This is stated on Twitter by WHO Director-General Tedros Adanom Gebreisus.

“Peter embodied all the best that is at WHO and the UN - professionalism, determination and empathy. It was really nice working with him. We will miss him very much, ”the statement said.

Pete accomplied everything that is best about @WHO and the @UN - professionalism, commitment and compassion. It was truly a pleasure working with him. He will be deeply missed.

- Tedros Adhanom Ghebreyesus (@DrTedros) January 24, 2020

It is noted that Salama joined the WHO team in 2016.