Systems Biology of Inactivated Rabies Vaccine in Healthy Adults With or Without Use of Broad Spectrum Antibiotics

Vaccination has been one of the most important and cost-effective public health interventions
to provide protection against infectious diseases. Since the introduction of the first
vaccine in 1796, there have been countless advances in the field. However, numerous gaps
remain to be addressed. An important gap is understanding the mechanisms that lead to
suboptimal immune responses to vaccination. It has been shown that the magnitude of the
immune response produced by vaccines is highly variable among individuals, with both genetic
and environmental factors playing an important role. More recently, emphasis is being placed
on the role of the microbiota in vaccine immunogenicity. The microbiome is the collection of
all microbial cells in and on the human body, with the majority being in the gastrointestinal
tract. Due to this link between microbiome and the immune system, it is important to further
understand the impact of the microbiome on the immune response to vaccination. This can be
done using systems vaccinology, which is the application of systems biology in vaccinology to
predict vaccine efficacy. The aim is to find molecular signatures, or patterns of gene
expression induced after vaccination, which can be used to correlate and predict the
development of protective immunity. The goal of this study is to determine whether alteration
of microbiota by antibiotic exposure can negatively impact the immunogenicity of rabies
vaccine, and to assess the innate and adaptive immune mechanisms responsible for that
phenomenon. The study also wants to evaluate the safety profile of the different antibiotics
and the lymph node sampling methods.

Half of the study participants will receive the rabies vaccine alone and half will receive
the rabies vaccine along with a 5 day course of antibiotics. The primary objective of this
study is to compare antibody titers after vaccination with a single dose of rabies vaccine in
adults with or without use of antibiotics.

Prior to the clinical trial portion of this study comparing the antibody titers between the
study arms, the researchers will evaluate lymph node sampling methods. The study will
determine whether Fine Needle Aspiration (FNA) or Core Needle Biopsy (CNB) is the best
technique for sampling lymph nodes. Once the best technique is determined, the ideal timing
of lymph node sampling will be examined by comparing follow up sampling at 1, 3 or 7 days
after vaccination. The technique and timing found to be best will be used throughout the
remainder of the trial.Subjects are followed on days 1, 3, 7, 14, 28, 180, and 365 post
randomization. Any grade 2 solicited adverse event (AE) (until D28 or up to 7 days after
lymph node sampling) or serious adverse event (SAE) (for the duration of the study) which may
not have been reported by the subject by calling the site as directed at a prior visit.

Blood samples for immunologic testing will be collected at screening (from D -35 to D -2), on
D0 (at vaccination), D1, D3, D7 (+/- 1 day), D14 (+/- 2 day), D28 (+/- 5 days), D180 (+/- 14
days), D365 (+/- 14 days) post vaccination for both groups to study innate and/or adaptive
immune responses.

Stool samples will be collected in both groups at screening (from D -35 to D -2), on D0 (at
vaccination), D1, D3, D7 (+/- 1 day), D14 (+/- 2 day), D28 (+/- 5 days), D180 (+/- 14 days),
D365 (+/- 14 days) post vaccination to study the gut microbiome. For Group A, stools will be
screened for Clostridium difficile carriage by PCR at screening (from D-35 to D-2).

Inclusion Criteria:

- Healthy individuals aged 18-49 years.

- Able to understand and give informed consent.

- Women of child-bearing potential (not surgically sterile via tubal ligation, bilateral
oophorectomy or hysterectomy or who are not postmenopausal for ≥1 year) must agree to
practice adequate contraception that may include, but is not limited to, abstinence,
monogamous relationship with vasectomized partner, barrier methods such as condoms,
diaphragms, spermicides, intrauterine devices, and licensed hormonal methods for 28
days before and 28 days after Rabies vaccination.

Exclusion Criteria:

- Receipt of the following:

- Receipt of blood products 3 months prior to vaccination or expected receipt
through 12 months after vaccination.

- Receipt of any live virus vaccines within 28 days prior to vaccination or
expected receipt within 28 days after vaccination.

- Receipt of any inactivated vaccine within 14 days or expected receipt within 14
days after vaccination.

- Receipt of any antibiotic 3 months prior to vaccination or expected receipt 28
days after vaccination.

- Receipt of probiotics and prebiotics 3 months prior to vaccination or expected
receipt 28 days after vaccination.

- Receipt of proton pump inhibitors, H2 receptor blockers, or antacids 3 months
prior to vaccination or expected receipt 28 days after vaccination.

- Presence of co-morbidities or immunosuppressive states such as:

- Chronic medical problems including (but not limited to) insulin dependent
diabetes, severe heart disease (including arrhythmias), severe lung disease, auto
immune diseases, thrombocytopenia and grade 4 hypertension. Grade 4 hypertension
per CTCAE criteria is defined as Life-threatening consequences (e.g., malignant
hypertension, transient or permanent neurologic deficit, hypertensive).

- Chronic neurologic conditions including seizure disorder, Parkinson's disease,
myasthenia gravis, neuropathy, or history of encephalopathy, meningitis or
ototoxicity.

- Any history of gastrointestinal disease including (but not only): documented
bacterial gastroenteritis or gastroenteritis associated with fever or associated
with presence of blood/mucus in stools in the last 3 months; inflammatory bowel
disease, and/or gastrointestinal surgery.

- Any history of kidney or liver diseases.

- Alcohol abuse, drug abuse, or psychiatric conditions that in the opinion of the
investigator would preclude compliance with the trial or interpretation of safety
or endpoint data.

- Any history of lymphoma involving axillary nodes or any history of breast cancer.

- Impaired immune function or known chronic infections including, but not limited
to, known HIV, tuberculosis, hepatitis B or C; organ transplantation (bone
marrow, hematopoietic stem cell, or solid organ transplant); immunosuppression
due to cancer; current and/or expected receipt of chemotherapy, radiation
therapy, steroids (i.e., more than 20 mg of prednisone given daily or on
alternative days for 2 weeks or more in the past 90 days , or high dose inhaled
corticosteroids); and any other immunosuppressive therapies (including anti-TNF
therapy), functional or anatomic asplenia, or congenital immunodeficiency.
Subjects receiving > 20 mg/day of prednisone or its equivalent daily or on
alternate days for more than 2 weeks may enter the study after therapy has been
discontinued for more than 3 months and Subjects are excluded if on high dose
intranasal steroids defined as > 960 mcg/day of beclomethasone dipropionate or
equivalent.

- Pregnancy or breast feeding

- Conditions that could affect the safety of the volunteers, such as:

- Severe reactions to prior vaccinations, including anaphylaxis

- History of Guillain-Barré syndrome

- History of bleeding disorders or current use of warfarin, aspirin, heparin,
nonsteroidal anti-inflammatory drugs (NSAIDs) or other blood
thinner/anticoagulant medications in the past week (for subjects undergoing lymph
node sampling)

- Use of anticonvulsants

- Use of digoxin or other forms of digitalis

- Any allergy to any component of the vaccine or lidocaine (for subjects undergoing
lymph node sampling)

- Allergy to vancomycin, metronidazole or neomycin as well as other aminoglycosides
(gentamicin, tobramycin, amikacin, streptomycin)

- Volunteers with any acute illness, including any fever (> 100.4 F [> 38.0C],
regardless of the route) within 3 days prior to vaccination.

- Social, occupational, or any other condition that in the opinion of the investigator
might interfere with compliance with the study and vaccine evaluation.

- Positive C difficile testing by PCR at screening or history of C difficile infection.

- Any grade 2 safety lab test results at screening

- Previously received any rabies vaccine or immunoglobulin.

- Are at high risk of exposure to rabies: veterinarians, animal handlers, rabies
laboratory workers, spelunkers, frequent contact with rabies virus or with possibly
rabid animals, international travelers who are likely to come in contact with animals
in parts of the world where rabies is common, and rabies biologics production workers.

- Bilateral inflammatory process of upper arms in the past 2 weeks.

- Prior breast or axillary biopsy and/or surgery.