A Phase 4 interventional study of Rabies Vaccine and Metronidazole in Rabies Human, sponsored by Emory University. Completed at 2 sites in United States. Open to participants aged 18 Years to 49 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2023-06-08.
Sponsored by Emory University · Phase 4, Interventional, and Basic science
The use of antibiotics changes micro-organisms in the intestines which may impact the body's vaccine immune response and alter the effectiveness of the rabies vaccine.
There will be two randomized groups (1:1 randomization). Group A will start taking an antibiotic regimen by mouth 3 days prior to vaccination and continue taking antibiotics the day of rabies vaccination and one day after vaccination for a total of 5 days. Group B will only receive the rabies vaccination and will not take any antibiotics. The dosage of each antibiotic is taken from their respective package inserts and does not exceed the maximum dose allowed for each antibiotic.
The purpose of the study is to look at immune response after rabies vaccination with or without the use of antibiotics from day of vaccination to 28 days post vaccination in both groups.
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. The composition of the microbiome has the ability to affect B and T cell development, which are important aspects of the adaptive immune system and major responders to vaccination.
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.
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 28 days after vaccination with the rabies vaccine in adults with or without use of antibiotics.
114 studies on the registry are indexed under Rabies; 15 are open to participants now.
This study's enrollment of 37 is below the median of 201 across 104 interventional studies indexed under Rabies.
Browse Rabies studies →Emory University is the lead sponsor of 1,405 studies on the registry; 225 are open to participants now.
Of its 237 completed or terminated interventional studies of FDA-regulated products, 178 (75%) have results posted.
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Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Receipt of the following:
Presence of co-morbidities or states such as:
Conditions that could affect the safety of the volunteers, such as:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Able to become pregnant: from the first period until menopause, unless permanently unable to through surgery (removal of the womb, or of both ovaries or both fallopian tubes).
Criteria for people of childbearing potential usually ask for a negative pregnancy test and for contraception during the study and for a time after it.
Periods have stopped for good: usually no period for 12 months in a row without another medical reason, sometimes confirmed by a blood test (FSH).
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
Vaccines made with a weakened form of the germ, such as measles–mumps–rubella (MMR), chickenpox and yellow fever. They can be risky when the immune system is weakened. Flu injections are not live; the nasal flu spray is.
A weakened immune system. It can come from an illness, such as HIV or some blood cancers, or from medicines that turn the immune system down, for example after an organ transplant or for an autoimmune disease; steroids at higher doses count.
Read whether the line is about a condition or about medicines, and which medicines and doses it means.
The US National Cancer Institute’s scale of how severe an adverse event is — any unwanted medical event during a study, such as a symptom, an illness or an abnormal test result, whether or not a treatment caused it. Whether it did is judged separately.
“Side effects of earlier treatment resolved to grade 1 or less” means they have settled to mild or gone.
The human immunodeficiency virus, which weakens the immune system.
Many studies now accept people whose HIV is controlled on treatment, judged by the viral load and the CD4 count. Check the limits this study sets.
Hepatitis B is a virus that infects the liver. These are separate tests: HBsAg positive usually means a current infection (a recent vaccination can briefly cause it too); total anti-HBc (HBcAb) positive means an infection now or in the past; HBV DNA measures how much virus is in the blood.
Some studies accept a past infection if HBV DNA is undetectable, sometimes with antiviral medicine during the study. Check what this study allows.
Anti-inflammatory medicines such as prednisone, prednisolone and dexamethasone — not the anabolic steroids used for muscle.
Studies differ in what they allow: check which steroid medicines, routes (tablets, injections, creams, inhalers, eye drops) and doses this study accepts.
A biopsy takes a small piece of tissue to examine. “Archival tissue” is a sample already taken, for example at diagnosis, and kept by the hospital.
Whether a stored sample will do depends on when it was taken, how much there is and what the study needs. Ask whether the study accepts your stored sample or needs a new biopsy.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Childbearing potential
Able to become pregnant: from the first period until menopause, unless permanently unable to through surgery (removal of the womb, or of both ovaries or both fallopian tubes).
Criteria for people of childbearing potential usually ask for a negative pregnancy test and for contraception during the study and for a time after it.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Postmenopausal
Periods have stopped for good: usually no period for 12 months in a row without another medical reason, sometimes confirmed by a blood test (FSH).
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraception
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Live vaccines
Vaccines made with a weakened form of the germ, such as measles–mumps–rubella (MMR), chickenpox and yellow fever. They can be risky when the immune system is weakened. Flu injections are not live; the nasal flu spray is.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Immunosuppression
A weakened immune system. It can come from an illness, such as HIV or some blood cancers, or from medicines that turn the immune system down, for example after an organ transplant or for an autoimmune disease; steroids at higher doses count.
Read whether the line is about a condition or about medicines, and which medicines and doses it means.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
CTCAE grade
The US National Cancer Institute’s scale of how severe an adverse event is — any unwanted medical event during a study, such as a symptom, an illness or an abnormal test result, whether or not a treatment caused it. Whether it did is judged separately.
“Side effects of earlier treatment resolved to grade 1 or less” means they have settled to mild or gone.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
HIV
The human immunodeficiency virus, which weakens the immune system.
Many studies now accept people whose HIV is controlled on treatment, judged by the viral load and the CD4 count. Check the limits this study sets.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hepatitis B tests
Hepatitis B is a virus that infects the liver. These are separate tests: HBsAg positive usually means a current infection (a recent vaccination can briefly cause it too); total anti-HBc (HBcAb) positive means an infection now or in the past; HBV DNA measures how much virus is in the blood.
Some studies accept a past infection if HBV DNA is undetectable, sometimes with antiviral medicine during the study. Check what this study allows.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Corticosteroids (steroids)
Anti-inflammatory medicines such as prednisone, prednisolone and dexamethasone — not the anabolic steroids used for muscle.
Studies differ in what they allow: check which steroid medicines, routes (tablets, injections, creams, inhalers, eye drops) and doses this study accepts.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Biopsy and archival tissue
A biopsy takes a small piece of tissue to examine. “Archival tissue” is a sample already taken, for example at diagnosis, and kept by the hospital.
Whether a stored sample will do depends on when it was taken, how much there is and what the study needs. Ask whether the study accepts your stored sample or needs a new biopsy.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Participants in this group will receive the rabies vaccines as well as an antibiotic regimen consisting of metronidazole, vancomycin, and neomycin sulfate.
Biological: Rabies Vaccine · Drug: Metronidazole · Drug: Vancomycin · Drug: Neomycin Sulfate
Participants in this group will receive the rabies vaccine.
Biological: Rabies Vaccine
A 1.0 milliliter (mL) dose of Imovax® will be given to participants on Day 0 and Day 28 of the study.
Also known as: Imovax
The antibiotic regimen will be given for five days beginning 3 days prior to vaccination, on the vaccination day, and one day after vaccination for a total for 5. The regimen will include 500 milligrams (mg) of Flagyl taken by mouth three times a day.
Also known as: Flagyl
The antibiotic regimen will be given for five days beginning 3 days prior to vaccination, on the vaccination day, and one day after vaccination for a total for 5. The regimen will include 125 mg of Vancocin taken by mouth four times a day.
Also known as: Vancocin
The antibiotic regimen will be given for five days beginning 3 days prior to vaccination, on the vaccination day, and one day after vaccination for a total for 5. The regimen will include 500 milligrams (mg) of Neomycin sulfate taken by mouth three times a day.
Also known as: Mycifradin
Antibody Titers
Antibody titers are examined by direct comparison of antibody titers in the blood. Rabies specific Immunoglobulin G (IgG) endpoint titer was measured by ELISA. The endpoint titer is defined as the reciprocal of the highest plasma dilution that gives a reading above the cutoff values. The cutoff is set based on the average plus 3 times the standard deviation of the reading of 1:160 dilution of baseline plasma.
Time frame: Day 28
Proportion of Participants Achieving Seroprotection
Participants are categorized as achieving seropositivity if rabies specific IgG endpoint titer is present.
Time frame: Day 28
Participant enrollment began July 5, 2018 and all follow up for the primary outcome measure was complete by June 2, 2022. Participants were enrolled at the Hope Clinic of the Emory Vaccine Center in Atlanta, Georgia, USA.
| Milestone | Rabies Vaccine With Antibiotics | Rabies Vaccine |
|---|---|---|
| Started | 19 | 18 |
| Completed | 14 | 15 |
| Not completed | 5 | 3 |
| Withdrew: Withdrawal by subject | 2 | 2 |
| Withdrew: Early termination from study | 3 | 1 |
Antibody titers are examined by direct comparison of antibody titers in the blood. Rabies specific Immunoglobulin G (IgG) endpoint titer was measured by ELISA. The endpoint titer is defined as the reciprocal of the highest plasma dilution that gives a reading above the cutoff values. The cutoff is set based on the average plus 3 times the standard deviation of the reading of 1:160 dilution of baseline plasma.
| IU/mL | Rabies Vaccine With Antibiotics | Rabies Vaccine |
|---|---|---|
| Antibody Titers | 217.39 ± 262.99 | 805.64 ± 943.85 |
Participants are categorized as achieving seropositivity if rabies specific IgG endpoint titer is present.
| Participants | Rabies Vaccine With Antibiotics | Rabies Vaccine |
|---|---|---|
| Proportion of Participants Achieving Seroprotection | 14 | 15 |
Collected over Information on adverse events was collected from the time when the study intervention began through Day 56 of the study.. Non-serious events are listed at a 0% frequency threshold.
| Group | Deaths | Serious | Other |
|---|---|---|---|
| Rabies Vaccine With Antibiotics | 0/19 (0%) | 0/19 (0%) | 2/19 (10.5%) |
| Rabies Vaccine | 0/18 (0%) | 0/18 (0%) | 1/18 (5.6%) |
| Event | Rabies Vaccine With Antibiotics | Rabies Vaccine |
|---|---|---|
| Upper respiratory infectionInfections and infestations | 1/19 | 1/18 |
| DiarrheaGastrointestinal disorders | 1/19 | 0/18 |
| Age, Categorical(Participants) | Rabies Vaccine With Antibiotics | Rabies Vaccine | Total |
|---|---|---|---|
| <=18 years | 0 | 0 | 0 |
| Between 18 and 65 years | 19 | 18 | 37 |
| >=65 years | 0 | 0 | 0 |
| Age, Continuous(years) | Rabies Vaccine With Antibiotics | Rabies Vaccine | Total |
|---|---|---|---|
| Mean | 32.42 ± 7.75 | 32.50 ± 6.58 | 32.46 ± 7.31 |
| Sex: Female, Male(Participants) | Rabies Vaccine With Antibiotics | Rabies Vaccine | Total |
|---|---|---|---|
| Female | 11 | 11 | 22 |
| Male | 8 | 7 | 15 |
| Ethnicity (NIH/OMB)(Participants) | Rabies Vaccine With Antibiotics | Rabies Vaccine | Total |
|---|---|---|---|
| Hispanic or Latino | 1 | 2 | 3 |
| Not Hispanic or Latino | 18 | 16 | 34 |
| Unknown or Not Reported | 0 | 0 | 0 |
| Race (NIH/OMB)(Participants) | Rabies Vaccine With Antibiotics | Rabies Vaccine | Total |
|---|---|---|---|
| American Indian or Alaska Native | 0 | 0 | 0 |
| Asian | 3 | 0 | 3 |
| Native Hawaiian or Other Pacific Islander | 0 | 0 | 0 |
| Black or African American | 10 | 10 | 20 |
| White | 6 | 8 | 14 |
| More than one race | 0 | 0 | 0 |
| Unknown or Not Reported | 0 | 0 | 0 |
| Region of Enrollment(Participants) | Rabies Vaccine With Antibiotics | Rabies Vaccine | Total |
|---|---|---|---|
| United States | 19 | 18 | 37 |
PDFs hosted by the registry, ClinicalTrials.gov.
Plan to share: No
Ran from Jul 2018 to primary completion in Jun 2022, 46 months.
Results were first posted in Jun 2023, 1 year after primary completion.
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This study is completed, as verified in May 2023. You cannot join it, but the record below documents what was studied.
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Studies of the drugs tested here: Metronidazole · Vancomycin · Neomycin