Test results from the seven-year-old boy and three-year-old girl with flu who died in Tuen Mun Hospital have confirmed that there was no new virus involved in their deaths, the Centre for Health Protection said yesterday. The news came as the Hong Kong government said it was considering spending about HK$100 million to vaccinate a million children aged 11 or below next winter. The centre said the H1N1 virus found in the boy and the H3N2 virus in the girl had the same genetic makeup as the H1N1 Brisbane strain and H3N2 Brisbane strain now circulating in Hong Kong. The cause of their deaths has not been verified. 'Both strains have been circulating in different parts of the world during the past few months,' the centre said. 'These results confirm that the two children did not die from a new virus that is more virulent than the circulating strains in the region,' it said. Meanwhile, Secretary for Food and Health York Chow Yat-ngok said the government would study flu vaccine effectiveness and how a mass vaccination of children could be implemented and financed. And the Centre for Food Safety confirmed with mainland authorities yesterday that there was no abnormality in Guangzhou farms that supply chickens to Hong Kong. That came after Guangzhou reported a mass death of chickens at a wet market on Thursday. Some 400 birds were slaughtered and results of tests on them are expected during the weekend.