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Published Date: 2019-04-03 22:45:13
Subject: PRO> Poliomyelitis update (24): comment
Archive Number: 20190403.6402674
POLIOMYELITIS UPDATE (24): COMMENT
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Date: Tue 2 Apr 2019, 1:12:02 pm IST
From: TJ John <tjacobjohn@yahoo.co.in> [edited]


This is regarding: PRO/EDR> Poliomyelitis update (23): Afghanistan (OZ) Archive Number: 20190401.6398265.

[The] comment about vaccine failure of OPV (5 doses) and the list of references are highly relevant and very much appreciated. Polio experts had not taken OPV failure as seriously as the problem really deserved. In India, OPV failure was a difficult problem to overcome, delaying elimination of wild polioviruses more than a decade after the target year of 2000. In 2002, failure in spite of 7 or more doses of OPV accounted for 15% of polio cases due to WPV type 1 and 25% of cases due to type 3. Thereafter, the frequency of such cases fluctuated from 52% to 62% (WPV type 1) and 29% to 64 % (WPV type 3) during 2004 to 2007.

While some experts have suggested that "competing infections for receptor sites" may explain why vaccine viruses fail to take, polioviruses use CD155 as receptor, and no other enteroviruses use it as their receptor. Alternate explanations are to be considered.

--
T Jacob John
Former (retired) Professor of Clinical Virology
Christian Medical College
Vellore, India
<tjacobjohn@yahoo.co.in>

[Many thanks to Prof. T Jacob John for his comments and providing additional data on the impact of OPV vaccine failures on the polio eradication effort in India. In addition, raising doubts re: the "competing infections for receptor sites" is an important issue. When I was preparing the post (Poliomyelitis update (23): Afghanistan (OZ) 20190401.6398265), I had remembered many discussions regarding competing receptor sites, but found the paucity of studies confirming this theory curious.

Noteworthy is that India has recently celebrated the 5th anniversary of having been certified as polio free, with the last case of WPV confirmed in India in January 2011. - Mod.MPP

HealthMap/ProMED map available at:
India: http://healthmap.org/promed/p/142]

See Also

Poliomyelitis update (23): Afghanistan (OZ) 20190401.6398265
Poliomyelitis update (22): Pakistan (WPV1), Nigeria (cVDPV2), vacc. postponement 20190328.6391970
Poliomyelitis update (21): global (Nigeria), Pakistan 20190321.6379811
Poliomyelitis update (20): (Pakistan, Nigeria) isolates, real-time surveill 20190315.6367838
Poliomyelitis update (10): (Afghanistan, Pakistan, Nigeria) positive environ. 20190131.6288339
Poliomyelitis update (01): global 20190104.6241814
2018
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Poliomyelitis update (62): (Nigeria, Niger) cVDPV2 20181228.6226490
Poliomyelitis update (01): global (Afghanistan) 20180105.5539242
2017
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Poliomyelitis update (47): Pakistan, global (Congo DR) 20171229.5526565
Poliomyelitis (01): Pakistan (GB), global, RFI 20170314.4898724
2016
----
Poliomyelitis update (21): IPV shortage, global 20161231.4733243
Poliomyelitis update (01): India, VDPV, wild type-free 20160115.3939297
.................................................mpp/msp/mpp

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