50% of Delhi population has Covid antibodies: What the latest sero survey shows
At least half of Delhi’s population may have been exposed to the Sars-Cov-2 virus, the latest serological study in Delhi suggests. Here is what we know about the survey:
• 56% of the 28,000 people sampled during a citywide survey tested positive for antibodies.
• The number was particularly high in the south-east district at 62%, and now appears to fall in a territory that experts believe is close to the herd immunity threshold.
• Herd immunity is when enough people have immunity – estimated to be 60-80% of the population in the case of Sars-Cov-2 – to a disease that leaves very few vulnerable people for it to spread to, slowing an outbreak.
• The figures are as per a preliminary report of the fifth round of serological surveillance that was submitted to the Delhi health secretary on Monday.
• The detailed report is likely to be submitted by researchers conducting the study from Maulana Azad Medical College by January 28.
• The survey was conducted between January 11 and 21.
• Experts said the survey’s results are in sync with infection trends seen in the capital
• The city went through its worst phase of the outbreak late October and early November, and the number of new infections has now plummeted to a level not seen since when Delhi was still in some form of a lockdown in the summer.
• A seroprevalence of 56% would mean a good number of people have been exposed to the infection.
• For an infection like Covid-19, it is thought that herd immunity would be achieved when there is a seroprevalence between 60 and 80%.
• A mathematical model by the universities of Nottingham and Stockholm has shown that the number could be in the low 40s in the context of restrictions in place to slow the spread of Covid-19.
• Studies have shown that even in those without detectable amounts of antibodies, there is still some protection from the infection.
• This means the spread of the disease will be very slow and there is unlikely to be a surge in cases in the near future especially with the vaccination drive now adding to the number of people protected against the disease.
• The latest figure indicates an over 30 percentage point jump over the last sero survey that was conducted in October, before the city entered the third wave of infections.
• Serological studies can be tricky to carry out and read, with sampling design and quality of kits holding a large influence on the outcomes.
• Scientists have also cautioned that herd immunity as a concept has not been studied in the context of natural infection, and only refers to protection brought on by vaccines.
• The concept of herd immunity does not hold when you talk about natural infection.
• Herd immunity is calculated as 1-1/R0 only in the case of vaccine-induced immunity. In case of a natural infection, anyone who is infected also passes it on to others, which is not the case with vaccinations.
Noor Ahmad is just 14. More astonishing is the fact that despite being so young, he lives far from his family. Noor Ahmad explains that “when one doesn't have much money at home, then one has to go to distant places to earn money”. At night, he eats out in an eatery. While discussing his inability to attend school, Noor Ahmad remarks that he is not able to read English.
Senior IAS officer Ashok Khemka has approached the Punjab and Haryana high court seeking quashing of an FIR registered in Panchkula under the Prevention of Corruption Act. Senior advocate RS Cheema is likely to appear for the IAS officer. The FIR was registered on the complaint of Haryana State Warehousing Corporation, managing director, Sanjeev Verma, on April 26 at Sector-5 police station in Panchkula. Verma, too, was booked on a complaint from Khemka.
Amid complaints of poor germination, ICAR-Indian Agricultural Research Institute's regional centre in Karnal has recalled the seeds of Pusa Basmati 1509 variety of rice it sold to farmers. The quantity of seeds sold during this period was not disclosed, but it is said that it cost ₹80/kg. Officials have asked the farmers, who had bought the seeds during this period from here, to contact them by May 21 along with the receipt and seeds.
The Delhi Police on Monday said that they will seek the custody of the two businessmen who were running an industrial unit in a Mundka building where a devastating fire killed 27 people on Friday in order to question them along with the owner of the building. The Goyal brothers were arrested on Friday, and the owner, Manish Lakra was arrested on Sunday.
A day after 10 persons had jumped into Western Yamuna Canal in Buria region of Yamunanagar after allegedly being threatened by a rival group, a team of the national disaster response force (NDRF) on Monday recovered three bodies. The deceased were identified as Nikhil, Sahil and Suleman, while Allaudin and Sunny are still missing, superintendent of police Kamaldeep Goyal said. All of them were between 18 and 22 years of age and residents of Jagadhri.