In short
This article summarizes clinical trials investigating the use of a pneumococcal vaccine containing serotype 18C polysaccharide conjugated to CRM197 and adsorbed on aluminum phosphate. The vaccine is being studied for prevention of pneumococcal disease in various populations, including healthy adults, infants, and those at increased risk. Key aspects examined include safety, immune responses, and effectiveness against pneumococcal infections when given alone or with other vaccines.
At a glance
- Populations studied
- Healthy infants, adults 18-64 at increased risk, adults 60+ years
- Key objectives
- Safety, immunogenicity, effectiveness against pneumococcal disease
- Vaccine formulations
- 13-valent, 20-valent pneumococcal conjugate vaccines
- Administration
- Intramuscular injection, 0.5 mL dose
- Primary outcomes
- Antibody responses, adverse events, vaccine effectiveness
- Secondary outcomes
- Co-administration effects, specific population responses
- Study designs
- Randomized controlled, open-label, observational
- Notable aspects
- Real-world effectiveness, co-administration studies, high-risk populations
What is the pneumococcal polysaccharide serotype 18C conjugate vaccine?
The pneumococcal polysaccharide serotype 18C conjugate vaccine is a component of broader pneumococcal conjugate vaccines that protect against multiple strains of Streptococcus pneumoniae bacteria. Specifically, this vaccine contains the capsular polysaccharide from serotype 18C of S. pneumoniae that is chemically linked (conjugated) to a carrier protein called CRM197.
The vaccine formulation also includes aluminium phosphate as an adjuvant to enhance the immune response. This specific serotype 18C component is included in pneumococcal conjugate vaccines like Prevenar 13 and Apexxnar.
How does it work?
The vaccine works by stimulating the immune system to produce antibodies against the capsular polysaccharide of the 18C serotype of S. pneumoniae. The key aspects of its mechanism are:
- The polysaccharide from the bacterial capsule acts as the antigen that triggers an immune response.
- Conjugation to the CRM197 protein carrier enhances the immune response, especially in infants and young children.
- The aluminium phosphate adjuvant further boosts the immune system's reaction.
- This results in the production of antibodies that can recognize and help neutralize the 18C serotype of pneumococcus if encountered later.
What is it used for?
This vaccine component, as part of broader pneumococcal conjugate vaccines, is used to prevent infections caused by the 18C serotype of S. pneumoniae, including:
- Invasive pneumococcal disease - like bacteremia and meningitis
- Pneumonia
- Otitis media (middle ear infection)
It is particularly important for protecting infants, young children, older adults, and those with certain health conditions that increase their risk of pneumococcal infections.
How is it administered?
The serotype 18C component is given as part of multi-valent pneumococcal conjugate vaccines. Key points about administration include:
- It is given as an intramuscular injection, typically in the thigh for infants or the upper arm for older children and adults.
- The dosing schedule varies by age and risk factors, but often includes a primary series in infancy followed by booster doses.
- For adults, it is usually given as a single dose.
- The typical dose volume is 0.5 mL.
How effective is it?
As part of pneumococcal conjugate vaccines, the serotype 18C component has shown good effectiveness:
- It induces a strong antibody response against the 18C serotype in most recipients.
- Clinical trials have demonstrated high efficacy in preventing invasive disease caused by this serotype.
- Population studies have shown significant reductions in 18C serotype infections after introduction of conjugate vaccines containing this component.
- The conjugate form provides better protection than older polysaccharide-only vaccines, especially in young children.
Safety and side effects
The pneumococcal conjugate vaccines containing the 18C serotype component have a good safety profile. Common side effects may include:
- Pain, redness, or swelling at the injection site
- Mild fever
- Irritability in infants
- Fatigue
- Headache
- Muscle pain
Serious allergic reactions are rare. The benefits of protection against pneumococcal disease generally outweigh the risks of side effects for recommended individuals.
Who should get vaccinated?
Recommendations for pneumococcal conjugate vaccines containing the 18C serotype component typically include:
- All infants, starting at 2 months of age
- Children and adolescents who didn't receive the vaccine as infants
- Adults 65 years and older
- Younger adults with certain medical conditions that increase pneumococcal disease risk
- Adults who smoke cigarettes
Specific recommendations may vary by country and individual risk factors. Patients should consult their healthcare provider to determine if vaccination is appropriate for them.
Ongoing research
Research continues on pneumococcal vaccines, including those containing the 18C serotype component. Some areas of ongoing study include:
- Development of next-generation vaccines covering more serotypes
- Optimizing vaccination schedules for different age groups and populations
- Long-term effectiveness and the potential need for additional booster doses
- Impact on pneumococcal disease epidemiology and serotype distribution
- Combination with other vaccines to reduce the number of required injections
This ongoing research aims to further improve the prevention of pneumococcal infections and optimize vaccination strategies.