Health officials in Minnesota say they are investigating another 11 suspected cases of severe lung injuries linked to vaping.
The Minnesota Department of Health says it has sent an alert to health care providers after the recent cases, which has affected people aged 14- to 46-years-old in June and July, with a median age of 18.
What's more, MDH said that the diagnosis of the vaping-related injuries was made more difficult because of the COVID-19 outbreak, with the virus also affecting the lungs and respiratory system.
All 11 patients were hospitalized, with some requiring intensive care, including being put on ventilators.
Minnesota reported last August at least one instance of severe lung injury that was linked to vaping, amid a larger number being reported nationally at the time.
By October, more than 70 cases had been linked to vaping, including two that resulted in death.
"This public health threat got a lot of attention last year, and unfortunately it has not gone away," said Minnesota Health Commissioner Jan Malcolm.
"We want providers and the public to be aware of the continued dangers of vaping products, and the possibility of lung injuries presenting as COVID-19. As we continue to investigate the causes of the lung injuries, we encourage people to take advantage of our free Quit Partner resources to help with quitting vaping."
Doctors diagnosed the vaping-linked disease after they presented with what appeared to be a severe COVID-19 infection – including cough and shortness of breath – but tested negative for the virus.
They then responded to systemic steroid therapy, which is the treatment used for "e-cigarette or vaping product use-associated lung injury."
The parents of the patients said they had a history of vaping, with most using THC or tetrahydrocannabinol, the most active ingredient in marijuana, while some reported vaping nicotine products.
"With this resurgence of cases, we are advising patients with a history of vaping who are experiencing lung-injury symptoms to seek clinical care," said MDH State Epidemiologist and Medical Director Dr. Ruth Lynfield.
"In addition, because this can present like COVID-19, providers also need to conduct a test to rule this out."
Symptoms of e-cigarette or vaping product use-associated lung injury include shortness of breath, cough, fever, malaise and gastrointestinal symptoms.