Quality Control of Vaccines PDF

Quality control of Vaccines Dr Javed Ingredients in vaccines • Vaccines contain tiny fragments of the diseasecausing organism or the blueprints for making the tiny fragments. They also contain other ingredients to keep the vaccine safe and effective. • Antigen • Preservative • Stabilizers • surfac...

Quality control of Vaccines Dr Javed Ingredients in vaccines • Vaccines contain tiny fragments of the diseasecausing organism or the blueprints for making the tiny fragments. They also contain other ingredients to keep the vaccine safe and effective. • Antigen • Preservative • Stabilizers • surfactants • Diluent • Adjuvants Antigen • All vaccines contain an active component (the antigen) which generates an immune response, or the blueprint for making the active component. The antigen may be a small part of the disease-causing organism, like a protein or sugar, or it may be the whole organism in a weakened or inactive form. Preservatives • Preservatives prevent the vaccine from becoming contaminated once the vial has been opened, if it will be used for vaccinating more than one person. • Some vaccines don’t have preservatives because they are stored in one-dose vials and are discarded after the single dose is administered. • The most commonly used preservative is 2-phenoxyethanol. It has been used for many years in a number of vaccines, is used in a range of baby care products and is safe for use in vaccines, as it has little toxicity in humans. Stabilizers • Stabilizers prevent chemical reactions from occurring within the vaccine and keep the vaccine components from sticking to the vaccine vial. • Stabilizers can be sugars (lactose, sucrose), amino acids (glycine), gelatin, and proteins (recombinant human albumin, derived from yeast). Surfactants • Surfactants keep all the ingredients in the vaccine blended together. They prevent settling and clumping of elements that are in the liquid form of the vaccine Diluent • A diluent is a liquid used to dilute a vaccine to the correct concentration immediately prior to use. The most commonly used diluent is sterile water. Adjuvant • Some vaccines also contain adjuvants. An adjuvant improves the immune response to the vaccine, sometimes by keeping the vaccine at the injection site for a little longer or by stimulating local immune cells. • The adjuvant may be a tiny amount of aluminium salts (like aluminium phosphate, aluminium hydroxide or potassium aluminium sulphate). Vaccine and types of vaccine Vaccine is a biological preparation that consists of either a whole organism or a part of it against which immunization has to be achieved. Types of vaccine 1)Live attenuated vaccine (no pathogenicity but having immunogenicity the ability of organism to provoke an immune response ) Example: measles, mumps, rubella and smallpox 2)Inactivated /killed vaccine: made from microorganisms (viruses, bacteria, other)have been killed by physical or chemical processes. Example: inactivated polio vaccine and Rabies vaccine • Toxoid vaccine: Use of toxin, a toxic substance produced by various bacteria that cause a disease. • In this case, the toxin is made harmless but can induce an immune response when administered to the body. Example Tetanus toxoids and Diphtheria toxoids • Subunit vaccine: It contains fragments /part of the pathogen such as proteins or polysaccharides or surface spikes instead of the whole organism. like Hepatitis B vaccine Quality evaluation of vaccines 1) Staining test 2) Inactivation test 3) Sterility test 4) Freedom from abnormal toxicity/General safety test Staining test ( Gram Staining) • Approximately 10 mL of the test sample is centrifuged at approximately 2,000 rpm for 30 minutes. The sediment or the bottom portion is spread on a glass slide, dried, and heat-fixed over a flame. • The smear is then stained by the Gram’s Method and, unless otherwise specified, examined microscopically. Criteria for judgment. • No bacteria shall be observed other than those defined in the individual monographs. Inactivation test • Each purified bulk should be tested in mice for effective inactivation of the virus before the addition of preservatives and other substances. • The test should be done with undiluted purified bulk material injected intracerebrally into 20 mice each weighing 15-20 gm each • Mice shall be observed for 14 days, at the end of the observation period no cytopathetic effects should be observed Safety of vaccines Freedom from abnormal toxicity/General safety test • The test was developed to detect possible toxic contamination derived from the manufacturing processes of the product. • Test in mice Take 5 healthy mice weighing 17-22g. Inject one human dose 1 ml Intraperitoneally .Observe the mice for 7 days If more than one animal dies preparation fails the test If one animal dies repeat the test. Preparation passes the test if no animal dies in the second group. Test in guinea pigs • Take 2 healthy guinea pigs (250-350 g). • Inject one human dose/ 5 ml Intra-peritoneally. • Observe guinea pigs for 7 days If more than one animal dies/shows ill health preparation fails the test If one animal dies/ shows ill health repeat the test Preparation passes the test if no animal dies/ shows ill health in the second group Sterility test (Direct Inoculation) Sterility of any killed/ inactivated or toxoid vaccine is essential step in quality assurance and certification of vaccine. It should be done using 20 vials from a commercial batch of any vaccine. well mixed vaccine should be aseptically transferred to each of the two media: • For bacteria – Fluid thioglycolate media (FTM) use for both aerobics anaerobic bacteria Media preparation – sample transferring into media –Incubation 30- 350c for 7 days • For fungi - proceed as described in the test for bacteria but use soyabean casein digest medium (SCDM) and incubate the plates at 20°C to 25 °C for 14 days. • If no growth appears then from each tube of inoculated medium, one ml of contents is transferred into tube containing 100 mL of fresh and sterile respective medium and incubated for 5 to 7 days as above. • There should always be a positive and negative control in the test. • .Growth of microbes should not be detected in any of the tube inoculated with vaccine; growth should always be visible in positive control and no growth in negative control. • The test takes 19 to 21 days to be completed. • In case of any confusion test must be repeated. Membrane filter Use membrane filters which are 50 mm in diameter and having: • nominal pore size not greater than 0.45 µm. • Pass the sample solution from filter paper . • The filter is then rinsed and then the membrane is transferred into the appropriate medium and incubated for 14 days for any microbial growth. Finished product testing POTENCY TEST • Potency assay is one of the main methods used for assuring the quality of vaccine which is based on the measurement of one or several parameters that have been shown to be related directly or indirectly with product efficacy. • The main types of potency tests performed for vaccine includes in-vitro titration of antibodies a common lab test used to detect and measure antibodies in the blood and in-vivo methods involving immunization of small laboratory animals (e.g., mice, rats & guinea pigs). Invitro-potency assay : Antibodies titration: • This test is used to estimate the presence and measure the amount of antibodies within a person’s blood. • Testing serum collected from vaccinated animal (serological test) for level of antibodies titers. • Titer level indicates that animal would be protected against disease or NOT. • Antibody titer refers to highest dilution of serum sample that causes a positive test reaction. IN VIVO POTENCY TEST • Testing in-vivo potency/efficacy/assay or virus content of vaccine to ensure that vaccinated recipient receives enough virus to induce a protective immunity. • Test animals are divided into two groups of 8-10 animals per group and housed separately. • One group of animals (adult mice, suckling mice and guinea-pigs,) is vaccinated while the other group remained unvaccinated to act as control group • Expose the vaccinated and unvaccinated animal with a virulent virus strain of disease, In this method the animal is observed on daily basis. • Potency of test vaccine expressed as a percentage of potency of standard vaccine. “At least 90 percent of the vaccinated animals should survive the challenge and show no clinical signs of the disease” • All unvaccinated control animals should die of disease. • Results is expressed in units of activity with reference to standard • Vaccines containing live microorganisms are generally tested for potency by determining their content of viable particles. • Example: In the case of BCG vaccine, dilutions of vaccine are prepared in a medium which inhibits clumping of cells, and fixed volumes are dropped on to solid media capable of supporting mycobacterial growth. After a 14 days the colonies generated by the drops are counted and the live count of the undiluted vaccine is calculated. Storage of vaccines • When a vaccine is too hot or too cold, it becomes less effective or even inactive. • Most vaccines require refrigerated storage at between 2 and 8 °C. • Some vaccines require temperatures as cold as -20°C. Some of the newer vaccines need to be kept ultra cold at -70°C. For frozen vaccines some of them can be safely stored for a limited time between 2 and 8°C. How the vaccines is shipped COLD CHAIN PATH https://www.youtube.com /watch?v=4SaDefN5L4k