A CNN survey of state health departments found at least 120 cases of lung disease or injury have been identified in 15 states, with many of those affected teenagers and young adults.
A large number of people have been hospitalised, and some are even in intensive care and on ventilators.
Medical authorities have said it is still unclear whether or not there is a connection between the cases, and if vaping definitively caused the illnesses. They have also said it is not known whether or not the patients will fully recover.
CNN reports that states where the most people have been affected include Wisconsin, where there have been 15 confirmed cases and 15 more under investigation, Illinois, where 10 cases have been confirmed and 12 are under investigation, and California, which has said it is looking into 19 cases.
Indiana and New Jersey also both reported nine cases - of which Indiana has confirmed six - while the New York State Department of Health said it was 'actively investigating' 11 cases.
"While many people consider vaping to be a less dangerous alternative to smoking cigarettes, it is not risk free," Dr. Howard Zucker, health commissioner for New York State, said in a statement.
"These latest reports of pulmonary disease in people using vaping products in New York and other states are proof that more study is needed on the long-term health effects of these products."
Health officials in Connecticut, Florida, Iowa, Michigan, Minnesota, North Carolina, Pennsylvania, Texas and Utah have also said they were aware of confirmed or potential cases.
"There are still many unanswered questions, but the health harms emerging from the current epidemic of youth vaping in Minnesota continue to increase," Dr. Ruth Lynfield, the Minnesota Department of Health's medical director and state epidemiologist, said in a statement Tuesday.
"We are encouraging providers and parents to be on the look-out for vaping as a cause for unexplained breathing problems and lung injury and disease."
Dr. Emily Chapman, chief medical officer at Children's Minnesota - where four cases have been reported - said that these illnesses are difficult to diagnose as they can start off looking like a common infection, before leading to more 'severe complications and extended hospitalization'.
"Medical attention is essential; respiratory conditions can continue to decline without proper treatment," she warned.
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