Six participants of the International AIDS Conference have been killed in the crash of Malaysian passenger plane flight MH17. Among them were professor Joep Lange from the Netherlands - among the world's most renowned HIV researchers - as well as Lucie van Mens, and Martin de Schutter from AIDS Action Europe and Glenn Thomas from the World Health Organization.

The AIDS Conference will take place nevertheless, "in recognition of the dedication of our colleagues in the fight against AIDS," wrote the International AIDS Society. The event will include a roundtable on the tragedy in an effort to cope.

Director of the United Nations AIDS program, Michel Sidibe, tweeted his reflection on the tragedy.

"We are all shocked," said Jürgen Rockstroh, an AIDS researcher in Bonn, Germany. Currently in Melbourne, Rockstroh was well-acquainted with Joep Lange from Amsterdam.

The international leading virus researcher and his partner and colleague Jaqueline Tongeren were both on board the downed plane. The father of five daughters was supposed to have given several talks at the conference - among them, about HIV tests that can detect infection within just a few minutes.

Lange was an expert in the field of medicinal AIDS therapy. He has strongly advocated for patients in Africa to gain improved access to effective drugs. At the 2002 AIDS summit in Barcelona he stated: "If we are able to deliver cold Coca Cola and beer to the most remotes regions in Africa, it shouldn't be impossible to do the same with drugs." To this end, he founded the PharmAccess Foundation in 2001, which aims to improve patients' access to AIDS medicine.

Jennifer Watt, a delegate in Melbourne who worked closely with Lange, described him as "the father of AIDS research in developing countries." Shortly after Lange's death was confirmed, mourners established a condolence site on Facebook.

President of the International AIDS Society and Nobel Laureate Francoise Barre-Sinoussi expressed shock. Her voice clearly trembled as she described what a wonderful person Lange was, and made clear how great a loss his death for the AIDS community is.

Certainly, the death of friends and colleagues will overshadow the conference and speeches; working groups and workshops are likely to take a back seat. HIV researcher Norbert Brockmeyer said the normally "cheerful mood" at the AIDS conferences will now be absent.

Nevertheless, Brockmeyer hopes that after a "period of paralysis," all conference participants will work "in the spirit of the deceased" with even greater vigor and dedication toward their common goal - to contain HIV/AIDS to the greatest extent possible by 2030.