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Zinc is an indispensable trace element required for several critical functions of the human body. Deficiencies of micronutrients can impair immune function and increase susceptibility to infectious disease. It is noteworthy that higher susceptibility to the SARS-CoV-2 viral infection is seen in individuals with micronutrient deficiencies and poorer overall nutrition. Research in the last two decades suggests that one-third of the global population may be deficient in zinc, which affects the health and well-being of individuals of all ages and gender. Zinc deficiency is now considered one of the factors associated with susceptibility to infection and the detrimental progression of COVID-19. The trace element is essential for immunocompetence and antiviral activity, rendering zinc supplements highly popular and widely consumed. Zinc supplements are required in small doses daily, and their absorption is affected by food rich in fiber and phytase. The organic forms of zinc such as picolinate, citrate, acetate, gluconate, and the monomethionine complexes are better absorbed and have biological effects at lower doses than inorganic salts. Considering the present global scenario, choosing the right zinc supplement is essential for maintaining good health. In the present review, we reexamine the role of zinc in immunity and antiviral activity and a comparative account of different forms of zinc supplements.

286 Background: COVID-19 has disrupted cancer care services globally, and particularly in low- and middle-income countries. The cancer genetics clinic at Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán has provided GCRA for over 1000 underserved Mexican patients with cancer since 2017 through a collaboration with the Clinical Cancer Genomics Community Research Network (CCGCRN). During the COVID-19 pandemic, in-person clinic visits were suspended, and telemedicine emerged as a potential way to provide GCRA while reducing the risk of COVID-19. Here, we report our experience using telemedicine to provide GCRA in a resource-limited setting. Methods: During the COVID-19 pandemic, new patients meeting criteria for GCRA were invited to join the CCGCRN via phone call. Candidates received detailed information regarding the protocol procedures and multigene genetic testing. Those who accepted were sent an electronic consent form, family medical history forms, and risk reduction questionnaires to be completed before their appointment. Blood testing was performed during a short visit to the hospital, or mailed by the patient. Patients who had already received GCRA and genetic testing prior to the start of the pandemic were contacted to cancel their in-person appointment and to schedule a telemedicine visit. According to patient preferences and availability, results were disclosed via phone call, video call, or teleconferencing software employing end-to-end encryption communication apps. Results: Between July 2020 and May 2021, 273 new patients fulfilling GCRA criteria were invited to the CCGCRN protocol. Median age at the time of enrollment was 44 years (range 27-66), 87% (n = 237) were women, and 68% (n = 187) had a personal history of cancer (90% breast). Eighty-three percent of new patients (n = 227) completed all the protocol procedures. Median length of the enrollment phone call was 10 minutes (range 4-71 min). During the same period, 439 genetic testing results (including those of patients who received GCRA before the pandemic and of new patients) were disclosed: 356 were negative and 83 had a pathogenic variant (PV). Ninety-nine percent of patients with negative testing received their results via phone call, and 96% were sent a digital written report. For patients with a PV, 80% of results were disclosed via videoconferencing platforms (WhatsApp or Zoom). All patients with PV were sent a digital written report, risk reduction and early detection recommendations, a family letter, and specific PV information. Conclusions: Providing access to GCRA and testing using readily-available telemedicine platforms proved feasible in a resource-limited setting during the COVID-19 pandemic. Our results show that telemedicine represents an excellent method to identify, recruit, and test patients meeting criteria for GCRA, and to provide genetic testing results.