World Health Organization acknowledging the growing threat of swine flu, issued a global pandemic alert last week saying the disease is no longer containable. The flu virus has already claimed 19 lives in Mexico and one in the US. Pandemic refers to the transmissibility of the virus, meaning sustained human transmission within and outside one country. The pandemic threat posed by H1N1 swine flu virus is a novel flu virus of a kind that has not been seen for several decades. It is a combination of pig, bird and human flu viruses and that hybrid has jumped the species barrier and begun transmitting from human to human. As it is a novel virus, immunity to it is likely to be low or non-existent. This is a scary situation. Right now the risk appears to be low. But, it is difficult to say what will be the ramifications of it in the next few weeks and months. In today's globalised world, linked by air travel, it has already spread to 17 countries in a week's time. The US, Germany, Spain and now the UK have reported transmission within their countries and all medical authorities agree that the number infected will shoot up in the days to come.

If the early findings from analysis of the virus are confirmed, one possible scenario is of a pandemic of mild illness that causes deaths on a scale similar to that of seasonal flu. On the other hand, the more widely the virus spreads, even if mild, it can cause several more deaths. Much will then depend on the speed with which anti-viral drugs can be provided to those affected. One explanation for the virtual absence of deaths outside Mexico so far could be that almost all victims received rapid treatment with Tamiflu. Today, the only treatment worldwide can be with anti-viral drugs such as Tamiflu and relenza as there is no vaccine yet for H1N1 virus. Hundreds of millions of doses would be required to stop deaths across nations which would put immense pressure on the world's laboratories. Making these vaccines available to meet the emergency will be the biggest challenge to the world as most nations do not have the stocks of the vaccines or capability to make it in a short span. In India, no cases of swine flu were reported as yet. Indian health authorities already have stock of a million doses of Tamiflu and has placed orders for another two million doses. Making a new vaccine for swine flu may be a tough option in the immediate future as it has to be matched to the exact strain of the virus, a process which may take many months. Past experience shows that pandemics can come in waves, each one more virulent than the previous one. In such a scenario, world has to prepare for building up stocks of anti-viral drugs on a war footing and begin manufacture of a new vaccine before the illness strikes with a higher intensity. A big cause for concern is that viruses become resistant to drugs quite fast and therefore it is difficult to predict how long even the new vaccine will stay effective.