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Priere de rappeler 1a reference :EPI/I8/446/7 GEN

Dr Albert Sabin3101 New Mexico Avenue NWAppt. 1001Washington D.C., 20016-5902In reply please refer to :

27 March 1991

Dear Dr Sabin,

Dr Henderson has shared with me the contents of your exchange of letters andyour paper "Perspectives on Rapid Elimination and Ultimate Global Eradication ofParalytic Poliomyelitis caused by Polioviruses" published in the EuropeanJournal of Epidemiology.

I do not believe that there is any serious doubt about the effectiveness,in terms of rapid wild poliovirus eradication, of administering OPV on amassive scale to all possible susceptibles over a very short period of time.This technique is clearly more effective in displacing the virus from thecommunity than immunizing susceptibles only through routine methods.

7, Experience in Israel, Oman, and,Fin~ has clearly demonstrated the-.. -efficacy of such a system and the recent vaccination days in the Americas haveshown its effectiveness in countries with varying climates, geography, and atdifferent stages of development.

It is likely that the same principles were involved in those countriesthat achieved wild poliovirus eradication in the 1960s and 1970s. Fear of thedisease at that time or the presence of major epidemics induced a massivedemand for immunization which was effectively met by mass administration tovirtually all young children. In most industrialized countries, such as theUnited Kingdom and Japan, but also countries such as Saudi Arabia and Malaysia,we have seen similar curves of incidence as virus eradication approached. Adramatic initial decline approaching, but not reaching, zero report~ cases wasfollowed some time later by a relatively small epidemic, presumably reflectingthe build-up or persistence of susceptibles at a time when wild poliovirustransmission had temporarily ceased. This small epidemic was, almost always,rapidly terminated as these susceptibles were either immunized or acquirednatural infection. Zero reported cases then followed.

ENCL: as mentioned

cc: Dr R.H. Henderson, Assistant Director-General, WHO

1211 GENEVA 27-SWITZERLAND Telegr.: UNlSANTE-GENEVA Telex: 415416 OMS Fax 791.07.46 1211 GENEVE 27-SUlSSE Telegr.:UNlSANTE-GENEVE

Dr Albert Sabin18/446/7 GEN

page 227 March 1991

1, These observations and the principles developed by Ciro de Quadros and his, 'team in the Americas have formed the basis for his success. Based on their

experience and that gained elsewhere in the world, the Third Consultation onPolio Eradication, meeting in Septe~90, developed recommendations andpolicy guidelines which helped~the b~is for WHO recommended policy.

The recommendations of the Third Consultation were then considered by theEPI Global Advisory Group (GAG) meeting in Cairo in~. I enclose themajor conclusions and recommendations of the GAG, as published in the WeeklyEpidemiological Record earlier this year. T~now constit~ WHO ~

I call your attention particularly to section 2.1, which describes theemphasis on raising immunization coverage at the community level, with therecommendation for intensified immunization activities, including the use ofnational, state/province or local immunization days directed at areas of lowimmunization coverage or where there is continuing transmission of disease.The specific recommendations for polio immunization activities are contained insection 3.1, which again discusses mass immunization to all children in anappropriate age range within a limited period of time. "Mopping-up" activitiesare recommended, not as an "isolated" effort, but as a planned administrationof OPV to all children of an epidemiologically appropriate age, regardless of

~~heir existing immunization status, and repeated four to six weeks later.

I

Mopping-up is a strategy to be used in countries where, for the greater part,poliovirus transmission has been interrupted, in areas of high-risk asdetermined by immunization coverage significantly below the national average orcontinued cases.

Section 4.3 details the critical role of surveillance in directing

()Jimmunization activities. Mopping-up depends on excellent surveillance both forcases of acute flaccid paralysis and for immunization coverage at the community

I level.

These new policies will demand for many countries a change in theirmethods, but will result, we believe, in strengthening primary health careincluding both immunization activities and disease reduction. Some countrieshave begun to implement these activities, with good success. In India, wheresurveillance has been dramatically improved and targeted mass immunizationactivities have been implemented, there has been a significant decline in casesreported, particularly in the large cities of Bombay, Delhi, and Madras. Weexpect considerable progress as more countries begin to include these policies.

Other key aspects and needs for global polio eradication, such as thedevelopment of the sophisticated laboratory network needed for virussurveillance and the requirement to achieve regular and reliable reporting ofcases are being tackled, as is the need to assure that the OPV used is of highquality and as temperature stable as we can make it. Our single biggest problemis lack of funding, which makes it extremely difficult to provide the practicalsupport to endemically affected countries at the level we would wish. The cadreof epidemiologists and health officers you advocate is certainly desirable, andwill eventually be required to deal with areas where recalcitrant transmissionpersists and where lack of resources makes it impossible to achieve successwithout external assistance. I hope that before we need to follow thatapproach, we will have reduced the scale of the problem to a more manageablelevel.

vi' Albert Sabin18/446/7 GEN

page 327 March 1991

WHO, with the considerable support of Rotary International, has nowcreated a unit specifically for polio eradication within EPI, with a teamconsisting of the team leader, two epidemiologists, and a virologist, hav~.~", >

strong links to research and vaccine quality activities in WHO. In each Reg1on,we have an epidemiologist. These staff act in a supportive role to theessential staff required at the country and sub-national administrative level.

The quote in your last paragraph by Bill Foege, If ••• the hundreds ofmillions of dollars that are being invested in the search for new and better

(

vaccines are a mockery if such vaccines can only be delivered to a fraction ofthose who need them," is a bit out of date, as the global EPI now reaches some80% of children at age 12 months. We hav,; now not only to reach the remaining20% who are probably at highest risk, but also to use the supplementaryactivities that will contain the virus.

For all our enthusiasm for achieving the earliest possible eradication ofpolio, and I hope it falls well within your own lifetime, we would be failingif we did not also capi.t n-li.ze on the outstanding achievements of the EPI inproviding channels for better health care and child development generally. Thisdoes not, or should not, in any way diminish the potential for early polioeradication. It should be a bonus.

I appreciated your paper and believe that your continuing commitment is asource of vitalization for the eradication initiative.

Yours sincerely,

Dr Nicholas A. WardMedical OfficerExpanded Programme on

Immunization

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