Updated — July 18, 11:45 p.m. ET:
A number of passengers aboard the Malaysia Airlines flight that was believed to have been shot down over Ukraine Thursday were delegates traveling to an international AIDS conference in Australia.
But the exact number of those on board who were attending the conference remains unconfirmed as the airline has yet to release a passenger manifest.
The International AIDS Society issued a statement Friday evening confirming the names of six colleagues who died aboard the plane.
In a statement, the AIDS 2014 organizers said they are "continuing to work with the authorities to clarify how the tragic loss of Malaysian Airlines flight MH 17 impacts our conference delegates, our conference partners, and our community as a whole. In recognition of our colleagues' dedication to the fight against HIV/AIDS, the conference will go ahead as planned and will include opportunities to reflect and remember those we have lost."
Chris Beyrer, who will take over the presidency of the International AIDS Society at the end of the global conference next week, told the Washington Post Friday that after speaking to authorities he was hopeful that "the actual number is much smaller" than 108.
Beyrer told the Post that it appears that the numbers are "an order of magnitude smaller than what has been reported."
Joep Lange was one of the passengers killed in the jetliner crash in Ukraine on Thursday, the Kirby Institute confirmed in a statement.
Lange was one of several HIV/AIDS researchers and activists on board Flight MH17, according to colleagues on Twitter. They were on their way to the AIDS 2014 conference in Australia, which begins on July 20.
U.S. doctor Seema Yasmin said Lange was an amazing father to his five daughters...
And an amazing researcher. "How do we measure how much a person has done for humanity? People like Joep change the course of epidemics."
Lange has been involved in HIV research and treatment since 1983. He worked in particular on pivotal trials in antiretroviral therapy and on the prevention of mother-to-child transmission of HIV.
He was on the board of many HIV-related foundations and was the founder and editor-in-chief of the journal Antiviral Therapy. He also published more than 350 papers in peer-reviewed journals.
From 1992 until 1995, Lange worked globally as a chief of the World Health Organization's program that worked on AIDS projects. He pushed the program to promote and initiate prevention, diagnosis, and treatment projects throughout the world. His projects continue in many countries, including Argentina, Brazil, Ivory Coast, Mexico, Tanzania, Thailand, Uganda, Uruguay, and Venezuela.
In 1995, Lange returned to his alma mater, the University of Amsterdam, to take up a position as a professor of internal medicine, researching and teaching about viral diseases. In 2007 he was awarded the Eijkman medal for his achievements in tropical medicine and international health.
From 2002 to 2004, he served as the president of the International AIDS Society.
The University of Amsterdam issued a statement on the loss of two of their staff members: Lange and his partner Jacqueline van Tongeren.
Joep was a great source of inspiration for everyone who aimed to contribute to solving the AIDS tragedy in Africa and Asia. He was shocked to see how, from 1996 onwards, expensive HIV therapies became available to patients in rich countries, but not in Africa, and he made it his mission to change this and to put an end to the gross inequality in access to life-saving medication.
The university also mentioned Lange's close association with his partner Jacqueline.
One of the milestones in his career was undoubtedly his presidency of the International AIDS Society. During this period in particular, he enjoyed the support of Jacqueline van Tongeren, who helped him organise a wide range of initiatives. Over the past few years Jacqueline served as head of Communications at the AIGHD. Thanks to her previous experience as an HIV-AIDS nurse, she was extremely familiar with the issues concerned. Over time, the bonds between Joep and Jacqueline developed far beyond those of a relationship between colleagues.
"The cure for AIDS may have been on that plane, we just don’t know," Trevor Stratton, an HIV/AIDS consultant told the ABC. "You can’t just help but wonder about the kind of expertise on that plane."
Boris Dittrich, an advocacy director with Human Rights Watch, said that these activists were "irreplaceable." "They worked for decades on the issue of AIDS, bridging the gap on human rights issues... this is just devastating."
Glenn Raymond Thomas, a Geneva-based spokesman for the World Health Organization, was also aboard the flight, the WHO confirmed.
In a statement WHO said, "Glenn will be remembered for his ready laugh and his passion for public health."
His twin sister Tracey said he died doing what he loved.
Pim de Kuijer, an AIDS activist from the Netherlands who was headed to the conference, was also on board, Aids Fonds confirmed in a statement today.
These are the last photos he posted to his Facebook page, and he wrote: "AIDS '14 conference and backpacking in Australia first, then Malaysia revisited. Jumpa lagi!" "Jumpa lagi" is a Malay phrase meaning "So long" or "See you later."
The 32-year-old was a parliamentary lobbyist for Stop AIDS Now! He had traveled extensively through Kosovo, Sierra Leone, Egypt, Ukraine, Russia, and Malaysia, his friend Nabeelah Shabbir wrote in the Guardian.
Lousewies van der Laan, a human rights advocate who worked with de Kuijer, called him "a brilliant, inspiring and caring activist."
He fought for equality and the right to accessible health care for all.
Another Aids Fonds member, Martine de Schutter, was also confirmed to be on board the flight.
Martine de Schutter had started a new job managing a program in January of this year called Bridging the Gap, which provides support for sex workers, LGBT people, and people who use drugs.
Prior to that she had worked for 10 years as executive coordinator of AIDS Action Europe, an NGO partnership on HIV and AIDS in Europe and Central Asia. She had been involved with initiatives including the EU HIV/AIDS Civil Society Forum, the HIV/AIDS Clearinghouse, and the successful lobby to get key populations included in the current EU HIV policy.
Loiuse van Deth, director of Stop Aids Now! described Pim de Kuijer and Martine de Schutter as "wonderful and inspiring people."
Lucie van Mens, a global advocate for female condoms and women's health, was also heading to the conference on board flight MH17, according to the International AIDS Society.
Lucie van Mens, who worked with the Chicago-based Female Health Company, was involved in HIV/AIDS prevention since 1995. She was a tireless advocate for the development and equal access to female condoms.
Maria Adriana de Schutter, of AIDS Action Europe, also died on the flight, the International AIDS Society confirmed Friday.
Organizers of the AIDS 2014 conference issued a statement on the tragedy:
The International AIDS Society (IAS) today expresses its sincere sadness at receiving news that a number of colleagues and friends en route to attend the 20th International AIDS Conference taking place in Melbourne, Australia, were on board the Malaysian Airlines MH17 flight that has crashed over Ukraine earlier today.
At this incredibly sad and sensitive time, the IAS stands with our international family and sends condolences to the loved ones of those who have been lost to this tragedy.
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.