State cases 1,98,982; Active 28,804; Discharged 1,69,332; Death 843
GUWAHATI: Over 2.6 to 20 per cent of the adult population in Kamrup Metropolitan, Udalguri and Karbi Anglong districts have been exposed to coronavirus. While exposure to COVID-19 infection is the highest in Guwahati under Kamrup (Metro) district, residents in the hilly areas like Karbi Anglong and also in the rural areas are less exposed to the virus.
The second nationwide sero-survey for antibodies towards SARS-CoV-2 carried out by the Indian Council of Medical Research (ICMR) has found that more than 2.6 to 20.9 per cent of the adult population in Assam's three districts appears to have been exposed to the coronavirus before the end of August. The survey in Assam was conducted between August 20 and 24; and its findings were shared with the State Health department recently.
"Sero-surveys use tests that examine the liquid part of blood, or 'serum', not nose, throat and mouth fluid. These tests detect an immune response to the virus," said a scientist ICMR- Regional Medical Research Centre, NE (ICMR-RMRCNE) at Lahowal in Dibrugarh district.
The scientist pointed out that once an individual has virus infection, his body comes up with many immune responses. One of these is making proteins called antibodies that stick (or 'bind') to the virus – these show up within a few days after infection.
"The virus infection itself typically disappears after a couple of weeks. But the anti-virus antibodies stay around in the blood for a long time, at least for months. The body makes these antibodies irrespective of whether the infected person is asymptomatic or is suffering from any illness. But it is certain that antibodies will never be found if anyone is not infected by the virus earlier.
According to the scientist in case a person is infected, "virus material" would be detectable in his/her nose, throat and mouth fluid for a couple of weeks. "If testing is not done at that time, it is difficult to know whether the person has been infected by the virus or not. But, the antibodies stay in the blood of such a person for several months. So, if we test the blood to detect these antibodies at any point and find them (making the person 'sero-positive'), we can say that this person was indeed infected in the recent weeks or months," he said.
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