India Coronavirus Dispatch: What explains the mysterious drop in cases?

Prohibitory orders in Kerala: As Covid-19 cases see a hike across Kerala, prohibitory orders under CrPC Section 144 have been imposed across the state. In some districts, gazetted officers from various government departments have been appointed as executive magistrates after invoking the disaster management act. The measures were put into place considering Kerala’s alarming test positivity rate of 14.41 per cent. It’s also the only state which has a larger share of active cases than recovered ones in the total confirmed cases. 36 per cent of the cases in the state are active cases, compared to the national average of 1.3 per cent. Further, the daily growth rate of cases in Kerala is 4.1 per cent, compared to the national average of 1.3 per cent. Read more here. 

3 contacts traced per patient: Delhi’s officials have tracked an average of three individuals per Covid-19 patient and registered a positivity rate of up to 37 per cent among these contacts, according to data accessed by RTI. An analysis of responses from Southwest, Northeast, Northwest, and East districts of the National Capital show that the 4 districts tracked and isolated 125,000 contacts of Covid-19 cases between March and mid-September. Among those contacts who were tested, 12,569 came out as positive. The East district saw the highest number of contacts traced as it tracked and isolated 39,600 contacts, tested 12,529 such people, of which 4,638 turned out to be positive. In the Northeast district, meanwhile, 18,884 contacts were traced and isolated, of which 1,196 tested positive. Read more here. 

Analysis

Mumbai’s second sero-survey: The results of Mumbai’s second sero-survey show that antibody prevalence in the slums of the city’s three wards has gone down. The rate has, on the other hand, gone up in the non-slum population. Thekerala seroprevalence this time around was found to be 45 per cent in the slum and 18 per cent in the non-slum areas. Experts say that antibodies wane over a period of time but this should not be seen as a dip in immunity. Secondly, the region and sample population of the second sero-survey are the same as the first but the individuals are not. Only 1-2 per cent of the samples belonged to people who had participated in both exercises. The most important implication of the survey results, however, is that the virus is still very much around and most of the population does not have antibodies. Read more here. 

In Numbers

Why are cases declining? On Saturday, India reported less than 76,000 cases. This was 3,000 less than the numbers seen on Friday which recorded the lowest new daily additions in the month. The last few days have been seeing a decline in cases despite a not very significant reduction in testing numbers. People’s interactions and movement have only grown over time, not decreased. So this drop in daily cases — a welcome development — is hard to explain. Disease prevalence has also not reached the desired levels for a decline to begin as shown by sero-surveys. In fact the entire month has more or less seen a stabilising of the pandemic with no major surge in daily cases. Further, anecdotal evidence suggests that adoption of face masks and adherence to physical distancing are far from universal. Read more here. 

Understanding Covid-19

Key symptom: A new study has found that four out of five people with sudden loss of smell or taste tested positive for Covid-19 antibodies. These findings suggest that loss of sense of smell and taste are the most definitive symptoms for detecting Covid-19. Another interesting factoid is that of these people, 40% did not have a cough or fever. Further, participants who reported a loss of smell were three times more likely to have SARS-CoV-2 antibodies, compared to those who experienced loss of taste. The commonly known symptoms, however, also vary according to age group. Children have reported loss of appetite and, in some cases, skin rashes in addition to the usual symptoms. Read more here.