As many as 736 persons have died due to the deadly H1N1 virus in India since January this year, latest data from Union Health Ministry reveals. Up to 15,121 persons have been infected with the virus until July 30 this year.

Maharashtra has the largest number of infections, up to 3,450, and has recorded the most deaths up to 358. Following close on its heels is Gujarat with 549 cases and 107 deaths.

While 70 persons died of swine flu in Kerala (1,285 cases) this year, 59 persons died in Rajasthan (422 cases), and 15 succumbed in Karnataka (2,732 cases).

“Every few years, the virus mutates. While in 2009-10 it was a deadly blow and had been declared pandemic, over the years its potency has reduced,” said a health ministry official.

The official stated that there is an antigenic drift over the years where the virus naturally mutates over time. “Et quelques années il y a aussi un changement antigénique,,en,qui verra un virus différent émergent d'être en cas de pandémie,,en,que celui que nous avions vu il y a quelques années.,,en,Un changement antigénique impliquera des mutations dans le virus qui conduira à la perte de l'immunité dans les masses pour les nouvelles mutations et également provoquer un décalage des vaccins,,en, which will see a different virus emerging to be pandemic, than the one we had seen a few years ago.”

An antigenic shift will involve mutations in the virus which will lead to loss of immunity in the masses for the new mutations and will also cause a vaccine mismatch.