# Research into individual vaccine immune responses

> Live situation record from CLSTR: https://clstr.news/situations/research-into-individual-vaccine-immune-responses
> Updated: 2026-09-19T07:30:01.000Z. Sources: 7. Developments: 3.

Researchers are investigating the biological drivers behind individual variability in vaccine immune responses and side effects. Studies focus on why some individuals experience more pronounced transient symptoms, such as fatigue and fever, while others have milder reactions.

Findings from the University of Geneva and Geneva University Hospital indicate that baseline innate immunity, specifically a higher interferon-related antiviral response, plays a critical role in the severity of side effects. Additionally, research involving over 4,000 participants suggests that ‘sentinel antibodies’—pre-existing defenses against microbes like Staphylococcus aureus or common respiratory viruses—may serve as predictors for vaccine efficacy. Higher levels of these antibodies have been linked to stronger responses to COVID-19 vaccinations, potentially helping to identify individuals at risk of a blunted immune response.

A study published in Science Translational Medicine, led by Arnaud Didierlaurent of the University of Geneva, further clarifies these variations. By monitoring 51 healthy individuals receiving either Moderna’s Spikevax or Pfizer-BioNTech’s Comirnaty, researchers identified underlying biological mechanisms that drive differing reactions. While the nocebo effect—where the expectation of negative outcomes increases symptom likelihood—contributes to these experiences, the study emphasizes distinct biological drivers. The research also notes that older individuals often experience fewer temporary side effects, likely due to age-related declines in immune function. Understanding these mechanisms is considered vital, as adverse reactions remain a significant factor in vaccine hesitancy.

## Timeline

### 2026-09-19: University of Geneva study identifies biological drivers of vaccine side effects

A study in Science Translational Medicine identifies biological immune system factors that influence individual reactions to mRNA vaccines, helping explain why side effects vary between people.

2 sources. https://clstr.news/cluster/university-of-geneva-study-identifies-biological-drivers-of-vaccine-side-effects

### 2026-09-18: Researchers study variability in individual vaccine immune responses

Researchers are studying why vaccine responses vary between individuals, identifying that existing sentinel antibodies may predict the strength of an immune response to new vaccinations.

2 sources. https://clstr.news/cluster/researchers-study-variability-in-individual-vaccine-immune-responses

### 2026-09-17: Researchers identify biological markers for vaccine response and side effects

New research suggests that innate immunity and pre-existing antibody patterns can predict both the severity of vaccine side effects and the strength of an individual's immune response to vaccination.

3 sources. https://clstr.news/cluster/researchers-identify-biological-markers-for-vaccine-response-and-side-effects

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Cite as: Research into individual vaccine immune responses. CLSTR, https://clstr.news/situations/research-into-individual-vaccine-immune-responses