This is the second part of my conversation with Professor Benjamin J. Cowling about influenza pandemic prevention and preparedness. The first part was about pandemic preparedness and genomics. In this part, Prof. Cowling focuses on national and global responses.
Professor Cowling is Division Head at the Division of Epidemiology and Biostatistics at the School of Public Health (SPH) at Hong Kong University.
Hong Kong is interesting because it is often considered to be one of the epicenters of influenza pandemics.
About Professor Cowling:
- He holds a PhD in medical statistics from the University of Warwick, has conducted postdoctoral work at Imperial College, London and has been the Head of the Division of Epidemiology and Biostatistics at SPH since 2013.
- He is also co-Director of the World Health Organization (WHO) Collaborating Centre for Infectious Disease Epidemiology and Control at SPH.
- His research is focused on infectious disease epidemiology. He has designed and carried out large community-based studies of influenza transmission and the effectiveness and impact of control measures. Recently, he has looked at respiratory virus transmission, influenza vaccination effectiveness, immunity to infections, and the potential causes and the interferences between respiratory viruses. He works closely with China’s Centers for Disease Control and Harvard University’s Center for Communicable Disease Dynamics.
- Professor Cowling is a Fellow of the Royal Statistical Society and a Fellow of the UK Faculty of Public Health. He is also Editor-in-Chief of “Influenza and Other Respiratory Viruses”, an Associate Editor of “Emerging Infectious Diseases”, a Section Editor of “PLOS ONE”, and founding editor of “PLOS Currents: Outbreaks”.
- He has 350 publications and has received numerous awards including a Croucher Senior Research Fellowship, HKU Outstanding Researcher Award, HKU Outstanding Young Researcher Award, and American Journal of Epidemiology (AJE) Article of the Year 2014.
Q: I’m aware of the International Health Regulations but what would you say is required to make a decision that there is an outbreak or a pandemic?
Prof. Cowling: For pandemics, there are clear criteria that the WHO General Director should follow to decide whether to declare one and what the next steps should be. Those criteria also have implications for vaccine production. Once these criteria have been met, the WHO General Director is supposed to announce that a flu pandemic has started. That is the trigger for vaccine manufacturers to drop whatever they are doing, if they are making seasonal flu vaccines to drop that, and to switch over to making the pandemic vaccine as soon as possible. But as I said earlier, it’s going to take about 6 months from that moment, because vaccine production is still a slow process
Q: Are outbreak scenarios practiced nationally and globally?
Prof. Cowling: Individual countries routinely conduct pandemic exercises. They get all the relevant officials together in a room and go through scenarios, such as what might happen if there is a pandemic with certain characteristics, what to do, etc. These exercises ensure that such people know what they are supposed to do and how they can deal with different kinds of scenarios and situations.
I am not personally involved in such governmental activities. The US Centers for Disease Control recently conducted a pandemic influenza exercise. The team spent a day together going through what to do in various scenarios. Of course, that won’t tell them what would actually happen. It just ensures that each person in the team knows what they are responsible for. It can also can shed light on situations that people haven’t really thought of, which allows them to think about how to deal with that in advance.
At the global level there are no such exercises. That is because WHO is, as noted, really a very small organization, much smaller than people would think. They can share information but they don’t actually do a lot of things themselves. In the Ebola case, for instance, the WHO response team was reduced in size before the 2014/5 outbreak, so they had to rely on individual countries to provide staff to go to Africa to help conduct the outbreak investigations and control measures. Those people in the hazmat suits were not WHO staff, they were co-opted from individual countries and from non-governmental organizations.
Q: From a scientific point of view, is there any way to halt or slow down the spread of a respiratory virus?
Prof. Cowling: Yes, the three tools we discussed earlier. Vaccination is the number one tool. The limitation is that they are not usually available for about 5-6 months. In the 2009 pandemic, for instance, by the time some countries got the vaccine it was too late. They already had suffered an epidemic. As for antiviral drugs, they are not usually used to limit the spread of disease in the community; but only used to treat severe cases. There is a limited amount available and the amount you would need to limit transmission is significant. You would also need to give it to people very quickly when they became ill in order to stop them to giving it to other people and that’s fairly difficult to do.
The only tools that we really have to limit transmission in the early stage of a pandemic are the non-pharmaceutical interventions we discussed, But, not all such interventions are equally effective. For instance, facemasks and handwashing are not very effective against respiratory infections for various reasons. One reason is that it’s hard to get people to fully comply with the recommendations. But even if they do, the biology of the viruses and the way they transmit limits the effectiveness of such measures.
Social distancing is much more effective. But closing schools and asking people to stay home can have massive economic consequences. That is one of the biggest fears with pandemics – it’s not so much that the pandemic itself will kill a lot of people, but that it will crush the economy by stopping the movement of people and trade.
Q: In your research on influenza transmission, are there any findings that could help stop the transmission of other airborne pathogens, such as filters in hospitals or airplanes?
Prof. Cowling: That’s a good question. For influenza, we try to find out exactly to what extent it spreads through the air or via contaminated hands and surfaces. It’s difficult to do that and it’s not easy to follow the virus to see how it is really spreading between people – but we are working on it.
I have done some research that suggests that quite a bit of transmission happens through very fine particles, called aerosols. These are very small particles that can stay in the air for a very long time – and can stay infectious for a long time. They can go through or around the material of facemasks. That’s a big concern if it truly is the case. It is very difficult to control a virus like influenza if it spreads in that way.
We have to find ways to improve ventilation. If it’s in hospitals, you may want to have the windows open rather than have central air conditioning. Having the windows open leads to stronger air flow and more rapid dilution of any viruses in the air. But for flu, hospital transmission is not a major problem. It is community transmission that is the big concern. Preventing transmission in closed spaces, like schools or shopping malls or buses or trains, in places where people are packed together in higher density, is very difficult. So maybe social distancing, asking people not to come out and to stay at home, especially if they are sick or have any kind of symptoms, those kinds of measures could be the most effective measures.
Q: Thank you so much!
Prof. Cowling: You’re welcome!