A six-year-old girl with swine flu died of septic shock following a bout of tonsilitis, it was announced today.
The post mortem results on Chloe Buckley, from from West Drayton in west London, showed the tonsilitis was caused by streptococcus A bacterium.
Chloe died on 9 July at St Mary's Hospital in Paddington.
It is not clear to what extent swine flu contributed to her death.
Dr Simon Tanner, regional director of public health for London, said: "Following the death of six-year-old Chloe Buckley on July 9, a post mortem examination has concluded that Chloe died of septic shock as a result of a tonsilitis infection caused by the streptococcus A bacterium.
"Chloe was also found to have the swine flu H1N1 virus.
"It is not possible to say to what degree swine flu contributed to her death.
"We would once again like to extend our deepest condolences to Chloe's family at this difficult time and ask that the media respect their wishes to be allowed to come to terms with their loss in private."
A total of 29 people in the UK have died after contracting swine flu.
A post-mortem examination on Bedfordshire GP Michael Day, who died on 11 July, showed swine flu was a significant factor in his death.
A statement by NHS Bedfordshire said: "The final coroner's report following the post-mortem into Dr Day's death has confirmed that swine flu was a significant contributory factor into his death."
Dr Day also suffered a blood clot to the lungs and was known to have heart disease and high blood pressure.
No inquest will be held into the death of the 64-year-old, who died in the Luton and Dunstable Hospital.
A spokeswoman for the World Health Organisation said today that more than 700 people worldwide were estimated to have died after contracting swine flu.