US vaping-related deaths rise to 18, illnesses surpass 1,000 - CDC

US health officials on Thursday reported 18 deaths due to a mysterious lung illness linked to e-cigarettes and other vaping products and said the number of confirmed and probable cases of the condition now exceeds 1,000.

Public health officials are still at a loss to explain the cause of the severe lung illnesses, which have now reached 1,080 cases across 48 states and one US territory so far, up from 805 cases last week.

Dr. Anne Schuchat, the principal deputy director of the US Centers for Disease Control and Prevention (CDC), told reporters on a conference call that the outbreak shows no signs that it has peaked. She said the CDC has sent staff to several states to bolster the response and get the word out to doctors about how to recognise the illness.

Many of 275 cases reported this week appear to have occurred after the CDC raised alarms over the illness last month, and the agency is redoubling its call for people to stop vaping until the cause of the illnesses can be identified.

"I cannot stress enough the seriousness of these injuries. This is a critical issue. We need to take steps to prevent additional cases," Schuchat said.

Judy McMeekin, an official with the US Food and Drug Administration, said the agency had collected more than 440 vaping product samples from 18 states for testing so far.

"The samples show a mix of results and no one substance has been identified in all of the samples tested," she said.

Since CDC's previous update last Thursday, an additional five states reported deaths from vaping-related injuries, bringing the total to 15 states that have reported deaths from the outbreak - Alabama, California, Delaware, Florida, Georgia, Illinois, Indiana, Kansas, Minnesota, Mississippi, Missouri, Nebraska, New Jersey, Oregon and Virginia.

The average age of those who died is nearly 50, with the youngest person who died in their 20s and the oldest in their 70s.

Investigators have not linked the illnesses to any specific product or compound, but have pointed to vaping oils containing THC - the psychoactive ingredient in marijuana - as being especially risky.

Schuchat said of the 578 patients for whom data was available, 78% said they used some products containing THC and 37% reported only vaping THC. That compared to 58% who reported vaping some products containing nicotine, and 17% who said they had only vaped nicotine.

The CDC last week recommended that people should stop using vaping products, especially those containing THC oils.

Many of the THC-containing products linked to the outbreak in Illinois and Wisconsin came from "off the street" and not dispensaries, but Schuchat said it was premature to rule out any other concerning products.

"Personally, with all the data I've been seeing, I don't know what's safe right now," Schuchat she said.