Reactive arthritis after COVID-19 vaccination: 17 cases.

OBJECTIVES: The aim of the study is to report a series of 17 cases of ankle bi-arthritis that occurred shortly after coronavirus disease 2019 RNA vaccination, and to discuss the potential role of these vaccines in the pathogenesis of this rheumatological manifestation. METHODS: All patients were examined in the same department and received a full work-up to investigate the usual causes of ankle bi-arthritis. No rheumatic inflammatory disease occurred after 9 months of follow-up. A post-vaccination serological follow-up in search of anti-Spike antibodies was requested for all patients. RESULTS: All patients recovered with low dose of prednisolone within <2 months, except one who could not be weaned off CS. The level of antibodies found was very high in all patients. CONCLUSION: The ankle bi-arthritis occurrence chronology, the follow-up and the similar clinical presentation might suggest a pathogenic role of RNA vaccination.

Nationwide Harmonization Effort for Semi-Quantitative Reporting of SARS-CoV-2 PCR Test Results in Belgium.

From early 2020, a high demand for SARS-CoV-2 tests was driven by several testing indications, including asymptomatic cases, resulting in the massive roll-out of PCR assays to combat the pandemic. Considering the dynamic of viral shedding during the course of infection, the demand to report cycle threshold (Ct) values rapidly emerged. As Ct values can be affected by a number of factors, we considered that harmonization of semi-quantitative PCR results across laboratories would avoid potential divergent interpretations, particularly in the absence of clinical or serological information. A proposal to harmonize reporting of test results was drafted by the National Reference Centre (NRC) UZ/KU Leuven, distinguishing four categories of positivity based on RNA copies/mL. Pre-quantified control material was shipped to 124 laboratories with instructions to setup a standard curve to define thresholds per assay. For each assay, the mean Ct value and corresponding standard deviation was calculated per target gene, for the three concentrations (107, 105 and 103 copies/mL) that determine the classification. The results of 17 assays are summarized. This harmonization effort allowed to ensure that all Belgian laboratories would report positive PCR results in the same semi-quantitative manner to clinicians and to the national database which feeds contact tracing interventions.

Assessment of Disinfection Potential of Q-Switch Nd: YAG Laser on Contaminated Titanium Implant Surfaces.

Peri-implantitis (PI) is a relatively frequent pathology that compromises the overall survival of the dental implant. Adjunctive approaches for the conventional mechanical debridement are being suggested to optimize the treatment of PI. The goal of the study was the assessment of the disinfection potential of the Q-Switch Nd: YAG laser on contaminated titanium implant surfaces. A total of 72 sterile titanium discs were used and divided into three groups: 24 contaminated titanium discs treated with the laser (study Group L), 24 contaminated titanium discs with no treatment (control 1-Group C), and 24 sterile titanium discs with no treatment (control 2-Group S). Multi-species biofilm was used: Porphyromonas gingivalis, Fusobacterium nucleatum, Aggregatibacter actinomycetemcomitans, Streptococcus mutans, Streptococcus sobrinus, and Prevotella intermedia. Commensal bacteria were included also: Actinomyces naeslundii, Actinomyces viscosus, Streptococcus cristatus, Streptococcus gordonii, Streptococcus mitis, Streptococcus oralis, Streptococcus sanguinis, Streptococcus parasanguinis, and Veillonella parvula. Parameters delivered per pulse on the targeted surfaces of the titanium discs were an energy density of 0.597 J/cm2 each pulse, a pulse power of 270 mW, a laser beam spot of 2.4 mm in diameter, and a rate of repetition of 10 Hertz (Hz) for a pulse duration of 6 nanoseconds (ns). The mode was no contact, and a distance of 500 micrometers was used with a total time of irradiation equal to 2 s (s). The collection of microbiological samples was made for all groups; colony-forming units (CFU) were identified by two different practitioners, and the average of their examinations was considered for each sample. The average of the TBC (CFU/mL) was calculated for each group. Values were 0.000 CFU/mL, 4767 CFU/mL, and 0.000 CFU/mL for Group L, Group C, and Group S, respectively. Therefore, the suggested treatment protocol was able to provoke a total disinfection of the contaminated titanium surfaces. A statistical difference was only found between Group L vs. Group C and between Group S vs. Group C. The difference was not significant between Group S and Group L. In conclusion, the present study confirmed that the Q-Switch Nd: YAG laser under our specific conditions can provide a total disinfection of the contaminated titanium surfaces.