Types of vaccines

Types of vaccines:

Types of vaccines DR.D.SHANKAR REDDY MD COMMUNITY MEDICINE

Types of vaccines:

Types of vaccines Live vaccines Live Attenuated vaccines Killed Inactivated vaccines Toxoids Cellular fraction vaccines Recombinant vaccines Small pox variola vaccine BCG Typhoid oral Plague Oral polio Yellow fever Measles Mumps Rubella Intranasal Influenza Typhus Typhoid Cholera Pertussis Plague Rabies Salk polio Intra-muscular influenza Japanise encephalitis Diphtheria Tetanus Meningococcal polysaccharide vaccine Pneumococcal polysaccharide vaccine Hepatitis B polypeptide vaccine Hepatitis B vaccine

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Vaccine Age Birth 6 weeks 10 weeks 14 weeks 9-12 months Primary vaccination BCG X Oral polio X X X X DPT X X X Hepatitis B* X X X Measles X Booster Doses DPT + Oral polio 16 to 24 months DT 5 years Tetanus toxoid (TT) At 10 years and again at 16 years Vitamin A 9, 18, 24, 30 ,36 ,42 ,48, 54, 60 ,66 and 72 months Pregnant women Tetanus toxoid (PW): 1 st dose 2 nd dose Booster As early as possible during pregnancy (first contact) 1 month after 1 st dose If previously vaccinated, within 3 years * A second dose of DT vaccine should be given at an interval of one month if there is no clear history or documented evidence of previous immunization with DTPw ** A second does of TT vaccine should be given at an interval of one month if there is no clear history or documented evidence of previous immunization with DTPw , DT or TT vaccines

The Cold Chain:

The Cold Chain The "cold chain" is a system of storage and transport of vaccines at low temperature from the manufacturer to the actual vaccination site. The cold chain system is necessary because vaccine failure may occur due to failure to store and transport under strict temperature controls.

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Polio vaccine most sensitive to heat requiring -20.c Vaccines which must be stored in the freezer compartment: Polio & Measles. Vaccines which must be stored in cold part but never allowed to freeze: typhoid, DPT, TT, DT, BCG . Opened multi dose vials should be discarded within 1 hour if no preservative is present or within 3 hours if preservative is present.

The Cold Chain Equipment :

The Cold Chain Equipment (a) Walk in cold rooms (WIC): They are located at regional level, meant to store vaccines up to 3 months and serve 4-5 districts. (b) Deep freezers (300 ltr ) and Ice lined Refrigerators (300/240 ltr ) : supplied to all districts and the WIC locations to store vaccines. Deep freezers are used for making ice packs and to store OPV and measles vaccines. (c) Small deep freezers and ILR (140 ltr ) : One set is provided to PHCs and Family Planning Centers.

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(d) Cold boxes: Cold boxes are supplied to all peripheral centers. These are used mainly for transportation of the vaccines. (e) Vaccine carriers: Vaccine carriers are used to carry small quantities of vaccines (16-20 vials) for the out reach sessions. 4 fully frozen ice packs are used for lining the sides, and vials of DPT, DT, TT and diluents should not be placed in direct contact with frozen ice packs. (f) Ice packs: The ice packs contain water and no salt should be added to it.

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Adverse Event Following Immunization (AEFI) Medical incident that takes place after an immunization, causes concern, and is believed to be caused by immunization. Types of AEFIs: 1. Vaccine reaction An event caused or precipitated by the active component or one of the other components of the vaccine (e.g. adjuvant, preservative or stabilizer). This is due to the inherent properties of the vaccine.

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2. Program Error: An event caused by an error in vaccine preparation, handling or administration. 3. Coincidental : An event that occurs after immunization but is not caused by the vaccine. This is due to a chance temporal association.

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4. Injection Reaction: Event caused by anxiety about, or pain from the injection itself rather than the vaccine. 5. Unknown: The cause of the event cannot be determined

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Vaccine reactions These may be classified into common, minor reactions or rare, more serious reactions. Common, minor vaccine reactions such as local reaction (pain, swelling and/or redness), fever and systemic symptoms (e.g. vomiting, diarrhoea, malaise) can result as a part of the immune response. Some of the non-antigenic vaccine components (e.g. adjuvant, stabilizers or preservatives) can lead to reactions. An ideal vaccine reduces these reactions to a minimum while producing the best possible immunity.

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Rare serious vaccine reactions such as high (39 - 40.4oC/ 102-104.7 oF ) to extreme fevers (>40.5oC /105 oF ) may indicate the possibility of: Sepsis or Toxic Shock Syndrome (TSS) resulting from a program error; or A coexisting illness and other accompanying signs.

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2. Program Errors Adverse events can occur as a result of inappropriate storage, handling, preparation and administration of vaccines. The most common program error is infection as a result of non sterile injection or poor injection technique. The infection can manifest as a local reaction (e.g., suppuration, abscess), systemic effect (e.g., sepsis or toxic shock syndrome), or blood-borne virus infection (e.g., HIV, Hepatitis B or Hepatitis C).

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3. Coincidental Events: Coincidental events have only a temporal association with vaccination and are not causally related. They are likely if: The same or a similar event also affected others in the same age group around the same time, but they did not receive the suspect vaccine(s). There is clinical/ laboratory evidence that the event is not related to immunization.

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Once an event is established as coincidental (e.g. pneumonia) no further investigation is required, other than what would be needed for the clinical management of the case. 4. Injection Reactions: Vaccinated children or adults can react in anticipation to and as a result of an injection of any kind. This reaction is unrelated to the content of the vaccine.

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Examples of injection reactions include fainting, light headedness, dizziness, tingling around the mouth and in the hands, and breath-holding in younger children, which in some cases can lead to unconsciousness. 5. Unknown: Unknown AEFIs imply that the cause of the event cannot be determined. Rule out all the above mentioned causes before reaching this conclusion.

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Investigating AEFIs On receiving reports of AEFIs from public or private sources, regarding both NIS and non-NIS vaccines, should conduct an investigation to: Confirm the reported diagnosis of AEFI and clarify the details and outcome. Determine whether unimmunized persons are experiencing the same medical event(s). Investigate the link between the vaccine given and the AEFI. Determine the contribution of operational aspects of the program to the reported AEFI .

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Determine whether a reported event was isolated or part of a cluster; Determine the cause of the AEFI to provide the best intervention/ medical care and take further actions deemed necessary.

Vaccination Coverage:

Vaccination Coverage Vaccination coverage is the percent of at risk or susceptible individuals, or population who have been fully immunized against particular diseases by vaccines or toxoid. To be significantly effective in prevention of disease on mass or community level at least a satisfactory proportion (75% or more) of the at risk population must be immunized.

Ways of achieving satisfactory immunization coverage:

Ways of achieving satisfactory immunization coverage Efficient immunization service; urban and rural Health awareness and cooperation of the public Periodic mass immunization campaigns, to cover those who missed regular immunizations Outreach programs in rural and nomad areas, and home visits

Vaccine surveillance and testing:

Vaccine surveillance and testing “monitoring vaccine effectiveness” Through: Randomized field trials Retrospective cohort studies Case-control studies Incidence density measures

Randomized field trials :

Randomized field trials The standard way to measure the effectiveness of a new vaccine introduced. In this type of trial, susceptible persons are randomized into two groups and are then given the vaccine or the placebo The vaccinated and the unvaccinated are followed through the high risk season of the year

Randomized field trials (cont.):

Randomized field trials (cont.) The attack rate (AR) is then determined in each group: AR = Number of persons ill Number of persons exposed to the disease next the vaccine effectiveness (VE) is calculated: VE = AR (unvaccinated) - AR (vaccinated) AR (unvaccinated) X 100

Retrospective cohort studies:

Retrospective cohort studies The antigenic variability of influenza virus necessitates frequent (often yearly) changes in the constituents of the vaccine to keep them up date with the new strains. Retrospective cohort studies are thus done to evaluate the protective efficacy of the vaccines.

Case-control studies:

Case-control studies Done because randomized control trials are very costly. VE = 1- AR (vaccinated) AR (unvaccinated) = (1- RR) or (1- OR)

Incidence density measures:

Incidence density measures They are used to determine the the optimal timing for administration of a new vaccine and the duration of the immunity produced. It has the following formula: ID = Number of new cases of a disease Person-time of exposure (days, weeks, months, years..)