Although scores of people lined up to give blood in Orlando on Sunday to help those injured during a horrific attack at a gay nightclub, significant restrictions remain in place for gay men who want to donate.

In December, the U.S. Food and Drug Administration (FDA) ended a 30-year ban on blood donations from bisexual and gay men. The ban, however, was replaced with a new rule stating that only men who have abstained from sex for a year can donate. The new rule mirrors similar policies in countries like Australia and Japan.

Blood donation centres, however, have been slow to adopt the change.

鈥淏lood centres like OneBlood have to do a lot of changes with our SOPs, computer software and internal training to get that change and we鈥檙e doing that diligently as fast as we can,鈥� OneBlood spokesperson Pat Michaels told 麻豆影视 Channel from Orlando on Monday.

Outside, a line snaked around the centre. Gay and bisexual men were not permitted to donate at the centre. All blood donations in the U.S., however, are already screened for HIV: the virus that causes AIDs.

鈥淲e had people from Pride Week here deliver food and water and help out, and they understand that blood centres had petitioned the Food and Drug Administration to make the change and the change had come and we鈥檙e still working on that now.鈥�

According to Michaels, OneBlood has still been overwhelmed.

鈥淚 have been here for 13 years鈥� and I鈥檝e never seen anything like this,鈥� he said. 鈥淲e just put out a call initially that we might need people to come in and donate. Seven-hundred people showed up at this centre here near downtown Orlando, only about a mile-and-a-half south of the Pulse nightclub, and it鈥檚 been overwhelming since.鈥�

On a typical day, Michaels says the centre receives about 30 to 40 donations. Michaels says they already have enough blood to supply the victims of the horrific attack.

鈥淏ut that doesn鈥檛 turn them away.鈥�

With files from The Associated Press