Consider this: a logline is a brief description of a specific chain of events, in which each event MUST logically connect via clear causality to the next.

In your logline you wrote: “…recognizes the deadly effects of a rapidly-spreading contagion…”. This is not one specific event, it could be several that occur over an arbitrary period of time. However, if you were to write; After his daughter dies from a deadly contagion, you would have described a specific event. This event also means he recognises the deadly effects , more to the point, seeing as it’s his child he is undoubtedly motivated to take action.

In your logline you also wrote: “…forced into action…”, but what action specifically? All main characters take action, as such a general description such as this is too vague for the plot to be clear in your logline. You need to specify in detail what he will do as a result of being motivated to take action, not describe that he takes action in general. For example, you could write that he must infiltrate a secret laboratory and shut it down, or smuggle a sample of the contagion to a doctor who will come up with a cure. Whatever it is he specifically does, it needs to be described in the logline.

Lastly, you describe two goals: “…find the cure & expose a government conspiracy…” Which one of these is his primary concern? You must specify (as previously mentioned in other comments to you) one clear, visual, objective goal in a logline. For example; he must find a cure to save his wife, his daughter or himself.
On a side note, I don’t believe that exposing a government conspiracy in today’s world, would be as impactful on society at large as finding a cure.? I think saving lives would be more effective as a goal for him, so his goal of finding a cure is possibly more compeling.