The Lancet Infectious Diseases, Volume 12, Issue 8, Pages 591 - 592, August
2012
doi:10.1016/S1473-3099(12)70189-5
Cite or Link Using DOI
Cite or Link Using DOIThe final push for polio
At first glance, efforts
to eradicate poliomyelitis seem in excellent shape. “Epidemiologically, the
picture has never looked better”, WHO's Oliver Rosenbauer told TLID.
Only 88 cases have been reported in 2012, a favourable contrast with the 252
cases reported by same time last year. India has been free of
poliomyelitis since January, 2011, which resolves any lingering questions about
the technical feasibility of eradication. Of the three countries classified by
WHO as having re-established transmission, Angola has not had a case since
mid-2011; the Democratic Republic of the Congo has not had a case since
December, 2011; and Chad has only had four cases thus far in 2012—the same
period in 2011 had 82 cases.
Elsewhere, outside of
the remaining three endemic countries—Afghanistan,
Pakistan, and Nigeria—no
cases of poliomyelitis have been reported. Moreover, Pakistan has registered a mere 22
cases this year; by this time in 2011, it had registered 58. Wild poliovirus
type 2 was eradicated in 1999, and the introduction of monovalent vaccines in
2005, and bivalent vaccines in 2009, provided additional impetus to the global
fight for eradication (the new vaccines are roughly three-times as effective as
the trivalent vaccine). The strategic plan of the Global Polio Eradication
Initiative for 2010—12 aims to cease transmission of the poliovirus by the end
of this year. “It would be premature to entirely rule out achieving the
end-2012 milestone”, noted the authors of Every Missed Child,
a report released by the initiative's independent monitoring board.
Yet, when the World
Health Assembly met in May, 2012, it adopted a resolution declaring “the
completion of poliovirus eradication a programmatic emergency for global public
health”. Meanwhile, experts—including the authors of the independent monitoring
board report—routinely use the term crisis when describing the present state of
eradication efforts. Why?
There are two key
reasons. First, the massive funding gap. The polio campaign for 2012—13 needs a
budget of US$2·2 billion, but current funding falls short by $945 million.
Thus, 68 campaigns in 33 countries have had to be cancelled. If the money is
not provided, 94 million children, mostly in west and central Africa,
will not be immunised. In view of the virus's persistence in Nigeria, notes Every Missed Child, “the
risk of an explosive return of polio in Nigeria and west Africa is
ever-present and raises the chilling spectre of many deaths and a huge
financial outlay to regain control”. The global financial benefit of polio
eradication has been estimated at $40—50 billion.
The second issue is the
absence of meaningful progress, particularly in endemic countries but also in
African nations with re-established transmission. Cumulatively, these countries
have an estimated 2·7 million children younger than 5 years who have not
received even one dose of vaccine. Even more children have been insufficiently
vaccinated. If not addressed, the consequences could be severe. “We're seeing
all over the world a build up of young adults who were never exposed to poliovirus,
because polio has been eradicated from their area and there have been declining
vaccination coverage levels”, explains Rosenbauer. “If poliovirus gets in this
group, there could be some really devastating outbreaks, far deadlier than we
have seen in the past.” Mathematical modelling suggests the possibility of
incidences of 200 000 cases per year within the next decade, wiping out nearly
all the gains of the 24 years since the international community committed to
eradication of polio.
In west Africa, for
example, insecurity in Mali,
the food crisis in the Sahel, and the onset of
the rainy season means that population movement is greater than normal. Nigeria has
already seen 52 cases this year; two-thirds of the global burden and a sharp
increase compared with the same period in 2011. Couple this rise with the
scaled-back vaccination campaigns in neighbouring countries and children in the
region are particularly vulnerable. An immunisation campaign in the highest
risk areas of Burkina Faso, Mali, and Niger was done earlier this month,
but a more comprehensive endeavour would be preferable.
Fortunately, problems
within the endemic countries should be resolvable. Crucially, polio is not
evenly distributed across the three nations. In Afghanistan,
it is concentrated in ten high-risk districts in the troubled southern
provinces of Helmand and Kandahar.
In Pakistan, the disease is
concentrated in Gaddap in Karachi, Pishin
district in Quetta, and the Federally
Administered Tribal Areas bordering Afghanistan. In Nigeria, polio
persists in four northern states.
All three countries have
issued national emergency action plans, which aim to involve civil society as
well as the public sector, much as India did. “The leadership at the
top is engaged, in Pakistan
in particular we've seen tremendous support from the government at the highest
level”, notes Carol Pandak (Rotary International) however, the difficulty is in
translating that support to the lower levels. Resistance to immunisation
campaigns can be ameliorated by engagment with religious and community
leaders—as UNICEF has done in Nigeria,
and Rotary International did in India
and is attempting in Pakistan.
Even the decision by the Taleban to ban vaccinators from some parts of Pakistan need
not be insurmountable. “We've been faced with these challenges before”, Pandak
points out, “and with the right negotiation they can be overcome.”
Full-size image (68K) Rotary
International
Countries
striving to eradicate polio should look to India for inspiration
Security issues—in Afghanistan, Pakistan,
and Nigeria's
Borno state—complicate matters. “In Afghanistan, the programme
sometimes has to try to access kids during periods of deep instability”,
explains Nicholas Grassly (Imperial College London, UK). “Those periods of access
are quite variable and some years there will only be a limited amount of times
that those kids are accessible.”
Nonetheless, Rosenbauer
points out that accessibility is actually increasing in Afghanistan: by
March, 2012, only 5% of children were inaccessible, compared with 30% at the
beginning of 2011. Yet vaccine coverage in both Afghanistan
and Pakistan
has decreased over the past few years. “That tells us that the problems are
probably more to do with management of the campaigns, operational issues and so
forth.” It is a common theme. In Pakistan, for example, polio is
concentrated within Pashto-speaking communities. Progress can be made by
ensuring vaccinators are the same ethnic origin, speak the same language, and
include women on their teams. The independent monitoring board's report praised
Pakistan—which
it had previously criticised for having a “deeply dysfunctional programme”—for
its “revitalised energy and augmented national emergency plan fit for the
purpose of stopping polio transmission”.
Experts agree that
countries striving to eradicate polio should look to India for inspiration. The Indian
Government offered strong support; migrant groups were identified and targeted
with immunisation campaigns; large numbers of technical staff were trained and
deployed (Nigeria has enacted a huge surge of technical staff—WHO alone has
increased the number of its staff in the country from 744 to 2950—and the
country has also started using global positioning system technology to help map
communities); and an advanced surveillance system was established. “Afghanistan, Nigeria,
and Pakistan
have all put in place plans that can turn the situation around”, Rosenbauer
says firmly. “But we're at crisis point until those plans are fully
implemented, and we need funding, otherwise we will see the international
spread of polio.”
