Polio / Polio

Polio continúa endémica en: Nigeria, Afganistán Pakistán e India. La iniciativa global de erradicación de polio de la OMS estableció que para 2013 no debe haber ningún niño paralítico en el mundo por el virus salvaje o por el virus derivado de la vacuna. En esta revisión se describen ambas vacunas contra el polio, la oral y la inactivada, su inmunogenicidad, seguridad y las condiciones a cumplir por un paíspara que cambie su esquema de vacunación de polio oral a inactivada. La vacuna polio oral ha permitido la erradicación de la enfermedaden varios continentes incluyendo América; sin embargo conlleva riesgos, tales como polio paralítica asociada a vacuna (VAP-siglas en inglés-) y parálisis producida por polio virus derivado de la vacuna (VDP-siglas en inglés-). La Vacuna Polio Inactivada (VPI) es segura e inmunogénica, puede ser administrada en combinaciones vacunales. Para que un país cambie a VPI debe tener cobertura y esquemaóptimo de esta vacuna, 90% de, cobertura de DTP3, vigilancia adecuada de parálisis flácida, no estar próximo en la actualidad o recientemente a un país con polio endémico. Altas coberturas vacunales son esenciales par asegurar una inmunidad adecuada de lapoblación

Polio remains endemic in Nigeria, Afghanistan, Pakistan, India. Strategic plan of Global Poliomyelitis Eradication Initiative (GPEI) of the WHO is that by 2013 no child will be paralyzed by a wild or vaccine derived poliovirus. This paper describes both oral and inactivated vaccine, safety concerns with the use of OPV, immunogenicity of IPV and the conditions to be full filled in order for a country to deliverIPV as a regular vaccine schedule. Oral polio vaccine has successfully contributed to global polio eradication in several continents including America. However, it carries risks, such as Vaccine Derived Poliovirus (VDP) and Vaccine Associated Paralytic Polio (VAPP). Inactivated Poliovirus Vaccine (IPV) is safe and immunogenic; it may be administered as monovalent or in a combined shot. Countries opting to switch from OPV to IPV should have: optimal IPV coverage and schedule, 90% of DTP 3 coverage, good surveillance of flaccid paralysis cases, and should not be near a country with endemic polio recently or at the present time. Are neither currently or were notrecently polio endemic nor has close contacts with such areas. High immunization coverage is essential to ensure adequate populationimmunity

Vaccination strategies for the last stages of global polio eradication.

Launched in 1988, the Global Poliomyelitis Eradication Initiative has enjoyed remarkable success. The WHO anticipates isolation of the last wild polio virus during late 2004/early 2005, paving the way for certification of a world free of polio in 2008. However, the ultimate objective of this campaign, discontinuation of polio vaccination, has been jeopardised by two recent developments: the characterisation of vaccine-derived polio viruses (VDPV), and renewed concerns over the risk of bioterrorism. The threat posed by VDPV has led the WHO to recommend discontinuation of OPV usage as soon as possible after eradication certification. Cessation of vaccination with OPV needs to be carefully designed to avoid creating conditions where VDPV will develop. For the longer term, strategies must be designed to guard against the risk of polio reemergence due to long-term VDPV excretors, accidental release of wild viruses or bioterrorism. The main strategies under consideration are a surveillance and response approach or a continuation of vaccination with IPV. Choosing between these strategies will pose a major dilemma for India and for many other countries.

Evaluation of pulse polio immunization in some districts of West Bengal & Assam.

A cross-sectional non-interventional survey was carried out in 5 districts of West Bengal and one district of Assam to find out the extent of coverage during IPPI. It was observed that in the recent rounds of IPPI, more than 95% coverage was observed in all the surveyed districts excepting in 24 Parganas South where coverage was around 92%. Situation at the Goalpara district further needed attention, as the coverage during February 03 as well as in the past two rounds were 90.13%, 88.13%, and 91.04% respectively. In all these districts booths were the main sites for IPPI dose though 1/3rd to 1/4th of the beneficiaries received immunization at home also. It was also observed that around 10% of the beneficiaries were not administered any PPI dose in the either of the rounds, in 24 Parganas (south) & Murshidabad districts, from where maximum number of Poliomyelitis cases were reported. At Goalpara it was 19%. Main reason for not being covered with PPI doses in either of the rounds in all the districts excepting Kolkata was "Not aware of the need for additional doses". In Kolkata "child sick" was the main reason. Health workers were main source of information of PPI in South 24 Parganas (67.13%), Malda (58.25%) & West Midnapur (54%). At Murshidabad "announcement through mike" (61.25%) was the main source of information while in Kolkata, TV was the main source (67.13%). Miking (56.38%) was the main source of information for PPI at Goalpara district of Assam. It was observed that involvement of multiple methods & media of communication was helpful in disseminating dates & other information of PPI.

Challenges in the final stage of polio eradication.

India and many other countries of the world have supported the resolution taken by the World Health Organization (WHO) in 1988 to eradicate poliomyelitis globally by the year 2000. At the beginning of 2002, there were 10 countries in the world with endemic transmission. India included in the high transmission area. WHO is preparing guidelines on the program response (both immunization and surveillance) to wild poliovirus isolation from the environment. This technology will be useful in monitoring the disappearance of vaccine virus after ceasing OPV vaccination.

Assessment of functioning of Pulse Polio Kendras and house to house activity in Delhi: is there any scope for improvement?

A cross sectional study was done to assess the performance of Pulse Polio Immunization Booths on National Pulse Polio Immunization day (NID) observed on 2nd December 2001. 55 booths located in Delhi were visited. House to house visits were made on 5 successive days to assess out-reach activities and hold focus group discussions with workers and mothers of the beneficiaries. Majority of the booths were within walking distance (96.4%) and accessible (94.5%) to the beneficiaries, had adequate trained staff reporting in time (88.5-90.4%), displayed IEC material (89.1%), marked the tally sheets in a correct manner (86.5%) and were administering polio vaccine within acceptable norms. Correct knowledge regarding vaccine vial monitor (VVM) was present among workers of 82.7% booths. The marking of children was not being done correctly in 38.2% booths. Efforts to disseminate key messages of next date of NID and routine immunization schedule, information about the disease and it's impact on life and removal of misconceptions regarding polio was observed to be poor (28.9-48.1%). During house-to-house visits coverage was found to be excellent barring a few isolated cases of unimmunized children due to various reasons. The finding of the study implies increased focus on training of the workers manning these booths, especially on dissemination of key messages and information about early symptoms and signs of polio, removal of misconceptions, correct marking of the children and houses and countering resistance to immunization.

Declining trend in routine UIP coverage.

Routine UIP coverage status in the state of West Bengal and three selected Municipal Corporation areas (Calcutta, Howrah and Siliguri) were studied during 1997-98 and 1998-99. Also, UIP coverage status in the 'high risk' areas of the State (areas which reported Polio cases during 1998) was studied during 1998-99. UIP coverage in the state of West Bengal was only 54.3% in 1997-98, which further declined to 48.1% in 1998-99. In the three urban areas, UIP coverage ranged between 57.3%-70.9% in 1997-98, which further declined to 29.6%-47.1% in 1998-99. Antigenwise coverage revealed very poor performance with DPT3, OPV3, and Measles in 1997-98 and further decline in 1998-99. Dropout rate was also very high. In 1998-99 drop-out rate ranged between 30.1% to 54.2% in different studied areas. Some other studies suggested that PPI activities, which are very visible and targetted programme, may adversely affect routine UIP services. There is urgent need for further probing to identify the reasons for such poor state of affairs, keeping PPI angle in mind and to initiate remedial measure urgently.

Evaluation of pulse-polio immunisation in rural area of Maharashtra.

An evaluation survey on Pulse-polio Immunisation (PPI) in January 2000 was carried out in rural areas of Maharashtra to assess the immunisation coverage, the knowledge regarding pulse-polio and the routine immunisation schedule. House-to-house survey was carried out and information was collected by interviewing the parents of 778 children. It was observed that PPI coverage was excellent i.e., 98%. Majority of informants were female. Knowledge about pulse-polio had a direct relationship with literacy. But knowledge regarding routine immunisation and the polio disease was not found satisfactory. Excellent coverage of pulse-polio Immunisation was found because of an organised and extensive campaign, use of mass media like T.V., radio, and home visits of peripheral health staff (as told by the informants). The distance of approach to a polio booth was less than a kilometre in almost all cases. Behaviour of health staff was satisfactory everywhere. The time-period required for getting vaccinated after arrival at the polio booth was less than 5 minutes. Thus it was a worthwhile attempt to evaluate PPI coverage is rural areas of Maharasthra. Excellent coverage of pulse-polio immunisation gives us the picture that poliomyelitis is on the verge of being eradicated from India, if the excellent coverage of PPI is followed by effective surveillence.

Strategies for eradication of poliomyelitis--the Indian experience.

Substantial progress has been made towards achieving global eradication of poliomyelitis by the end of the year 2000; the goal set by the World Health Assembly in May 1988. The basic strategies to eradicate polio are: attaining high routine coverage with at least three doses of OPV; conducting national immunization days (NIDs) in polio endemic countries; establishing a sensitive system of acute flaccid paralysis (AFP) surveillance to track wild poliovirus circulation; and conducting "mopping-up" immunization when polio is reduced to focal transmission. By the end of 2000. India was in the midst of the sixth National Immunization Days (NIDs). Surveillance system for Acute Flaccid Paralysis (AFP) continued to achieve the recommended non-polio AFP rate of at least 1 per 100,000 population < 15 years per year (1.88 for week 51 ending 23rd December 2000), the adequate stool specimen collection rate was 83% that met the target of > 80%. Some States in the south and west have started to implement mopping-up immunization campaigns as the end-stage strategy to eliminate the last remaining foci of transmission. While most of India appears to be well placed to eradicate polio by the end of 2000 or shortly thereafter, concerns remain about low coverage in parts of the densely populated northern States of Uttar Pradesh and Bihar where high intensity transmission persists. The Government of India has embarked upon an intensified strategy that relies on extra rounds of NIDs; house-to-house immunization to reach previously missed children; and aggressive mopping-up campaigns including pre-emptive mopping-up in the known reservoirs in Uttar Pradesh and Bihar. Extensive microplanning and supervision of the supplementary immunization activities is critical to achieve the target of polio eradication.

Polio eradication--a success in sight.

India took a giant step closer to eradicating polio through the strategy of National Immunization Days-PPI. In order to validate the reported coverage for 1999-2000, UNICEF had undertaken the CES for PPI on the request from GOI. The paper is a presentation of findings from 15 states, carrying the data as of Aug. 31, 2000. The modified cluster sampling has been used in this study. Data reveals that out of 15, 10 states have more than 95% coverage for at least 3 doses, MP and Gujarat at the top with 99% coverage. Despite this high coverage level, huge number of children is still unreached. Nearly 5 lakh children are left out in UP alone. Ironically, higher proportion of urban clusters have zero dose children. Apart from lack of awareness about date and need of additional doses, lack of positive attitude among parents are major cause of not getting any of the doses. Qualitative research pinpointed some more reasons for non-compliance--apprehension about side effect, knowledge and traditional barriers. According to the service providers and influencers, lack of proper training and monetary compensation are major demotivating factors.

Poliomyelitis in India: past, present and future.

In that they were made in temperate countries, most of the studies on poliomyelitis may not apply in sub-continent of endemic infantile paralysis. This review brings together data on polio in India, to present any changes which may have occurred since 1940. Only about 2% of children with polio die in the acute illness; about 95% of all cases have paralysis of one or both legs. In lameness surveys the adjustments for deaths and for arm paralysis are unnecessary and inflate the prevalence. Surveys suggest that prevalence has risen, but there may be other explanations for the figures. Around sentinel centres with effective cold chains, prevalence has decreased rapidly. The figures of the National Baseline Prevalence survey are examined. There are few cases of provocation, but a new phenomenon of aggravation by unnecessary intramuscular injections given to children with fever has been described. Such unnecessary injections are thought to be the cause of more severe paralysis in about 45% of cases and of converting a non-paralytic attack into paralysis in another 30% of the perhaps 200,000 cases in India each year. Aggravation is thought to be caused by a mechanism similar to the effects of physical activity. It is possible that massage might have a similar effect. Abscesses or their treatment may precipitate paralysis. The median age of paralysis fell by almost a half from about 2 yr to 1 yr, but may now have risen as many younger children receive vaccine. Rehabilitation has been neglected, with long lasting consequences. Assessment of disability should be based on need and not on current ability. Ethically, prevalence surveys should offer opportunity for immunization and rehabilitation. Prevalence of paralysis, numbers attending for rehabilitation and immunization have been analysed by gender and differences examined. The gender-gap widens with age after paralysis: there may be a high mortality among girls with paralysis. Past prevalence calculated from surveys might be seriously underestimated if many girls have died. The monthly pattern of polio was no different in epidemic years. Pulse immunization could be tried just before the seasonal rise each year. Difficulties of comparing vaccination schedules and the criteria for assessing the potency of vaccine are analysed. Paralysis among Indian soldiers in World War II suggests that adult cases may occur, but are not reported. Present investigations should concentrate on babies and adult cases. Research using virulent strains should be prohibited. The very low case-fatality rate suggests that many of the circulating viruses are of low virulence. The increasing proportion of cases with unnecessary injections just prior to paralysis might have caused the lower median age of paralysis, the severity of paralysis and at least part of the increasing prevalence of polio. The seasonal increases of polio might, in part, be a reflection of the injections given for fever caused by other infections. A national campaign against unnecessary injections for young children is urgently required. For children with fever, there is a strong case for postponing even DPT injections.

Is accidental oral polio vaccine overdose harmful?

This study aimed to assess the safety of accidental oral poliovaccine [OPV] overdose. The study included 29 children, less than 5 years old, who received an overdose of OPV. 15 of them were managed by gastric lavage and were followed up for 2 months to record any hazards of OPV overdose. The results revealed that most of the children who are exposed to accidental overdose of OPV were aged 12 months and more [85.7%] and females [67.9%]. 71.4% of the children had received more than three doses of OPV essential vaccination. Only two signs appeared during the follow up period; the first one is fever and appeared during the first two weeks from exposure to overdose and the second is cough and appeared in the third and fourth weeks after exposure. It was concluded that no specific hazards were recorded and OPV overdose is safe among the previously vaccinated children, whether gastric lavage is done or not

Control of poliomyelitis in Kuwait

The use of oral poliovirus vaccine [OPV] in the early 1960[s] marked the beginning of the State's effort in controlling poliomyelitis in Kuwait. During the next two decades, despite the vaccine's availability and use, the disease continued to cause disability and death. However, with the massive and sustained use of the trivalent OPV since 1963G and the introduction of neonatal supplementary immunization with monovalent type 1 [MOPV] in 1976G along with strengthening of the surveillance activities against poliomyelitis, the incidence of the paralytic disease began declining and by the mid-eighties it disappeared altogether. With no cases of paralytic poliomyelitis reported in Kuwait since 1986G, the disease is largely controlled. The epidemiology of poliomyelitis in Kuwait has been examined here in retrospect. The paper profiles about 3 1/2 decades [1958 G to 1992 G] of efforts that led to this impressive virtual elimination of poliomyelitis. In order to maintain this status and eventually achieve the goal of eradication without the rare occurrence of vaccine-associated paralysis, it is, in our opinion, necessary to adopt an approach of combined vaccination with the inactivated polio vaccine [IPV], preferably in the neonatal age, followed by OPV. Simultaneously, monitoring the presence and circulation of wild poliovirus in the environment and continuous surveillance should be carried out for timely intervention