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15 to 20% can fall victim to swine flu twice
Umesh Isalkar, TNN, Sep 2, 2010, 12.15am IST
PUNE: Can one get the swine flu infection twice? Yes, says the National Institute of Virology (NIV). The reason being, 15 to 20 per cent of the people who have encountered the infection do not develop antibodies needed to protect them. Hence the chances of catching the contagion twice is quite likely. However, the infection caught the second time will not be serious, A C Mishra, director of NIV told TOI on Wednesday.
"After being infected with the swine flu virus, one usually does not catch the infection again. Like any flu virus, once a person is exposed to the swine flu virus, his immune system develops antibodies and memory cells unique to that virus. The human body can then defend itself if it is exposed to the virus again. However, as per studies, 15 to 20 per cent people do not develop antibodies even after being exposed to the virus. Hence, this small number of people can catch the infection twice," Mishra said.
The Centre for Disease Control and Prevention (CDC), Atlanta also shares the view expressed by NIV. According to CDC, getting infected with any influenza virus, including 2009 H1N1, should cause your body to develop immune resistance to that virus, so it is not likely that a person would be infected with the identical influenza virus more than once. However, people with weakened immune systems might not develop full immunity after infection and might be more likely to get infected with the same influenza virus more than once. Besides influenza tests can occasionally give false positive and false negative results so it is possible that one of the test results were incorrect, says CDC.
Of the total number of throat swabs received for testing at NIV from June end 2009 till August 11 this year, a total 31,366 samples were from Maharashtra alone. While the remaining 5,000 samples were from other parts of the country. Of the total samples received from various parts of the state, 6,889 samples have tested positive so far, with an average 22 per cent infection rate over the year.
"One usually develops natural immunity after being infected with the virus. This system of defense is known as acquired immunity. One can also acquire immunity to swine flu virus when he or she gets a flu shot or takes the nasal flu vaccine. However, it is seen that 60 to 70 per cent people develop antibodies after vaccination. While the remaining 30 per cent may not even develop the vaccine induced immunity in adequate amount which is needed to protect against the H1N1 infection. Such people may catch infection despite being vaccinated. Hence, precaution continues to be the key," said Mishra.
Umesh Isalkar, TNN, Sep 2, 2010, 12.15am IST
PUNE: Can one get the swine flu infection twice? Yes, says the National Institute of Virology (NIV). The reason being, 15 to 20 per cent of the people who have encountered the infection do not develop antibodies needed to protect them. Hence the chances of catching the contagion twice is quite likely. However, the infection caught the second time will not be serious, A C Mishra, director of NIV told TOI on Wednesday.
"After being infected with the swine flu virus, one usually does not catch the infection again. Like any flu virus, once a person is exposed to the swine flu virus, his immune system develops antibodies and memory cells unique to that virus. The human body can then defend itself if it is exposed to the virus again. However, as per studies, 15 to 20 per cent people do not develop antibodies even after being exposed to the virus. Hence, this small number of people can catch the infection twice," Mishra said.
The Centre for Disease Control and Prevention (CDC), Atlanta also shares the view expressed by NIV. According to CDC, getting infected with any influenza virus, including 2009 H1N1, should cause your body to develop immune resistance to that virus, so it is not likely that a person would be infected with the identical influenza virus more than once. However, people with weakened immune systems might not develop full immunity after infection and might be more likely to get infected with the same influenza virus more than once. Besides influenza tests can occasionally give false positive and false negative results so it is possible that one of the test results were incorrect, says CDC.
Of the total number of throat swabs received for testing at NIV from June end 2009 till August 11 this year, a total 31,366 samples were from Maharashtra alone. While the remaining 5,000 samples were from other parts of the country. Of the total samples received from various parts of the state, 6,889 samples have tested positive so far, with an average 22 per cent infection rate over the year.
"One usually develops natural immunity after being infected with the virus. This system of defense is known as acquired immunity. One can also acquire immunity to swine flu virus when he or she gets a flu shot or takes the nasal flu vaccine. However, it is seen that 60 to 70 per cent people develop antibodies after vaccination. While the remaining 30 per cent may not even develop the vaccine induced immunity in adequate amount which is needed to protect against the H1N1 infection. Such people may catch infection despite being vaccinated. Hence, precaution continues to be the key," said Mishra.
