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 The agency said blood banks can continue collecting and preparing
platelets and plasma if an FDA-approved pathogen-reduction
technology is used. Current pathogen-reduction technology is not
approved to treat whole red blood, which is used for most
transfusions.
The guidelines come as Zika is spreading rapidly through the
Americas, with more than 30 affected countries in Latin America and
the Caribbean. The virus has been linked to a spike in cases of a
rare birth defect known as microcephaly in Brazil, prompting health
officials to declare a global health emergency.
Researchers have begun to study the consequences of Zika
transmission through the blood, but that work could take six to 12
months to produce results. In the meantime, the FDA said people at
risk of having been infected with the virus defer donating blood for
at least four weeks.
"We believe the new recommendations will help reduce the risk of
collecting blood and blood components from donors who may be
infected with the Zika virus," Dr. Peter Marks, director of the
FDA's biologics division, said in a statement.
The Centers for Disease Control and Prevention (CDC) has identified
Puerto Rico, the U.S. Virgin Islands and American Samoa as areas
with active Zika transmission and health experts expect some
localized outbreaks may occur in the southeastern United States
later this year.
There is considerable evidence from prior Zika outbreaks that the
virus can be transmitted in the blood. What is less clear is whether
that transmission causes the recipient to become ill. Dengue and
chikungunya viruses, which are carried by the same mosquito as the
Zika virus, do not typically cause illness in patients when
transfused.
Much remains unknown about Zika, including whether the virus
actually causes microcephaly. Brazil is investigating the potential
link between Zika infections and more than 4,300 suspected cases of
microcephaly. Researchers have confirmed more than 460 of these
cases as microcephaly and identified evidence of Zika infection in
41 of these cases, but have not proven that Zika can cause
microcephaly.
The studies under way in Brazil to further understand the clinical
consequences of Zika transmission through the blood could take six
to 12 months to complete.
"No-one feels comfortable waiting for the results of those studies
to be concluded," said Dr. Michael Busch, director of the Blood
Systems Research Institute. "There’s a lot of work going on to
understand the value and need for blood screening."
Busch, who is widely considered one of the world's leading experts
on transfusion medicine, added that it is possible for private
companies to develop a test for investigational use by the time the
mosquito season moves into full swing in the summer.
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The two companies the government is relying on to make such a test
are Hologic Inc and Roche Holding AG. Each have platforms that they
can turn to making a virus test quickly.
Roche spokeswoman Nicole Rueppel said the company is testing
prototypes in its laboratories but that further evaluations with
clinical samples need to be conducted.
The FDA said its guidance is for immediate implementation in areas
with active Zika virus transmission for those at highest risk,
including pregnant women. It recommends implementation within two
weeks for the remainder of the population in such areas.
The FDA recommended that areas with active Zika transmission fulfill
blood orders from areas in the U.S. without transmission except when
the blood is tested with an FDA-licensed or investigational
screening test. The agency also suggested exceptions could be made
for platelets and plasma subjected to pathogen-inactivation
treatment.
The FDA also formally endorsed recommendations made by the American
Association of Blood Banks that donors at risk for Zika virus be
deferred from donating blood for four weeks.
That includes people who have had symptoms suggestive of Zika virus
during the previous four weeks, those who have had sexual contact
with a person who has traveled to, or lived in, an area with active
Zika virus transmission during the prior three months, and those who
have traveled to areas with active transmission of Zika during the
past four weeks.
(Reporting by Toni Clarke; Editing by Sandra Maler and Bill Rigby)
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