SARS-CoV-2 Infection Is at Herd Immunity in the Majority Segment of the Population of Qatar.

BACKGROUND: Qatar experienced a severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) epidemic that disproportionately affected the craft and manual worker (CMW) population, who comprise 60% of the total population. This study aimed to assess ever and/or current infection prevalence in this population. METHODS: A cross-sectional population-based survey was conducted during July 26 to September 09, 2020, to assess both anti-SARS-CoV-2 positivity through serological testing and current infection positivity through polymerase chain reaction (PCR) testing. Associations with antibody and PCR positivity were identified through regression analyses. RESULTS: The study included 2641 participants, 69.3% of whom were <40 years of age. Anti-SARS-CoV-2 positivity was 55.3% (95% CI, 53.3%-57.3%) and was significantly associated with nationality, geographic location, educational attainment, occupation, and previous infection diagnosis. PCR positivity was 11.3% (95% CI, 9.9%-12.8%) and was significantly associated with nationality, geographic location, occupation, contact with an infected person, and reporting 2 or more symptoms. Infection positivity (antibody and/or PCR positive) was 60.6% (95% CI, 58.6%-62.5%). The proportion of antibody-positive CMWs who had a prior SARS-CoV-2 diagnosis was 9.3% (95% CI, 7.9%-11.0%). Only seven infections were ever severe, and only 1 was ever critical-an infection severity rate of 0.5% (95% CI, 0.2%-1.0%). CONCLUSIONS: Six in every 10 CMWs in Qatar have been infected, suggestive of reaching the herd immunity threshold. Infection severity was low, with only 1 in every 200 infections progressing to be severe or critical. Only 1 in every 10 infections had been previously diagnosed, which is suggestive of mostly asymptomatic or mild infections

Elimination of hand-wrist radiographs for maturity assessment in children needing orthodontic therapy

Our aim was to evaluate the validity of the cervical vertebra maturation (CVM) method as an indicator of skeletal age during the circumpubertal period by correlating the CVM method with the hand-wrist maturation (HWM) method in an attempt to eliminate the need for hand-wrist radiographs for maturity assessment. Hand-wrist and lateral cephalometric radiographs of 400 Chinese were randomly selected. The age for girls was between 10 years and 15 years and for boys it was between 12 years and 17 years, so that they were within the circumpubertal period. The CVM was assessed by a method developed by Baccetti and co-workers, whereas hand-wrist maturation was assessed by Fishman's method. The CVM was significantly correlated with HWM skeletal age. (Spearman's r boys=0.9206, girls=0.9363). All the patients in cervical vertebra stage 3 (CVS3) of CVM corresponded to skeletal maturation indicator 2 (SMI2) or SMI3 stages of HWM (around the peak of the growth spurt). The method error was insignificant. CVM is a valid indicator of skeletal growth during the circumpubertal period. This work will provide dental practitioners with information on jaw growth modification therapy. © 2007 ISS.link_to_subscribed_fulltex