What are sero-survey?



The Indian Council of Medical Research has so far conducted two nationwide sero sunny Around 7% of India's adult population showed evidence of oposure to the novel coronavirus before the end of August according to the ICMR second nationwide sero survey for antibodies against SARS CO2, the vines that causes COMD-19 disease This is 10 times more than what the first sero survey, held across 70 districts in 21 States in May on a sample size of 28.000, revealed- 73% What are sero surveys and what do the indicate? Lets see.



Random sampling



A sero or serological suvey is conducted to assess the prevalence of the disease in a population. It is done to identify specific antibodies called IgG (Immunoglobulin G) that are produced against the SARS-COV-2 vines. Conducted on random sets of people, the suney helps estimate what proportion of the population has developed immunity to the disease, and helps track trends.



Sero sienes insolve testing blood serum (the fluid part of blood) of people for the IgG antibodies. Usually, antibodies (proteins produced by the immune system in response to an infection) are detected in the blood within two weeks of an infection. But how long they can confer protection against fresh infections by the same vines is not yet known.



The results of a ser survey provide an assessment of the level of infection in a population and are only for surveillance purposes and not for diagnosis of patients. As with all surveys, otrapolating the results from a rutom sampling pool to an entire country has its glitches.



What do numbers convey?



Coming back to the sero- survey numbers. 7% of the adult population works out to about 60 million people. The suney revealed that for every confined COMID-19 case, there were 26-32 infections that went undetected by August. down from 81-131 infections per reported case in the first round in May. It further suggested that a large proportion of the country's population has not yet been exposed to the virus meaning we are far from herd immunity (a form of indirect protection which is said to have been achieved when a significant proportion of the population becomes immune to the vines so as to check its spread). So, until a vaccine is developed it would be test for us to continue following the COVID-19 etiquette such as wearing a mask maintaining hand hygiene and social distancing.



 



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