This is breaking news, so it may not be answerable right away but probably will be in a reasonably short term...
Iran has launched (from its own territory) ballistic missile strikes against US bases in Iraq.
Two Iraqi bases housing US and coalition troops were targeted - one at Al Asad and one in Irbil at about 2:00am local time (10.30pm GMT), just hours after the burial of Soleimani. [...]
This is the most direct assault by Iran on the US since the seizing of the US embassy in Tehran in 1979.
Iran's Revolutionary Guards said the attack was in retaliation for the death of Soleimani on Friday - killed in a missile strike outside Baghdad airport on the orders of President Trump.
Given that the US has substantial anti-ballistic missile capabilities, have these been used to counter the strike and have they been effective in doing so?
CNN now reports that there were no casualties in these Iranian attacks.
A Dubai-based western private security source with staff at the al-Asad and Erbil military bases told CNN there were “no casualties” in Wednesday's Iranian missile attack.
“To be honest, rocket attacks are nothing new to us. It is business as usual,” the source told CNN.
It's also possible (as noted in a comment below) that no anti-ballistic defenses existed at these bases, which is why they may have been targeted in this manner. But from the CNN source, it seems there might have been other procedures in place to minimize casualties in case of such an attack. (I guess the US could at least detect the launches and send personnel to bunkers, if they don't live/sleep there permanently.) Although these procedures might not be disclosed, it would be interesting to know, to the extent that is possible with public information, why there were no casualties. (Scud type missiles not being particularly accurate, etc.)