The effect of plant stanol ester consumption on the vaccination response to a COVID-19 vaccine

Plant stanols are known to lower low-density lipoprotein cholesterol (LDL-C).
However, studies have suggested that these compounds also beneficially
influence the immune system, e.g. increasing vaccine-specific antibody titers.
BMI and age have previously been negatively associated to vaccination
responses. These results are very relevant in light of the current COVID-19
pandemic. If plant stanols indeed have beneficial effect on the immune system,
people with overweight or obesity and higher age might benefit from consuming
plant stanols prior to receiving the COVID-19 vaccination. We here decided to
focus on subjects with overweight or obesity.

The primary objective of this study is to demonstrate clinical benefits of
consumption of plant stanols (delivered via products enriched with plant stanol
esters) on the vaccination response to a COVID-19 vaccine in overweight or
obese patients aged 18 years or older.

A double-blind, randomized, placebo-controlled trial will be carried out. The
intervention period lasts at least 6 weeks.

The intervention group will receive mini drinks (100 mL) containing 2g plant
stanols each (present as plant stanol esters esterified to rapeseed oil) and
are required to take two drinks daily in order to reach a required dose of 4g
plant stanols per day. The control group will receive control mini drinks
containing rapeseed oil without plant stanols esterified to it and are also
required to take two drinks per day. Both drinks are oat-milk based and
blueberry flavored.

Subjects will be screened via telephone to determine eligibility. If a subject
fulfills all criteria, a baseline visit is planned where the informed consent
is obtained at the start. If the consent form is signed, a baseline blood
sample will be taken and subjects will start consuming the mini drinks until
they receive an official invitation from the government to make an appointment
for their the COVID-19 vaccination. This means that the time period between the
start of consuming the stanol ester enriched products and the actual
vaccination might differ between participants, but the minimal period for
consumption of the drinks is 2 weeks prior to the receiving the vaccination.
People that receive their vaccination in the first two weeks of the study will
be excluded from the study. We ask the volunteers to visit the university for a
blood sample the day before the vaccination. Following the COVID-19
vaccination, participants will continue to consume the mini drinks and will
visit the study site weekly for blood sampling for 4 weeks. There are no direct
benefits for study subjects. The intervention and control mini drinks are
considered to be safe. The study team is not involved in the vaccinations as
such and we do not interfere with the official routes of vaccination planning
by the government. Some study subjects may report pain during venipuncture.
Subjects that do not fully adhere to the study protocol will be excluded from
analyses and a per protocol analysis will be performed. Time investment will be
approximately 3 hours in total. This estimation excludes travel time. The total
blood sampling volume over the entire study period will be approximately 78 mL.