|
 The case, caused by a strain of the virus known as type 2 that had
come from a vaccine, is the second setback in a week for global
efforts to eradicate polio. Two cases were reported in Ukraine last
week..
Preliminary tests showed the 19-month-old was paralyzed on July 20,
seven days before being brought to Mali for treatment. The strain is
the same as one found in Siguiri in Guinea's Kankan region in August
2014.
"The risk of spread is considered to be high in both countries due
to low rates of vaccination coverage in both Mali and Guinea," WHO
spokesman Cory Couillard said in a comment to Reuters.
"Both countries are taking coordinated emergency response measures
to bring the outbreak to an end quickly."
Vaccine-derived polio infection are caused when the virus spreads
after being excreted by people who have been immunized with live
oral polio vaccine. Unvaccinated children and people with low
immunity are then at high risk of becoming infected via contaminated
water and sewage.
Vaccine-derived polio virus (VDVP)outbreaks are rare, but pose more
of a risk in populations where health systems are fragile and
immunization coverage is low.
WHO figures show Guinea's polio vaccination coverage fell from 63
percent to 42 percent in 2014, as the Ebola outbreak caused chaos
and overwhelmed an already weak national health system. In Mali, by
contrast, polio vaccination coverage rose to 84 percent in 2014,
from 72-77 percent in preceding years.
There is no cure for polio, which attacks the nervous system and can
cause irreversible paralysis within hours of infection.
A global vaccination campaign has largely stamped out the virus, and
only Pakistan and Afghanistan have reported cases of wild polio
virus this year.
As the world has moved closer to its goal of eradicating polio,
specialists warn such vaccine-derived cases could jeopardize the
progress.
[to top of second column] |
Writing in the Public Library of Science Pathogens journal in
August, researchers led by Javier Martin of Britain's National
Institute of Biological Standards and Control said VDPV represents
"a real risk of polio re-emergence in the post-eradication era".
One way of combating that risk is to switch from using live oral
polio vaccines (OPV) - which are highly effective, cheap, easy to
deliver but contain live virus strains - to "inactivated" vaccines (IPV),
which carry no live virus.
Unlike OPV, however, IPV is expensive and difficult to deliver
because it has to be injected by trained health workers in clinics.
Wile most wealthy countries used OPV to stop wild polio transmission
then switched to IPV when they were sure they had the virus beaten,
that is not easy in poor countries with limited health services,
infrastructure and resources.
(Additional reporting by Kate Kelland in London, Editing by Angus
MacSwan)
[© 2015 Thomson Reuters. All rights
reserved.] Copyright 2015 Reuters. All rights reserved. This material may not be published,
broadcast, rewritten or redistributed.
 |
