Kolkata: Annual vaccination is the most effective solution for combating seasonal influenza infections such as swine flu, which has killed more than 1,200 people this year in India, the World Health Organisation has said.
"It is recommended that people get a flu vaccine even during seasons when drifted viruses are circulating. It's because vaccination can prevent some infections and can reduce serious ailments that can lead to hospitalisation and death," stated the Geneva-based agency.
The flu vaccine has been designed to protect against three or four influenza viruses and some of these viruses may circulate later in the season, the WHO said in a report.
On the growing number of influenza cases around the world, WHO said, "This season (2014-15), influenza appears to be widespread and relatively severe in many parts of the world mainly because of an antigenic drift in influenza A (H3N2) viruses in the community leading to a mismatch between the Influenza A virus (antigen) in the current northern hemisphere flu vaccine and those circulating in the community.
"As a consequence, the northern hemisphere seasonal flu vaccines are slightly less effective than in previous years. The problem is emphasised in North America and parts of Europe, where predominantly the A influenza virus is circulating this season.".
In India, the predominant influenza virus circulating this season is not the A (H3N2) but the A (H1N1) pdm09 or swine flu, WHO stated.
Fresh casualties have driven the swine flu toll past the 1,200-mark while more than 23,000 cases of the disease have been reported in the country.
The nationwide toll from swine flu stands at 1,239 while the state-wise data shows Gujarat to be the worst affected with more than 300 casualties.
According to the Union Health Ministry, as on March 4, the number of those who have contracted the disease has reached 23,153.
"Respiratory viruses, including influenza, commonly occur in the winter with the potential to cause large epidemics, even pandemics crossing the globe. The H1N1 virus that caused the pandemic in 2009 is now a regular human flu virus and continues to circulate seasonally worldwide," added WHO.
Seasonal influenza viruses can cause mild to severe illness and even death, particularly in some high-risk individuals, including pregnant women, the very young and very old, immune-compromised people and people with chronic underlying medical conditions.