adults. However, how SARS-CoV-2 infection and vaccine regimens affect vaccine-elicited immunity remain unclear.
This is a ...cross-sectional study recruiting adults aged ≥70 years with comorbidities in Hong Kong. Demographic and clinical information were collected using a questionnaire. Neutralizing antibody (nAb) titers (against ancestral and Omicron strains) and SARS-CoV-2-specific T cell response were analyzed according to infection and vaccination status. Multivariable regression analysis was performed to assess the associations of BNT162b2 and booster doses with higher nAb titers, with adjustment for comorbidities.
In July 2022, 101 patients were recruited, of whom 25 (24%) had previous infection. Overall, the geometric mean titer (GMT) of BA.5 nAb was 2.8-fold lower than that against BA.2 (P < 0.0001). The ancestral strain and BA.2 titers were higher for the 3-4-dose-BNT162 group than the 2-dose-BNT162b2 group. Non-infected individuals in the 3-4-dose-CoronaVac group had a more robust T cell response than the 2-dose-CoronaVac group (P = 0.0181), but there was no significant difference between the 2-dose-BNT162b2 and 3-4-dose-BNT162b groups. Patients who had heterologous CoronaVac-BNT162b2 prime-boost regimen had 3.22-fold higher BA.5 nAb titers than those who were primed/boosted with CoronaVac (P = 0.0207). Patients with hybrid immunity had higher Omicron nAb titers than those with vaccine-only immunity. Multivariable analysis showed that BNT162b2 and booster doses were independently associated with higher ancestral strain nAb titers.
Our data support the use of booster doses for older adults with or without prior infection. Non-infected individuals primed with CoronaVac will benefit from heterologous mRNA vaccine booster.
Richard and Carol Yu, May Tam Mak Mei Yin, The Shaw Foundation Hong Kong, Michael Tong, Marina Lee, Government Consultancy Service (See acknowledgements for full list).
Positive bone margins have been shown to be associated with worse locoregional control and survival performance in oral oncology patients. With the application of computer-assisted surgery and ...patient-specific surgical guides, the authors can accurately execute the preoperative osteotomy plan. However, how well the authors can predict the margin distance in the final histopathology with a preoperative computed tomography (CT) scan, the factors associated with it, and how much leeway CT should spare when designing the osteotomy planes during virtual surgical planning (VSP) remain to be investigated.
Patients from January 2021 to December 2022 with benign or malignant jaw tumors and with signs of bone marrow involvement in the preoperative CT scan in our center were prospectively recruited to the study. VSP and measurement of the closest margin distance in the CT scan were performed by the single team of surgeons. The resection specimen was processed, and the margin distances were measured by a dedicated senior pathologist with the knowledge of orientation of the osteotomy planes.
A total of 35 patients were recruited, with 21 malignant and 14 benign cases. Sixty-eight bone margins were quantitatively analyzed. No significant difference in margin distances measured from the CT scan and final histopathology was detected ( P =0.19), and there was a strong correlation between the two (r s =0.74, P <0.01). A considerable amount of variance was detected in the level of discrepancy between margin distances measured in the CT scan and final histopathology (overall SD=6.26 mm, malignancy SD=7.44 mm, benign SD=4.40 mm). No significant correlation existed between the two margin distances when only maxilla tumor margins were assessed ( P =0.16).
The bone margin distance in VSP is reliably correlated to the final pathological margin distance. A leeway distance of 15mm and 9mm should be considered when designing the osteotomy planes for malignancy and benign cases, respectively. Extra attention should be paid to maxilla cases when predetermining the osteotomy planes during VSP.
Hong Kong has had a low incidence of COVID-19 vaccine related anaphylaxis, partly due to its Vaccine Allergy Safety (VAS) guidelines for screening those at higher risk of COVID-19 vaccine-associated ...allergic reactions. We characterize the initial experience of the VAS clinics, as well as the impact of unnecessary referrals to the vaccination program.
All patients attending the VAS Clinics of the public and private health services between February and June 2021 were reviewed.
Out of 1127 patients assessed at VAS clinics, 1102 (97.8%) patients were recommended for vaccination. Out of those contacted, more than 80% (450/558) received vaccination successfully; the remaining had not yet booked their vaccinations. The majority (87.5%) of patients not recommended was due to potential excipient allergies. Males were significantly more likely to be recommended (OR = 5.822, 95% CI = 1.361–24.903, p = 0.007), but no other features were associated with recommendation for vaccination. Almost half (45.1%) of public service referrals were rejected due to insufficient information or incorrect indications for referral. The majority of cases (56.2%) of patients referred for suspected “anaphylaxis” did not fulfil diagnostic criteria.
COVID-19 vaccination is very safe and 98% of high-risk patients were recommended for vaccination. Barriers to VAS include a high proportion of inappropriate referrals, inaccurate diagnoses of anaphylaxis and inability to diagnose excipient allergies. Our data validates that a prior history of COVID-vaccine unrelated anaphylaxis should be removed as a precaution for vaccination. Closer collaborations between primary care and allergy specialists and changes in pharmaceutical legislation should be made a priority to promote vaccination uptake.
The objective of this study is to evaluate if nurse-led repeated prescription (NRP) could ensure non-inferior disease control and would be accepted in Chinese patients with controlled hypertension ...(HT) in primary care clinics. A 12-month follow-up non-inferiority randomized trial was conducted. The non-inferior margins for systolic and diastolic blood pressure were 6.6 mmHg and 3.7 mmHg, respectively. Eligible patients (>18 years of age) with HT were randomized to the NRP and usual care (UC) groups for their regular clinical follow-up. We used ANCOVA to study the difference-of-difference of the blood pressures between the two groups. The levels of patient acceptance and experience of NRP were assessed by the observed opt-out rate and a qualitative analysis. We found no statistically significant differences in BP blood pressure between the NRP (N = 194) and UC (N = 199) groups. Only 4 of the participants in the NRP group opted out due to a preference for assessment by a physician. The interviewed participants (N = 12) felt positive about NRP, because they experienced more relaxed communication with the nurse and believed that the eligibility to join the NRP program was an indication of optimal BP control. We observed no adverse events. The findings show that NRP was well accepted and found to be non-inferior to physician consultation for HT management.
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