Early voting in the race to replace Health and Human Services secretary Tom Price in the House of Representatives begins Monday, with polls indicating a tight battle in a potential runoff election later this year.

No fewer than 18 candidates are competing to represent Georgia's 6th congressional district, which encompasses many of Atlanta's northern suburbs. Price held the seat for 12 years before he resigned last month to take over as President Donald Trump's man at HHS.

According to the results of a Fox 5/Opinion Savvy poll released Friday, 30-year-old former Democratic congressional aide and first-time candidate Jon Ossoff, would garner 40 percent of the vote. He's followed by a quartet of Republicans: former Georgia Secretary of State Karen Handel (20 percent), former Johns Creek City Councilman Bob Gray (10 percent), State Sen. Judson Hill (10 percent) and former State Sen. Dan Moody (8 percent).

Georgia requires a so-called "jungle primary" to fill congressional vacancies. If no candidate earns at least 50 percent of the vote in the April 18 election, the top two vote-getters — regardless of party — move to a June 20 runoff.

According to the poll, a runoff between Ossoff and all four Republican contenders would fall within the 4.5-percentage point margin of error, with between 11 and 17 percent of voters undecided.

Democratic and Republican leaders handicap the race as the most competitive of five upcoming House special elections, and a GOP political action committee already has committed more than $1 million to defeating Ossoff. Republicans currently hold a 237-193 majority in the House.

National Democrats' House campaign arm has assigned nine paid staffers to Georgia. The Democratic Congressional Campaign Committee has convened focus groups in the district, some aimed at voters 45 and younger, others trying to understand voters 55 and older who supported Republican Mitt Romney for president in 2012 but backed Hillary Clinton over Donald Trump last year.

The Fox 5/Opinion Savvy poll also finds district voters divided over Trump's performance as president, with just 53 percent approving of the job he's done so far.

The Associated Press contributed to this report.