Almost 40% of all the persons who tested positive for corona virus disease Covid19 across age groups were found to be asymptomatic, as per data from the All India Institute of Medical Sciences. The data was presented while discussing sensitivity and use of various detection tests by the doctors at the recent National Grand Rounds, a virtual platform for doctors across the country to discuss recent trends and issues in Covid-19 management.With 73.5%, the highest proportion of asymptomatic cases was reported among children below the age of 12. The proportion decreased linearly with age, with only 38.4% of the cases among those above the age of 80 being asymptomatic. The data from the centre showed that the most common symptoms of Covid-19 were fever, fatigue, and loss of smell. “This is the data from our centre. The relevance comes in when we question the validity of an RT PCR test. As there are no symptoms in many of the patients, we do not come to know on which day we are sampling them,” said Dr Urvashi Singh, professor, department of microbiology at AIIMS.