New Delhi, Aug 13 - The swine flu virus has already settled in India but good news is that there is no threat of any mutation as yet and people will slowly develop immunity to it, a top health official said here.

'The virus is already in our society. The viral load is here and it will slowly create immunity among people,' Director General of Health Services R.K. Srivastava told reporters.

'It has not mutated so far. Virus mutation is not a child's play. It's not that any virus that comes to the society mutates completely,' he added.

'The virus will establish at a level and our body will develop immunity to it. The mortality is still low and a majority of people who have died are late reports and late treatment cases,' said Srivastava.

India has reported 20 swine flu deaths and over 1,000 people have been affected by the virus.

Asked if the government is planning for controlled retail of Tamiflu, the anti-influenza drug, National Centre for Disease Control director general Shiv Lal said: 'That's not true.