Nigel Klein: paediatric infectious diseases expert who correctly hypothesised that children could have breaks from HIV treatment

Nigel Klein was a world expert in paediatric immunology, who mapped children’s immunity and their reactions to infections, paving the way for more effective treatment.

Klein began his career in the 1980s when the world was grappling with the HIV epidemic. In the late 1990s Klein showed that a baby’s developing immune system works in their favour: if you give a baby with HIV antiretroviral therapy as soon as possible, their thymus gland sustains less damage and their concentration of CD4 cells, which fight infection, recovers faster than an adult’s.

Klein’s dual roles as clinician and research scientist were complementary, and he was passionate about translating research findings into better treatment for children. From 1996 he was a consultant in paediatric infectious diseases and immunology at Great Ormond Street Hospital in London, which had one of the largest HIV clinics for children and their families in Europe. At the same time, he lectured and carried out research at University College London (UCL).

Klein had a wide breadth of research interests, evidenced in …