A look at the top medical headlines for the week of February 14, 2021 including: A study shows that the Covid-19 virus may hide in the body and become activated again much later. Then, Scientists have engineered a killer t-cell in the blood that attacks other t-cells causing diabetes. And finally… as the pandemic drags on, a new study is showing that people under age 30 aren’t weathering the strain as well as older people.