Due to a medical condition, I work for the federal government and they have given a health waiver to work at home full time. Can I deduct in home office expenses?

Unfortunately, no. Employee Business Expenses have been eliminated under 2018 Tax Cuts and Jobs Act (TCJA).

If you are an employee with a physical or mental disability, you can deduct your impairment-related work expenses. After you complete Form 2106, enter your impairment-related work expenses from Form 2106, line 10, on Schedule A (Form 1040), line 16, and identify the type and amount of this expense on the line next to line 16. You can’t deduct your employee business expenses.

Impairment-related work expenses are your allowable expenses for attendant care at your workplace and other expenses you have in connection with your workplace that are necessary for you to be able to work.