Where the need is greatest / by T. Jacob John

Where the need is greatest T he ancient Ayutvedic system of Indian medi-cine fought against the deep-rooted and widely prevalent superstitions of magico-mythical causes and cures of diseases, and propagated the concept of physical causes and cures. For example, Ayurveda recognised masoorika (smallpox) and romanthika (measles) as contagious diseases and prescribed quarantine measures. It developed an astounding array of herbal extracts for treating successfully a variety of human illnesses. · But for infantile paralysis (poliomye- litis) , no cause or cure was found. The disease struck at random, paralysing one or more limbs of an otherwise healthy infant or young child. It affected perhaps one child in 500; thus it did not appear to be contagious, and no indiscretion on the part of the parents nor any imbalances in the baby's "body humours" could be incriminated as the cause. So this illness was classified as 'graha dosha ' (in Sanskrit, evil influence of planets). Even today, for many in the developing world the crippling disease of polio seems to be outside the realm of human control, to be suffered as the fate of the unfortunate child. As far as immunization activities are 28 by T. Jacob John concerned, the countries of the world may be classified into three categories: countries with a tradition of providing excellent health care and successfully Or T. Jacob John is Professor and Head of the Department of Virology and Microbiology, Christian Medical College and Hospital, in Vellore, Tamilnad u, India. He is also the Programme Director of the Centre of Advanced Research in Virology at Vellore, under the Indian Counci l of Medical Research. integrating childhood immunization services into it, such as countries of Europe and North America; countries which have introduced the Expanded Programme on Immunization (EPI) in the mid- or late 1970s and have achieved excellent results, such as countries of Central and South Amer- ica and of the Mediterranean region, China, Hong Kong, Korea, Malaysia, Singapore, Sri Lanka and Taiwan; and countries which have achieved only slow progress and continue to have high morbidity, disability and mortality due to vaccine-preventable diseases. This third category deserves special encouragement, guidance and help. In many Asian and African coun- tries, the incidence of paralytic polio- myelitis is very high. To judge by Europe and the United States, one would have predicted one case of paralytic disease in about 1,000 polio- virus infections. In reality, in many developing countries there are about ten cases per 1,000 children. Of ten children with poliomyelitis, one may die in the acute phase of disease, two or three may recover completely and six or seven may have residual paraly- sis. If schoolchildren are surveyed in these countries, we would find four to eight lame children per 1,000. A small proportion of children may have both lower limbs severely paralysed - we do not find them in schools. For these countries, polio is a major public health problem. Why should we eradicate poliomyelitis? Disease, disability or death of a child evokes sorrow and sympathy; but this has failed to create the necessary political will to eradicate or even control poliomyelitis in some countries. More convincing reasons exist and they should be highlighted. There are strong economic reasons for preventing polio. The cost of treatment and rehabilitation of a child with polio, the loss of productivity of parents when the child is sick and the subsequent diminution of productivity and buying power of the individual afflicted with paralysis, together add up to a very substantial national loss. I have estimated that the total financial loss due to one case of polio is sufficient to immunize 10,000 children and prevent 100 cases of the disease. A second compelling economic reason is that it will be less expensive to eradicate polioviruses than to perpe- tually continue immunizing. If invest- ment is to be made for eradication, the cost will be less now than later. A third economic reason is that the basic infrastructure to control and even eradicate poliomyelitis has already been created in most countries at considerable cost; it is more profitable An immunization session in an Indian village. Systematic use of vaccines will help all countries to eradicate polio by the year 2000. W ORLD HEALTH. December 1989 to reap its full potential benefits than to under-use the investment. In short, poor countries cannot afford the national waste due to poliomyelitis; control and eradication will actually result in saving more than the invest- ment. The saving due to the eradi- cation of smallpox is well-known. Two excellent tools Wild poliovirus transmission has already been eradicated from large territories such as Canada, Japan, the Scandinavian countries and the United States. This is the best proof that it can be achieved elsewhere too. Indeed we expect that wild polioviruses will be eradicated from all Central and South American countries within a year or two. The oral live attenuated poliovirus vaccine (OPV) and the · injectable (inactivated) poliovirus vaccine (IPV) are both excellent tools in our hands to achieve this. In some developed coun- tries, which ·we classified as category one, eradication was achieved with immunization coverage rates of 70 to 90 per cent of infants and young children, using either vaccine. The second category countries have achieved success in controlling the disease (reducing the incidence by 90 to 99 per cent) by using OPV in one or another schedule of doses. In Cuba wild virus was eradicated by the use of a dose of OPV given every six months to all children up to ten to 15 years. In China, Hong Kong and Singapore, polio was controlled by giving five to seven doses of OPV per child during the first five years of life. In some 14 countries in Central and South America, two doses of OPV are given two months apart, in simultaneous country-wide campaigns, to all children below six years, irrespective of the number of doses given during primary immunization in infancy. Some countries, such as Gambia, were initially successful in controlling the disease by wide coverage with three doses of OP\1. But when wild poliovirus was re-introduced, large epi- demics occurred, indicating that child- ren immunized with three doses of OP\1 did not necessarily act as barriers for wild virus transmission. It is there- fore prudent to over-immunize rather than titrate the number of doses to what is barely necessary to control the disease, especially for sustaining the control and for moving towards eradication. The modem IPV with enhanced potency ( eiPV) is an alternate vaccine, which has given excellent results in our studies in tropical southern India. This vaccine is readily combined with diphtheria-pertussis-tetanus vaccine into a quadruple (DPTP) vaccine, thus W ORLD HEA LTH . December 1989 simplifying the routine immunization schedule. These experiences in different tropi- cal and developing countries clearly show that control and indeed eradi- cation can be achieved even in the third category countries by the strategic and intelligent use of either vaccine, or a combination of both vaccines. For countries which prefer OP\1, either several (five to seven) serial doses may be given, starting as early as in the neonatal period; or primary three-dose immunization may be followed by annual two-dose campaigns. We found that three doses given in annual pulses of immunization for all children under two years of age will effectively control polio. For those countries which prefer eiP\1, two or three doses of DPTP may be given in routine immunization. For countries which prefer a combination, one or two doses of eiPV may be given first, followed by two or more doses of OP\1, or vice versa. "Infantile paralysis, used to be blamed on the evil influence of planets. Today we know better. But for many children handicapped by polio - like this young girl in India - the only appliance available may be a simple stick. Since polioviruses do not have a non-human reservoir, they can be eradicated. The effort ·towards a global eradication of polioviruses must truly be international. Unlike the case of smallpox eradication, one uniform tactic of immunization applied every- where will not succeed in the case of polio. We have enough talent to design appropriate tactics for different countries; we have sufficient tools to eradicate poliovirus . transmission; and the world does have sufficient resources to fight this disease. This war against polioviruses must be waged and won. Together we can do it. • 29