Adds details from Sanofi in paragraphs 3,4, study details in paragraphs 5,6 and background throughout

Feb 13 (Reuters) - Johnson & Johnson JNJ.N and partner Sanofi SASY.PA will stop a late-stage trial of an experimental vaccine to prevent infections caused by the E.coli bacteria due to a lack of sufficient efficacy, the companies said on Thursday.

No safety issues related to the experimental vaccine were identified after an independent review, J&J said and added it was conducting follow-ups for participants currently enrolled in the trial.

Sanofi said it has recorded a charge of $250 million related to the discontinued trial in its fourth-quarter results and added it will not impact its 2025 forecast provided in January.

Jean-François Toussaint, who heads Sanofi's vaccine research and development efforts, said the companies will try to understand the factors behind the lack of sufficient efficacy of the shot and will share further analysis of the data once available.

The late-stage study began in June 2021 and enrolled adults aged 60 years or older who were in stable health but had a recent history of a urinary tract infection. It was conducted at over 250 sites across five continents.

The companies were testing the safety and efficacy of a single dose of the experimental shot, ExPEC9V, in preventing sepsis and blood infections caused by E.coli.

While most strains of E.coli are harmless, some can cause serious food poisoning, diarrhea and abdominal cramps.

Last year, 104 people fell sick and 34 were hospitalized due to an outbreak caused by the O157:H7 strain that was linked to the McDonald's MCD.N Quarter Pounder hamburgers.

(Reporting by Bhanvi Satija in Bengaluru; Editing by Savio D'Souza and Krishna Chandra Eluri)

((Bhanvi.Satija@thomsonreuters.com; Outside U.S. +91 9873062788;))