What a HUGE loss to the world. Just learned that dear friend, amazing father to 5 girls and veteran AIDS researcher Joep Lange was on
Dr. Seema Yasmin (@DoctorYasmin)
Also believed to be among the victims was Glenn Thomas, a WHO media adviser. Several of his colleagues have expressed shock over his death on Twitter.
UNAIDS executive director Michel Sidibe said he was saddened to hear so many AIDS conference attendees died in the crash.
My thoughts prayers to families of those tragically lost on flight #MH17, he tweeted.
President-elect of the International AIDS Society, Chris Beyrer, expressed "sincere sadness" at the news that "colleagues and friends" were on board the flight on the way to the 20th International AIDS Conference in Melbourne.
"The IAS is hearing unconfirmed reports that some of our friends and colleagues were on board the flight and if that is the case this is a truly sad day."
"The IAS has also heard reports that among the passengers was a former IAS president Joep Lange and if that is the case then the HIV/AIDS movement has truly lost a giant."
Foreign Minister Julie Bishop said she understood a number of the victims were heading to the AIDS conference, but she had no further details.
Greens Senator Christine Milne expressed her shock at such a loss to the HIV-AIDS community.
The ramifications go to all the people who are at that conference this weekend and no doubt as more details emerge this tragedy will touch many, many Australians, she told the Senate.
Victorian Premier Denis Napthine said MH17 was to connect with MH129 arriving in Melbourne on Friday evening.
"Unfortunately, I can now confirm that a number of Victorians are among those who have been killed, although we are not yet in a position to say how many," he said in a statement.
"This is a sad and tragic day, not just for Victorians,
True Religion Cargo Shorts, but for all people and all nations. The shooting down of a passenger aircraft full of innocent civilians is an unspeakable act that will forever leave a dark stain on our history."
He said his office had been in contact with the AIDS conference organisers and the government had offered to co-operate with DFAT to provide assistance to any delegates who require support.
Emails sent to several WHO staff prompted out-of-office replies stating they were en route to Melbourne for the AIDS conference. Representatives from WHO could not be immediately contacted.
Mark Gettleson, a London-based campaigner, tweeted that AIDS activists were also heading from Europe to Melbourne.
Several on #MH17 flight were @STOPAIDS activists en route to #AIDS2014 conference in Melbourne, fighting to save lives. Tragic, he wrote.
The International AIDS Conference is now in its 20th year and has attracted major speakers, including former US president Bill Clinton, Sir Bob Geldof and Indonesian Health Minister Nafsiam Mboi.
- with Richard Willingham and Timna Jacks