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Editorial Indian Pediatrics 2003; 40:195-203 |
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Setback in Polio Eradication in India in 2002: Reasons and Remedies |
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The number of cases of poliomyelitis caused by wild polioviruses in India had declined from 1126 in 1999 to 265 in 2000 and 268 in 2001. Reversing this trend, there were 1509 cases during 2002, accounting for over 87% of cases detected globally (1). Poliovirus type 1 accounted for 1404 (93 %) cases, indicating that it was truly an outbreak, which in the face of intense eradication efforts, was a severe setback. The remaining cases were due to poliovirus type 3. The number of districts with polio had declined to 63 in 11 States in 2001, but in 2002 cases occurred in 149 districts in 16 States. The numbers of cases in these two years in various States are presented in Table 1. Cases occurred in six States that were without polio in 2001. Did poliovirus type 1 survive in them and circulate silently before showing up in 2002 or did they get introduced from outside? TABLE I– Virologically Confirmed Cases of Paralytic Poliomyelitis Reported From Various States in India in 2001 and 2002.
Originally the target year for achieving eradication had been set as 2000, but now it has been shifted to the year 2005 (2). We believe that India can achieve zero status of wild-virus polio earlier than 2005 provided we understand the reasons for the setback in 2002 and take effective remedial inter-ventions without delay. It is heartening to acknowledge that the Central and State Governments have initiated these exercises. The components of the eradication strategy are adequate immunization, disease surveillance and virological investigations (3). Immunization, both routine (UIP) and SIAs are guided and directed by the Department of Family Welfare of the Ministry of Health and Family Welfare of the Government of India (GOI), and imple-mented by the corresponding agencies of the State Governments. Vaccines are partly purchased and partly received as donations, and given to State Governments free of charge. The tactics of immunization for polio eradication are formulated each year and recommended to the GOI by the Polio Eradication Expert Group that usually meets twice each year. The National Polio Surveillance Project (NPSP), a joint operation by the GOI and the World Health Organiza-tion (WHO), manages the AFP surveillance. The virological surveillance is conducted by the network of polio laboratories, technically and financially supported by WHO. The disease under surveillance is acute flaccid paralysis (AFP), being the predomi-nant clinical manifestation of poliovirus infection. The WHO has set the criterion of adequacy of surveillance as the detection of not less than one case of AFP other than due to polio, per 100,000 children under 15 years, per annum. India as a whole and the polio-affected States individually have maintained more than adequate AFP surveillance prior to and during 2002. Virological investigations consist of collection of stool samples from children with AFP as early as possible after the onset of paralysis, their transportation under cold condition to one of the nine national poliovirus laboratories without delay and their prompt processing for virus isolation and identification according to prescribed procedures. All poliovirus isolates are submitted to one reference laboratory (The Enterovirus Research Centre in Mumbai, under the Indian Council of Medical Research) for tests including gene sequencing to distinguish wild viruses from vaccine viruses. The performance quality of each component of the virus investigation system passes the WHO standard of adequacy. The detection and quantification of continued circulation of wild viruses in India are the results of the high quality clinical and virological surveillance, but the increase in cases in 2002 is due to inadequate performance of immunization efforts. The first case of polio in Gujarat in 2002 was on 28 June and the last case (known at this time) was on 14 December. Similarly, the first case in West Bengal was on 22 May and the last case on 20 November. There are epidemiological clues and evidence from genetic investigations that in both States the introduced viruses caused circulation in their territories. Considering that disease occurs in only about 0.5 % of infected children, the virus circulation was quite large. Obviously the speed and coverage of immunization in both States had declined from the time infection was virtually eliminated there, by 2001. Moreover, the ‘mop-up’ immunization in response to detected cases was ineffective to interrupt transmission. This experience is a warning for all other States as well. As long as risk of importation of wild virus exists, all States are vulnerable for reintroduction. The Molecular Epidemiology of Wild-Virus Polio in 2002 The data on the molecular epidemiology of polioviruses generated in the reference laboratory have provided invaluable help in understanding the dynamics of the outbreak described above. Wild-virus polio is diag-nosed on the basis of detecting poliovirus in the stool sample of the affected child and confirming that it is wild virus and not of vaccine virus lineage. Poliovirus isolates can be distinguished as of wild or vaccine origin by ‘intratypic differentiation’ (ITD) tests (4). Every isolate of poliovirus obtained through surveillance is subjected to ITD tests. The poliovirus genome consists of single-stranded RNA. The nucleotide sequence of the VP1 region of the genome of a poliovirus isolate is established and compared with that of wild and vaccine viruses to determine its origin. In addition, the sequence data allow the classification of viruses into ‘genetic clusters’ with common ancestry prior to one or more passage(s) in human subjects. Poliovirus genome incorporates occasional nucleotide substitutions (mutation) during multiplication cycles within the human host. With increasing number of multiplications in humans through transmission and circulation, such substitu-tions (mutations) accumulate. Thus, based on the number of accumulated mutations and their specific sequences, several lineages of wild viruses had been detected in India in the past. By 2001, the number of type 1 lineages had shrunk to three. They were geographi-cally confined to Uttar Pradesh and Bihar, attesting to the remarkable progress made by the country along the path towards eradica-tion, except for these two States. Molecular epidemiology showed that the sporadic cases of wild-virus polio in 2001 in the remaining 9 States were due to viruses originating in Uttar Pradesh or Bihar. Was the type 1 outbreak in 2002 in the 16 States (10 with and 6 without cases in 2001) due to the same lineages or due to other lineages that had circulated undetected? The studies in the reference laboratory have shown clearly that all wild type 1 viruses of 2002 have belonged to the three surviving lineages of 2001 and that they were intro-duced to new territories from Uttar Pradesh or Bihar. Unfortunately the introduced virus(es) established local transmission chains in West Bengal, Gujarat and Delhi in 2002, but not in Maharashtra, Madhya Pradesh or Orissa. In short, the setback in 2002 can be pinpointed to inadequate immunization in Uttar Pradesh and Bihar not only in 2002, but also in the preceding years. The Inadequacy of Immunization as the Reason for the Setback What was the inadequacy of immuniza-tion in Uttar Pradesh and Bihar? According to the guidance from WHO, India uses exclu-sively the oral poliovirus vaccine (OPV) for the universal immunization programme (UIP) and for the polio eradication initiative. The ultimate measure of adequacy of immuniza-tion is the elimination of wild virus trans-mission. However, in order to reach that goal we must know what constitutes adequate immunization in terms of policy and plan. The components of this endeavor are routine immunization (UIP) and supplementary immunization activities (SIAs), particularly the annual repetitive pulse immunization. If routine immunization had ensured that all children were protected from disease when infected, then pulse immunization would have eliminated wild virus transmission. Fairly large numbers of children continued to get polio in Uttar Pradesh and Bihar right through 2001, exposing that even the combination of routine and pulse immuniza-tions was not enough to protect all children from disease, let alone achieve elimination of virus transmission. For successful outcome, virtually all children in sequential birth cohorts must receive several doses of OPV at a speed matching or competing with that of wild virus infection. The speed of transmission of wild viruses may be deduced from the age distribution of polio cases, since the number of cases is proportional to the number of infections. The median age of polio cases has remained at or below 18 months during the pre-vaccination era, the UIP years and the eradication initiative with pulse immuniza-tions. Thus we know that among the susceptible children who get poliovirus infection, 50% do so by 18 months of age irrespective of the immunization coverage. The increasing coverage with immunization has reduced the number of cases, therefore the number of infections, in recent years, but the speed of wild virus transmission has not slowed down in the remnants of susceptible children, suggesting that the ‘herd effect’ of OPV, routine plus pulse, has been minimal. In an efficient UIP 85-95 % infants would get at least 3, may be 4, doses depending on the place of birth (home or institution) and the nature of service provider (public sector or private sector). Infants under the care of Academy members would get 5 doses. If the annual pulse immunisation were also efficient they would get 2 more doses, adding up to 5-7 doses in the first year of life. During the second year of life they would get 2 more pulse doses, for a total of 7-9 doses by 24 months of age. Later they would get further incremental doses over 3 more years. This speed of immunization with liberal doses of OPV reaching infants and toddlers through UIP and pulse campaigns is what resulted in interruption of wild virus transmission in the majority of States in India by 2000-2001. In Uttar Pradesh and Bihar, either the coverage or speed of immunization or both have not been sufficient to eliminate transmission, prevent disease or even avert an outbreak. The inadequacy was gross. Although the UIP coverage with 3 doses of OPV (along with diphtheria-tetanus-pertussis vaccine, DTP) in infancy, as reported by the Government functionaries in these two States have been better than 90 % (5), independent assessment has shown that in reality it has been only in the range of 15-25%. Thus UIP performance was highly unsatisfactory. There is anecdotal information from Academy members that there has been an increase in cases of whooping cough and diphtheria in recent years, indicating that the decline in routine immunization coverage is a recent development. This deterioration may be partly due to the shift of UIP from ‘Central sponsorship’ (when all expenses were provided from the Central Government) to State’s responsibility (with programme expenses to be borne by the State and only vaccines supplied from the center). We understand that some 7000 posts of auxiliary nurse midwives were vacant in Uttar Pradesh in 2002, not filled due to financial constraints of the State. Under these circumstances pulse immunizations could have adversely affected the routine immunization delivery. Apparently health workers are involved in micro planning for weeks before the pulse campaigns; consequently other activities suffer. Instead of admitting the deficiencies and attempting to solve them, the path adopted by health functionaries from village level to district and State levels was to deny them by showing inflated vaccine coverage data. In the absence of surveillance for vaccine-preventable diseases, discrepancy in coverage levels could be debated; since the AFP surveillance and virological investigations are of high quality, polio cases have acted as ‘truth detectors’. There are discrepancies also in the reported coverage in pulse immunization and the ground reality. During 2001 and 2002, pulse immunization consisted of booth-based distribution of OPV followed by house visit, search for unimmunized under-five children, giving of OPV and marking the house with coded information on what was done. On cross checking, it was found that children in 10-15 % of houses marked as ‘immunized’ were actually not immunized. Immunization coverage in children with non-polio AFP may be taken as a surrogate value for children without polio, or in other words, the general childhood population. Data from the AFP surveillance system showed in 2001 that 10% of children with non-polio AFP in Uttar Pradesh had received 3 or fewer doses of OPV, but this had increased to 16% in 2002. In Central and Eastern Uttar Pradesh the proportion of such children increased from 9% in 2001 to 32% in 2002. Thus, the extent and speed of immunization coverage, already inadequate in 2001, had further deteriorated in Uttar Pradesh in 2002. Among children with polio in 2002 in Uttar Pradesh, 61% were Muslim children, showing that they were disproportionately over-represented suggesting worse immunization coverage for their children than in the majority community. Apparently, the contrast between the vigor to promote OPV and the neglect of other vaccines, especially against measles, made the Muslim community suspect the safety of OPV and the honesty of purpose of the programme. Remedies The numbers of cases of polio reported in 2000, 2001 and 2002 by calendar months are presented in Fig 1. As seen in the Figure, the numbers were very low in February to May each year, indicating that the wild virus transmission is at its lowest during this interval each year. In 2003 this season will in all probability coincide with the post-epidemic phase of the 2002 outbreak. This gives us a window of opportunity to interrupt transmission by carefully planned and efficiently executed immunization efforts. During the outbreak in 2002, nearly all susceptible children in Uttar Pradesh and Bihar would have been infected with wild virus type 1 and thus immunized. Infants born since then would not be so immunized since wild virus transmission would be at its lowest for some months. The speed with which they are immunized with multiple doses of OPV will, during the low infection, determine if transmission can be interrupted. Therefore, special efforts are needed to improve routine immunization coverage in all infants from January 2003 onwards. In addition, in these two States pulse immunization in the low transmission period (such as in April and May) would enhance both the coverage and the speed of immunization in the crucial birth cohort of children born since early 2003. If these activities are conducted diligently, there is an excellent chance that we may be able to achieve the interruption of wild virus transmission in these two States in the first half of 2003 itself.
Fig. 1. Distribution of cases of paralytic poliomyelitis due to wild poliovirus infection by month, 2000-02 The next national pulse immunization will be in January and February 2004. Infants born in Uttar Pradesh and Bihar after May 2003 will have to be immunized to prevent them from circulating polioviruses; therefore State-wide pulse immunization must be repeated once more between July and November. This will also add to the doses in infants born earlier, thus contributing to the speed and coverage of immunization essential to achieve and maintain interruption of transmission. Had the routine immunization coverage been satisfactory, then such additional pulsing would not be needed, but this year is of critical importance, both for India and the whole world. Analysis of immunization status of children in Gujarat and West Bengal in 2002, with wild-virus polio and with non-polio AFP, indicates that immunization coverage levels had declined in them also, resulting in continued transmission of imported virus albeit in limited locations. Wild viruses repeatedly reached children in Delhi State from neighboring Uttar Pradesh. Fortunately in the three States and also in others with polio in 2002, the routine OPV coverage had been quite high in the past and the deficiencies could and should be addressed rapidly with reinvigorated efforts. With such urgent steps taken to bridge the immunity gap, they could avoid additional pulse immunization during 2003. However, in all these States, ‘mop up’ immunization around each and every case of polio should be continued as in the past. It is essential that routine immunization coverage in infants in all States is maintained well above 85-90%. The next national pulse immunization should be of high quality in all States. How to Improve Routine Immunization? The lion’s share of routine immunization in India is given by the UIP through Government health centers and hospitals. When a child is sick, parents will seek out health care in spite of inconveniences. Since immunization is for well children, parents should not feel any inconvenience when they are ready to bring children to the health centers or clinics. An approach that has worked well in some States is to earmark one day a week, usually every Wednesday, for immunization outreach. * We feel that the concerned State Govern-ments should ensure that the selected weekly day, preferably Wednesday, is kept sacrosanct for immunization outreach programs by the staff, no matter what other programs are prioritized for the season, including even the preparation for pulse immunization for polio eradication. * Every Primary Health Centre, Community Health Centre, Taluka Hospital and District Hospital should provide immunization on the selected day every week, thus ensuring at least 52 days in an year when parents can get children immunized without any excuse by the staff or shortage of any vaccine. Immunization should also be made available in all RCH clinics as the mothers often take children along with them. * In the clinics immunization should be made available during the entire working hours instead of during limited hours. * Very large hospitals in the public and private sectors should open immunization clinics preferably every working day of the week. * For all institutional deliveries, a dose of OPV must be given before the infant is sent home. * As cohorts of new parents have to be educated on the need and availability of vaccines, awareness creation should be repetitive, throughout the year, and through several channels, including the print and electronic media. * Family-retained immunization records are useful as a management tool and as an educational tool. At every clinic visit of each sick child the health care worker or the pediatrician should ask for the immunization card and scrutinize it. It will help to increase awareness, detect missed doses that can be completed, avoid duplication of doses, and improve the respect given to immunization by the parents. How to Improve Quality of Supplemental Immunization Activities? SIAs include pulse immunization and ‘mop up’ immunization around each detected polio case. Nation-wide pulse immunization is otherwise known as national immunization day (NID) and State-wide or regional pulsing is also called sub-national immunization day (SNID). Earlier under the ‘remedies’ subtitle we have indicated that State-wide pulse immunization should be conducted in Uttar Pradesh and Bihar twice (two doses) in the first half of 2003 and again twice in the second half. Whether such additional pulsing is necessary or not in Delhi, Gujarat and West Bengal has to be decided in light of the evolving epidemiology of polio in the early months of the year; as we write this it is too soon to make an assessment of its need. As a general principle we argue that mop ups need not and should not be conducted in 2003 in the States that conduct State-wide pulse immunization such as Uttar Pradesh and Bihar. In those States where the risk of polio is not high the pulse immunization should be confined to booths (fixed points), but in high-risk States additional house-to-house search and immunization must be conducted this year, on account of the crisis situation prevalent there. In order to decentralize the monitoring of SIAs to the district level, the establishment of District Task Forces (DTFs) in Uttar Pradesh and Bihar has been recommended by the Polio Eradication Expert Group (see below). The DTF should meet every month round the year and closely monitor AFP surveillance and virological investigations and the planning and implementation of SIAs. In addition the DTF can also monitor the progress in strengthening routine immuniza-tion. We suggest the following specific steps to improve the coverage of SIAs. * Chief Minister, Minister for Health, Chief Secretary and Secretary for Family Welfare in Uttar Pradesh and Bihar should monitor pulse immunization, polio eradication efforts and their progress on regular periodic basis. This will generate and exhibit the political will sorely needed for achieving success. * The DTFs should be established immediately. They should include representatives from local communities, profes-sional organizations, suitable non-governmental organizations (NGOs) and other locally important constituencies. They should be convened by the district health officer /district immunization officer. Their monthly reports of activities should be reviewed regularly by the Director of Health Service/Public Health and reported to the panel listed above. * Unless given earlier, the family retained immunization cards should be handed over at the pulse immunization booth so that the parents could present them at the clinics for routine immunization. If given earlier, immunization cards should be inspected at the booth, the pulse dose entered and parents advised to go to the appropriate place on the appropriate day for other vaccines. Lost cards should be replaced at this opportunity. * The primary health care service and routine immunization should be improved so that people regain confidence in the Government public health system. The DTFs should oversee these activities. How Can IAP Contribute to Remedial Measures? What Can Individual IAP Members Do? * It is proposed that IAP members could provide free treatment to all children affected by polio paralysis, both for acute polio and for any other ailments, and that they will help in rehabilitation of polio-affected children with help from NGOs. * At each clinic visit of each sick child, the family-retained immunization card should be asked for; immunization history reviewed and discussed; and plans be made for correcting any deficiencies. * Everyone can display a poster in the waiting area and/or consultation room, emphasizing the importance of routine immunization and the schedule and days of immunization. Suitable posters are available from the IAP Committee on Polio Eradication. Once the new dates for pulse immunization are announced, suitable posters and dates of pulse immunization should be displayed in the waiting area and/or consultation room. * Once-a-week free immunization services may be rendered to deserving families. * Talented members could write articles on routine and pulse immunization in local newspapers; give interviews on Radio; and try to utilize cable television network also. They could offer their services for giving motivational talks to local NGOs. * On the days of pulse immunization, the clinic may be opened to serve as polio immunization booth. Visiting nearby booths and staff and volunteers may encourage them and help improve motiva-tion and job satisfaction. * After the pulse immunization, if UNICEF approaches IAP members, they should fill up forms of ‘Process Evaluation’. How Can IAP Branches Help? * Branches could adopt a slum or nearby village and take responsibility of vaccination of that area. They may take help from the local Rotary Club (being an official partner of polio eradication initiative) or other NGOs for this purpose. * Branches may provide health checkup services and free medicines to overcome resistance and increase acceptance for immunization. ‘Health’ camps/melas’ may be organized with the help of local UNICEF Social Mobilization Co-ordinators and NGOs. * Branches could actively involve all doctors practicing in that area, especially those who are popular or prominent and arrange direct face-to-face dialogue or small group meetings, to ensure their understanding, involvement and participation. * Regular interaction with media will help propagate the message of polio eradica-tion and routine immunization. They should be alert to detect and immediately counter any negative propaganda by anybody. * Branches should keep their members informed about achievements and future strategies. They could provide IEC material to all doctors in that area. Contributors: TJJ proposed the idea for this manuscript. TJJ, NT, JMD drafted the manuscript. TJJ approved the manuscript and will serve as the guarantor for the paper. Funding: None Competing interests: None T. Jacob John, Naveen Thacker, Jagadish M. Deshpande | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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