Saint Louis University has converted part of its former hotel in the Salus Center
into a 24-room research suite to house volunteers who will be intentionally exposed
to influenza to see if investigational vaccines keep them from getting sick.
Daniel Hoft, M.D., Ph.D., directs SLU's Center for Vaccine Development. Photo by Ellen
The Extended Stay Research Unit will allow SLU to take its vaccine research to the
next level, said Daniel Hoft, M.D., Ph.D., director of SLU’s Center for Vaccine Development.
SLU is funded by the National Institute of Allergy and Infectious Diseases, which
is part of the National Institutes of Health, as one of nine Vaccine and Treatment
Evaluation Units that study vaccines to protect against infectious diseases and emerging
“SLU has invested in this because it is an important way to potentially contribute
significantly to the development of a universal flu vaccine,” said Hoft, who also is director of infectious diseases, allergy and immunology at SLU.
Intentional Flu Exposure
The facility allows SLU to conduct human challenge influenza studies, which differ
from the more common flu vaccine clinical trials historically done at SLU.
“Human challenge studies are a way to get a lot of information quicker, with a smaller
number of volunteers and less cost than a traditional vaccine study,” Hoft said.
“In a traditional flu study, we vaccinate people and see if their immune systems respond
by creating antibodies that fight flu. In a human challenge study, we vaccinate people,
then deliberately challenge their bodies by exposing them to flu to see if they get
A human challenge study typically is conducted early in vaccine research, after an
initial Phase 1 study assesses if a vaccine is safe when given to a small group of
How Challenge Studies Work
Human challenge study volunteers are given a vaccine or placebo, then intentionally
exposed to a strain of the influenza virus. Volunteers are quarantined in SLU’s challenge
unit for about 10 days.
During that time, they are observed and have blood and lung tests and nose swabs to
see if they are infected with flu and shedding the virus, which means the virus is
present in mucus and other body secretions and can be transmitted to others. They
are not allowed to go home until tests show they are negative for infection for two
“You know when they’re exposed to the flu, so can plan exactly when to study it. You
are not waiting for nature to take its course. If a challenge trial shows the vaccine
protected a small group of volunteers against flu, you can be much more confident
the vaccine is more likely to be worth the hundreds of millions of dollars of investment
to go through phase 3 development,” Hoft said.
Volunteers for human challenge studies typically receive compensation of about $3,500
for their time and travel. Nurses are in the unit around the clock to monitor and
care for them.
The Extended Stay Research Unit has the trappings of a staycation for those willing
to risk getting the flu. Everyone who participates in a human challenge flu study
is quarantined in the unit because it takes time for symptoms to develop and the contagious
period to end. Those who don’t get sick and are not shedding the challenge virus will
be able to leave a little earlier than those who are infected.
The facility can accommodate as many as 24 study volunteers in hotel-style rooms that
are equipped with private bathrooms, TV and internet.
Common areas with comfy chairs offer spaces to socialize, read or watch TV with picture-window
views of the Arch. Catered meals are served in the dining room/kitchen area, and there
is exercise equipment for a quick workout.
The in-patient challenge unit has been carefully designed to protect the safety of
study volunteers and non-study participants in the building. The facility is separated
from offices in the rest of the building by double-door entrances that create negative
pressure. It has a sophisticated HVAC system for aerosol containment because recent
animal data has demonstrated flu can be transmitted through tiny droplets in the air.
“For research purposes, we need strong infection control, including upgraded air filtration
systems and N95 masks that fit closely to the face and filter airborne particles,”
There is a “clean room” with work spaces for non-volunteers who come and go into the
unit, and a changing area where nurses and doctors don or remove personal protective
equipment (PPE) that they wear whenever interacting with volunteers who might be infected
The Future of Research
Hoft said the new research facility is ideal to conduct research for a universal influenza vaccine, which is one of the federal government’s priorities. Currently, vaccines are engineered
to protect against only the strain of flu that researchers predict will be circulating
each year. That means new vaccinations are needed annually, and sometimes those vaccines
don’t work if flu predictions are off.
A universal flu vaccine would protect people from many strains of flu, including pandemics.
“We can give people a vaccine and challenge them with more than one virus, maybe at
different times, to quickly access the actual breadth of protection against different
strains of flu,” Hoft said. “This is important because no one vaccine currently protects
against all strains of influenza, which changes year to year.”
In addition to testing flu vaccines, Hoft said the new Extended Stay Research Unit
can be used to develop vaccines for other illnesses, such as RSV (respiratory syncytial
virus), a sickness that can cause breathing problems and be deadly for babies.
He also believes the research unit holds potential for drug development: challenge
a volunteer with an illness, then see if an investigational drug works as a therapy.
Hoft said the Extended Stay Research Unit likely will conduct a small pilot study
with an industry sponsor sometime within the next six months.
Contact and Additional Information
To learn more about all of the vaccine research being conducted at Saint Louis University,
visit vaccine.slu.edu, call 314-977-6333 or email firstname.lastname@example.org.
Established in 1836, Saint Louis University School of Medicine has the distinction
of awarding the first medical degree west of the Mississippi River. The school educates
physicians and biomedical scientists, conducts medical research, and provides health
care on a local, national and international level. Research at the school seeks new
cures and treatments in five key areas: infectious disease, liver disease, cancer,
heart/lung disease, and aging and brain disorders.