Chlamydia Trachomatis Vaccine Research Through The Years
Katelijn Schautteet
1Department of Molecular Biotechnology, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000 Ghent, Belgium
Abstract
Chlamydia trachomatis is a Gram-negative obligate intracellular bacterium. It is the leading cause of bacterial sexual transmitted infections . World Health Organization figures estimated that over 90 million new cases of genital C. trachomatis infections occur worldwide each year. A vaccination program is considered to be the best approach to reduce the prevalence of C. trachomatis infections, as it would be much cheaper and have a greater impact on controlling C. trachomatis infections worldwide rather than a screening program or treating infections with antibiotics. Currently, there are no vaccines available which effectively protect against a C. trachomatis genital infection despite the many efforts that have been made throughout the years. In this paper, the many attempts to develop a protective vaccine against a genital C. trachomatis infection will be reviewed.
1. Introduction
2. Chlamydia muridarum versus C. trachomatis Mouse Models
As there are considerable differences between the C. muridarum and the C. trachomatis murine model, it is difficult to make direct comparisons. In order to understand the pathogenesis of human chlamydial infections completely, it is absolutely necessary to thoroughly investigate chlamydial infection in its natural human host .
3. Protective Immune Responses to C. trachomatis
A Chlamydia Outbreak Is Threatening The Koala Population In Australia
- to copyLink copied!
- to copyLink copied!
- to copyLink copied!
Related video above: Did you know koalas have nearly identical fingerprints to humans?
About 400 Australian koalas will be vaccinated against chlamydia as part of a trial that researchers say they hope could play a significant role in the longer-term survival of the animals.
Chlamydia, a sexually transmitted disease also found in humans, has spread widely among Australian koalas, affecting half the animals in some areas.
“It is a cruel disease that causes debilitating conjunctivitis, bladder infections and at times, infertility,” Amber Gillett, Australia Zoo Wildlife Hospital veterinarian and coordinator of research, said in a statement on Friday as the trial began.
The bacterial disease, which can be spread from mothers to their newborns, can also cause blindness, researchers say.
The koalas will each receive one dose of the vaccine and will be microchipped before being released into the wild.
“While this vaccination will directly benefit each of the animals, the trial will also have a focus on the protection provided by vaccination,” said Peter Timms, professor of microbiology at the University of the Sunshine Coast, which is leading the trial.
Although in many cases chlamydia can be treated with antibiotics, the researchers said they hope the vaccine will help improve the survival and reproduction of the animals.
Screening For Chlamydia And Gonorrhea
Chlamydia and gonorrhea are among the most common sexually transmitted infections in the US. The rate of chlamydia infection among women is nearly double the rate among men based on 2019 CDC data. Gonorrhea infection is more prevalent in men than in women. Infection rates are highest among adolescents and young adults of both sexes. In 2019, 61% of all reported chlamydia infections, and in 2018 54% of new gonococcal infections, were among persons aged 15 to 24 years.
Chlamydial and gonococcal infections in women are usually asymptomatic and may lead to pelvic inflammatory disease and its associated complications, such as ectopic pregnancy, infertility, and chronic pelvic pain. Infection in men may lead to urethritis and epididymitis. However, men are often also asymptomatic.
The USPSTF recently updated and affirmed their 2014 recommendation for the screening for chlamydia and gonorrhea. Recommendations include:
For sexually active women, including pregnant persons, screen for chlamydia and gonorrhea if they are:
- 24 years or younger
- 25 years or older and at increased risk for infection
Women 25 years or older are at increased risk if they have:
- A previous or coexisting STI
- A new or more than 1 sex partner
- A sex partner having sex with other partners at the same time
- A sex partner with an STI
- Inconsistent condom use when not in a mutually monogamous relationship
- A history of exchanging sex for money or drugs
- A history of incarceration
For sexually active men:
References:
Also Check: How Long Before Signs Of Chlamydia
Medical Contraindications/exemptions For Covid
Earlier this month, we reviewed contraindications for influenza vaccination. As the nation discusses mandatory COVID-19 vaccination, we primary care clinicians are being asked to certify contraindications and precautions for these vaccines.
The only true contraindications for any of the COVID-19 vaccines are:
- Severe allergic reaction after a previous dose or to a component of the COVID-19 vaccine.
- Immediate allergic reaction of any severity after a previous dose or known allergy to a component of a COVID-19 vaccine.
Patients with these reactions should not get the same type of COVID-19 vaccine . There is a list of chemical components in each vaccine at the link below .
There are also precautions for COVID-19 vaccination. If a precaution exists, a patient may get the vaccine, but preferably in a prepared medical setting with supplies and personnel capable of recognizing and addressing anaphylaxis . These patients should be observed for 30 minutes rather than the usual 15.
Precautions:
- Any immediate allergic reaction to other vaccines or injectable therapies.
- A history of a contraindication to mRNA vaccines is a precaution to Janssen vaccine and vice versa.
It is important to discuss these precautions with the patient to reach a shared decision – discussing risk for acquiring COVID-19, risk of severe COVID-19 illness, and unknown risk of anaphylaxis in people with such reactions to other vaccinations.
The following are considered NEITHER contraindications NOR precautions:
Promising Immune Response From Chlamydia Vaccine
The two versions of the vaccines were well tolerated and immunogenic no participants of the placebo group achieved an immune response.
Shattock commented: The findings are encouraging as they show the vaccine is safe and produces the type of immune response that could potentially protect against chlamydia. Folmann explains the reason for its success was the vaccines combination of neutralizing antibodies and T cells.
The most important result is that we have seen protective antibodies against Chlamydia in the genital tracts. Local immunity in the genital tract is important to stop the infection as quickly as possible Follmann added in a statement. This will help to generate a long term immune response against the bacterial condition.
Due to the vaccines success, the researchers are planning to move into further clinical trials to find out whether it is truly protective or not, Shattock explained. It is likely that the more effective of the two, the CTH522 vaccine adjuvanted with CAF01 liposomes, will become the primary focus of future trials.
In the long term, the researchers are considering combining their chlamydia vaccine with the successful HPV vaccine in the same target population, to further prevent severe consequences these STIs can have on womens health, notes Folmann.
Related Companies
Don’t Miss: Signs Of Chlamydia In Mouth
Why Do We Need A Vaccine
The World Health Organization estimates that more than one million new infections with the four curable sexually transmitted diseases chlamydia, gonorrhoea, syphilis and trichomoniasis are acquired each day. With around 131 million annual infections, chlamydia remains the most common sexually transmitted bacterial disease.
Chlamydia is primarily a disease in young adults, with the highest incidence of infections observed in adolescents and young adults. However, since three in four infections remain asymptomatic, the actual incidence is likely to be underestimated.
Untreated and repeated infections are the main drivers of chlamydia-associated morbidity. One in every six infected women develops ascending infection and pelvic inflammatory disease, which contributes to chronic pelvic pain and is a leading cause of tubal factor infertility and ectopic pregnancy.
C. trachomatis infection is strongly associated with increased susceptibility to other sexually transmitted diseases, particularly gonorrhoea and HIV. Infection during pregnancy poses a risk of adverse outcomes such as miscarriage, stillbirth and preterm birth by either direct foetal infection, placental damage, or severe maternal illness. In men, C. trachomatis mainly causes epididymitis, and in both men and women infections can trigger reactive arthritis in a minority of cases.
The Host Response To Infection
Since widespread antibiotic therapy was introduced serum anti-Ct antibodies have declined in parallel with increased Ct prevalence. Whilst clearing infection, antibiotics may alter the development of immunity. It remains controversial whether pathology is caused directly by infection or by the immune response. There is evidence that women who make a pro-inflammatory, interferon- dominated cytokine response have less re-infection and infertility than those who make IL-10 and IL-4 dominated Th2 responses. As IFN- induces a persistent non-infectious state in Ct in vitro it remains unclear whether a Th1 response completely clears infection in vivo. Th1 dependent IgG2 antibodies to Ct antigens are higher in women with cervicitis and PID indicating that Th1 responses may be associated with inflammatory pathology.
You May Like: If You Test Positive For Chlamydia
How Does The Vaccine Work
At Statens Serum Institut, our vision is a vaccine that targets the bacterium immediately after it enters the genital tract. We have designed a vaccine that elicits both cell-mediated and humoral immunity. The first line of defence is mediated by neutralising antibodies, to reduce initial infectious load and once the bacteria are intracellular, they will be targeted by a bactericidal cell-mediated immune response.
After completion of an extensive discovery programme in the search for vaccine candidates, a first-generation vaccine candidate , based on the major outer membrane protein of the C trachomatis bacterium, has now completed clinical phase 1 trial testing.The trial aimed to assess the safety and ability to provoke an immune response of the CTH522 chlamydia vaccine. 35 women, not infected with chlamydia, were included in the trial. The vaccine was safe, and all women in the trial developed an immune response against chlamydia.
During the trial, blood samples were collected which showed that all vaccinated women had generated specific antibodies and T-cells targeting chlamydia. Local immunity in the genital tract is important to stop the infection as quickly as possible and during the trial high levels of antibodies were found in mucous secretion, including the special mucosal antibody IgA, which effectively can block chlamydia early in the course of infection.
Full Speed Ahead On The Development Of The Vaccine
The question now is if the vaccine will protect against Chlamydia when women are infected in the real world.
Research shows that the combination of antibodies and T cells does protect against Chlamydia, but, of course, we have to test the vaccine in larger and more long-termed clinical trials to see if it protects against infection. Given the results at hand, we have accelerated our further clinical trials, says Frank Follmann.
Professor Peter L. Andersen, Head of SSIs Center for Vaccine Research, continues:
The HPV vaccine has shown us how effective vaccination can be against a sexually transmitted infection. We hope to do the same with Chlamydia and, in the long term, combine the two vaccines.
You May Like: What Is Azithromycin 500mg Used To Treat Chlamydia
A 2016 Study Ran By University Of Queensland Calculated There Were Around 330000 Koalas Left In Australia
About 400 Australian koalas will be vaccinated against chlamydia as part of a trial that researchers say they hope could play a significant role in the longer-term survival of the animals. Chlamydia, a sexually transmitted disease also found in humans, has spread widely among Australian koalas, affecting half the animals in some areas.
It is a cruel disease that causes debilitating conjunctivitis, bladder infections and at times, infertility, Amber Gillett, Australia Zoo Wildlife Hospital Wildlife veterinarian and coordinator of research, said in a statement on Friday as the trial began.
The bacterial disease, which can be spread from mothers to their newborns, can also cause blindness, researchers say. The koalas will each receive one dose of the vaccine and will be microchipped before being released into the wild.
What Are The Symptoms Of Chlamydia
In most cases, chlamydia has no symptoms.
In women, chlamydia usually infects the cervix first, causing cervicitis . That can cause pain, irritation, or vaginal discharge. Chlamydia infections can also involve the urethra, leading to urethritis and causing pain while urinating .
In men, chlamydia bacteria can infect the urethra and lead to urethritis , which causes pain while urinating and urethral discharge. Untreated chlamydia infection can also cause epididymitis, swelling in the tubes on the back of the testicles, causing pain .
In both women and men, chlamydia can infect the eyes, causing chlamydial conjunctivitis symptoms include redness, irritation, and tearing. Chlamydia can also infect the rectum, either through anal sex or the spread of bacteria from the vagina. This might produce pain, discharge or bleeding, or no symptoms at all .
Chlamydia trachomatis is also responsible for lymphogranuloma venereum , an infection of the lymphatic system, causing tender, swollen lymph nodes. It can also cause inflammation in the rectum accompanied by gastrointestinal symptoms .
While we arent there yet, it looks like there may be hope for a chlamydia vaccine in the near future. Researchers are particularly encouraged because of the success of the vaccine against another common STI, human papillomavirus . Hopefully, further trials and vaccine research will lead to a genital chlamydia vaccine.
Don’t Miss: How To Make Chlamydia Go Away
Australian Koalas To Be Vaccinated Against Chlamydia In New Trial: ‘it Is A Cruel Disease’
Lisa Maree Williams/Getty
Hundreds of koalas in Australia are one step closer to being protected from chlamydia.
About 400 koalas are set to receive a dose of a chlamydia vaccine as part of a trial at Queensland’s Australia Zoo Wildlife Hospital, Reuters and The Guardian reported. Because chlamydia is so pervasive among koalas, those running the trial hope that it will help the species’ long-term survival.
The koalas involved in the trial, which kicked off on Friday, will get a jab of vaccine and a microchip, so that they can be tracked, before being sent back into the wild.
Chlamydia, typically a sexually transmitted disease, can also be transferred from mother koalas to their joeys. Some koala populations in areas of south-east Queensland and New South Wales have as high as a 50 percent infection rate, The Guardian reported.
RELATED: Save the Koala Day Is Coming! Celebrate by Working from Home with a Bunch of Koalas
“While this vaccination will directly benefit each of the animals, the trial will also have a focus on the protection provided by vaccination,” Peter Timms, professor of microbiology at the University of the Sunshine Coast, said.
Timms and several of his colleagues published a report in Nature last year about their chlamydia vaccine for koalas, which was developed over 10 years and shows promise of being more effective than antibiotics.
RELATED VIDEO: Baby Koala Reunited With Mother After Falling From Tree
How Std Testing Can Help
If you’re sexually active, thenSTD testing is always a smart idea, and it’s easier than you might expect, too. Testing for chlamydia and gonorrhea typically involves providing a urine sample. An HIV test will require a blood test or swabbing the inside of your mouth. Genital herpes and syphilis can both be done through a blood test and if you’d like to get tested for HPV, you should start with a Pap test. Get tested regularly, no matter how healthy you think you are. Affordable testing has become so widely available – finding a center is easier than ever.
If you are interested in ordering an STD test including a gonorrhea test or herpes testing contact e7 Health today to request an appointment, or book an appointment online.
You May Like: Tested Negative For Chlamydia And Gonorrhea But Still Have Discharge
Features Of Chlamydia In Sheep Vaccine
Enzootic abortion in sheep Enzootic abortion was relatively unknown in the country until 1972 whereby there was a massive outbreak of abortions and stillbirths in ewes. In some flocks . Enzootic abortion was relatively unknown in the country until 1972 whereby there was a massive outbreak of abortions and stillbirths in ewes. In some flocks abortions were as high as 60%.
This disease is caused by an organism called Chlamydia psittaci and is one of the biggest causes of abortions and stillbirths in sheep and goats. This organism is found throughout the world, including South Africa. There are other syndromes associated with this disease, for example, respiratory tract and digestive tract infections. The organism may infect a wide range of hosts including cattle, birds and humans.
Immunological Markers Of Infection Pathology And Protective Immunity
Antibodies and T-lymphocyte responses to several Ct proteins have been described. Infection rate and organism load on reinfection decrease with age suggesting development of at least partial protective immunity.
Antibody responses require CD4-T-lymphocyte help. B-lymphocytes and antibodies recognize native-protein epitopes which are not necessarily linear, whereas T-lymphocytes recognise short linear peptides in the context of self MHC-I for CD8-T-cells and self MHC-II for CD4-T-cells. CD4-T-cells can be activated as pro-inflammatory Th17 and Th1 cells or as Th2 cells. Both Th1 and Th2 cells help B-cells to make antibody but the immunoglobulin subclasses produced differ. As different immunoglobulin subclasses vary in biological activity this may be relevant to pathology following infection.
Ct heat shock proteins are analogous to human HSPs and antibodies to cHSP60 are associated with autoimmunity. Ct STI is associated with antibodies to sperm in semen and IgG antibodies to cHSP60 are associated with reproductive failure. Sperm have several surface HSPs and cross-reaction with cHSPs may initiate autoimmune responses to sperm. IgG responses to cHSP60 does not correlate with pathology in women but women with tubal infertility have a high prevalence of antibodies to cHSP60.
Don’t Miss: How Long Can Chlamydia Last
In Development: Hiv Vaccines
The human immunodeficiency virus is the agent that causes Acquired Immune Deficiency Syndrome . HIV can be transmitted via sexual contact with an infected person.
When a person first contracts HIV, he may have a mild to moderate illness with fever. After these symptoms subside, the virus persists in a stealth mode and causes slow damage to the immune system. Medications can keep people healthy for many years and perhaps even indefinitely. A person with HIV infection that has progressed to AIDS can also benefit from treatment with medicines. There can be a substantial restoration of immune function while the patient remains on active treatment. A person with AIDS has great difficulty fighting other diseases because of damage to the bodys disease-fighting white blood cells.
Progress toward an HIV vaccine has been slow since the virus was isolated in 1983. Only three HIV vaccines have been tested in clinical efficacy trials. It is difficult to make a vaccine for HIV for several reasons:
- HIV mutates, or changes, much more rapidly than most other viruses. Targeting a vaccine to a rapidly changing virus is challenging task for vaccine researchers.
- HIV damages the cells of the immune system. But to be effective, a vaccine must trigger the immune system to fight the disease agent. So, a challenge for HIV vaccine researchers is to develop a vaccine for HIV that must interact with the immune system in a way that is very different from the natural behavior of the virus.