Gonorrhea is a common sexually transmitted disease that is caused by the bacteria Neisseria gonorrhoeae (N. gonorrhoeae). When transmitted, the bacteria infects mucous membranes of the body including the throat and reproductive tract. Another route of transmission is from a pregnant person to their baby as the baby passes through the birth canal. Gonorrhea infection in neonates can lead to life-threatening infections and long-term health complications.
While the Centers for Disease Control (CDC) estimates that the rate of gonorrhea infection in the United States is around 1.6 million new cases per year, a study found that the global prevalence of gonorrhea infection was close to 78 million. Additionally, global health studies show that gonorrhea disproportionately affects women, newborns, and people in low- and middle-income countries. As such, many have called for a vaccine to be developed that will help control the rate of infection. Recently, the biotech company Intravacc announced that it has received close to $15 million dollars from the National Institute of Allergy and Infectious Diseases (NIAID) to develop a prophylactic, intranasal vaccine against the bacteria that causes gonorrhea, N. gonorrhoeae.
The vaccine will use Intravacc’s proprietary outer membrane vesicle (OMV) platform technology to deliver the vaccine. N. gonorrhoeae is in a class of bacteria called gram-negative, diplococcus bacteria. And, like all Gram-negative bacteria, N. gonorrhoeae contains an outer membrane and an inner cytoplasmic membrane. The outer membrane of N. gonorrhoeae produces OMVs that bud and then detach from the bacteria during active growth. These vesicles then deliver the bacterial payload to cells of the body and help the bacteria unleash its pathogenic effects when it infects a human. Intravacc is planning on making use of this function as it develops its vaccine. (See the embedded video below for an excellent talk on this technology from Labroots’ 2018 Microbiology and Immunology conference).
The vaccine, called NGoXIM, is based on N. gonorrhoeae OMVs. The company will modify the OMVs with sustained release microspheres containing a cytokine called interleukin-12 (IL-12). IL-12 is a naturally occurring substance produced by the immune cells of the body that helps to fight infections. During gonorrhea infection, the N. gonorrhoeae bacteria suppresses the immune system, and as such, the vaccine will help the body stimulate IL-12 and reverse immunosuppression.
Intravacc has stated that their proof-of-concept studies with the vaccine have shown promise in animal models and other studies have shown this technology to be effective as well. Now the company will work on making the vaccine deliverable intranasally. The intranasal route of administration has many advantages over traditional, intramuscular vaccines, such as: the low volume of the vaccine required for intranasal administration; the ease of administration, especially self-administration; and the rapid induction of mucosal immunity. The company will continue to work towards studying the toxicity and efficacy of the vaccine and hopes to soon move the vaccine to clinical trials.
Sources: CDC; American Pregnancy Association; PLOS One; Vaccine; Intravacc; NIAID; Journal of Infectious Diseases; Indian Journal of Pharmaceutical Sciences;