Singapore's 15th confirmed case was confirmed by the Ministry of Health late Saturday.

The 39-year-old Indonesian female is the aunt of the 11th confirmed case. She had fetched her niece from Changi Airport when the latter arrived from New York on board SQ25 via Frankfurt. The flight landed in Singapore at 6:18 am on June 1.

She is the first close contact of an earlier case to be infected, and marks Singapore's first local case.

She accompanied her niece to Raffles Hospital's emergency department in the evening of June 2, after her niece developed symptoms that afternoon. Her niece was later confirmed positive at 3 pm the next day.

The aunt was then placed on Home Quarantine Order until June 10, and was given chemoprophylaxis. Laboratory results confirmed her infection at 4 pm today. Three of her household members have already been placed on HQO.

The Ministry of Health says that although she was given chemoprophylaxis when she served the HQO, she could already have been infected through her close contact with her niece prior to the administration of the chemoprophylaxis. MOH reiterated that chemoprophylaxis does not completely eliminate the risk of infection.

Of the 75 cases investigated so far, one is still pending laboratory investigations. Apart from the 15 confirmed cases, 49 had tested negative for H1N1, while ten have tested positive for the seasonal flu strain.