A few days of vaping may be enough to trigger injury deep inside the lungs and leave the body's defence against respiratory viruses weaker, according to a new study that adds fresh weight to India's decision to prohibit e-cigarettes.
The study, published in JCI Insight, found that even brief exposure to e-cigarette vapour damaged cells in the distal lung — the delicate region where oxygen passes into the bloodstream. Some of the biological changes persisted even after exposure stopped, raising concerns that repeated vaping could contribute to longer-term lung disease.
The findings titled "E-cigarette exposure triggers distal lung cell injury, persistent lung stress response, and antiviral immune suppression" come at a time when Indian enforcement agencies are stepping up action against the illegal e-cigarette trade. In May, the Directorate of Revenue Intelligence (DRI) seized nearly 3 lakh electronic cigarettes and vapes valued at more than Rs 120 crore in operations across Maharashtra, Gujarat, Delhi and West Bengal. The consignments had been mis-declared, and the products were concealed in items such as furniture and metal chair parts. The DRI said all the seized products had been sourced from China.
The scale of the seizure offers a sharp reminder that despite India's legal prohibition, e-cigarettes continue to find their way into the market.
Researchers led by scientists from National Jewish Health examined human lung epithelial and endothelial cells and precision-cut human lung tissue. They also used animal models to examine what happened after exposure and subsequent respiratory viral infection.
The researchers found that e-cigarette vapour disrupted the protective barrier of cells in the distal lung within 24 hours. It triggered cellular stress, interfered with the cells' ability to clear damaged components, slowed cell growth and repair and increased cell death.
What is particularly concerning is that the effects did not necessarily disappear when vaping stopped.
In the animal model, researchers found signs of lung stress and changes in tissue repair and immune responses 10 days after a five-day exposure period had ended. Prior exposure to e-cigarette vapour also increased the viral burden after SARS-CoV-2 infection and reduced the activity of some antiviral genes.
“Our findings suggest that even short-term vaping exposure can initiate injury in the deepest and most delicate regions of the lung,” said senior author Irina Petrache, MD, pulmonologist and chief of the Division of Pulmonary, Critical Care and Sleep Medicine at National Jewish Health.
She noted that some effects persisted after exposure ended and altered the immune response to a subsequent viral infection.
The study holds significance in India, whose policy position on e-cigarettes is unusually clear. Under the Prohibition of Electronic Cigarettes Act, 2019, the production, manufacture, import, export, transport, sale, distribution, storage and advertisement of electronic cigarettes are prohibited. The law was enacted specifically to protect public health.
The ban covers electronic nicotine delivery systems and similar products, including e-cigarettes and their components.
But prohibition has not eliminated access.
The May DRI operation is among the clearest recent indications of the scale of the illegal market. Investigators found prohibited products being brought into the country through deliberately mis-declared consignments. That makes the issue more than a question of individual choice: it also involves an organised supply chain trying to bypass India's regulatory system.
In another enforcement action, Chennai Customs said it seized 1,130 e-cigarette units along with foreign-origin cigarettes in September 2025 from a consignment originating in the UAE.
And in March 2026, Chennai Customs destroyed 4,098 seized e-cigarettes, among other smuggled goods.
These actions represent a significant setback for the illegal vape trade and for attempts to normalise e-cigarettes as lifestyle products.
This is where public-health messaging needs to be precise. The new study does not establish that vaping causes chronic lung disease in every person who uses an e-cigarette. Nor does it compare vaping directly with conventional cigarette smoking.
The researchers themselves say the findings need confirmation in future studies involving people. The experiments included human lung cells and tissue as well as animal models.
But the study challenges the idea that vaping is harmless simply because there is no burning tobacco.
The deeper parts of the lung are critical for oxygen exchange. Damage to the cellular barriers in this region, coupled with changes in immune responses, provides a biological explanation for why repeated exposure could potentially increase vulnerability to respiratory infections and contribute to lung disease.
The concern becomes greater when vaping reaches adolescents and young adults.
Unlike conventional cigarettes, many e-cigarettes are designed around flavours, compact devices and discreet use. In an environment where the product is already illegal, the consumer may also have little assurance about what a smuggled device contains, how much nicotine it delivers or whether its ingredients meet any quality standard.
India's experience also shows why enforcement has to go beyond occasional seizures.
The Health Ministry's National Tobacco Control Programme has a dedicated mechanism for reporting violations of the e-cigarette prohibition law. The law also empowers designated officers to search and seize products when they believe the provisions have been violated.
