Feature

ERADICATING POLIO THROUGH PULSE POLIO IMMUNIZATION PROGRAMME

Dr. Sanjay Roy

Poliomyelitis, as polio is scientifically known, is an acute viral infection of human intestine. But it may also effect the nervous system in about 1% and cause paralysis to any part of the body, or even result in the death of the patient.

When an individual susceptible to exposure of infection gets the disease, one of the following may occur:

Inapperent(sub-clinical) Infection: this occurs approximately in 95 per cent of poliovirus infection. There are no presenting symptoms. Recognition only by isolation.
Abortive Polio Or Minor Illness: occurs approximately in 4-8 per cent of the infection. It causes only a mild or self limiting illness due to viraemia. The patiernt recovers quickly.
Non paralytic polio: occurs approximately in one per cent of all infections. The presenting features are stiffness and pain in neck and back. The disease lasts for two to ten days. Recovery is rapid.
Paralytic polio: occurs in less then one per cent of infections. The virus enters the brain and causes varying degree of disability.

Polio has disappeared from the American and the European continent as a result of effective vaccination efforts. The World Health Organization (WHO) seeks to replicate this experience in the developing countries also by promoting Pulse Polio Immunization Programme. Under this, the strategy to be followed is simple—administer polio vaccine to all the children in the risk zone, so that the disease can be eliminated once and for all.

Eradication

This disease affects mainly children who are vulnerable to the infection of polio by spreading from one child to another. If one child carries the germs of this disease, then he may also transfer this disease to another child. It spreads in unhygienic conditions, and is therefore likely to effect (a) people living in unsanitary conditions, and (b) children who are weak, or are suffering from malnutrition or have low body resistance. There is no sure and effective cure for polio, therefore the only strategy can be to eradicate it completely.

Until now vaccination was done to individual child, as and when the parents brought the child for vaccination. But this was clearly ineffective. In the year 1990, for example, 10,400 children got infected by the polio virus, (G.o.I. Annual Report, Health and Family Welfare). Year round routine immunization programme is bound to have low success in country like India with high population density, and poor sanitation.

The strategy which is now being promoted by the WHO and the Indian government, has the following salient features:

Simultaneous administration of vaccine;
Oral administration of the vaccine;
Covering 100% children below 3 years of age.

When all the children are given the vaccine at the same time, the polio virus which is normally active in the intestine of the children, are replaced by the non-disease causing harmless virus in the vaccine. If almost all the children are freed from the virus at any given time, then this disease can not survive because this virus cannot live outside the human body for long.

Oral vaccination

Oral vaccination is best suited for ending this crippling disease because (a) it is easy to administer, (b) it is cheap, (c) it then reaches the intestine directly and prevents the multiplication of disease causing polio virus, and (d) when the vaccine gets flushed out of the child with the stool, it may spread to other children also, who may not have been immunized. Strategies for polio eradication in India:

Conduct pulse polio immunisation for two days every years for three to four years or until polio is eradicated.
Sustain high level of routine immunisation.
Monitor OPV coverage at district levels and below.
Improve surveillence capable of detecting all cases of polio.
Ensure rapid case investigation, including the collection of stool samples.
Arrange follow-up of all cases of paralytic polio at 60 days to check for residual paralysis.
Conduct outbreak control for cases confirmed or suspected to stop transmission.

Pulse polio programme began on 9^th December 1995, when it reached 8 crore 78 lakh children all over India. Six weeks later, the second dose of the vaccine was administered and about 9 crore 36 lakh children were immunized. This programme has since become an annual feature. The recent round of immunization was conducted on 6^th December 1998, in which 13 crore 36 lakh children were immunized.

If public interest and enthusiasm for this programme can be sustained, then it will not be long before this disease becomes history.