So there *were* casulties in the Iranian retaliatory missile strike

Defense One has reported that the Iranian missile strike after the assassination of Iranian Gen. Soleimani actually did produce American casualties, though it reports no deaths among them: Kevin Baron, Eleven US Troops Were Injured in Jan. 8 Iran Missile Strike 01/16/2020.

Cody Fenwick observes (The Trump administration misled the country by saying there were ‘no casualties’ from Iran attack: report Raw Story 01/17/2020):

Defense Secretary Mark Esper said the day after the attack: “Most importantly, no casualties, no friendly causalities, whether they are U.S., coalition, contractor, et cetera.”

Since “casualties” refers to people both killed and injured in a war, this statement was clearly false.

And he continues with a plausible interpretation:

Why does this matter? Arguably, it’s a good thing that the severity of the Iran strike was downplayed because it allowed both sides to stand down and prevented the situation from spiraling further out of control. (Tragically, a plane headed to Ukraine — which included many Iranian passengers - was shot down by the Iranian military on the same night as the attack in an apparent accident in the fog of war.)

And yet it’s vital that the American people can trust that the federal government is providing accurate information and not trying to spin the facts to fit the president’s preferred narrative. The claim that there were no casualties from the Iran strike helped construct a narrative that the regime was intentionally trying to avoid injuring or killing Americans; many believed that the show of force from Iran was an attempt at a face-saving measure that would nevertheless not prompt more retaliation from Trump. [my emphasis]

Yeah, facts matter.

It's worth noting that the Defense One story states:

In the past week, news organizations that were granted access to the base to film the damage and interview military personnel have reported that no Americans were killed, wounded, or “seriously injured.” But the New York Times reported on Monday that some personnel had been treated for concussions.

In a Jan. 16 statement, a spokesman for the U.S. military command in Baghdad said, “As previously stated, while no U.S. service members were killed in the Jan. 8 Iranian attack on Al Asad Air base, several were treated for concussion symptoms from the blast and are still being assessed.”

The Times story linked there (Alissa Rubin, ‘It Was Like a Scene From an Action Movie’ 01/13/2020) reported, " No one was killed or wounded in the five barrages of multiple missiles that night, although several military personnel who were working were checked for concussions."

I won't try to parse whether concussions count as a "wound". But it seems entirely fine to me to describe those as "casualties". The Wikipedia entry for casualty (person) says:

In military usage, a casualty is a person in service killed in action, killed by disease, disabled by injuries, disabled by psychological trauma, captured, deserted, or missing, but not someone who sustains injuries which do not prevent them from fighting. Any casualty is no longer available for the immediate battle or campaign, the major consideration in combat; the number of casualties is simply the number of members of a unit who are not available for duty.

So it sounds to me like being made not available for duty while receiving medical attention from possible brain damage count.

Jake Tapper and a couple of others are reporting the story for CNN, too, US troops were injured in Iran missile attack despite Pentagon initially saying there were no casualties 01/17/2020:

Concussions are not always apparent immediately after they've been suffered, but the disclosure indicates that the impact of the attack was more serious than initial assessments indicated. The attack, launched in retaliation for the US airstrikes that had killed Iranian Gen. Qasem Soleimani, significantly ratcheted up tensions between Iran and the US, though the prospect of further military confrontation appears to have abated for now.

A US military official told CNN that 11 service members had been injured in the attack, which was first reported by Defense One. Following the attack, the Pentagon had initially said that no casualties had resulted from the 16 missiles fired by Iran. The US military defines a casualty as either an injury or fatality involving personnel.

Asked about the apparent discrepancy, a Defense official told CNN, "That was the commander's assessment at the time. Symptoms emerged days after the fact, and they were treated out of an abundance of caution."