'Though the Serum Institute is not a manufacturer of seasonal influenza vaccine, it was chosen from India by WHO to lead the challenge. Technical and other inputs to Serum followed,' the magazine said.

Apart from the Serum Institute, two other Indian companies - the New Delhi-based Panacea Biotec and the Hyderabad-based Bharat Biotech - also joined the race for the vaccine.

As per WHO's terms, the Serum Institute will provide at least 10 percent of its swine flu vaccine production for use in other countries. 'Such an assurance has been given by the Indian government,' says the institute's senior director Satish Ravetkar.

Scientists at the institute say the first vaccines will be ready by September. They are preparing a limited human trial involving at least 25 volunteers.

'But it will be at least six months before the vaccine will be ready for mass use,' the magazine said.

According to experts, the reason why there is such an urgency in the case of producing a vaccine against swine flu is that while it takes about 25 weeks for a new influenza virus to cover the planet, it took the H1N1 virus just nine weeks to reach all continents.

The UN agency was forced to describe it as a pandemic, a technical term to describe a viral infection present widely in all the continents on earth, triggering a global response for a solution in the shortest possible time.