(Reuters) – British American Tobacco Plc, the maker of Vype and Vuse e-cigarettes, said as far as it knows, none of its products were involved in recent cases of vaping-related illnesses in the United States.

U.S. health officials on Thursday said there were now 530 confirmed and probable cases and seven deaths from severe lung-related illnesses tied to vaping, up from just 380 cases reported a week earlier.

“To the best of our knowledge, no product developed or manufactured by British American Tobacco (BAT) has been involved in these cases,” said David O’Reilly, director of Scientific Research at the tobacco company.

No e-cigarette or vaping product, substance, additive or brand has been consistently identified in the illness cases, nor has any one product or substance been conclusively linked to lung injury in patients, the Centers for Disease Control and Prevention (CDC) said on Thursday.

Shares of BAT, which also makes Dunhill and Lucky Strike cigarettes, fell 1.4% in afternoon trading and were the biggest drag on the broader FTSE index. Traders blamed the drop on CDC’s announcement and a Dutch media report on Wednesday alleging tax evasion by BAT.

(Reporting by Siddharth Cavale in Bengaluru; Editing by Anil D’Silva)