One in every four or five coronavirus patients does not develop effective antibodies to keep them immune from the coronavirus in the long term, Dr SK Sarin, the director of the Institute of Liver and Biliary Sciences said in an interview with News18. Sarin also leads a five-member panel to assist Delhi Chief Minister Arvind Kejriwal.

Sarin also claimed that waiting for people to develop herd immunity was not a viable solution. “We do not want our people to get infected to an immunity that may be transitory, that may not be lasting, that may bring you more deaths,” he said. “I don’t think the concept of allowing ‘herd immunity’ is the best way. Yes, you may develop it silently like the people who got it without suffering.” He added that to be protected from Covid-19, a vaccine was the only hope.

The doctor said that to get “herd immunity”, nearly 80% of the population in Delhi, which is 1.6 crore people, would need to contract the infection. He cited the serological survey done in the national Capital that revealed 23.48% of the participants developed Immunoglobulin G antibodies that indicate they may have been infected by the coronavirus.

He said the study showed that when the infection rate was around 2.6% in Delhi, out of two crore people, only 1.5 lakh had the virus. He added that this meant 0.6% of the population carried the virus, but 23% had antibodies.

According to the US’ Centers for Disease Control and Prevention, serology tests are “those that look for antibodies in blood”. “If antibodies are found, that means there has been a previous infection,” it said. “However, there is a chance a positive result means that you have antibodies from an infection with a virus from the same family of viruses (called coronaviruses), such as the one that causes the common cold.”

Sarin said the Delhi study also pointed to two things – firstly, several people were missed out during testing and that those with antibodies in their system were asymptomatic. “All antibodies are not ‘neutralising’ ones,” he added. “So these people can actually get the infection. Second, after sometime, these antibodies decline. Third, and very importantly, these antibodies are not produced in everybody.”

The doctor said that it was impossible to get everyone tested and claimed that the positivity rate – an approximate figure to ascertain whether testing figures were at the same level as the rate of infection spread – may rise to 30% from nearly 24%.

Sarin added that Delhi was doing better now and that the estimates had suggested that the Capital’s case count would “reach the hump” in July and then decline. “Secondly, it does not mean that we are testing the right people always,” he said. “There is always scope to do better.”

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