Vaccination Groups 1-3
What is vaccination? • Latin: vacca-cow • The first vaccine is from the cow (cowpox virus) • Immunization: artificially inducing immunity to protect one from disease. • Vaccination is the administration of antigenic material (vaccine) to produce immunity to a disease. • The most effective and cost-effective way to prevent infection?
Vaccine • a suspension of attenuated or killed microorganisms (viruses, bacteria, or rickettsiae), or of antigenic proteins derived from them • stimulate the body’s own immune system to protect the person against subsequent infection or disease
Forms of vaccine? Contents of vaccine? Live but weakened form of bacteria or virus Killed or inactivated form of pathogen Purified material e.g protein • Vaccine before contracting the disease vs that after (Post-exposure prophylaxis) e.g. rabies • Injection vs oral e.g. lived attenuated polio • Adjuvant added to boost immune respose e.g. tetanus toxoid
Active Immunization • Induction of ‘acquired’ immunity • By ‘priming’ with antigen • Immunity comes from T cells and B cells with their antibodies • Adjuvant: to boost immune response Passive Immunization • Provides temporary protection through administration of exogenously produced antibody or memory T cells • E.g. physiological trans-placental transfer of antibody from mother to foetus
Types of vaccines (1) Live, attenuated • Alters a living pathogen so that it becomes harmless or less virulent • small risk of reversion of virulence (immunocompromised) • Virus-like particle vaccine: viral protein lacking nucleic acid, not infectious e.g. HPV, HBV vaccine (2) Inactivated (or killed) • Micro-organisms grown in culture and then killed by methods like heat, formaldehyde • virus capsid protein evoked response, booster shot required • Toxoids: modified bacterial toxin that has been rendered nontoxic but retains the ability to stimulate the formation of neutralizing antibody (anti-toxin) • Subunits: antigen , but weaker antibody response e.g. bacterial toxin
BCG • Bacillus Calmette-Guérin • Tuberulosis • Attenuated live Mycobacterium bovis
BCG • Claimed 80% effective for 15 years; • However => vary according to geography • greatest effect in preventing miliary TB or TB meningitis
BCG • Neonatal BCG vaccination introduced in April 1952 • Done within 3 days after birth • Current policy = all newborn + children under 15 yrs without prior BCG • Coverage >98%
BCG • In Hong Kong , statistics shows significant reduction of TB notification rate in young age group
Hepatitis B Vaccine First Anti-cancer Vaccine Hepatitis B vaccine prevents hepatitis B disease and its serious consequences like hepatocellular carcinoma .Therefore, this is the first anti-cancer vaccine. Safe and Effective Scientific data show that hepatitis B vaccines are very safe for infants, children, and adults. There is no confirmed evidence which indicates that hepatitis B vaccine can cause chronic illnesses.
Hepatitis B Vaccine The Standard Hepatitis B Vaccination Regimen • A 3-dose schedule given at 0, 1, 6 months is the standard regimen. • After the priming first dose, a second dose at 1 month shall be able to elicit a satisfactory humoralresponse. The third dose, which serves a boosteringeffect, shall challenge the immune system not less than 2 months after the second dose. • Increasing the interval between doses should not diminish its efficacy, but decreasing these intervals might interfere with antibody response and protection.
Hepatitis B Vaccine Booster Doses • Current data show that vaccine-induced hepatitis B surface antibody (anti-HBs) levels may decline over time • However, immune memory (anamnestic anti-HBs response) remains intact indefinitely following immunization. • Persons with declining antibody levels are still protected against clinical illness and chronic disease.
Hepatitis B Vaccine Post-vaccination Testing • After routine vaccination of infants, children, adolescents, or adults post-vaccination testing for adequate antibody response is not necessary. Post-vaccination testing IS recommended for persons who: • are immunocompromised (e.g., hemodialysis patients) • received the vaccine in the buttock • are infants born to HBsAg (hepatitis B surface antigen)-positive mothers • are healthcare workers who have contact with blood • are sex partners of persons with chronic hepatitis B virus infection Post-vaccination testing should be completed 1-2 months after the third vaccine dose for results to be meaningful. A protective antibody response is 10 or more milliinternational units (>=10mIU/mL).
DTaP-IPV Vaccination • Introduced since1981 in various countries, e.g. Japan, US, Canada, Australia, New Zealand • Introduced to Hong Kong Childhood ImmunisationProgramme in February 2007 • Advantages of DTaP-IPV Vaccination: • IPV: eliminate risk of vaccine-associated paralytic poliomyelitis (VAPP) • Acellularpertussis: lower incidence of vaccination reactions compared with whole-cell pertussis vaccine • Reduces number of vaccinations to be taken in same visit
DTaP-IPV Vaccine • Route of Administration: Intramuscular Injection • Efficacy of DTaP-IPV: • 95% against diphtheria • Virtually 100% against tetanus • 85% against pertussis • 99% against polio • Schedule: • 1st dose : 2 months • 2nd dose : 4 months • 3rd dose : 6 months • Booster doses: 18 months, Primary 1, Primary 6 * * dTap-IPV Vaccine: Diphtheria, Tetanus, acellularPertussis (reduced dose) & Inactivated Poliovirus given
Side Effects • Common side effects • anorexia, irritability, restlessness, drowsiness, mild fever • Local reactions: pain, redness and swelling at the injection site • Moderate to severe side effects • High fever (40.5oC/105oF or higher) • Persistant inconsolable crying (>3 hours) • Febrile seizures • hypotonic-hyporesponsive episodes • Transient benign swelling of entire upper arm or thigh after the 4th and 5th doses of DTaP vaccines • Breathing difficulty or coma
What is MMR? • The MMR vaccine used in Hong Kong was M-M-R II (Merck, Sharp and Dohme) • A lyophilized product that contains the three live attenuated viruses • Administered by injection
When given? • 1st dose (since 1988) • 12 months after birth by MCHC and private doctor • 2nd dose (since 1998) • At primary one • Supplementary mop up immunization • At primary six who does not have previous 2nd dose
Effectiveness • 2-5% fail to develop immunity after one dose • Epidemic in 1997 prompted the introduction of 2nd routine dose • Highly effective
Adverse events Previous documented adverse events
Pneumococcal conjugate vaccine The first pneumococcal conjugate vaccine (PCV7) was licensed in the United States in 2000. It includes purified capsular polysaccharide of seven serotypes of S. pneumoniae (4, 9V, 14, 19F, 23F, 18C, and 6B) conjugated to a nontoxic variant of diphtheria toxin known as CRM197. The serotypes included in PCV7 accounted for 86% of bacteremia, 83% of meningitis, and 65% of acute otitis media among children younger than 6 years of age
The vaccine is administered intramuscularly. It does not contain thimerosal as a preservative, and is available only in single-dose vials. In a large clinical trial, PCV7 was shown to reduce invasive disease caused by vaccine serotypes by 97%, and reduce invasive disease caused by all serotypes, including serotypes not in the vaccine, by 89%. Efficacy against pneumonia varied depending on the specificity of the diagnosis. The vaccine reduced clinically diagnosed pneumonia by 11%, but reduced pneumonia confirmed by x-ray with consolidation of 2.5 or more centimeters by 73%. Children who received PCV7 had 7% fewer episodes of acute otitis media and underwent 20% fewer tympanostomy tube placements than did unvaccinated children. The duration of protection following PCV7 is currently not known. After four doses of PCV7 vaccine, more than 90% of healthy infants develop antibody to all seven serotypes contained in the vaccine. PCV7 has been shown to be immunogenic in infants and children, including those with sickle cell disease and HIV infection.
Side Effects • In studies, most reactions after PCV13 were mild. They were similar to reactions reported after PCV7, which has been in use since 2000. Reported reactions varied by dose and age, but on average: • About half of children were drowsy after the shot, had a temporary loss of appetite, or had redness or tenderness where the shot was given. • About 1 out of 3 had swelling where the shot was given. • About 1 out of 3 had a mild fever, and about 1 in 20 had a higher fever (over 102.2°F). • Up to about 8 out of 10 became fussy or irritable. • Life-threatening allergic reactions from vaccines are very rare. If they do occur, it would be within a few minutes to a few hours after the vaccination.
Contraindications and Precautions • Contraindication • A condition in a recipient that greatly increases the chance of a serious adverse reaction • Precaution • A condition in a recipient that might increase the chance or severity of an adverse reaction, or • Might compromise the ability of the vaccine to produce immunity
Bacille Calmette-Guerin (BCG) Vaccine • 1. babies who are symptomatic HIV carriers or suffering from AIDS • 2. has received other live vaccines in the past four years • 3. on long term corticosteroids • 4. immunodeficiency • 5. pregnancy • 6. cancer
Hepatitis B Vaccine (HBV) • Children with serious allergic reaction to yeast (for baking bread) • Children with serious allergic reaction to previous dose of HBV
Diphtheria, Tetanus, acellular Pertussis & Inactivated Poliovirus Vaccine (DTaP-IPV Vaccine) • Immediate anaphylactic reaction to any of the vaccine components or following previous dose of DTaP-IPV vaccine. • Encephalopathy or other neurological conditions within 7 days following previous dose of DTaP-IPV vaccine or a pertussis-containing vaccine. • Serious allergic reaction to streptomycin, neomycin or polymyxin B.
Pneumococcal Conjugate Vaccine • serious allergic reaction to previous dose of PCV • serious allergic reaction to diphtheria toxoid-containing vaccine
Measles, Mumps and Rubella (MMR) Vaccine • 1.serious allergic reaction to a previous dose of MMR vaccine • 2.known history of severe allergy to gelatin or neomycin • 3.individuals with the following conditions: cancer on long term corticosteroids immunodeficiency • 4.pregnancy* • 5. has got immunoglobulin or other blood products (eg. blood transfusion) within the past 11 months • 6. has received other live vaccines in the past four weeks. • *women should avoid pregnancy for 3 months after vaccination
DTaP-IPV Vaccine: Diphtheria, Tetanus, acellular Pertussis & Inactivated Polio Virus Vaccine MMR Vaccine: Measles, Mumps & Rubella Vaccine Pneumo: Pneumococcal Vaccine *Compared with past Vaccination Programme: 1. Polio vaccine is incorporated into DTaP vaccine 2. Pneumococcal vaccine is included Source: http://www.fhs.gov.hk/english/health_info/class_topic/ct_child_health/ch_immunization_i1.html
OPV: Oral Polio Vaccine Main difference is that Polio vaccine is separated from DTaP vaccine Source: http://apps.who.int/immunization_monitoring/en/globalsummary/countryprofileresult.cfm
Difference between HK and Singapore • Diseases covered by vaccination programmes in the two countries are similar
Difference between HK and Australia Hong Kong has an extra vaccination on: • Tuberculosis Australia has extra on: • Rotavirus • Hemophilus Influenza type b • Meningococcus • HPV • Hepatitis A (for at risk groups) • Chicken pox