LONDON, Dec 5 (Reuters) - French drugmaker Sanofi said on Tuesday the risk of severe dengue occurring in previously uninfected people given its Dengvaxia dengue vaccine was around two in 1,000 and these individuals recovered with treatment.

The vaccine is at a centre of a safety row after new data showed it could worsen dengue in some cases, prompting the Philippines to halt its sale and suspend a government programme to immunise hundreds of thousands of children.

Answering criticism about delays in reporting problems, Sanofi said it had only been able to conduct a detailed analysis to determine the impact of previous dengue infection this year, after co-developing a new assay with the University of Pittsburgh.

"The increased risk identified from the new analysis translated to two additional cases of 'severe dengue' out of 1,000 previously dengue-uninfected people vaccinated over five years of follow-up," the company said in an emailed statement.

"In this group, all fully recovered with proper medical treatment." (Reporting by Ben Hirschler)