Indian Medic

One of the most striking aspects of practicing medicine in a developing country like India is the whole wide range of medical conditions we get to see. Not only diseases like Polio and Whooping cough which are termed exotic in the developed nations but also their share of scourges in the form of modern epidemics of diabetes, hypertension etc which were hardly seen when India was just a farming nation. We see and study the whole spectrum of diseases even though major international textbooks limit the diseases that have been already eradicated from most of the world to a page or two at the most.

Having been trained in India, in a General hospital I have been intimately aware of the battle we have been raging with Polio with guidelines provided by the WHO. It’s a matter of disgrace for my peers and me that India is one of the four countries that have yet to eradicate polio while the rest of the world has succeeded in doing so. The other countries in the list are Pakistan, Afghanistan and Nigeria. These four countries are described as Endemic for Polio while there are a few more countries with importation Polio problems. It can be argued that it is because of the abundance of the wild poliovirus in these regions, three of which abut geographically. But there is more to this saga than that.
India was one of the signatories to the WHO declaration in 1988 to eradicate polio by the year 2000, which was later extended to 2005. Even though we have stepped into 2007 the goal still eludes us.

Polio is not a killer disease. If you are lucky enough it will pass you as nothing more than a flu, but one in 200 cases develop Acute Flaccid Paralysis which on resolution lead to atrophy of muscles and residual paralysis. There are three types of Polio viruses of which Type 1 causes most epidemics. The Vaccines currently being used to immunize children against polio are of two types OPV and IPV.

OPV or Oral polio vaccine is the weapon that is being primarily used to battle polio in India. Following is the salient features of the Eradication strategy
1) Routine Immunization - Three routine OPV doses should be received by infants at ages 6, 10 and 14 weeks.
2) National Immunization days - Conducting Pulse Polio Immunization (PPI) programme by providing additional OPV doses to every child aged <5>
3)Surveillance of acute flaccid paralysis (AFP) to identify all reservoirs of wild poliovirus transmission.
4) Mopping Up- intensive house-to-house, child-to-child immunization campaigns are conducted over a period of days to break the final chains of virus transmission.
Add to this Ring Immunization in which when a case of polio is detected all children less than 5 years of age within a radius of 5 km are immunized within 48 hours.
When all this is added up, an average Indian child may receive upto 20 doses of OPV by the time he turns five. The Eradication strategy has made a tremendous difference in bringing down the incidence of Polio from almost 40,000 in 1981 to 300 in 2006. Still it has not succeded…

One of the most purported reasons for the apparent failure of the eradication strategy is the non-maintenance of the Cold chain. Cold chain is essentially the series of machines employed in keeping the OPV at the recommended temperature of 4 degree Celsius, which includes Walk in freezers the district levels to small refrigerators at PHCs and the ubiquitous Ice box taken into the field. More often than not, it is failure to maintain the highly sensitive OPV at the specified temperature that causes it to lose potency and eventually leading to ineffective immunization. Introduction of Vaccine Vial monitors or blue indicators on the vial itself, which indicate if the vaccine is viable or not has rectified the above said problem to a certain extent. (see inset picture)

The other major argument is over the choice of the vaccine itself.

OPV or Sabin vaccine has been selected as the mode to eradicate Polio for a variety of well-established reasons. It is cheap (which goes a long way in its favor), easy to administer (just two drops in the infants’ mouth are enough), it produces Systemic immunity as well as local intestinal immunity (which prevent re-infection from wild viruses), antibody production is quick and the person excretes the vaccine virus, which infects other people propagating Herd immunity. Thus, it is also useful in controlling epidemics.
The points that go against it are stringent storage conditions required as mentioned above and the small but potential chances of Vaccine induced paralysis since a live virus is being administered.

The counterpart of OPV is the IPV (Inactivated Polio Vaccine) or the Salk vaccine, which though not popular in India has its own merits and demerits. It is a costly vaccine, difficult to manufacture and administer (given Subcutaneous or Intramuscular), gives only systemic immunity and does not prevent reinfection, also no role in epidemic control. The good part is however is that being a killed vaccine there is no risk of vaccine induced paralysis, is easy to store, has a longer shelf life and is hundred percent effective after the second dose. In addition, it can be combined with the DPT vaccine ( Diphtheria, pertussis and Tetanus) and given as a quadruple vaccine without changing the current National immunization schedule.

Most of the countries that have successfully eradicated polio have done so with the help of IPV or a combination of OPV and IPV. Considering that the cost factor is one of the major determinants in the usage of OPV alone in India, experts say that the mass administration of IPV may work out cheaper than the 20 doses of OPV that an average child gets. The current National immunization schedule is as follows -