How Big Is The Sun?
 

Yash Paul, Jaipur

Polio eradication: Who cares?

Anaxagoras, who lived in Athens, Greece, had suggested in 450 B.C. that the sun was so huge that it was probably larger than the Peloponnesus, roughly the southern third of Greece. His critics thought this estimate excessive and absurd (page 148, Cosmos by Carl Sagon). Anaxagoras had grossly under-estimated; he was not suggesting that sun is one-third of Europe or the Earth, now we know that the sun is many times bigger than our Earth.

In the August 2000 issue of the Indian Pediatrics I had stated: "Paralytic polio including fatal polio occurring in children who had received large number of OPV doses should be a reason for serious concern regarding the efficacy of OPV including the improved vaccine with enhanced P3. In addition, there will always be a risk of VAPP". All this was stated in the article entitled 'Polio Eradication Strategy: Need for Re-appraisal'. More than the contents of the article, the title was reason for many raised eye brows and ruffled feathers. WHO had ordained that polio will be eradicated globally by end of 2000, and questioning the strategy in August 2000 was nothing short of madness.

In the December 2000 issue of the Indian Pediatrics Dr. Naveen Thacker had stated: "The observations made by Dr. Yash Paul and the perceived interpretations are unfortunate because these come at a critical time when India is moving towards final stages of polio eradication. The strategy for eradication has been well defined by the Government of India and endorsed by World Health Organization (WHO) and has proved successful globally including our neighboring countries".

The 8th meeting of the National Certification Committee for Polio Eradication (NCCPE) held in Delhi during May 2003, was attended by Dr. N.K. Arora, (convener) Dr. Harsh Vardhan Former Health Minister, Delhi, Dr. Jacob John and Dr. A. Parthasarathy among other experts including a member of Planning Commission. On 11th May 2003, when the Chairman had asked when polio eradication was envisaged, some had suggested end of 2003 and some stated beginning of 2004. When I stated that by this vaccine and strategy not till 2099, every one present laughed.

In response to my article entitled 'Can Polio be eradicated from India through present Polio Eradication Program?' published in the August 2003 issue of BMJ-South Asia Edition, in the October 2003 issue of BMJ-South Asia Edition Dr. R.N. Srivastava, Member, Case Classification Committee, NSPS had stated: "This is in reference to the "view point" on the subject of polio eradication in India by Dr. Yash Paul. Not many would agree with his concern that 'polio free India still remains a distant dream.' Majority of the experts believe that polio eradication in our country is just round the corner despite setbacks and difficulties". In the same issue Dr. Jay Wenger, Project Manager, NPSP-WHO, India had stated: "Thus, the outbreak of 2002, and the problems of polio eradication were not caused by failure of OPV or occurrence of VAPP, but failure to vaccinate children adequately."

In the November 2003 issue of the Indian Pediatrics Dr. Jacob John had stated: "Dr. Paul disagrees with my assessment that the failure to eradicate wild viruses is due to inadequate vaccine coverage." He had further stated: "I disagree with Dr. Paul's audacious prediction that India will not succeed to eradicate polio unless his three directives are followed. His first directive to take appropriate remedial measures for the high incidence of vaccine failure is superfluous."

As part of global polio eradication, polio eradication program was launched in India in 1995. In addition to routine OPV vaccination, two rounds of pulse polio immunization were introduced. In 1999 quantity of P3 vaccine viruses was increased from 500,000 to 600,000 per dose of two drops of OPV, and number of  vaccination rounds were increased to 5-6 rounds per year for some states. In 2005 monovalent OPV1(mOPV1) and later monovalent OPV3(mOPV3) were introduced in Uttar Pradesh. It was stated that monovalent vaccines are 2 - 3 times more effective than trivalent oral polio vaccines. In year 2007 monovalent OPV1, and OPV3 were administered in Bihar also in addition to trivalent oral polio vaccine (tOPV). In 2007, number of vaccination rounds for Uttar Pradesh was increased to a round every month. But polio has not been eradicated from India.

In the July 2005 issue of the Indian Pediatrics I had stated: "It can be said that present eradication program ensures that polio is not eradicated. Polio cases will continue to occur because of vaccine failure and due to mutant vaccine polioviruses. Infected immunocompromised children will continue to spread for prolonged period in the community wild as well as mutant vaccine polioviruses".

Following observations can provide clues to the reasons for failure of OPV to eradicate polio from India.

1. Differential response to OPV.

Pulse polio immunization was launched in India in 1995. Some states became polio free by 1997 and some became polio free slightly later. No polio cases have been reported from these states. Uttar Pradesh and Bihar have never been polio free during this period, while polio incidence declined in rest of the country.

2. Incidence of vaccine failure is on rise.

In a study by Ahuja et al. for 1989 - 1994 period, it was reported that among polio cases, incidence was 14% in 1989 and increased to 22.9% in 1994 who had received three or more doses of OPV(1). In Rajasthan, percentage of polio cases who had received five or more doses of OPV was 32.7% in 1999(2) and 58.6% in 2000(3). These observations are substatiated by the data in Table 1.

3. VAPP after subsequent dose.

Risk of VAPP is highest with the first dose of OPV, but, in India majority of VAPP cases occurred after subsequent OPV doses.

4. Increase in polio cases by WP3.

Grassly et al. had stated that children from Bihar show better response to OPV3(4). Now more cases of polio by WP3 are occurring, in Bihar.

It is difficult to understand how the experts had envisaged polio eradication by OPV. On the other hand it is difficult to believe that the experts are unable to understand that polio cannot be eradicated by the current polio vaccines. May be they understand the reality but do not wish to acknowledge due to the reasons best known to them.

P.S.

Should there be any reasons for concern?

In an Editorial in the May 2008 issue of the Indian Pediatrics Dr. Roland W. Sutter, Dr. Hamid Jafari and Dr. Bruce Aylward have stated: "Do we need a change in the polio eradication strategies? The strategies have eliminated polio from all but two states in India (and more than 120 countries globally)." They have stated further: "Uttar Pradesh may have already interrupted poliovirus type 1 transmission and also appears to be on track to possibly interrupt type 3 transmission in 2008."

Thus, there should be no reason for us to even think that polio eradication is evading us. But, the actual data by NPSP may be a reason for concern as can be seen in Table 2. It can be seen that during 1999 and onwards, number of polio cases in November and December 2007 and January to April 2008 have been highest, even higher than those which occurred in 2002, when there were 1600 polio cases.

-Yash Paul, Jaipur, India.

E-mail : dryashpaul2003@yahoo.com

References :

1. Ahuja B, Gupta VK, Tyagi A. Paralytic poliomyelitis (1989 - 1994): report from a Sentinel Center. Indian Pediatr 1996; 33: 734 - 745.

2. Paul Y. Polio Eradication Strategy: Need for Re-appraisal. Indian Pediatr 2000; 37: 913 - 916.

3. Paul Y. Accuracy of the national polio surveillance project data in Rajasthan. Indian J Pediatr 2002; 69: 667 - 673.

4. Grassly NC, Fraser C, Wenger J. Deshpande M, Sutter RW, Heymann DL, et al. New strategies for the elimination of polio from India. Science 2006; 314: 1150 - 1153.