24 Questions
How is the potency of a test vaccine expressed?
As a percentage of potency of standard vaccine
What happens to unvaccinated control animals in the potency test?
They die of the disease
How are vaccines containing live microorganisms generally tested for potency?
By determining their content of viable particles
What happens to vaccines when stored at incorrect temperatures?
They become less effective or inactive
What is the temperature range for refrigerated storage of most vaccines?
Between 2 and 8°C
How are vaccines containing live microorganisms tested for potency?
By determining their content of viable particles
What is the significance of observing at least 90 percent survival in vaccinated animals during a potency test?
It indicates that the vaccine is effective
What is the purpose of using an unvaccinated control group in a potency test?
To compare the effects of vaccination with no vaccination
How long can some frozen vaccines be safely stored at refrigerated temperatures?
For a limited time between 2 and 8°C
What is the temperature requirement for shipping some newer vaccines?
Ultra cold at -70°C
What is the purpose of surfactants in a vaccine?
Prevent settling and clumping of liquids
Which type of vaccine uses weakened organisms that retain immunogenicity but lose their ability to cause disease?
Live attenuated vaccines
What is the purpose of adjuvants in some vaccines?
Improve immune response
What is the purpose of a diluent in a vaccine?
Dilute the vaccine before use
What type of vaccines use dead organisms or viruses as antigens?
Inactivated or killed vaccines
What is the purpose of staining tests for evaluating vaccine quality?
Detect contaminating bacteria using the Gram method
What does the inactivation test for evaluating vaccine quality involve?
Injecting a sample into mice to ensure virus has been effectively killed before other substances are added
What is tested in the sterility test for evaluating vaccine quality?
Absence of bacteria and fungi in final product
What is tested in the potency assay for evaluating vaccine quality?
Amount of antibodies present in the vaccine to ensure effectiveness against targeted disease
What do vaccines contain to keep them safe and effective?
Tiny fragments of the disease-causing organism or blueprints for making the fragments
What is the purpose of preservatives in vaccines?
To prevent the vaccine from becoming contaminated once the vial has been opened
What is the most commonly used preservative in vaccines?
2-phenoxyethanol
What do stabilizers in vaccines prevent?
Chemical reactions from occurring within the vaccine
What is an antigen in a vaccine?
An active component that generates an immune response
Study Notes
- Surfactants are substances that help keep the ingredients in a vaccine blended together, preventing settling and clumping of liquids.
- A diluent is a liquid used to dilute a vaccine before use, most commonly sterile water.
- Some vaccines contain adjuvants, which improve immune response, often through prolonging vaccine presence at the injection site or stimulating local immune cells. Adjuvants may include aluminum salts.
- There are several types of vaccines:
- Live attenuated vaccines, which use weakened organisms that lose their ability to cause disease while retaining immunogenicity. Examples include measles, mumps, rubella, and smallpox.
- Inactivated or killed vaccines, which use dead organisms or viruses as antigens. Examples include inactivated polio vaccine and rabies vaccine.
- Toxoid vaccines, which use harmless toxins produced by bacteria to induce an immune response. Examples include tetanus toxoids and diphtheria toxoids.
- Subunit vaccines, which use fragments of the pathogen, such as proteins or polysaccharides or surface spikes. Examples include the hepatitis B vaccine.
- The quality of vaccines is evaluated through several tests:
- Staining tests, which use the Gram method to detect contaminating bacteria.
- Inactivation tests, which ensure that the virus has been effectively killed before other substances are added.
- Sterility tests, which check for the absence of bacteria and fungi in the final vaccine product.
- Freedom from abnormal toxicity and general safety tests, which detect any potential toxic contaminants.
- The staining test is a microscopic examination of a sample smear after staining with the Gram's method. No bacteria other than those specified in individual monographs should be observed.
- The inactivation test involves injecting a sample into mice to ensure the virus has been effectively killed before other substances are added. No cytopathic effects should be observed after a 14-day observation period.
- The freedom from abnormal toxicity and general safety test is designed to detect possible toxic contamination from the manufacturing process. The test is conducted in mice and guinea pigs, and no animals should die or show signs of illness during the observation period.
- The sterility test involves inoculating 20 vials of the vaccine into fluid thioglycolate media for bacteria and soybean casein digest medium for fungi. No growth should be observed in any of the tubes inoculated with the vaccine. A positive and negative control should always be included in the test.
- Membrane filters, with a nominal pore size not greater than 0.45 µm, are used in the sterility test to further ensure the absence of bacteria and fungi.
- The potency of a vaccine is tested through methods such as antibody titration, which measures the amount of antibodies present in the vaccine to ensure it will be effective against the targeted disease.
- The in-vitro potency assay involves testing a serum sample collected from a vaccinated animal to determine the level of antibodies present, which indicates the animal's protection against the disease. The antibody titer is the highest dilution that causes a positive test reaction.
Test your knowledge about the ingredients in vaccines and the quality control procedures involved in their production. Learn about antigens, preservatives, stabilizers, and other components that ensure vaccine safety and efficacy.
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