A pall fell over the United Nations on Friday as staff and delegates came to terms with the death of as many as 100 HIV/AIDS researchers and advocates who were on Malaysia Airlines Flight 17, which was shot down a day earlier in eastern Ukraine.

The group was traveling to the 20th International AIDS Conference in Melbourne, Australia, when the plane carrying a total of 298 people was brought down over a rebel-controlled area near the border with Russia. Everyone on the plane is believed to have died.

UN staff members told VICE News that they were still awaiting a full accounting of who was on the plane. Malaysia Airlines has not yet released the identities of all of the passengers, and there were conflicting reports of the number of people onboard who were headed to the AIDS conference.

UNAIDS has confirmed the death of Dr. Joep Lange, the former head of the International AIDS Society, and the World Health Organization confirmed that Glenn Thomas, a press officer, was also among the passengers. Dr. Lucie Van Mens, another researcher, was also reported killed, along with AIDS lobbyist Pim de Kuijer of Stop AIDS Now and Martine de Schutter of Bridging the Gaps, an NGO that works to expand access to preventative measures in order to stop transmission.

Conference organizers have so far only been able to confirm the death of seven people traveling to Melbourne, according the Washington Post.

After the flight crashed, questions immediately arose about whether the conference would proceed. On Friday the International AIDS Society announced in a statement that “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.”

Lange, who headed the department of global health at the University of Amsterdam, was well known in the research community after working on HIV/AIDS for more than three decades, virtually since the virus and syndrome became a pandemic. Lange was one of the first to push for so-called “combination therapies” to be applied in developing countries, rather than a regimen of a single drug. This approach eventually led to the anti-retroviral drug cocktails that today are capable in many cases of limiting transmission and preventing HIV from developing into AIDS.

In the 1990s, Lange helped create the Netherlands-Australia-Thailand Research Collaboration, which studied a two-drug combination treatment for Thai HIV patients.

“The group’s first two studies at Chulalongkorn Hospital in Bangkok helped establish a future teaching model for sites around Thailand and the region,” wrote David Cooper, one of Lange’s colleagues at the time. “These two studies were pivotal to the future success of HIV-NAT, which has become a powerhouse of internationally recognized HIV research.”

This year’s Melbourne conference is focused in part on the potential for an HIV vaccine. It’s unclear how many on the plane were involved in that effort or what research was lost among those who perished.

The deaths of so many in the close-knit research community were particularly surreal for its members given the geopolitical implications of the crash, an event that managed to push even Israel’s invasion of Gaza from the front pages of the world’s newspapers.

In New York, the Security Council met Friday morning for an emergency meeting on Ukraine. Addressing the council and Russian UN Ambassador Vitaly Churkin, US Ambassador Samantha Power told the council that investigators “cannot rule out technical assistance from Russian personnel” in the firing of the anti-aircraft missile that American authorities claim downed the plane.

Echoing Russian President Vladimir Putin, Churkin responded by questioning the routing of the plane, though he did not deny that separatists might have fired the missile.

“Any normal person must wonder, I think, why did Ukraine air dispatchers send a plane into a war zone,” Churkin said. “We place all blame on the Kiev powers or government.”

Speaking at the White House shortly after Churkin’s remarks, President Barack Obama confirmed that US intelligence authorities believe that Russian-backed separatists were responsible for the incident.

“We know that they are heavily armed and they are trained, and we know that that’s not an accident,” Obama said. “That is happening because of Russian support.”

It may be some time before the HIV/AIDS research community is able to come to terms with the human cost of the loss of Flight 17. After a break of only a few hours, the Security Council is set to meet Friday afternoon for another emergency meeting, this time on the situation in Gaza.

Speaking at the UN Secretariat, Simon Bland, New York representative at UNAIDS, told VICE News that researchers were still absorbing the tragedy.

“This is indeed very difficult to come to terms with,” Bland said. “If the AIDS movement tells us anything, it is resilience — the conference will go ahead, the work goes ahead, the remarkable progress goes ahead to meet the challenges of today and tomorrow. Those on the plane would wish it no other way.”

More than 35 million people currently live with HIV/AIDS, including 3.3 million children.

“There have been setbacks in the past and there will be setbacks in the future,” Bland added. “We can and will end AIDS.”