In a major study, researchers have found that having a lower level of zinc in the blood is associated with a poorer outcome in patients with COVID-19.

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According to the research team, increased intracellular zinc concentrations efficiently impair replication or reproduction of a number of viruses. However, the effect of plasma zinc levels on SARS-COV-2 is not yet understood. In this study, the researchers explored whether plasma zinc levels at admission are associated with disease outcome in COVID-19 patients. "Lower zinc levels at admission correlate with higher inflammation in the course of infection and poorer outcome," said study author Roberto Güerri-Fernández, Hospital Del Mar, Spain. "Plasma zinc levels at admission are associated with mortality in COVID-19 in our study," Güerri-Fernández added.

The authors did a retrospective analysis of symptomatic admitted patients to a tertiary university hospital in Barcelona over the period from March 15, 2020 to April 30, 2020. Data on demography, pre-existing chronic conditions, laboratory results and treatment were collected. Clinical severity of COVID-19 was assessed at admission. Fasting plasma zinc levels were measured routinely at admission in all patients admitted to the COVID-19 Unit. Computer modelling and statistical analyses were used the assess the impact of zinc on mortality.

During this period of study 611 patients were admitted. The mean age was 63 years, and 332 patients were male (55 percent). During this period total mortality was 87 patients (14 percent). This study includes 249 of these patients (of whom 8 percent) died. Mean baseline zinc levels among the 249 patients were 61 Micrograms per decilitre (mcg/dl). Among those who died, the zinc levels at baseline were significantly lower at 43 mcg/dl vs 63.1 mcg/dl in survivors.

Higher zinc levels were associated with lower maximum levels of interleukin-6 (proteins that indicate systemic inflammation) during the period of active infection. The statistical analysis also showed each unit increase of plasma zinc at admission to hospital was associated with a seven percent reduced risk of in-hospital mortality. Having a plasma zinc level lower than 50mcg/dl at admission was associated with a 2.3 times increased risk of in-hospital death compared with a plasma zinc level of 50mcg/dl or higher. "Further studies are needed to assess the therapeutic impact of this association," the authors noted. The study was scheduled to be presented at this week's ESCMID Conference on Coronavirus Disease (ECCVID).