Zika
virus spreading explosively, says World Health Organisation
Director
general convenes emergency committee, saying ‘level of alarm is
extremely high’ as virus has now been detected in 23 countries
Matthew Weaver and
Sally Desmond
Thursday 28 January
2016 18.16 GMT
The World Health
Organisation has convened an emergency committee to discuss the
“explosive” spread of the Zika virus, which has been linked to
thousands of birth defects in Latin America.
“Last year the
disease was detected in the Americas, where it is spreading
explosively,” Margaret Chan, the WHO director general, said at a
special briefing in Geneva. It was “deeply concerning” that the
virus had now been detected in 23 countries in the Americas, she
added.
One WHO scientist
estimated there could be 3-4m Zika infections in the Americas over
the next year.
The spread of the
virus has prompted governments across the world to advise pregnant
women against going to the areas where it has been detected. There is
no vaccine or cure for Zika, which has been linked to microcephaly, a
serious condition that can cause lifelong developmental problems.
Chan said: “The
level of alarm is extremely high. Arrival of the virus in some cases
has been associated with a steep increase in the birth of babies with
abnormally small heads.”
She added: “A
causal relationship between Zika virus and birth malformations and
neurological syndromes has not yet been established – this is an
important point – but it is strongly suspected.
“The possible
links have rapidly changed the risk profile of Zika from a mild
threat to one of alarming proportions. The increased incidence of
microcephaly is particularly alarming as it places a heartbreaking
burden on families and communities.”
Chan outlined four
reasons for alarm: “First, the possible association of infection
with birth malformations and neurological syndromes. Second, the
potential for further international spread given the wide
geographical distribution of the mosquito vector. Third, the lack of
population immunity in newly affected areas. Fourth, the absence of
vaccines.”
This year’s El
Niño weather patterns meant mosquito populations were expected to
spread, Chan added. “For all these reasons, I have decided to
convene an emergency committee under the international health
regulations,” she said.
The committee will
meet on Monday and will advise on the international responses and
specific measures in affected countries and elsewhere.
Brazilian
authorities estimate the country could have up to 1m Zika infections
by now, and since September, the country has registered nearly 4,000
cases of babies with microcephaly.
The Zika outbreak
and spike in microcephaly cases have been concentrated in the poor
and underdeveloped north-east. But the south-east, where São Paulo
and Rio de Janeiro are located, is the nation’s second hardest-hit
region. Rio de Janeiro is of particular concern, since it will host
the Olympic games this summer.
The president of the
International Olympic Committee, Thomas Bach, said the IOC was in
“close contact” with Brazilian authorities and the WHO, and that
all national Olympic bodies would be advised on how to deal with the
virus before the Games started.
The Brazilian
president, Dilma Rousseff, has pledged to wage war against the Aedes
aegypti mosquito that spreads the virus, focusing on getting rid of
the insect’s breeding grounds.
The US Centers for
Disease Control and Prevention said there had been 31 cases of Zika
infection among US citizens who travelled to areas affected by the
virus, but so far there had been no cases of transmission of the
virus through mosquitoes in the US itself. The White House said its
experts were most concerned about its potential impact on women who
are pregnant or could become pregnant.
US officials said
the country had two potential candidates for a vaccine, and might
begin clinical trials in people by the end of this year. But experts
in disease control have warned they do not expect to have a vaccine
available in 2016.
Dr Anthony Fauci,
director of the National Institute of Allergy and Infectious
Diseases, said on Thursday that previous research into dengue fever,
the West Nile virus and the chikungunya virus would give scientists
an “existing vaccine platform” which could be used as “a
jumping-off point” for finding a cure to the Zika virus.
“It is important
to note that we will not have a widely available safe and effective
Zika vaccine this year and probably not in the next few years,”
Fauci said, before adding that scientists might be able to begin “a
phased clinical trial in this calendar year”.
Addressing the
global threat, Lawrence Gostin, a public health law expert from
Georgetown University, warned that Zika had an “explosive pandemic
potential”.
Speaking to the
BBC’s World Service, Gostin, a member of a commission that
criticised the WHO for its response to Ebola, said: “With the Rio
Olympics on our doorstep I can certainly see this having a pandemic
potential.”
He said every review
of the WHO’s response to Ebola found that it was “too little, too
late”.
Interviewed minutes
before Chan’s announcement, he said: “I’m disappointed that the
WHO has not been acting proactively. They have not issued any advice
about travel, about surveillance, about mosquito control.
“The very first
thing I would propose is a global mosquito eradication effort,
particularly in areas with ongoing Zika transmission. We really need
to declare war on this species of mosquito.”
The WHO’s
leadership admitted last April to serious missteps in its handling of
the Ebola crisis, which was focused mostly on three west African
countries and killed more than 10,000 people.
Some critics have
said the WHO’s slow response played a major role in allowing the
epidemic to balloon.
Zika is related to
yellow fever and dengue. An estimated 80% of people that have it have
no symptoms, making it difficult for pregnant women to know whether
they have been infected.
Anne Schuchat,
principal deputy director of the Centers for Disease Control and
Prevention, said: “We really do expect there to be a lot more
travel-associated cases. For the average American who is not
travelling this is not something they need to worry about. For people
who are pregnant and considering travel to the affected areas, please
take this seriously.”
She said living
conditions in the US, including lower human density in urban areas
and access to air conditioning, meant people were at less of a risk
of contracting the virus than those living in South and Central
American cities.
“We don’t have
local transmission of the virus in the US right now,” added Fauci.
“There’s essentially no risk at all because we don’t have
locally transmitted Zika virus in the US.”
“We believe this
is a time-limited infection in women, men and children,” said
Schuchat. “People have symptoms for up to about a week, not months
and years of chronic viral infection. We know four out of five people
with this infection have no symptoms.”
She added the Zika
virus passed very quickly through the bloodstream and in most cases
the virus would clear from the bloodstream within about a week.
Asked when the
babies of pregnant mothers could become infected with the virus,
Schuchat said the foetus was most at risk of contracting microcephaly
through Zika in the first trimester of the pregnancy. Scientists did
not yet have “sufficient knowledge to know what effects in the
second and third trimester”, she cautioned.
There has been one
reported case of the Zika virus through “possible sexual
transmission”, while a second case was found in a man’s semen.
However, Schuchat highlighted that scientific research clearly showed
Zika was “primarily transmitted through the bite of an infected
mosquito”.
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