_IMMUNIZATION
_ An individual may be immunized by :
1.Vaccination- Active immunization.
2.Passive immunization : Protective antibodies are used in serum
VACCINATION
(Active Immunization)
Vaccinations are done with vaccines which contain specific antigens. So vaccine is used for artificial active immunization.
Types of vaccines
1. Toxoids, e.g. diphtheria toxoid, tetanus toxoid
2. Killed (inactivated) microorganisms, e.g. killed pertussis vaccine, rabies vaccine.
3. Live attenuated microorganism, e.g. BCG vaccine, polio vaccine, measles vaccine.
4. Subunit vaccines contain individual protective antigens.
Booster Dose. After primary immune response, if sufficient time elapses between initial and subsequent vaccination (booster dose) there occurs secondary immune response or booster response. It occurs due to presence of memory cells. Booster doses of vaccines are to be given for tetanus, diphtheria and poliomyelitis at appropriate need.
1.Vaccination- Active immunization.
2.Passive immunization : Protective antibodies are used in serum
VACCINATION
(Active Immunization)
Vaccinations are done with vaccines which contain specific antigens. So vaccine is used for artificial active immunization.
Types of vaccines
1. Toxoids, e.g. diphtheria toxoid, tetanus toxoid
2. Killed (inactivated) microorganisms, e.g. killed pertussis vaccine, rabies vaccine.
3. Live attenuated microorganism, e.g. BCG vaccine, polio vaccine, measles vaccine.
4. Subunit vaccines contain individual protective antigens.
Booster Dose. After primary immune response, if sufficient time elapses between initial and subsequent vaccination (booster dose) there occurs secondary immune response or booster response. It occurs due to presence of memory cells. Booster doses of vaccines are to be given for tetanus, diphtheria and poliomyelitis at appropriate need.
_Program and Schedule of Vaccinations
A. Children. Schedule of vaccination at different ages.
(a) EPI (Expanded program of Immunization) for children introduced by Bangladesh Government to cover seven diseases- tuberculosis, diphtheria, pertussis (whooping cough), tetanus, poliomyelitis, measles and Hepatitis B virus. Triple vaccine DPT is used for diphtheria, pertussis and tetanus. DPT consists of diphtheria toxoid, killed pertussis bacteria and tetanus toxoid. Recently Hepatitis B vaccine has been included with EPI to prevent Hepatitis B virus.
Vaccination- as per age:
1. At birth to 1 month: BCG- one injection.
2. Age 6 weeks- First dose of:
(a) Triple vaccine (DPT- Diphtheria, Pertussis, Tetanus). Then 2 more doses at monthly interval. Total 3 doses, and
(b) Oral polio vaccine (OPV). Then 2 more doses by mouth at monthly interval. Total 3 doses.
3. Age 9 months: Measles vaccine. One injection only.
(b) Further Vaccinations:
1. School entry (Age 5 years): Diphtheria toxoid, tetanus toxoid.
2. Age 10 to 13 years: BCG in tuberculin negative child.
3. Girls aged 11-13 years: Rubella vaccine.
B. Pregnant Women. Two dosages of 0.5 ml tetanus toxoid are given during 7th and 8th month of first pregnancy. If next pregnancy is after 5 years then she will need a single booster dose.
C. Other Vaccines:
1. MMR (Measles, Mumps, Rubella) Vaccine.
4. Typhoid Vaccine: Limited use.
5. Cholera Vaccine: Limited use.
6. Chickenpox Vaccine.
7. Hepatitis A Vaccine.
8. Smallpox Vaccine. Not in use as smallpox has been eradicated from world. The vaccine contains avirulent mutants of the smallpox virus (live vaccine).
Herd Immunity
It is the immunity of a community and depends on immunization (vaccination) of a proportion of the population. Example: If 75% of the children of the community are immunized against diphtheria, then the whole community is protected.
A. Children. Schedule of vaccination at different ages.
(a) EPI (Expanded program of Immunization) for children introduced by Bangladesh Government to cover seven diseases- tuberculosis, diphtheria, pertussis (whooping cough), tetanus, poliomyelitis, measles and Hepatitis B virus. Triple vaccine DPT is used for diphtheria, pertussis and tetanus. DPT consists of diphtheria toxoid, killed pertussis bacteria and tetanus toxoid. Recently Hepatitis B vaccine has been included with EPI to prevent Hepatitis B virus.
Vaccination- as per age:
1. At birth to 1 month: BCG- one injection.
2. Age 6 weeks- First dose of:
(a) Triple vaccine (DPT- Diphtheria, Pertussis, Tetanus). Then 2 more doses at monthly interval. Total 3 doses, and
(b) Oral polio vaccine (OPV). Then 2 more doses by mouth at monthly interval. Total 3 doses.
3. Age 9 months: Measles vaccine. One injection only.
(b) Further Vaccinations:
1. School entry (Age 5 years): Diphtheria toxoid, tetanus toxoid.
2. Age 10 to 13 years: BCG in tuberculin negative child.
3. Girls aged 11-13 years: Rubella vaccine.
B. Pregnant Women. Two dosages of 0.5 ml tetanus toxoid are given during 7th and 8th month of first pregnancy. If next pregnancy is after 5 years then she will need a single booster dose.
C. Other Vaccines:
1. MMR (Measles, Mumps, Rubella) Vaccine.
4. Typhoid Vaccine: Limited use.
5. Cholera Vaccine: Limited use.
6. Chickenpox Vaccine.
7. Hepatitis A Vaccine.
8. Smallpox Vaccine. Not in use as smallpox has been eradicated from world. The vaccine contains avirulent mutants of the smallpox virus (live vaccine).
Herd Immunity
It is the immunity of a community and depends on immunization (vaccination) of a proportion of the population. Example: If 75% of the children of the community are immunized against diphtheria, then the whole community is protected.
_PASSIVE IMMUNIZATION
_ Preformed antibodies
are
artificially introduced in a host. Temporary
protection against infection can be achieved. Serum preparations are
used for passive artificial immunization : The followings are used.
1. Antitoxins. Antiserum containing toxin, neutralizing antibodies specific for a toxin is given. (a) Diphtheria antitoxin is prepared in horse by injecting toxoid of C. diphtheriae. Used in the treatment and prophylaxis, (b) Tetanus antitoxin. One prepared in horse is not recommended. Used in prophylaxis and treatment, (c) Botulism antitoxin is prepared in horse.
2. Immune globulin (gamma globulin) is prepared from pooled normal adult human plasma or serum. It contains IgM antibodies. Used for hepatitis A and measles.
3. Specific immune globulin. It is gamma globulin obtained either from convalescent patients (people who have recently recovered from the disease), or from people who have been hyper-immunized against a specific infectious disease. Example : (a) Hepatitis B immune globulin, (b) Rabies immune globulin, (c) Tetanus immune globulin.
NOTE: Maternally Acquired Antibody. Protection is afforded by maternally derived antibodies passively acquired by : (1) Placental transfer of IgG, (2) Milk. Secretory
IgA remains in the intestine of the child and protects the mucosal surface and other colostral Ig (IgG and IgM) are absorbed in the intestine.
1. Antitoxins. Antiserum containing toxin, neutralizing antibodies specific for a toxin is given. (a) Diphtheria antitoxin is prepared in horse by injecting toxoid of C. diphtheriae. Used in the treatment and prophylaxis, (b) Tetanus antitoxin. One prepared in horse is not recommended. Used in prophylaxis and treatment, (c) Botulism antitoxin is prepared in horse.
2. Immune globulin (gamma globulin) is prepared from pooled normal adult human plasma or serum. It contains IgM antibodies. Used for hepatitis A and measles.
3. Specific immune globulin. It is gamma globulin obtained either from convalescent patients (people who have recently recovered from the disease), or from people who have been hyper-immunized against a specific infectious disease. Example : (a) Hepatitis B immune globulin, (b) Rabies immune globulin, (c) Tetanus immune globulin.
NOTE: Maternally Acquired Antibody. Protection is afforded by maternally derived antibodies passively acquired by : (1) Placental transfer of IgG, (2) Milk. Secretory
IgA remains in the intestine of the child and protects the mucosal surface and other colostral Ig (IgG and IgM) are absorbed in the intestine.