Sanguine Connections: The Benefits of Longitudinal Vaccine Studies
Welcome to Sanguine Connections, exploring the process, challenges, and nuances of biospecimen procurement for translational studies.
Charting Immunity: The Benefits of Longitudinal Studies in Vaccine Research
As flu season approaches, vaccines matter more than ever for protecting people against the flu and other infectious diseases. Understanding why vaccines work is key to making them better. Longitudinal studies — tracking biological samples, usually blood, before and after vaccination — are central to that work. This post covers the basics of baseline data, walks through a few notable longitudinal vaccine studies, and looks at the challenges and payoffs of prospective collections for vaccine research.
The essentials of baseline data
Baseline, or pre-vaccine, samples set a reference point for immunological studies. They show a person’s starting immune status. By comparing baseline samples to post-vaccination samples, researchers can spot exactly what the vaccine changed — whether that’s activating a specific immune pathway or triggering antibody production. These comparisons help researchers:
- Determine a new vaccine’s efficacy
- Identify biomarkers for immune response
- Study how vaccine effectiveness differs across populations
- Support safety monitoring by revealing adverse reactions or unexpected effects
Examples of longitudinal studies for vaccines in the literature
Evaluation of antibody binding of influenza vaccine over multiple years
Researchers from University of Georgia tracked antibody response to the flu vaccine over six straight flu seasons. Their cohort of hundreds aimed to show how immune response differs by age and health status. The team drew blood at vaccination time, plus three to five more timepoints afterward. They found several factors that shape vaccine-induced immune response, including age, health status, and prior exposure. Follow-up omics studies are now underway to build predictive models for host response and vaccine effectiveness.
Analysis of immune response to mRNA SARS-CoV-2 vaccine in older adults
Among the many longitudinal COVID-19 studies, one from Ravussin et al. focused on how older adults responded to the mRNA vaccine across multiple doses. Older people face a higher risk of severe COVID-19 and death, so they were prioritized for vaccination during the pandemic. But age and other health conditions can reduce antibody development and levels — which is exactly why this population needed closer study. The researchers combined blood analysis, medical records, and questionnaires before vaccination, after dose two, and after dose three, producing a rich dataset. They note real limits in cohort diversity, including under-representation of frail or chronically ill people. Even so, they characterized the immune response and found links to lifestyle and health conditions. For example, in line with other studies, they found people with hypertension had a weaker antibody response to vaccination.
Assessment of antibody protection for the flu in breastmilk
Lactating women are often left out of clinical trials, for understandable reasons — researchers worry about infant safety, and physiological changes can complicate results. A team from Mount Sinai studied flu protection for breastfed infants by measuring seasonally-relevant hemagglutinin-specific antibodies in breastmilk. Lactating women in a New York cohort gave milk samples before, and two weeks after, their seasonal flu vaccine. The team could measure IgG, sAb, and IgG HA titers in the breastmilk, but these titers weren’t significantly boosted after vaccination — with one exception: an HA immunogen that had been in the vaccine for several years, unlike others that were new that season. The authors suggest future vaccine development should include this population, to identify effective passive protection through breastmilk.
Challenges for longitudinal vaccine studies
The studies above — and vaccine studies in general — tend to share the same challenges: recruiting a diverse cohort, managing multiple collection timepoints (sometimes with multiple sample types), and gathering detailed health information. Sanguine is built to handle these challenges, with a large donor network across the US. Here’s one example of a successful vaccine study, where a biopharma company focused on immunology and virology partnered with Sanguine on a flu vaccination study.
Background: The study needed 50 healthy adults, ages 18 to 80, who planned to get that year’s flu vaccine. Each participant made two visits: one within a month before vaccination, and a second two to four weeks after. Sanguine recruited nationally for in-home collections, letting donors schedule visits at their convenience.
Collection: The team collected whole blood and saliva at the first visit, and blood only at the second. They isolated plasma from part of the whole blood, then sent both blood samples to the biopharma company for analysis. Saliva went to Sanguine for HLA-typing.
The team also built a custom questionnaire covering vaccination history, COVID-19 infection history, and general demographics.
Result: The study completed 98 of 100 planned visits, plus extensive donor data and multiple sample collections — giving the scientists strong data to answer their research questions.
Longitudinal studies are essential for understanding vaccine efficacy and safety. By collecting multiple timepoints and detailed donor data, researchers can uncover key insights into immune response, find new biomarkers, and catch potential adverse or unexpected reactions. The challenges — cohort diversity, keeping participants engaged, and gathering thorough donor data — are real, but Sanguine’s direct-to-donor model is built to work through them and support the virology community.
For more in-depth insight into the Sanguine difference, explore the blogs below or contact us to get started.
By: Eliza Small, Ph.D.
Director, Content Marketing at Sanguine
