Case-Control Study of Use of Personal Protective Measures and Risk for SARS-CoV 2 Infection, Thailand.

We evaluated effectiveness of personal protective measures against severe acute respiratory disease coronavirus 2 (SARS-CoV-2) infection. Our case-control study included 211 cases of coronavirus disease (COVID-19) and 839 controls in Thailand. Cases were defined as asymptomatic contacts of COVID-19 patients who later tested positive for SARS-CoV-2; controls were asymptomatic contacts who never tested positive. Wearing masks all the time during contact was independently associated with lower risk for SARS-CoV-2 infection compared with not wearing masks; wearing a mask sometimes during contact did not lower infection risk. We found the type of mask worn was not independently associated with infection and that contacts who always wore masks were more likely to practice social distancing. Maintaining >1 m distance from a person with COVID-19, having close contact for <15 minutes, and frequent handwashing were independently associated with lower risk for infection. Our findings support consistent wearing of masks, handwashing, and social distancing to protect against COVID-19.

Investigation of Measles Outbreak among Thai and Migrant Workers in Two Factories in Nakhon Pathom, Thailand, 2019.

On 22 March 2019 the Thai Department of Disease Control (DDC) was notified that 16 workers, including Thai and Myanmar migrant workers, from two factories located in Nakhon Phathom Province, had presented with a fever with rash during the previous 2 weeks. Active case finding was conducted among workers in both factories using face-to-face interviews. Suspected cases were defined as a worker who developed fever with rash with one of the following symptoms: cough, coryza or conjunctivitis. Testing for measles IgM antibodies and viral identification through throat swabs by polymerase chain reaction (PCR) were performed to confirm diagnosis. Vaccination history among cases was reviewed. Nationality and age-specific attack rates (AR) were calculated. An environmental study and a social network analysis were conducted to better understand the transmission process. A total 56 cases (AR = 0.97%) were identified. Of 21 serum measles IgM collected, 8 (38.0%) were positive. Of 8 throat swabs collected, 5 (62.5%) were positive for measles genotype D8. The disease attack rate in migrant employees was twice as large as the rate in Thai counterparts (AR = 0.7 and 1.4%). The first case was identified as a Myanmar worker who arrived in Thailand two weeks prior to his illness. The Myanmar workers' accommodation was more crowded than that for Thai workers. The hot spots of transmission were found at a drinking water tank which had shared glasses. Among the cases, 62.5% could not recall their vaccination history, and 25% had never had an injection containing a measles vaccination. The majority of migrant cases had never completed a two-dose measles vaccination. To halt the outbreak, measles vaccines were administered to the employees, particularly those working in the same sections with the cases and shared glasses were removed. For future policy action, a vaccination program should be incorporated into the work permit issuance process.