Delhi Health Minister Satyendra Jain on Wednesday said the government is going to conduct a monthly serological survey to formulate better policies to contain the coronavirus in the national Capital, PTI reported.

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 says. “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.”

At a press conference, Jain said the results of a sero survey conducted from June 27 to July 5 came out on Tuesday, according to which about 24% of those tested have antibodies. “That means they were infected and have recovered,” he said. “Most of these people who were sampled did not know that they were infected earlier.”

Blood samples of 21,387 people were taken at random and tested for antibodies for the survey in Delhi. The results on Tuesday revealed that 23.48% of the participants developed Immunoglobulin G antibodies that indicate they may have been infected by the coronavirus. The study also noted that a large number of those infected were asymptomatic.

The health minister said the next survey will be conducted from August 1 to 5.

The Progressive Medicos and Scientists Forum alleged that the results of the serological survey show the “utter failure” of the central and state governments to control the pandemic. The results imply that the total number of cases in the Capital should be around 47 lakh in relation to the city’s population of two crore, however, it is not clear if this can be generalised.

So far, Delhi has recorded 1,25,096 coronavirus cases and the toll stood at 3,690.

Follow today’s updates on the pandemic here.