* Distribution expected to be toughest logistical challenge ever

* First vaccines could be ready as early as November

* Could require 5x world's 2019 air vaccine trade - Seabury

SYDNEY, Oct 15 (Reuters) - Only 28% of participants in the air cargo industry feel they are well prepared to distribute a COVID-19 vaccine once available, according to a survey released on Wednesday, as the industry begins to gear up for a major logistical challenge.

Ground handlers and airports feel less prepared than freight forwarders and airlines, according to the survey conducted by The International Air Cargo Association (TIACA) and Pharma.Aero which found 36% of participants planned to invest in additional physical or digital infrastructure.

TIACA Vice Chairman Sanjeev Gadhia, who heads Nairobi-based air cargo operator Astral Aviation, said the global distribution of the COVID-19 vaccine would be the toughest logistical challenge ever faced, with an estimated 10 billion doses requiring distribution in 2021 and 2022.

More than 40 vaccine candidates are already undergoing clinical trials, according to the World Health Organization.

"We know that as from November the first vaccines might be ready to be transported," Gadhia told Reuters via email. "TIACA and Pharma.Aero call for more collaboration and transparency: information on vaccines specifications, volumes, production sites, trade lanes, is desperately needed by all."

Large cargo airlines like Korean Air Lines Co Ltd and Hong Kong's Cathay Pacific Airways Ltd have been investing in expanding pharmaceutical handling capabilities as they seek alternative revenue sources with passenger demand at a fraction of last year's levels.

"Yield on vaccines are high compared to general cargo, hence airlines will have a financial benefit to transport vaccines and to invest in the supporting equipment," said Gadhia, whose own airline is adding a freighter later this month.

Accenture's Seabury Consulting estimates the global roll-out of a vaccine will generate 65,000 tonnes of air freight, which is five times the air vaccine trade in 2019.

"I think what is going to likely happen is there will be public-private partnerships between governments, international freight forwarders and airlines" said James Jordan, a senior associate at law firm HFW's Asia aerospace and insurance practices.

"But the scale of the operation is such that they will need to utilize the aircraft from not just your primary airlines but the second and third-tier airlines as well," Jordan added. (Reporting by Jamie Freed; Editing by Christian Schmollinger)