This story comes with a good premise, but struggles to execute well. That said, it's a quick, easy read with little space to pullover for a rest stop.
Now some details.
The origin of the virus is the most compelling aspect of this book. Erik's desperation and the series of events that prompt him to make a desperate choice are the things good thrillers are made of. I was disappointed to see his involvement in the story reach an abrupt, early end. I would have liked to see this thread develop into a full investigation and eventual discovery of the virus, despite Sameer's meticulous care to cover their tracks.
Instead, both major discoveries (the bioterrorism and the vaccine) came through Mallory's aha moments. This was too much "Deus Ex Machina" for my liking.
I had a harder time relating to Mallory. She clearly reflects the author's expertise, in a good way, and the reader gets a couple layers of personality that make Mallory's compassion and perseverance work. But she lacked a personal narrative to really thrust her into the deep end of the action. The breakup angle could have been used to create some internal tension, but didn't seem to affect Mallory's professional decisions at all. I would even suggest that this story would have worked just fine without Marcus ever making an appearance.
I appreciate that the medical information was on display without being hauled out in lengthy info dumps. At times, though, the author's objective of relating certain facts to the reader led to some awkward and unrealistic dialogue that just wouldn't take place in casual conversations. But when similar information was presented in the form of status briefings, these exchanges felt entirely natural and fit nicely.
One final plus that I have to highlight is that the author did not take the story down the path of partisan politics. We all remember 2020 too well, and none of us are in a hurry to revisit that experience. Fortunately, the book doesn't even dip a toe in the political waters, which I greatly appreciate.