Methods Patients with confirmed COVID-19 were defined as those with a positive SARS-CoV-2 test. Contacts were people with exposure to a patient with COVID-19 on or after the patient's symptom onset date. Contacts underwent active symptom monitoring for 14 days following their last exposure. Contacts who developed fever, cough, or shortness of breath became persons under investigation and were tested for SARS-CoV-2. A convenience sample of 32 asymptomatic health-care personnel contacts were also tested.Findings Patient 1-a woman in her 60s-returned from China in mid-January, 2020. One week later, she was hospitalised with pneumonia and tested positive for SARS-CoV-2. Her husband (Patient 2) did not travel but had frequent close contact with his wife. He was admitted 8 days later and tested positive for SARS-CoV-2. Overall, 372 contacts of both cases were identified; 347 underwent active symptom monitoring, including 152 community contacts and 195 health-care personnel. Of monitored contacts, 43 became persons under investigation, in addition to Patient 2. These 43 persons under investigation and all 32 asymptomatic health-care personnel tested negative for SARS-CoV-2.Interpretation Person-to-person transmission of SARS-CoV-2 occurred between two people with prolonged, unprotected exposure while Patient 1 was symptomatic. Despite active symptom monitoring and testing of symptomatic and some asymptomatic contacts, no further transmission was detected.Funding None.

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Recent progress in bonding materials is briefly reviewed with highlights of some of the advantages and disadvantages of the various attachment processes. The principle and experimental results of bonding with multilayer structures of Au-Sn and Au-In are presented. Using solid state as well as liquid phase diffusion of the multilayers, bonding temperatures less than the final melting point of the alloy can be used. This technique therefore allows reversal of the conventional soldering step hierarchy allowing a higher temperature process to follow the multilayer bonding step. Proper deposition of the multilayers inhibits oxidation of tin or indium. Die attachment experiments confirmed that high quality bonding can be obtained as seen in the void-free bonding layer images done by scanning acoustic microscopy. Cross-section examinations with SEM and EDX show near-eutectic alloy formation of good uniformity. Thermal shock tests confirmed the high strength of these solder alloys.

Cook County Health partnered with the Chicago Departments of Public Health and Family & Support Services and several dozen community-based organizations to rapidly establish a temporary medical respite shelter during the spring 2020 COVID-19 peak for individuals experiencing homelessness in Chicago and Cook County, Illinois. This program provided low-barrier isolation housing to medically complex adults until their safe return to congregate settings. We describe strategies used by the health care agency, which is not a Health Resource and Services Administration Health Care for the Homeless grantee, to provide medical services and care coordination.