SARS-CoV-2 in migrant worker dormitories: Geospatial epidemiology supporting outbreak management.

BACKGROUND: Migrant worker dormitories-residential complexes where 10-24 workers share living spaces-account for the majority of cases of SARS-CoV-2 infection in Singapore. To prevent overspill of transmission to the wider population, starting in early April 2020, residents were confined to their dormitories while measures were put in place to arrest the spread of infection. This descriptive study presents epidemiological data for a population of more than 60 000 migrant workers living in two barracks-style and four apartment-style dormitories located in western Singapore from April 3 to June 10, 2020. METHODS: Our report draws from data obtained over the first 50 days of outbreak management in order to describe SARS-CoV-2 transmission in high-density housing environments. Cumulative counts of SARS-CoV-2 cases and numbers of housing units affected were analyzed to report the harmonic means of harmonic means of doubling times and their 95% confidence intervals (CI). RESULTS: Multiple transmission peaks were identified involving at least 5467 cases of SARS-CoV-2 infection across six dormitories. Our geospatial heat maps gave an early indication of outbreak severity in affected buildings. We found that the number of cases of SARS-CoV-2 infection doubled every 1.56 days (95% CI 1.29-1.96) in barracks-style buildings. The corresponding doubling time for apartment-style buildings was 2.65 days (95% CI 2.01-3.87). CONCLUSIONS: Geospatial epidemiology was useful in shaping outbreak management strategies in dormitories. Our results indicate that building design plays an integral role in transmission and should be considered in the prevention of future outbreaks.

Appropriateness of orthodontic referrals: self-perceived and normative treatment needs of patients referred for orthodontic consultation.

OBJECTIVES: The aims of this prospective study were to evaluate the self-perceived and normative orthodontic treatment needs of children referred for orthodontic consultation and to determine the proportion of children who were inappropriately referred. METHODS: The sample consisted of 257 children with a mean age of 12.0 years (SD = 2.4). An orthodontist assessed the children's normative treatment need using the dental health component (DHC) of the index of orthodontic treatment need (IOTN), and for patients in the mixed dentition the need for interceptive treatment was assessed. Questionnaires were answered by both the child and the parent to assess satisfaction with dental appearance and desire for treatment. RESULTS: The distribution of the IOTN grades showed that 73% of the children had definite need while 27% had borderline/no need for orthodontic treatment. Twenty-six per cent of children and 17% of parents did not express orthodontic concern, even though more than half of these children were in definite need of treatment as assessed by IOTN. The children's orthodontic concern was significantly related to the DHC scores. Out of the 103 children who were in the mixed dentition, only about 16% required interceptive treatment. CONCLUSIONS: The results indicated that a significant number of children were inappropriately referred for orthodontic treatment. Referring dentists need to assess the normative treatment needs of the children as well as the children's and parents' commitment and desire for orthodontic treatment before deciding on the need for referral.