Czech investigators from Charles University explored whether vaccines against various diseases influence perceived attractiveness, examining how health signals might be reflected in everyday impressions. The study appeared in Evolutionary Psychology, a scientific journal focused on how evolutionary factors shape human behavior and perception.
The experiment involved 21 healthy, non-smoking men aged 18 to 40 who had not received vaccines for hepatitis A/B or meningococcus in the previous ten years. Participants supplied samples of body odor, took facial photographs, and recorded voice samples at two points: 14 days before vaccination and 14 days after receiving the specified vaccines.
Attractiveness judgments were provided by 88 female raters who assessed the men based on three criteria: body odor, facial appeal, and voice timbre. These judgments were used to gauge correlations between health-related signals and overall attractiveness across the pre- and post-vaccination periods.
The researchers observed a significant positive relationship between scent appeal and apparent health both before and after vaccination. In practical terms, this suggested that healthier-seeming individuals tended to emit more attractive odors, a relationship that persisted as health status changed with vaccination.
Notably, the data indicated a reduction in the intensity of the body odor after vaccination, coupled with an improvement in the perceived quality of the odor. This pattern points to a perceptual shift where healthier individuals may be judged as emitting more pleasant and less overpowering scents following immunization.
Conversely, the study found that facial attractiveness appeared to decline after vaccination, indicating that improvements in scent-based health cues did not translate into higher assessed facial beauty within the observed timeframe.
Voice evaluation, by contrast, showed no measurable change as a result of vaccination, suggesting that vocal characteristics were not sensitive indicators of health status in this particular study design.
Overall, the researchers proposed that multiple sensory cues contribute to assessments of health, supporting a “multiple message” hypothesis. They argued that people parse external information from others across different channels, integrating scents, facial features, and vocal traits in distinct ways when judging health and attractiveness.
These findings align with broader lines of inquiry into how social judgments are formed from a constellation of cues, and they echo ongoing discussions about how health signals influence interpersonal interactions in real-world contexts. While the study focuses on vaccine-related changes, it contributes to a wider understanding of how sensory information informs perceptions of health and desirability in social settings.
Earlier research in related fields has explored whether aspects of appearance may subtly influence judgments in legal or social outcomes, a reminder that attractiveness and perceived health can intersect with decision-making in various realms. The current investigation adds nuance by showing that different sensory modalities may track health in different ways and at different times following a health intervention.