In
May 1988, the World Health Assembly committed the member nations
of the World Health Organization (WHO) to achieving the goal
of global eradication of poliomyelitis. This goal is defined
as:
·
no cases of clinical poliomyelitis associated with wild poliovirus,
and
·
no wild poliovirus found worldwide despite intensive efforts
to do so.
The
polio eradication initiative (PEI) is a global collaborative
effort. WHO, UNICEF, Rotary International, the US Centers for
Disease Control & Prevention (CDC), and a number of national
governments and nongovernmental organizations are strongly committed
to the initiative. Their generous financial and technical support
has been critical in achieving the significant progress made
to date.
Experience
in several of the world’s WHO Regions, where polio has
been eliminated, has demonstrated that the recommended strategies
are effective and that global eradication of polio is feasible.
WHO Regions that have been certified as polio-free are the Americas
(last case in 1991, Peru; Region certified polio-free in 1994),
the Western Pacific Region (last case in 1997, Cambodia; Region
certified 2000), and the European Region (last case in 1998,
Turkey; Region certified 2001).
The
primary strategies for achieving this goal are:
·
Attaining high routine immunization:
immunize every child aged <1 year with
at least 3 doses of oral poliovirus vaccine (OPV). Paralytic
polio can be caused by any of 3 closely-related strains (serotypes)
of poliovirus. Trivalent OPV (OPV3) provides immunity against
all 3 types. Three routine OPV doses should be received by infants
at ages 6, 10 and 14 weeks.
·
National Immunization Days (NIDs):
Conduct Pulse Polio Immunization (PPI) programme by providing
additional OPV doses to every child aged <5 years at intervals
of 4-6 weeks. The aim of NIDs/PPI is to “flood”
the community with OPV within a very short period of time, thereby
interrupting transmission of virus throughout the community.
Intensification of the PPI programme is accomplished by the
addition of extra immunization rounds, adding a house-to-house
“search and vaccinate” component in addition to
providing vaccine at a fixed post. The number of PPI rounds
conducted during any particular year is determined by the extent
of poliovirus transmission in the country. In recent years,
several rounds have been conducted throughout the year –
especially in the northern states of Uttar Pradesh and Bihar,
which have carried a heavier burden of poliovirus – in
an attempt to break the last chains of transmission. Intensification
of PPI requires meticulous programme planning, intensive supervision
and monitoring and extensive social mobilization.
·
Surveillance of acute flaccid paralysis (AFP)
to identify all reservoirs of wild poliovirus transmission.
This includes AFP case investigation and laboratory investigation
of stool specimens collected from AFP cases, which are tested
for polioviruses in specialized laboratories.
·
“Mopping-up” immunization:
when poliovirus transmission has been reduced to well-defined
and focal geographic areas, intensive house-to-house, child-to-child
immunization campaigns are conducted over a period of days to
break the final chains of virus transmission.
