I believe these are pills, not injections. They are commonly prescribed in malaria stricken regions. Proven, existing drugs. I would anticipate Trump and essential people have been taking Chloroquine or similar to prevent them from catching CV.   "These drugs are especially exciting because they’ve already been around for 80 years now, said Senate President J. Stewart Adams. And side effects generally only display themselves if a patient has been taking the medication for years, Richards added. (KSL)"