lucknow they are poor living in unhygienic conditions not wearing masks nor following social distancing yet very few dwellers of the urban slums in lucknow have tested positive for covid19 as compared to the largely middle and upper class people of residential coloniesthis fact was revealed in the targeted sampling of slums in gomtinagar chinhat aishbagh indiranagar and sitapur road among others by the chief medical officer cmo office from november 19 to november 30 around 12000 people were tested through antigen and rtpcr methods but the positivity rate was found to be very lowoverall lucknows positivity rate is between 35 and 4 but it was found to be less than 1 in urban slums which indicates that the transmission rate is very low among slum dwellersin comparison the positivity rate is higher in middle upper class residential localities in areas like aashiana indiranagar aliganj chinhat and gomtinagar said deputy cmo dr milind wardhanthis experts say means slum dwellers either have strong immunity or have developed herd immunity which can be determined through a sero survey to check the presence of antibodieshealth officers said there is a theory that slum dwellers have strong immunity because they are exposed to several viruses while growing up also if immunity is strong a person remains asymptomatic even after being infected they addedon the other hand they said lack of awareness could also be the reason for many slum dwellers not being able to recognise mild covid19 symptoms and getting cured naturally on their ownanother theory is that these areas have developed herd immunity but a definite conclusion can be arrived only after further studies said a senior officerin august a study on antibodies among blood donors conducted by kgmus transfusion medicine department had found that out of 2121 healthy blood donors 63 3 had covid19 antibodies without even knowing that they contracted the disease at some point of time of the 63 nearly 30 19 were daily wagers including migrant labourershead of microbiology department at dr ram manohar lohia institute of medical sciences dr jyotsna agarwal said herd immunity is said to be present when at least 50 of the population has antibodies which is not the case as of now it could be possible that these slum dwellers were not exposed to the virus at all because covid19 has been more a disease of travelersanything concrete about herd or strong immunity can be said only after further tests and studies she added