International Travel Off the Table for Six Months: Coronavirus Q&A

An empty security area at San Francisco International Airport on April 2.
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With coronavirus infection rates slowing in some of the worst-hit countries, governments are now weighing whether they might soon be able to ease restrictions to avoid further damage to their economies.
I asked Peter Collignon, an infectious diseases physician and professor of clinical medicine at the Australian National University Medical School, about the latest developments in the pandemic, and how countries might slowly return to normal as infection rates decline and restrictions are eased.
Jason Gale: Peter, can you tell us what kinds of indicators will governments be using to determine whether current measures — border closures, curbs on public gatherings, physical distancing policies, etc — have been effective in controlling the epidemic?
Peter Collignon: The main indicator we need to use is what is the current level of new infections within the community, in other words what is happening with your epidemic curve. If your epidemic curve is continuing to rise, it means you haven’t got control of the epidemic and you may even need to think about putting new controls on. But if your epidemic curve is falling or at a low level but stable, then gradually you can start thinking about taking some of the controls off. This virus is likely going to be around for two years at least, which means all the measures we have in place — vigorous hand-washing, physical distance — might need to continue for a while.
JG: What are your views on current testing levels, and what do we need to be doing more of?
PC: A lot and a lot more! At the moment, we don’t know enough and the only way to know more is by testing — more and more people in the community, including people without risk factors. Covid-19 should be part of the tests that GPs test for as part of their routine panel. We should also be testing sewage, which could be the best way of testing the whole of the community. We also need antibody testing to understand what proportion of the community has been exposed to the virus and have immunity.

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A medical worker seals a test from a patient at a drive-through testing facility at Millennium Medical Group in Michigan on April 7.
Photographer: Emily Elconin/Bloomberg

JG: As some countries seem to be bringing the outbreak under control, people are keen to know what an eventual reopening looks like? What sort of measures might still need to be in place in three months or six months as we await a treatment regimen or eventual vaccine?
PC: There are some measures we will need to keep. A safe and effective vaccine isn’t likely to be available in large amounts for 18 months to two years. How long we keep restaurants closed, for example, will depend on the spread within communities. The levels of control need to be inversely proportional to how many new cases you have and what the epidemic curve is looking like.
JG: Is eradication of the virus still an option for countries where outbreaks are currently controlled and contact tracing is robust? If we expect the virus to become seasonal, is herd immunity the only viable strategy at this stage, which means eventually more than half of us will need to get sick?
PC: It would be nice, but I don’t think it’s a realistic goal. No country has been able to achieve it. I think eradicating this is difficult. It’s the transmission of the virus from people who have no or minimal symptoms, so it can go undetected until people are sick enough to go to the hospital. It’s why we need the antibody tests to know who has been exposed to the virus. I think we’re stuck with it.
JG: The issue of mask-wearing is a hot topic in many countries. WHO has just updated its guidance, and stopped short of suggesting widespread community use. Is this solid policy, or is this a political hot potato for WHO?
PC: I think there is still a lot we don’t know about masks. I don’t think there is any evidence that respirator masks are any better than surgical masks for protection in the community. Respirator masks are most important for certain high-risk procedures performed by health-care workers. I do think that if we are getting widespread community spread then masks made from cloth may have a place particularly. Masks may have a greater effect on protecting the community from individuals who are infected. The benefit of cloth masks is that they can be washed at home in hot water and dried in the sun, and you are not decreasing the supply of critical medical supplies.

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Travelers wearing protective masks inside the Hankou railway station in Wuhan, China on April 8.
Source: Bloomberg

JG: We’re hearing that the coronavirus can attack other areas of the body besides the lungs? Where else can it cause disease and how significant is this?
PC: It’s predominantly the respiratory tract. There is no doubt that it can replicate in other areas, such as the gut and cause diarrhea. There has been some suggestion of other organs, such as the heart, being infected, but we need more evidence for this.
JG: We’ve all read reports of possible re-infections, and there still seems to be some confusion about whether people who recover acquire immunity. What has to happen before we can answer this question definitively?
PC: We need a lot more antibody tests done in large populations to know. There may be some people who get infected twice, but currently we believe that is uncommon. The vast majority of people who recover from Covid-19 appear to develop protective immunity. The question is how long that protection lasts.
JG: We’ve seen airlines lay off thousands of staff and travel grind to a halt. Even after economies begin to open, do you have any insight into how long it may take before people are flying again, and what our airports can do to protect travelers and keep new outbreaks from developing?
PC: International travel will be off the table for at least six months. I think travelers will be quarantined for two weeks here in Australia. We really need more information before we can know when to lift restrictions. I suspect we will find travel insurance won’t cover people. I can’t imagine international travel as a tourist is going to be on the horizon in under six months.
JG: A lot of the focus has been on Asia, Europe, and the U.S., but Iran shows the dangers facing less-developed regions like sub-Saharan Africa. Do you have concerns on that front, both from a humanitarian standpoint and the risk the virus may return from those regions?
PC: In countries where sanitation and hygiene is poor, and there’s a lot of crowding, it’s likely to circulate undetected, and they are less likely to have the resources to manage the threat. Also it will harm whatever tourism industry they might have. We are all focused on the U.S. and Europe, but if you are resource-poor you are going to do a lot worse.

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A volunteer sprays the ground to disinfect a public bus terminus in Tehran on March 27.
Photographer: Ali Mohammadi/Bloomberg

JG: We’ve seen a lot of reports of people testing positive for coronavirus despite not displaying any symptoms. How prevalent do you think this is?
PC: There seems to be a wide spectrum of disease that people can have. I think we have to be careful about “asymptomatic” cases because a lot of people are pre-symptomatic and some may have a very mild form of the disease. Antibody tests will help to tease out some of these questions about how silently the infection may be spreading. Over the next month or two we should have tested groups in the population to see how many people have antibodies and therefore have been exposed to the virus.
JG: As societies grapple with ways to keep people safe, what sort of measures can we take in future given the virus is likely to be seasonal?
PC: I can’t see how spraying streets does very much. But cleaning with detergents and other agents that kill the virus are important. These should be directed at high-risk areas such as door handles, patient-alert buzzers, commode chairs. The more something is touched, the more it needs to be cleaned. But if you are sick, don’t go to work, don’t use public transport. Masks, I don’t think we know. During SARS, when people were using masks in Hong Kong, there is some evidence that there were fewer respiratory-tract infections. I think we need to learn from this particularly because this virus won’t disappear.
JG: The past few years have seen avian influenza, SARS, MERS, the swine flu pandemic, and renewed outbreaks of Ebola. Is there a pattern here, and do you expect more zoonotic viruses as a result of population growth/mass food production?
PC: Yes! Most of the diseases that have emerged as problems for humans have come from animals. Just about every viral diseases you can think of have their origins in animals. SARS-CoV-2 is just an example. The more we disturb the environment, the more population growth we have, the more intensive farming we have without adequate biosecurity, the higher the risk. This reinforces the problems that occur when we have exotic animals and people in close contact.

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