The fifth serological survey in Delhi has shown that 56.13% of the residents have developed antibodies against the coronavirus, Health Minister Satyendar Jain announced on Tuesday.

Jain said that the Capital has largely won the fight against the coronavirus crisis. “We should continue to practice Covid-appropriate behaviour,” he added.

The health minister said that the latest serological survey involved around 28,000 samples and was the largest one undertaken by the Delhi government. It was conducted from January 15 to 23.

The highest prevalence of antibodies was recorded in South East Delhi – 62.18%. North Delhi recorded the lowest seroprevalance of 49.09%.

The survey indicates that the Capital is moving towards herd immunity. Experts say that herd immunity is achieved when the majority of a population becomes immune to a disease through vaccinations or through mass spread of the infection.

On Monday, Delhi recorded 121 new Covid-19 cases and three deaths. The toll was the lowest in 10 months, authorities said. However, the government urged people not to stop taking precautions.

Delhi’s fourth sero survey, which was conducted in October, had shown that 25.5% of the population had been exposed to the infection and developed antibodies against it.

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.”

Serological surveys reveal how many people may have been infected with the novel coronavirus in an area but they do not show how many people are immune to the virus. It still isn’t clear how long antibodies last in infected persons and how many antibodies are needed to protect a person from reinfection.