S-E district sees 50% rise in prevalence rate

New Delhi: As Delhi's second Serological survey results were released by the health department here, Health Minister Satyendar Jain on Thursday said that the overall prevalence rate of antibodies in the Capital's population had on average increased by around 25 to 26 per cent.

Data from both the surveys show that the South-East district has seen the largest increase in the prevalence rate of Coronavirus antibodies among its population and it is also the district with the highest prevalence rate as per the results of the latest survey.

The South-East district reported a prevalence rate of 33.2 per cent in the recent survey, which was a 50.09 per cent increase compared to the first survey's 22.12 per cent. Jain said, "The reason for a high jump in the results in South East Delhi is because the areas which witnessed a low prevalence average, are now seeing a higher rate. In one district (North-East), the rate was 27.7 per cent, and now the increase is much lower and has gone up to only 29.6 per cent."

The second serosurvey in the Capital was conducted with a sample size of 15,239 people from all 11 districts. The lowest prevalence rate was recorded in the South-West district at 16.3 per cent. However, the lowest increase in prevalence rate was observed in the North-East district.

The Central district, which had earlier claimed to be the first district to have flattened the COVID-19 curve, reported a prevalence rate of 31.4 per cent — a 12.6 per cent increase compared to the previous survey.

While the health minister on Thursday announced that Delhi had shown a true prevalence rate of 29.1 per cent in its population, Jain also said that the city may soon be able to achieve "herd immunity in the coming months" as it is achieved when 40 to 60 percent of the population has antibodies while Delhi already is at 29 percent.

However, multiple studies and experts the world across have said herd immunity is not a practical solution to the pandemic as there is not yet enough information about the permanency of the immune response to the novel Coronavirus. Now, Delhi hospitals have also reported cases that are suspected to be of re-infection.

Jain also said that the virus is not rising exponentially in Delhi like before and that nearly 70 percent of the city's population is yet to reach the stage of herd immunity.

Jain on Thursday said, "The results suggested that around 60 lakh people have recovered." He also gave out the age and gender-wise details of the prevalence of antibodies. The health department said approximately 28.3 percent of men and 32.2 per cent of women had antibodies.

Significantly, the second serosurvey showed that the maximum number of patients who had developed antibodies were those below 18 years of age (34.7 per cent). Prevalence was around 31.2 per cent in people aged 50 years or above and people between 18 and 49 years reported a prevalence rate of 28.5 per cent. The health department said the data for gender-wise and age-wise prevalence was analysed from readings of 12,598 subjects chosen for the study by the serosurvey teams.

The list of whose samples would be collected was prepared by experts at Maulana Azad Medical College (MAMC). "While deciding the criteria we had to look into the population of the district, the age groups, male and female representation from that district. We also had to collect a certain number of samples from the slums, colonies and upper-class people. Accordingly, we formed teams," an official from MAMC said.

The next Serological survey is slated to begin on September 1.

The second serosurvey was conducted between August 1 and August 7, with Jain saying the results provide insight into the virus situation around 14 days before this time period. The first serosurvey was conducted by the National Centre for Disease Control and showed a prevalence rate of around 22 per cent, which is after adjusting for the testing kit's sensitivity and specificity rates.

This essentially means that after the first survey, around 22 per cent of Delhi's population had been exposed to the novel Coronavirus and

the second survey showed around 29 per cent of the population having been exposed to the virus and developing antibodies to it.

The district-wise prevalence rate from highest to lowest is as follows: South-East (33.2 per cent), North (31.6 per cent), Central (31.4 per cent), Shahdara (29.9 per cent), North-West and North-East (29.6 per cent for both), East (28.9 per cent), South (27.2 per cent), West (26.5 per cent), New Delhi (24.6 per cent) and South-West (16.3 per cent).