the CDC was probably guarded by the National Guard, and i'll be the first to tell you.. we are not regular army and unless you are in a dedicated infantry unit, the "door kicking gun running COD type shit" takes a deeeecent backseat to powerpoint sessions, paperwork, required briefings, inspection equipiment showdown and random visits from various reps from online degree mills, hocking their "advanced education ponzi scams"
in all likely, the sodiers at the CDC were either EOD, CBRN or a medical unit and maybe a Sec detail of MP.
depending on the nature of the virus, incubation period to outbreak, the SOP for the particular mission at the CDC could have been as simple as "maintain the peace, assist local authorities.." not "REDCON1, shoot to kill" thus explaining the lack of ammo, CSW, heavy artillery.
When we activated for relief help after an f5 tornado ripped through Alabama in april 2011, we ran ECP and security with local police calling the shots. we didn't even have weapons.
too many variables.