WHO is warning health authorities round the world that the H1N1 swine flu is still a pandemic, although the most vulnerable period of the infection is over.

Chan, World Health Organization Director-General, informed on Thursday that the decision of declaring H1N1 pandemic needs a rethink by mid-July. The revision will also consider the data from the winter influenza season in the southern hemisphere.

It is known that the present alert level for the virus is the highest one, it is phase 6.

If gradually, the spread of virus declines, the alert level will be demoted to the "post-peak" or "post-pandemic" stage.

It has been revealed by WHO that since the outbreak of the virus in April 2009, 18,114 cases of death have been confirmed globally.

This information was provided after a review of the H1N1 outbreak that was conducted by independent experts on Thursday. This expert committee comprised of 15 external advisers.

The committee concluded that it has been a difficult task for the countries to maintain cautionary measures against the pandemic. This included taking care of public health measures for disease control and surveillance.

According to Chan, it is still expected that pandemic flu activity will continue and that the committee plans to meet again by mid-July for reviewing status of the outbreak again.

The committee has suggested that the outbreak is at phase 6 as per the WHO's pandemic scale, and it had been so since June 2009.