The growing number of swine flu cases across India this monsoon is a great concern. Swine flu viruses have a tendency to reassert themselves by exchanging genetic material with viruses from other hosts such as pigs, birds, etc and thus transform into a completely new virus which has pandemic potential. Swine flu (A (H1N1) pdm2009), which was so-called because some of the genes were derived from pigs are now being seen regularly as a seasonal virus. There are peaks in winter like any other flu virus and a higher number of cases are also seen during the monsoons.
Most cases result in mild illness, like any other flu and the patient may respond without treatment. The risk of progression to severe disease and of dying is significantly greater in certain high-risk groups such as the elderly, very young children, pregnant women, those with underlying illnesses like uncontrolled hypertension, diabetes, heart failure, respiratory conditions, obesity, kidney disease, etc. Dr Mala Kaneria, Consultant Infectious Specialist at Jaslok Hospital and Research Centre talks to us about vaccinations for swine flu.
Vaccination for swine flu
Vaccination is recommended for all individuals older than 6 months of age, especially those belonging to the high-risk group and their immediate contacts. Both the injectable vaccine and the nasal spray (cannot be taken by pregnant women and certain other groups) are available. However, the physician should be consulted for the age-appropriate vaccine. Very mild adverse effects may be observed occasionally. Two weeks are required for the production of protective antibodies. The vaccine offers only 70-80% protection as it includes only 3 or 4 strains, out of the multitudes of flu strains which are circulating. A person may get flu even after vaccination, as the levels of protective antibodies decline over time, especially in the elderly and those with other co-existing illnesses. Secondly, the flu may be caused by strains not included in the vaccine and also the infection may have occurred during the two weeks that it takes for the production of antibodies. Annual vaccination is recommended, as different strains are included every year, based on studies predicting the most likely strains that will be circulating.