An estimated 100 AIDS researchers were on board the ill-fated Malaysia Airlines flight that crashed in Eastern Ukraine near the Russian border yesterday, including former president of The International AIDS Society and renowned researcher, Joep Lange.

The Boeing 777, which was flying from Amsterdam to Kuala Lumpur, was a connecting flight for those en route to the International AIDS Conference in Melbourne, which was planned to take place this weekend. Delegates in Sydney have said that he was travelling on the MH17 flight to the conference with an estimated 100 AIDS researchers.

Several prolific figures in the AIDS research community have spoken to press and taken to Twitter to express their feelings about the doomed flight, which is believed to have been shot down after US authorities said intelligence analysis showed it had been hit by a surface-to-air missile, a suggestion that has been discredited by both Ukranian government and pro-Russian rebels.

According to The Independent, Canadian HIV researcher Trevor Stratton told ABC that researchers had been close to a vaccine against AIDS saying, “There were some really prominent researchers that have been doing this for a very long time and were getting close to vaccines and people are talking about cures and the end of AIDS, and you can’t help but wonder what kind of expertise was on that plane”.

Professor Richard Boyd confirmed to The Guardian that of the 298 people who lost their lives, there were “some serious HIV leaders”. He explained, “This will have ramifications globally because whenever you lose a leader in any field, it has an impact. That knowledge is irreplaceable”.

International AIDS Society spokesman Michael Kessler said, “At this incredibly sad and sensitive time the IAS stands with our international family and sends condolences to the loved ones to those who have been lost to this tragedy”.

Clive Aspin, a veteran HIV researcher who attended the pre-conference session in Sydney, also spoke out emotionally to The Guardian, “There’s a huge feeling of sadness here, people are in floods of tears in the corridors. These people were the best and the brightest, the ones who had dedicated their whole careers to fighting this terrible virus. It’s devastating”.

UK AIDS charity organisation Terrence Higgins Trust tweeted a simple but heartfelt message about the tragedy:

Stunned by reports that #AIDS2014 delegates inc leading researcher Joep Lange were on #MH17. Terrible news for #HIV community.

— TerrenceHigginsTrust (@THTorguk) July 17, 2014