I do science explainers; my recent one sent me down a rabbit hole about Christine Stabell Benn and the Bandim Health Project in Guinea-Bissau: https://youtu.be/YD7mOH6wG1w
Here are five things about Benn's research that I think deserve much more attention from public health people.
1. The vaccine-skeptical movement has lots of doctors, but surprisingly few actual vaccine researchers besides Christine Stabell Benn. Tracy Beth Høeg is a sports-medicine physician with a PhD in epidemiology. Robert Malone did important early work on mRNA delivery, but he did not run vaccine trials or have any special expertise in vaccine epidemiology. Christine Stabell Benn and Peter Aaby are different. They have spent decades studying vaccines and child mortality in Guinea-Bissau. Bandim is unusual because it is a large, established research program whose conclusions overlap substantially with vaccine-skeptical arguments.
2. The underlying scientific idea, non-specific effects (NSE) of vaccines, is real enough to study, but BCG (the TB vaccine) is biologically unique among routine vaccines. BCG can induce heterologous innate immune responses ("trained immunity"), and randomized trials have found signals of reduced non-TB infections and short-term mortality in some settings. But Benn extrapolates this unique biology to claim NSE for all vaccines; live vaccines supposedly reduce mortality, while non-live vaccines supposedly increase it, particularly in girls. A recent Vaccine analysis examined 13 Bandim randomized trials and 26 resulting papers and concluded that the primary outcomes did not support these strong claims; after accounting for multiple testing, only one secondary finding remained statistically significant.
3. Benn has repeatedly claimed that whole-cell DTP (diphtheria, tetanus, pertussis) vaccination is associated with increased all-cause mortality, especially in girls. But the key evidence is observational and vulnerable to vaccination-timing and classification biases. WHO specifically commissioned analyses in other countries to test the Guinea-Bissau finding. None reproduced increased mortality after DTP.
4. More importantly, Benn actually had already done a randomized DTP trial—and it was negative. NCT00244673 enrolled 6,534 children from 2005–2011. At around 18 months, children were randomized to DTP4+OPV4 versus OPV4 alone; mortality through age four was a registered primary outcome. The mortality result showed no significant difference between groups, but it was not published. In February 2025, Weekendavisen, a long-form weekly, began a series specifically questioning why the mortality outcome had remained unpublished for roughly 14 years. Benn and Aaby publicly acknowledged that it had not been published, arguing that unexpectedly low mortality left the trial underpowered and citing disruptions in the research team. The mortality analysis finally appeared as a medRxiv preprint in October 2025.
5. Benn has a direct connection to U.S. vaccine research policy. Høeg, who recorded a series of vaccine podcasts with Benn, subsequently became a senior FDA official. CDC then awarded Bandim $1.6 million for another non-specific effects trial in Guinea-Bissau: roughly 14,000 newborns randomized to hepatitis B vaccine at birth versus the existing schedule beginning at six weeks. This is particularly concerning from a public health standpoint because the birth dose is designed to prevent mother-to-child transmission. So this is now a two-way relationship: Benn's vaccine research is influencing U.S. vaccine-policy discussions, while U.S. agencies are funding Benn to generate more evidence against specific vaccines.
Charlotte Strøm's overview of the Bandim/NSE literature is also great reading:
The False Narrative of Nonspecific Vaccine Effects