Israeli trial links brain's reward centre to stronger vaccine antibody response

A team from Tel Aviv University, the Technion and Tel Aviv Sourasky Medical Center (Ichilov) reported in Nature Medicine on 19 January 2026 that activity in the brain's reward system was linked to how strongly people responded to a vaccine. The randomised, double-blind trial was led by neuroscientist Professor Talma Hendler of Tel Aviv University and the Sagol Brain Institute and neuroimmunologist Professor Asya Rolls, with first authors Dr. Nitzan Lubianiker, now at Yale, and Dr. Tamar Koren.

The researchers enrolled 85 healthy adults. While lying in an MRI scanner, some participants watched real-time feedback of their own brain activity and learned, through mental strategies of their choosing, to raise activity in the ventral tegmental area, a small region involved in reward and motivation. Other groups trained a different brain region or received no training. All of them then received a hepatitis B vaccine, and their antibody levels were measured over the following weeks.

Across participants, those who managed to increase activity in the ventral tegmental area had larger rises in antibodies against hepatitis B. The link was specific to that region and was not seen for a neighbouring reward area or control regions. People who reported using positive expectation, imagining good outcomes, as their strategy sustained the highest activity. As Scientific American noted, the average antibody levels did not differ significantly between the training groups, so the evidence rests on the correlation between brain activity and immune response, and the biological pathway connecting them is still unknown.

Rolls's laboratory had earlier shown in mice that stimulating the reward system strengthens immune defences. The new work is the first evidence that a similar link exists in people, and the authors suggest it could help explain part of the placebo effect.