Top British scientist steps down from WHO

Sir Jeremy was promoted to assistant director-general in May 2025, as part of a broader leadership shake-up. He joined the WHO as chief scientist in 2023, after almost a decade at the Wellcome Trust.

Along with Dr Tedros, the director-general, and other senior figures, Sir Jeremy was closely involved in implementing a painful down-sizing of the WHO following the US departure.

Historically, the US had been the agency’s top donor, and the funding cuts have hit the agency hard.

It has committed to slashing nearly a quarter of its global workforce and shrinking its headquarters in Geneva. Under a new organisational structure, 10 divisions were merged into four.

Sir Jeremy was responsible for one of these: Health Promotion, Disease Prevention and Control.

Speaking in March, he said: “2025 was a very difficult year. When you imagine any organisation – public or private – reducing its workforce by 30 per cent, it is extremely painful. Many institutions usually do this gradually: 10 per cent one year, another 10 per cent the next. Doing it all in a single year was awful, and the organisation lost many good people. Human resources did their best.

“I participated in the architectural overhaul and organisational redesign of WHO,” he added in an interview with the Swiss daily, Le Temps. “It is far from perfect, but the reform we have undertaken is as strategic as possible to ensure the organisation is better adapted to the health challenges of the next 20 years.”

While Sir Jeremy’s position at the WHO was a senior posting, working at the WHO, like other parts of the UN, can be frustrating, owing to its structure and governance.

The WHO is beholden to member states and is subject to enormous pressure at international level, which determines its funding stability, influences outbreak investigations, and tests its ability to act on issues that require consensus, such as the pandemic treaty.

But it is also riven by internal politics, and at the moment several senior officials, including several regional directors, have stepped back from their roles to campaign for Mr Ghebreyesus’s job as head of the organisation. His second and final term as director-general will end on August 15 next year.