Of the 142 Tablighi Jamaat members who had been quarantined at AIIMS, 129 have recovered, and a lot of them have agreed to donate their blood for plasma therapy to treat Covid-19 patients in Delhi.

Speaking to the Times of India, Dr Sushma Bhatnagar, chairperson of Covid-19 services at the Jhajjar hospital said:
We requested some of the recovered patients to donate their blood, and they readily agreed. Now, we are working on the logistics for the donation and their stay.
She also informed that members of the Jamaat had agreed to give their blood samples for future research.
Most of the Tablighi members are from outside Delhi, some of them foreigners. They cannot return to their hometowns during the lockdown. We will talk to the authorities on where to shift them and how to coordinate the blood donation.

The idea of using recovered people’s plasma to help patients has been used earlier, for instance during the outbreak of Severe Acute Respiratory Syndrome (SARS), also caused by a human coronavirus.