The Hindu : Is polio immunisation risk-free in State?

Online edition of India's National Newspaper
Friday, Jan 09, 2004

Kerala

Kerala

Is polio immunisation risk-free in State?

By Roy Mathew

THIRUVANANTHAPURAM, JAN. 8. Should Kerala continue with Pulse Polio Immunisation Programme? An answer may not come by easily because of the complexities involved.

Kerala has been free of polio for the past three years. According to international norms, a country could be declared free of polio if no incidence of the disease is reported for three years.

In India, 190 cases were reported up to November 22 in 2003. So, Kerala is also forced to continue with the programme. As the programme is not risk free, the question arises whether it should continue with the programme for fear of propagation of the virus from the neighbouring States.

As the polio vaccine contains attenuated virus, administration of vaccine can cause vaccine associated paralytic polio in rare cases. The risk level is around one per million. Every year, around three million children are administered vaccine in the State. So, there is the likelihood of three children being affected in the State. As many as 181 cases of vaccine associated paralytic polio were reported in the country in 1999.

The alternative to oral vaccine is injections that contain killed virus. Though risk free, it is costly, and hence could not be used widely in India. (In the United States, the health authorities only use the injections as use of oral polio vaccine could lead to claims for heavy damages from those affected by vaccine-associated polio).

Kerala is having an effective system of routine vaccinations. So, administration of the vaccine comes as additional doses to most of the children. This is when additional doses are not advised even for vitamins, critics say.

Polio immunisation is also based on what is called herd immunity. According to this principle, even children living in proximity to vaccinated children would get immunity as the attenuated viruses are excreted by large number of children in the community and reach the rest of the population through the environment. Thus, pulse immunisation means repeatedly inoculating the population twice or thrice every year. It has been found that herd effect is limited. Whether it would have any adverse effect on the rest of the population as the level of viruses in the atmosphere shoots up is not known. The doses are administered to children under the programme without proper medical supervision. Though only children below the age of five need be administered, at least in a few cases, even older children have been given the vaccine in Thiruvananthapuram.

The administration of the vaccine is not advisable in the case of immuno-compromised patients, especially children affected by AIDS. However, volunteers sometimes administer the vaccine to children even without the consent of the parents, and they can include immuno-compromised children.

The programme began in the country in 1995. Initially, it was claimed that the country would become free of polio in a few years because of the herd effect. Then, date was extended to 2000. Now, it is hoped that the target could be achieved by 2005. So, some doubts have arisen whether the strategy is working.

Polio cases have been reported last year from Karnataka, Tamil Nadu and Andhra Pradesh. This may suggest that the programme did not reach all parts of the States. However, it has been reported the children who developed polio at Bellary in Karnataka had been administered the vaccine previously.

Kerala has been free of the diseases for several years barring a single case reported from Kondotty in Malappuram in 2000. It was found that the child in question had been administered the vaccine though the child might not have taken the full dose. However, polio immunisation programme had been going on in the district since 1995.

There is fear that the emphasis on polio immunisation would lead to neglect of the routine immunisation programme as in other States. Since, Kerala has the health care network, it should be possible to keep children free from polio through routine immunisation, especially when no case had been reported for three years. Polio immunisation as such is a costly project though the money comes as assistance from the Central Government. This year's expenditure will be Rs. 2.2 crores.

The Government seems to be trying to hide the real facts from the people. The press note issued by the Health Minister, P. Sankaran, this year had the following lines:

"The wild polio virus that cause polio can live only in the intestines of people, especially children. As the polio vaccine is being given on the same day (under the Pulse Polio Immunisation Programme), the wild viruses living in the intestines would be excreted and destroyed. The immunisation programme is being implemented in accordance with this principle. The months from November to February have been chosen for the programme as infectivity of polio is the highest during these months." Actually, the programme is being organised in winter to reduce the risks from the virus circulating in the atmosphere for long. According to a study published in Lancet a few years ago, the altered viruses in the vaccine can be replicated in the gut of immunised children, and gradually, these could revert to forms that cause virus.

There is thus the distinct possibility of circulation of vaccine-derived poliovirus that cause the disease. This suggests that there would be risk of the disease, as long as live oral poliovirus vaccine is not replaced with inactivated polio vaccine.

Printer friendly page
Send this article to Friends by E-Mail

Kerala