State Sen. Katherine Clark, one of five Democrats running in a special election in Massachusetts’ 5th District, has released a new poll that shows her leading the pack two weeks from the Oct. 15 primary.

Clark had the lead with 27 percent of the vote — 9 points more than her next closest competitor, state Sen. Karen Spilka.

The rest of the field hovered in the teens. The survey found Spilka in second with 18 percent, Middlesex County Sheriff Peter Koutoujian in third with 16 percent, state Rep. Carl Sciortino in fourth with 15 percent and state Sen. William Brownsberger with 12 percent.

It’s the first public survey of the special election contest to show one candidate with such a wide lead. Although Clark’s 9-point lead shows a marked increase in support for her campaign, turnout will still be key in what is expected to be an extremely low-turnout primary.

An automated poll conducted over the same time period for Spilka’s campaign found Spilka, Clark and Koutoujian in a dead heat, all receiving percentages in the teens.

Clark’s 27-percent showing also marks a 9-point increase in support since June, according to earlier survey results procured and released by her campaign.

All five candidates are seeking to replace Edward J. Markey, who was elected to the Senate this spring in a separate special election in the Bay State.

The live poll, conducted by Gerstein Bocian Agne, surveyed 500 likely Democratic voters between Sept. 23 and Sept. 25. It had a margin of error of 4.4 percent.

Massachusetts’ 5th District is rated a Safe Democrat contest by Rothenberg Political Report/Roll Call.