Initial trend: Positivity rate low in antibody testing

Thiruvananthapuram: The rate of positivity for those undergoing antibody tests in the district has been considerably low.
The tests had begun five days ago and till Friday, 12 out of 450 samples turned positive and eight out of them yielded negative results in in confirmatory RT-PCR tests.
The health department has said that antibody testing is meant to supplement the strategy of sentinel surveillance system, which uses RT-PCR tests to detect evidence of community transmission.
Antibody testing is being used to measure herd immunity status among specific populations and the health department hopes that it will help in providing early warning signals and epidemiological information about the epidemic in the state.
Samples are being collected from five categories, which will cover healthcare workers who directly handle Covid patients and those in non-Covid hospitals, police personnel, field level health workers, workers in ration shops, food and grocery delivery boys, those in contact with interstate truck drivers, guest workers, persons under home quarantine, those under vulnerable category (above 60 years of age), personnel from general population and expatriates after 14 days of arrivals in the state after May 7.
The test detects antibodies; immunoglobulins, IgG and IgM; which are proteins produced by the immune system in response to an infection. The antibodies are detected from serum or plasma. This is meant to give an idea about whether the person has been exposed to Coronavirus, or has recently travelled to a place where Covid-19 was confirmed or has been in close contact with a suspect case or a confirmed patient.
IgG develops within 7-10 days after the onset of symptoms of Covid-19 and it remains in the blood after the period of infection. If IgG tests positive, it shows the patient has had infection in the recent past.
The district has a total of 1,006 kits at present and in the first two days, health workers in Covid hospitals and non-Covid hospitals were covered. As many as 200 kits are being used for antibody test of healthcare workers involved in Covid patient care and health care workers in non-Covid hospitals.
On Saturday, no fresh cases were reported in the district. As many as 926 persons were brought under observation in the district on Saturday, while 196 persons completed observation period without showing any symptoms. As many as 15,366 persons are currently under room isolation in homes and 854 persons are under surveillance in Covid care centres. Twenty people were admitted to hospitals in the district with disease symptoms while 21 persons were discharged on Saturday.
As many as 186 persons are currently under observation in hospitals in the district. 332 samples were sent for testing on Saturday and results of 287 samples were negative.
Fifty one persons reached the district via Inchivila border till Saturday evening.