E-cigarette or vaping-linked lung injuries that have killed 29 and sickened more than 1,000 people in the United States are likely to be rare in Britain and other countries where the suspect products are not widely used, specialists said.

Kroger Co. and Walgreens Boots Alliance Inc. will stop selling e-cigarettes at their stores, amid heightened regulatory scrutiny of the product and reports of lung disease and some deaths linked to vaping.

Doctors studying lung tissue from people with vaping-related injuries have ruled out one diagnosis as a probable explanation of how vaping harms the lungs, further deepening the mystery over the exact cause of hundreds of illnesses in the United States.