General

 

POLIO VIRUS VACCINE

(LIVE, ORAL, TRIVALENT)
By
C.V. MALLIKARJUNA MURTHY, M.Sc.
Senior Drugs Inspector, Tamilnadu

ORAL POLIO vaccine has become very popular with the public. Now a days it is being given to almost all children as a matter of routine. There is considerable demand for the vaccine even in villages. The Chemists and Druggists, because of the demand have started selling and dispensing this vaccine. There are various precautions to be taken during storage, transportation and administration of this vaccine. If they are not taken the vaccine cannot be effective. But the parents of the child will be thinking that the child is really protected when it is not. The agony of the parents and the misery of the child can very well be imagined when a child who received that ineffective vaccine gets polio later on. The damage cannot be undone. The damage lasts for the entire life of the child.

It is therefore necessary to know what this polio is, what this oral polio vaccine does, and the manner in which it needs to be stored and dispensed.

What is Polio ?

Poliomyelitis or polio as is commonly known is an acute infectious disease primarily of children which affects the central nervous system. The disease is caused by an enterovirus known as the polio virus with three distinct antigenic serotypes, type 1,2, and 3. The virus is rapidly inactivated by heat, dessication formalin, chlorine and Ultra violet irradiation.

The incubation period, on an average is 17 days and the infection spreads through faecal to oral route. It is primarily an infection of the alimentary tract with the virus multiplying in the regional lymph nodes. Clinical evidence of the Infection starts only when the virus, after multiplying in the lymph nodes passes into the blood system and localizes in the Central nervous system. Only a small percentage of the infected persons suffer from a clinical disease and in only a minority of these there is paralysis or meningo encephalitis.

There is no specific treatment for the paralysis produced by the poliovirus. In addition to the general supportive measures that are recommended in any acute infectious disease physiotherapy must be initiated immediately. Physiotherapy is of vital importance in acute and convalescent phases and must not be ignored under any circumstances.

Oral polio vaccine is most valuable as prophylactic agent. It has no curative value.

What is a Vaccine ?

Vaccines are either dead or living attenuated organisms administered to an individual either for prophylaxis or sometimes to ameliorate the disease caused by the organisms with the hope of providing development of antibodies in vivo. Thus vaccines are generally administered for prophylactic purposes i.e. to prevent the disease. Oral Polio Vaccine and B.C.G. Vaccines are examples of vaccines containing live attenuated organisms. While the Oral Polio Vaccine is called the Sabin Vaccine, the Killed Polio Vaccine(K.P.V.) is called the Salk vaccine. The former is given orally while the latter is given parent rally. Sabin and Salk are the names of the discoverers of the vaccine.

What is Oral Polio Vaccine ?

Oral Polio vaccine is comprised of the three serotypes of polio viruses duly attenuated. The viruses are usually propagated in Kidney, tissue culture. The potency is expressed in terms of the amount of virus contained in the recommended does as tissue culture ineffective doses, (TCID 50). The approximate concentration of polio virus in each strain in a 0.5 c.c. dose or a 2 drops dose is as follows :

Type 1 800,000

Type 2 100,000

Type 3 500,000 doses

What is the Colour of the Vaccine ?

Oral polio vaccine normally contains phenol red as a PH indicator. The colour of the vaccine is pink although some containers of the vaccine stores in dry ice may exhibit a yellow colouration, due to the very low temperature or possible absorption of carbon –dioxide. The colour of the vaccine prior to use (red-pink-yellow) has no effect on the virus or the efficacy of the vaccine. If however, a multiple dose container of vaccine turns from red to pink to yellow after it has been thawed and entered it should not be used since this may be an indication of Bacterial contamination.

Why is Oral Polio Vaccine given ?

The purpose of administering any attenuated live virus vaccines is to stimulate the body mechanism to produce an active immunity by stimulating the natural infection without producing untoward symptoms of the disease. The accomplish this with live polio virus vaccine it is necessary for the virus to multiply in the intestinal tract. A primary series of this vaccine is designed to produce an antibody response to polio virus types 1,2 and 3 . This response is comparable to the immunity induced by the natural disease. The antibodies thus formed help to protect the individual against clinical poliomyelitis infection by all three types of polio virus.

How should the Oral Polio Vaccine be stored ?

The shelf life of the vaccine depends on the manner of storage adopted. The shelf life is 2 years when stored at 24° C, 6 months when stored at +4° C and 21 days when stored at +22° C as per a manufacturer ‘s claim. Bulk storage of vials (unopened) should be in a deep freeze at sub zero temperatures.

During administration the vials of the vaccine must be stored in ice.

The vaccine should not be frozen and thawed repeatedly since repeated freezing and thawing has a deleterious effect on the potency of the oral polio vaccine. The efficacy of the vaccine depends entirely on the administration of live viruses to the individual. If somehow or other any proportion of the living viruses of any of the serotypes is inactivated, the vaccine of any of the serotypes is inactivated , the vaccine ceases to be an effective immunizing agent. With the use of such vaccines which contain significant proportion of inactivated virus, one is actually a false sense of security.

An un-opened container of vaccine that has been frozen and then is thawed may be carried through a maximum of 10 freeze thaw cycles provided the temperature does not exceed 8°C during the periods of thaw and provided the total cumulative duration of thaw does not exceed 24 hours. If the 24 hours period is exceeded the vaccine then must be used within 30 days during which time it must be stored at a temperature no higher than 8°C.

What are the precautions to be taken during administration ?

a) Administer the appropriate quantity of the vaccine by withdrawal from the vial through a sterilized syringe.

b) Sterilize the individual spoon in boiling water or steam and cool it completely before transferring individual dose to it from the vaccine vial.

c) Do not dilute the vaccine in water, milk or syrup before its administration to the child.

d) Do not sterilize the spoon to be used for vaccination with any disinfectant like Dettol, Lysol, or any other antiseptic.

e) Do not give oral polio vaccine in hot humid and crowded room. The vaccine should be given preferably in an air-conditioned room.

f) Do not administer any batch of oral polio vaccine unless you are sure that the vaccine was kept frozen during its transport to your organization.

Is there any special advice for the parents of the child receiving polio vaccine ?

a) Oral polio vaccine is to be given to all children more than 3-6 months of age.

b) Three dosed of the vaccine at monthly intervals are to be given to protect the child adequately.

c) The vaccine should not be given to any child suffering from dysentery, diarrhea, vomiting and fever. Similarly it should not be given if the child is on cortico-steroids.

d) Breast feeding must be stopped for a period of at least six hours before as well as after the administration of the vaccine. During this period the child must be fed artificially. The child should not be starved.

e) Hot drinks like tea,coffee or milk must not be given for a period of half an hour after the administration of the vaccine.

Will Oral Polio Vaccine prevent, modify existing or incubating polio myelitis

No.

Can Oral Polio Vaccine be given to children below six weeks old

Administration to the new borne under six weeks is not generally performed because of varying persistence of material antibodies.

How safe is administration of Oral Polio Vaccine ?

Expert opinion is in agreement that administration of live oral polio vaccine is generally an effective and safe method of protecting population against the natural disease.Paralytic diseases following the ingestion of live polio virus vaccines has been reported in individuals receiving the vaccine and in some instances in persons who were in close contact with subjects who had been given live oral polio vaccine. The rare occurrences of “Vaccine related cases “ were considered compatible with vaccine induced disease. It has been estimated that the risk of vaccine induced paralytic polio myelitis is about one chance per million doses. The risk must be considered by the physician and such information should be conveyed to the parents at the time of vaccination.

How often it is necessary to give Oral Polio Vaccine ?

Primary series is given as stated when the child is between 3 to 6 months of age. A total of three doses are given at monthly intervals. Thereafter on entering elementary school all children who have completed primary series should be given a single follow up dose. Booster dosed thereafter are considered not necessary.

How long can the un-opened Oral Polio Vaccine in the liquid state be effective ?

Un-opened vials of the vaccine in liquid state may be used for upto 30 days provided they have been stored at 2° to 8°C during that period.

How long can the opened vials be effective ?

Once opened the vaccine must be refrigerated and used within 7 days.

Thus it may seen that great care is necessary when handling oral p

   
Powered by Allied Softech Pvt. Ltd.