Preventing Pandemic: The Global Strategy to Stop a Bird Flu Pandemic Before It Starts (Or Control It, If It Does)

Dr. David Nabarro was appointed as UN Systems Senior Coordinator for Avian and Human Influenza in September 2005. Before that, he served the World Health Organization in Geneva for six years, including a stint as Executive Director in the Office of the Director-General. Nabarro became a physician in 1973 and had jobs with the UK National Health Service, the District Child Health Office in Dhankuta District, East Nepal, the London School of Hygiene and Tropical Medicine Department of Human Nutrition and the Save the Children Fund. He was also Chief Health and Population Adviser at the UK Official Development Administration (now known as the Department for International Development) headquarters in London and Director of Human Development in the UK Department for International Development.

Multinational Monitor: Is an outbreak of avian influenza, transmissible among humans, inevitable?

Dr. David Nabarro: The position of the World Health Organization, as I understand it, is that an influenza pandemic is inevitable sometime in the future. But the precise cause of that pandemic and the timing of its occurrence cannot be stated at this stage. It may be avian influenza - it may even be the current H5N1 virus which is causing such severe problems among poultry. But it may well be due to another influenza virus.

MM: Are you able to estimate the relative likelihood of an outbreak due to H5N1?

Nabarro: No. I don't offer any odds at all on whether H5N1 will itself be the cause of an influenza pandemic or just simply lead to sporadic human cases, nor am I able to talk about the potential size of a pandemic, nor am I unfortunately able to talk about our potential success in containing a pandemic were it to start. That's because these are all matters so dependent on factors of chance. That includes the location where events take place. So on all these issues, the statement of any kind of precision on risk is just about impossible - at least for me.

MM: What are the key steps for countries to take to prevent an outbreak of a pandemic from H5N1 or other virus?

Nabarro: At the moment, we are focusing on two key approaches. One is the control of H5N1 outbreak in bird populations, and preventing H5N1 from being transmitted to humans. This is, up to now, a rare event. In order to reduce the incidence of H5N1 avian influenza outbreaks in birds, it is absolutely essential that countries have adequately functioning animal health services that are capable of undertaking surveillance of animal health, particularly bird health, and ensuring that if there are die-offs, those are picked up and action istaken. The action has to consist of stamping out the disease at source in the affected flocks of birds, which will be a poultry farm or a backyard; the introduction of movement controls; and improvement of biosecurity (or the relationship between humans and birds), so there is less likelihood of infected birds spreading disease to humans.

MM: Can you say more about how to improve biosecurity?

Nabarro: This is a difficult challenge, especially in locations where people live closely with birds. Our core message is that there should, wherever possible, be a clear separation between the location where animals or birds are kept and the places where humans live, eat, sleep, work and play, so as to reduce the likelihood of the humans getting infected, particularly by pathogens that are excreted in fecal material of birds or other animals.

I want to add one other point: We are also very keen to encourage the safekeeping of large animal flocks so that there is no incidence of contagion between animals and animals, for example, wild birds and poultry, or animals and humans. It is quite tricky to introduce that kind of biosecurity in all sectors of agriculture, whether we are talking about the commercial sector or the backyard sector. The commercial sector has various degrees of sophistication. But the UN Food and Agriculture Organization and the World Health Organization are very keen to encourage more attention to be given to biosecurity because we would like to see a reduction in the likelihood of transmission of pathogens from animals to humans.

MM: What is the second key element in the preparedness strategy?

Nabarro: As well as dealing with the animal disease, the World Health Organization is also keen that countries are able to prepare themselves for a possible human pandemic. That means having the capacity in their public health services for sufficient disease surveillance. It also means having laboratory services that can deal with samples from humans that have got disease that might be avian influenza or other forms of influenza. And it means having the capacity to investigate infections rapidly.

It also means having the capacity to contain an outbreak of human-to-human transmitted type virus; and having the capacity to respond with crisis services and systems for ensuring the continuity of governance and of economic systems, as well as health services, in case pandemic does actually start.

So we have two sides to the strategy. One is dealing with the animal disease, improving biosecurity and ensuring that animal disease is stamped out at source with efficient culling and compensation to those who are affected. And the second is detecting potential causes of human diseases early, containing them and mitigating any possible pandemic.

MM: Focusing on the prevention strategies you mentioned - surveillance, laboratory services and investigation - in the developing countries and especially Africa, presumably those capabilities are limited. Are they improving as you sound the alarm?

Nabarro: It has always been quite difficult for poor countries to sustain effective disease surveillance systems.

These are quite expensive to run. They require a very high degree of supervision. They require efficient lab services. Scientists have to spend a lot of time analyzing samples that turn out to be negative yet maintaining vigilance so that the rare positive sample is detected accurately and acted on promptly.

But because pathogens can easily travel across borders and move around the world rapidly, disease surveillance systems are a global good. And by and large, most poor countries are finding that they have to pay for at least some of this global good out of their own resources. They have other acute demands on their resources. Understandably they are either not meeting the costs of extra services at all or, more commonly, are only meeting the cost irregularly. So effective and efficient disease surveillance systems are not often to be found in poor countries.

They aren't necessarily very strong in all wealthier countries, either. They have been somewhat neglected in recent years in some wealthier countries. Funds that might have been spent on disease surveillance may have been diverted to the provision of curative healthcare at the expense of public health.

MM: If sufficient donor aid comes in to address these problems in developing countries, is it realistic to look for a rapid fix?

Nabarro: We have discussed two challenges: first: improving animal health with improved biosecurity and better surveillance of animal disease; second: improving human public health through effective detection of pathogens and rapid response. Neither challenge is going to be met very rapidly.

These are not areas in which quick fixes are possible. They require building capacity and training people. They require incentives to make certain the trained persons stay in post, because people who are skilled in these areas are also highly transferable. They require a great deal of sustained investment and attention.

Is the money coming on board? Yes, we have seen a generous pledge of a billion dollars worth of grant aid around avian and pandemic influenza, made in Beijing in January this year, as well as $.9 billion of loan assistance, which is mostly money coming from the World Bank and the Asian Development Bank. A lot of these funds will either go to animal health or human health surveillance and response capacity building. Care is being taken to make sure that the money is well spent. This will have a significant added impact on what is happening to health systems, particularly in Asian countries. My current anxiety is that the resources that were provided, particularly at the Beijing conference, will be insufficient for us to build up capacity in Africa. My focus right now is on what more we can do for African nations.

MM: Presumably the story is even worse for country capacity to enact containment strategies, if there is an outbreak?

Nabarro: Yes and no. The one thing about containment is that it is a pretty finite task. Once the alarm goes up that there is something that looks like human-to-human transmission occurring, it should be possible to implement the protocols that are being agreed - between countries and the World Health Organization - with standard operating procedures for what happens in case of a suspect pandemic virus candidate emerging. These protocols should be capable of being implemented immediately. The agreements between the WHO and countries on the use of the protocols should cover the deployment of a surge-force of public health personnel and other support staff who will be invited into a country to work with the national health authorities so as to initiate containment. There will also be advance agreements about the particular actions that the national authorities will put in place once this kind of alarm occurs. I hope that such agreements - between governments and the World Health Organization - will be concluded over the next few months and that they will spell out how the protocols will be operated. I don't think that all countries will want to agree immediately, but I suspect that there will be near universal acceptance of the protocols. If this happens we will be in a pretty good situation.

This is all on top of negotiations of the International Health Regulations that took place at successive meetings of the World Health Organization's governing bodies and were given the approval early in the Executive Board of WHO in January.

MM: What are the prospects for vaccine development, and does that offer any hope for cutting off the whole problem?

Nabarro: The most sophisticated and efficient way to deal with a serious public health threat caused by a pathogen against which the human body can potentially defend itself is through a vaccine. The vaccine programmes the body so that it can deal with the pathogen and others like it; the vaccine prevents that pathogen from wreaking havoc.

The problem is that, at the moment, we don't have the capacity to develop a polyvalent vaccine that could deal with any kind of Influenza A virus that might be the cause of a human pandemic. So, we have to wait until the pandemic virus appears before we can initiate development of a vaccine that we are certain will work. Other vaccines can be developed in advance but their effectiveness will not be known until the pandemic starts.

That is inefficient. There is quite a lot of thought among immunologists that it should be possible to develop more sophisticated vaccines - through modern cell biology techniques - that would have much broader capacity against a range of influenza viruses and be effective. I don't know personally enough about the science on this, but this is something on which the World Health Organization is working quite intensively with the scientific community and the vaccine manufacturers. For the time being, there would be an interval of a number of months between the first appearance of a pandemic virus and the development of enough vaccine for the control strategies to tackle it.

MM: In light of that, how important is the stockpiling of Tamiflu? Is it an appropriate public health strategy? And, if yes, how much should countries stockpile?

Nabarro: The most important thing to stress is that there are a range of measures that WHO advocates for dealing with the containment of a potential pandemic. They include a number of non-medical, non-pharmaceutical measures, like social distancing or restrictions on population movement, and also the use of face masks and other forms of personal protective equipment. These are very important.

Most available scientific evidence suggests that they are important, as part of the overall containment strategy.

Secondly, it is important when thinking about the use of Tamiflu to focus on the way in which it is going to be used and to ensure that the staff and personnel who are likely to be at the frontline in any containment exercise are the people for whom the antiviral medicine oseltamivir (Tamiflu), or any other similar medication that can prevent illness and death as a result of an influenza infection, are prioritized. That means that when we are talking about stockpiles, we are talking about a stock of medicines - particularly oseltamivir - and protective equipment that can be made available to people who are in need of them in frontline situations.

I can't give a figure on an amount of oseltamivir that should be kept by individual governments. I have not myself, frankly, the necessary qualifications and in any case, I don't think it is right, because it is much more important to ensure that sufficient quantities of medicines and protective equipment are available to protect frontline workers who are at risk.