Internist-infectiologist Meta Roestenberg and Arabist Petra Sijpesteijn elected as members of KNAW
The Royal Netherlands Academy of Arts and Sciences (KNAW) has elected 16 new members, including two academics from Leiden. Internist-infectiologist Meta Roestenberg from the LUMC is a pioneer in research on vaccines and infectious diseases and Arabist Petra Sijpesteijn is mapping the history of the early Islamic world.
The 16 new members – seven women and nine men – are excellent researchers who also attach great importance to their role in society. They will be officially installed on 28 September 2026. KNAW members provide input on the most pressing global challenges.
Infection models
Malaria is caused by a mosquito-borne parasite. It is difficult to develop vaccines against parasites; they are biologically complex and have evolved to evade detection by the human immune system. In her research, Roestenberg utilises living malaria parasites that have been artificially weakened. This approach has shown great promise in initial clinical trials.
Roestenberg has also pioneered the development of controlled human infection models (CHIMs), a method that involves the controlled infection of human volunteers, allowing researchers to study the immune system response and the effect of vaccines and drugs. Roestenberg has developed CHIMs for schistosomiasis and hookworm, parasitic tropical diseases that affect millions of people.
As these models involve infecting healthy volunteers, she is also concerned with the ethical aspects of this method and has featured in a short documentary on this subject, titled First, do no harm (Marit Geluk, 2021).
Roestenberg has an extensive network of vaccine researchers, not only in Europe and the US but also in Africa and Asia. She drew on this network to establish the non-profit organisations InFECT-NL and INFECTA, which aim to connect expertise in the Netherlands and accelerate early-stage clinical trials of new vaccines and medicines.
Ancient Arabic texts
Originating in what is now Saudi Arabia, Islam spread across a vast area spanning present-day Spain to India following the death of the Prophet Muhammad in 632 CE. The first accounts of this historical transition were recorded two centuries later, long after the Islamic empire had come into being.
We still know very little about the rise of a political, social and cultural Islamic society in this vast region in the centuries following Muhammad’s first revelations. Papyrologist Petra Sijpesteijn has done groundbreaking research mapping the history of the early Islamic world, drawing on largely neglected and difficult-to-interpret sources.
Using coins, seals, inscriptions and papyri – texts written on papyrus in Arabic, Greek and Coptic – she explores such questions as: how did the Islamic conquerors take control? How did they deal with existing religions? Did the conquest represent a radical upheaval for the population?
For example, Sijpesteijn studied the correspondence between a Muslim administrator in Egypt and his subordinate between 730 and 750 CE. While the Arab/Muslim administration and infrastructure were well established by then, Egyptian expertise and practices remained important.
Sijpesteijn has a remarkable talent for interpreting this kind of information and placing it within its historical context. She is deeply committed to making these sources accessible, the originals of which are scattered across multiple museums.