UN agencies bickering over bird flu
The danger of zoonoses is well recognised; many of the World’s most virulent infectious diseases have jumped the species barrier including anthrax, Ebola, HIV, Marburg, plague, Q-Fever, Rabies and Yellow Fever. Although the mortality rate for most of them is not as high as, for example, Ebola, variants of the influenza virus are possibly some of the most worrying zoonoses. Throughout history some of the most devastating pandemics have been due to influenza, such as the Spanish flu of 1918. But drawing up useful risk assessments is increasingly difficult as UN agencies cannot agree about the threat.
Avian influenza has been relatively high in the public consciousness for a long time. Arising mostly out of the developing parts of South-East Asia, where rural populations live in close quarters with their livestock, bird flu has been spread around the globe by infected migratory birds. The H5N1 subtype of the influenza A virus has been of particular concern over the last decade, and World Health Organisation (WHO) figures indicate 565 human cases, leading to 331 deaths globally since 2003 (accurate to 19 August 2011). Reported cases of H5N1 peaked in 2006 and have been declining ever since, but according to Food and Agriculture Organization (FAO) Chief Veterinary Officer Juan Lubroth over the last two years the H5N1 has been discovered in poultry and wild birds in countries that had been virus-free for several years.
Currently, a major concern is a newly identified variant of the H5N1 subtype known as H5N1-2.3.2.1, which has proved resistant to existing vaccines. The truly worrying element is not the fact of the virus mutation itself – all viruses evolve and change over time and a new vaccine can be developed – but the wide variation in approaches to the potential threat by different organisations. The WHO, FAO and World Organisation for Animal Health (OIE), all UN agencies, have different stances. Governments and health organisations rely on advice from these agencies to build their own risk assessments. All nations, especially now, have limited resources so effective resource scheduling is essential.
Food and Agriculture Organization
On 29 August the FAO published the warning “FAO today urged heightened readiness
and surveillance against a possible major resurgence of the H5N1 Highly Pathogenic
Avian Influenza amid signs that a mutant strain of the deadly Bird Flu virus is
spreading in Asia and beyond, with unpredictable risks to human health.” After giving
the recent statistics, the alert ends with a quote from Juan Lubroth, “Preparedness
and surveillance remain essential. This is no time for complacency. No one can let
their guard down with H5N1.”
The FAO’s opinion is that the emergence of a mutant strain of H5N1 capable of resisting existing vaccines is a worrying development, something that should be taken note of, and a change that should be reflected in risk assessments.
World Health Organization
The WHO, responsible for developing and coordinating global public health activities,
has played down the emergence of the new strain. A WHO statement on 30 August reads:
“…this evolution of the H5N1 virus poses no increased risk to public health. It
is not considered unusual because influenza viruses are constantly evolving, especially
in areas where they circulate regularly in poultry…the identification of this newly-reported
H5N1 virus clade does not change the current public health implications of the H5N1
avian influenza viruses for humans. Human cases of H5N1 infection remain rare and
sporadic events, occurring mostly in areas where H5N1 viruses circulate regularly
in poultry.”
The WHO statement came a day after the FAO warning and is clearly intended as a response to it. The message that most readers will take away from the statement is that the WHO considers the new mutation to be of little consequence, and that beyond the need to keep monitoring the situation it should not be allowed to significantly influence risk assessments.
Office International des Epizooties
The OIE has decided to sit on the fence. In a statement on 31 August, a day after
the WHO response, they said “OIE recommends keeping up with active surveillance
in bird populations, encouraging national veterinary services to be prepared to
quickly report and respond to unusual animal disease events that may represent more
serious disease in animals or that may pose increased risk to humans…The OIE Reference
Laboratory in Harbin, China, has developed a new vaccine seed strain that experimentally
protects poultry from the identified H5N1 virus clade 2.3.2.1. This vaccine, once
available for field use, will be used in countries where H5N1 virus clade 2.3.2.1
has been identified. Registration and manufacturing of a poultry vaccine with the
new seed strain is in progress.”
Other than giving the welcome confirmation that a new vaccine is being developed to tackle the new strain of H5N1 the OIE has resisted offering new advice, and does not give an opinion of the relative threat associated with H5N1-2.3.2.1.
Weighing up the advice
That different experts have varying opinions on the threat level is not surprising,
even if they are working from the same data. But the notable fact here is that different
experts working from the same data have such wildly differing opinions that in consecutive
days the FAO and the WHO, both UN agencies, can put out directly contradictory statements,
each vying for greater acknowledgement.
It is of course the case that countries have their own experts to perform risk assessments. While the opinions and advice offered by the various UN organisations will be taken note of they will not be the exclusive basis on which decisions are made. But the great differences in the stances of the agencies mean that reconciling one or both of them with other available information is very difficult. From a scientific point of view it may be best to follow the precautionary principle and plan for the worst to happen – a pandemic of a new strain of flu that is resistant to drugs. The difficulty will be, as ever, assigning resources that may well never be used, especially in times of budget cuts.