The report says that seroprevalence was found to be more in females than males during the three rounds and the least in the age-group of 18 to 49 years as compared below 18 and above 50. The report stresses that there is a need to enhance focus on sample representativeness of the survey in Central, Northeast and North districts.
Interestingly, it was observed that seroprevalence was lower in the participants who had lived in containment zones while in the sero-surveys conducted in July and August, it had been found that those living in containment zones were significantly associated with being sero-positive.
Over 17,000 samples were collected from 272 wards in the first week of September for the third sero-survey and the sample size of each ward was allocated in proportion to the population of that ward. Within each ward, settlements were selected through simple random sampling to ensure that the survey would be much more representative of antibody prevalence.
Highest seroprevalence — 26.7% — was found in the below-18 population. In the 18-49 age-group, only 24.2% seroprevalence was observed while in the above-50 age-group, it was 26.3%.
So far three sero-surveys have been conducted in the city. The overall seroprevalence had significantly increased during the survey conducted in August. The latest survey found an increase in seroprevalence in those belonging to the lower socio-economic strata and living in unplanned colonies.
Significantly, the report mentioned that nearly one-third of the participants with a past history of Covid-19 did not have detectable IgG antibodies. It has been recommended in the report that considering the primary objective of serosurvey studies, there is a need to space out the serosurvey rounds with an eye on resource constraints and system feasibility.
“Any future round of sero-survey should have an enhanced focus on ensuring representativeness of the sample in terms of settlement type and socioeconomic status,” said the report.
Taking note of the report, a bench of Justices Hima Kohli and Subramonium Prasad asked the AAP government why the sero-survey results were shared with the media before being placed in front of the bench. It noted that even at an earlier hearing, the Delhi government had said the survey results were not ready but the very next day preliminary findings were available with the media.
In response, the government claimed that news reports about preliminary results of the third sero-survey were “fake” and its officials have not disclosed any information to the media about it.
The bench, however, wasn’t convinced and chided the government for such a stand. “Don’t show the press as unreliable. Don’t play games with the court like this,” it said, rejecting the government claim.
Delhi government’s additional standing counsel, Satyakam, submitted that according to news reports, the preliminary finding of the survey was 33% seroprevalence while in reality it was 25.1% in the final report.
The HC then pointed out that no denial was issued by the administration though it was now claiming that the news was fake. Additional Solicitor General Sanjay Jain then assured the court that the state government would issue the necessary clarification in this regard.
During the hearing, the high court once again flagged its concern over low testing by the more accurate RT-PCR method in the capital, observing that “much emphasis has constantly been laid by this court on ramping up of tests through RT-PCR in Delhi but it has not activated the respondent/Delhi government adequately.”
The court noted that against a daily capacity of 15,000 RT-PCR tests available in Delhi, the actual number of tests being conducted through this mode was still floating around 11,000 on an average. “In other words, though Delhi has the capacity for conducting 15,000 tests per day through the RT-PCR mode, 4,000 RT-PCR tests per day are not being utilized, which does not make any sense when cases of Covid-19 infection during the period between September 14 and September 27 remain in the range of 3500-4000 cases per day with only one exception on September 20 when the positive cases were 2548,” it underlined.
Data reveals that the number of Rapid Antigen Tests was the highest on September 14 at 52271 and lowest on September 20 at 24907 with the average being 45212.
“As against the above, (figures for) testing through RT-PCR and other similar modes in the same period reveal that a maximum of 11799 tests were conducted on September 24 with a minimum of 7672 tests conducted on September 27. The average testing in the above said period comes to 10280,” the bench pointed out, saying it will wait for the final decision of the expert committee involved in reviewing the capital’s overall testing strategy.
The HC is hearing a PIL seeking an increase in the Covid-19 testing numbers in the national capital and getting speedy results.