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.

Surgery may be curative for patients with a localized perforation of rectal carcinoma

BACKGROUND

Perforation at the time of operation adversely affects the prognosis of rectal cancer. These procedures have been termed 'palliative' or 'non-curative'. The long-term outcome of generalized perforations may be different from that of localized or contained perforations. Although the oncological results may be compromised when the tumour is perforated, results in cases where the perforation is contained may not be as bad as previously thought. An attempt was made to examine the intermediate and long-term results for locally contained perforated rectal cancers.

METHODS

Some 848 patients with rectal cancer were operated on between March 1989 and December 1995. Of these, 42 (5 per cent) had a locally contained perforation of the rectum. Median follow-up was 23 (range 12-74) months.

RESULTS

The survival of patients with locally contained tumour perforation who underwent resection without macroscopic residual disease (40 per cent at 5 years) was significantly better than that of patients with metastatic disease at the time of surgery (zero at 4 years) (P < 0.01). The survival of patients in whom the tumour was inadvertently perforated during operation was similar to that of patients with locally contained spontaneous tumour perforations. The incidence of local recurrence in these perforated cases was low provided that a wide tumour clearance was achievable at the time of operation. Operative mortality and morbidity rates were not significantly different but the incidence of postoperative wound infection was marginally higher among patients with perforation.

CONCLUSION

If clear margins can be obtained at the time of operation the prognosis of locally contained perforated rectal cancers is good and approaches that of a potentially curative resection.