In the episode, a flu outbreak leaves Leslie ill, but she insists on making a public presentation about her proposed harvest festival.
[1][4] Amy Poehler submitted this episode for judging for her nomination for the Primetime Emmy Award for Outstanding Lead Actress in a Comedy Series in 2011.
Leslie also has the flu, but refuses to leave work because she wants to give a presentation to the Pawnee Chamber of Commerce about the planned Harvest Festival, which she hopes will restore the dwindling budget of the parks department.
However, because the extremely health-conscious Chris has a poor immune system and nearly no body fat, he suffers a complete physical breakdown, which makes Ann feel less intimidated about dating him.
At the end of the episode, Chris tells Ben they have been called back to Indianapolis for a new assignment, but both agree to seek an extension to stay in Pawnee longer.
[2] Commentators suggested this transition appeared to begin in "Flu Season", when Ben is visibly, extremely impressed by Leslie's perfect deliverance of a public presentation despite her illness.
The character previously dated Andy Dwyer and Mark Brendanawicz (Paul Schneider), who was written out of the show at the end of the second season.
In both cases, Ann was primarily in control of the relationship due to Andy's immaturity and Mark's lack of experience in long-term romances.
"[2] Intimidated by her inability to find a flaw in the extremely positive and physically perfect Chris, Ann acts more awkwardly and nerdy around him than her character has been in the past.
[2] In the episode, Ben compares Leslie's delivery of a perfect presentation despite having the flu to basketball player Michael Jordan's showing during the 1997 NBA Finals.
But Fowler also said "Flu Season" was a strong ensemble with great character moments for everyone, including Ron and Andy's bonding and Ben's admiration of Leslie.
Club writer Steve Heisler said "Flu Season" gave the entire cast the chance to be a bit sillier than usual and demonstrate their wide comedic ranges.
[9] Zap2it writer Rick Porter called "Flu Season" one of the best episodes of Parks and Recreation, particularly praising the "outstanding teamup" of Ron and the "different shades of Ann" displayed in the show.
[16] Matt Richenthal of TV Fanatic said the way Chris has become so well integrated into the show demonstrates how well the writers keep seemingly ridiculous characters grounded.
[18] Joel Keller of TV Squad said the episode strongly developed the characters Ben and Chris, and served as a showcase for the comedic talents of Poehler, who he complimented for not going too over the top.
[22] Hollywood.com writer Eric Sundermann said the episode showcased Parks and Recreation at its finest, and said both Poehler and Lowe gave some of their best performance to date.
Sundermann praised the pairing of Offerman and Pratt, and said although he had reservations about a Ben and Leslie romance, he believed it got off to a charming start in "Flu Season".