1918 Today

Surveillance: Knowing is the half battle … and response is the other half

The 1918 "Spanish Flu" pandemic killed between 20-100 million people worldwide. Understanding how a modern day 1918-like influenza pandemic would unfold today is essential to mitigate the next biological disaster.

In the last installment of Metabiota's 1918 Today Campaign, we highlighted how today's pandemic risk is shaped by changes in human mobility over the past 100 years. The current installment focuses on surveillance, initial detection, and response to an influenza pandemic. How have our surveillance and initial response capacities improved since 1918 and what does that mean for our risk today?

Why are surveillance, detection, and response important?

• Surveillance is the ongoing collection, analysis, and dissemination of data with the purpose of detecting disease events in populations and informing the development and implementation of interventions and measuring their effectiveness.
• Early detection of a pandemic spark can lead to earlier implementation of interventions.
• Interventions help mitigate an influenza pandemic's impact and can include: effective risk communication, behavioral and social distance practices, infection control practices, and vaccines.

The Past

In 1918, the public health community had to rely on vague reports of unusual disease activity to determine a pandemic was underway. There were no laboratory tests to detect the pandemic spark or to diagnose the disease. The term "influenza" had existed since the mid-eighteenth century to describe the disease, but scientists would not discover the influenza virus until 1933.

Unusually high disease activity was first detected in a US military camp in the spring of 1918. Doctors were unsure of its cause and described the disease as having a short duration with no complications. Shortly after, a second wave of disease activity hit. Symptoms were unusually severe compared to typical influenza symptoms, causing doctors to first misdiagnose the disease as dengue, cholera or typhoid fever. Public health officials also detected another unusual aspect of the 1918 pandemic—a dramatic age shift in the mortality rate, especially among the working age population, instead of the typically-affected very young and elderly (Figure 1).

Figure 2. Drop in genetic sequencing costs can reduce the amount of time to recognize a pandemic.

Source: National Human Genome Research Institute.

Despite these advances, gaps in surveillance remain. Global health experts believe the 2009 influenza pandemic sparked in February in Mexico, but it was first detected when it reached the United States in April. Unfortunately, many countries were unprepared in their surveillance and response during this pandemic.

By the end of the pandemic, 18,500 laboratory-confirmed deaths had been reported worldwide. However, health agencies recognize the burden of the pandemic was substantially underreported due to people not seeking medical care and laboratories being too overwhelmed to test for the virus. Models accounting for these factors estimate that there were actually between 151,700 and 575,400 influenza-related deaths globally.

The Future

Surveillance, early detection, and response will likely improve in the coming years. A growing number of countries have engaged in the Joint External Evaluation (JEE) process to meet IHR core capacity targets. In addition to improved influenza surveillance in humans there is also an increased emphasis on influenza surveillance in animals through the application of One Health principles, to more quickly detect pandemic sparks. One Health considers human health, animal health, and the environment to be fundamentally interconnected. It requires maintaining robust animal health infrastructure, biosecurity, and veterinary public health capacities. Metabiota has played an integral part in One Health through its work on the USAID PREDICT project.

The democratization of technological advancements in influenza testing across the globe is closing the gaps in surveillance. Over the next few decades, genetic sequencing costs are likely to continue to plummet, and new diagnostics including rapid point-of-care tests will likely reach even the most remote areas of the world. Technologies such as these will help strengthen the weakest links in the global influenza surveillance system.

As for interventions, the holy grail would be the realization of a universal influenza vaccine. Instead of racing against the clock to develop a new vaccine, scientists could have a vaccine ready even before a pandemic starts. Even without a universal vaccine, there are encouraging trends to speed up vaccine development through next-generation technologies including cell-based vaccine platforms.

Technological progress and democratization may seem inevitable, but they do not occur without significant investment. These investments must have a global reach to realize the dividends of a global influenza surveillance system. Social unrest, corruption, and conflict can impede effective surveillance and response measures. Surveillance will continue to be essential to ultimately mitigate the health and economic impact of a 1918-like influenza pandemic.

The Takeaways

• The explosion of scientific knowledge and health infrastructure in the past 100 years allows for quicker detection, better surveillance, and more effective response to influenza pandemics.
• Despite these advances, gaps in health system capabilities delay early detection of a pandemic.
• Any delay in detection reduces the efficacy of interventions and causes irreparable harm to mitigate health and economic costs.