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Novel Coronavirus Is a Reminder: The Best Defense against a New Viral Outbreak Is Early Detection

Infectious disease surveillance networks already exist, but they can be highly porous

Visitors to the Temple of Heaven, Beijing.

This article was published in Scientific American’s former blog network and reflects the views of the author, not necessarily those of Scientific American


With over 360 people now dead and over 20,000 infected, the current outbreak of a new coronavirus, 2019-nCoV, has quickly escalated to become a serious global problem that has now been declared a Public Health Emergency of International Concern by the World Health Organization. Having spread to 24 countries, including 11 confirmed cases in the United States, more than 56 million people are now in lockdown in China.

But in some ways, outbreaks such as this should come as no surprise. Deforestation and the sale of live wild animals or bushmeat, such as bats and monkeys, make the emergence of new viruses inevitable, while population growth, dense urbanization and human migration make their spread easier. What is surprising is that, although we are better able to respond to such threats than ever before, we are still not fully prepared.

Screening at airports is likely to be of limited use in preventing its further spread, but we now at least have the ability to rapidly identify and genetically sequence new pathogens, to help accelerate the time it takes to develop treatments and vaccines. We also have mechanisms in place, such as through the Coalition for Epidemic Preparedness and Innovation and Gavi, the Vaccine Alliance, to help stimulate the development of vaccines and make them available quickly once we have them. However, despite this, our ability to swiftly detect threats in the first place is seriously wanting, and that is worrying.


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Infectious disease knows no borders, so when it comes to controlling outbreaks, timing is everything. The speed at which this outbreak was identified and communicated, and the fact that 2019-nCoV has been genetically sequenced, are positive steps, with more than one vaccine now already in development. But even though vaccines for coronaviruses are far simpler to develop than those for diseases like malaria or HIV, it will still take months before the first clinical trials take place and at least a year before a vaccine could possibly be available for use. As context, the Ebola vaccine Ervebo, which is now being used in the Democratic Republic of the Congo, is one of the fastest vaccines to get regulatory approval, and that took five years. That’s why it is so important to detect threats as early as possible, before they spread, and why good disease surveillance is so important.

Infectious disease surveillance networks already exist across the globe to do precisely this. However, they can be highly porous and of varying effectiveness. In some ways, we are lucky the 2019-nCoV emerged in China, where there exists a strong public health system.  During the West Africa Ebola epidemic, it took three months before the very first case, patient zero, was confirmed by a laboratory, because that community was outside of an efficient disease surveillance network. Also new threats are more common than perhaps most people realize. Since 1940 more than 330 emerging infectious diseases have been identified. If deforestation and the unregulated sale of bushmeat continue, then we should expect to see more.

Deforestation runs the risk of exposing humanity to as yet unencountered viruses—often through contact with wild animals like bats, exotic canine species and monkeys, or vectors like mosquitoes—increasing the risk of outbreaks of both new and existing diseases. Indeed, genetic analysis of 2019-nCoV suggests that it most likely came from a bat.

With 2019-nCoV, the third new severe outbreak of novel coronaviruses in the last two decades, we still don’t have enough information to know how virulent it is—but with a rising death toll, we have to be worried. We also don’t know how easily it can be transmitted from human to human, although we now have confirmation that this is occurring.

Nor do we know exactly where it originated. It is possible that first the transmission of the virus from animal to human took place at the market in Wuhan where live wild animals were sold. But if other people were infected in rural areas before the animal was brought to market, that means that with good surveillance it might have been possible to detect the threat before it reached densely populated areas.

There are no guaranteed solutions to ensure infectious diseases are always detected early, before they reach densely populated areas. But we do have one cost-effective way of widening the net, through increased government investment in primary health care, particularly in lower-income countries. Primary health care is typically the first point of contact people have with medical and health services when they get sick, and so is ideal for early detection of diseases. But in many parts of the world it is still very limited or even non-existent. Even in middle-income countries, where health care provision can be relatively good, there can exist large clusters of communities that are missing out. When it comes to new emerging infectious diseases, people in rural areas, those close to forests and those consuming bushmeat are our biggest concern, because these are essentially our underserved blind spots. 

National immunization programs can help change that. With 90 percent of the world’s children now receiving at least one routine vaccination, childhood immunization already has a larger reach than any other medical intervention. In addition to this, immunization provides an impetus for other vital health components that are not only essential to vaccination but can help strengthen primary health care.

These include supply chains, trained health workers, data systems and, crucially, disease surveillance and in some cases basic laboratory testing. Extending routine immunization systems to that last 10 percent will not only make those communities healthier and save lives, but also will put in place the basics of a health care warning system.

No matter how we achieve it, primary health care must be strengthened at a global level to reach every community if we are to widen the surveillance and response net and be fully prepared for these kinds of outbreaks. Until we have a resilient and universal primary health care system, we will be leaving some communities out.  And when the next emerging infectious disease strikes, that may simply not be enough.