Avian flu (H5N1), swine flu (H1N1), severe acute respiratory syndrome (SARS) – in recent years, a series of new diseases with the potential to become pandemics have raised global concerns about a repeat of the 1918 Spanish Flu outbreak, believed to have infected one-third of the world’s population and killed between 50 and 100 million people in three waves in a little more than one year.

Some in the medical community believe a tiny change in the H5N1 “bird flu” virus, allowing it to be passed through human contact, could kill up to 90 million people across the globe. SARS came out of China and spread rapidly in 2002, but only infected an estimated 8,000 people worldwide, most in the first six weeks, with a 10 percent death rate. But the biggest concern now is not H5N1, but H1N1 – already declared a pandemic by the World Health Organization.

“It’s not the pandemic we expected, in the sense of an avian influenza epidemic, but we have seen H1N1 infection in troops all around the world, as well as an outbreak at the Air Force Academy,” said Col. Robert DeFraites, director of the Armed Forces Health Surveillance Center (AFHSC), which has been directly involved with H1N1 since the beginning. “Clearly, the operational impact of influenza is just as relative today as in 1918, especially fighting a flu epidemic while maintaining extended combat operations.

“The good news is we have no indication the H1N1 virus has changed at all since last winter. Preparing for it as a continued epidemic and preparing a tailored vaccine specifically to counter those strains of virus the world’s experts feel will be circulating at the time the vaccine is given is something we did not have in 1918, which is a huge advantage. If you have a vaccine that is even 60 percent effective, that’s a good start in reducing the outbreak of disease.”

AFHSC is the central epidemiological resource for the U.S. armed forces and part of a network that provides influenza surveillance around the world, along with the Naval Health Research Center in San Diego and the U.S. Air Force School of Aerospace Medicine in San Antonio. Early in the current H1N1 outbreak, those two were responsible for identifying five of the first eight swine flu cases in the United States, which were among the first in the world.

“That showed the value of having a network and some advanced preparation, although it was not set up specifically for H1N1,” DeFraites said. “It was not just luck. They were prepared to deal with those specimens in an expedited way and get that strain identified a lot faster than otherwise would have been the case. A civilian health service would have taken longer because of its different focus.”

The U.S. Department of Defense (DoD) has been a leader in tracking and identifying influenza strains since the 1918 pandemic, in which the military was among the hardest hit of the initial victims. It also has been responsible for the creation of vaccines to fight seasonal influenza, including H1N1, according to Lt. Col. (P) Wayne E. Hachey, director of Preventive Medicine and Surveillance within the Office of the Assistant Secretary of Defense for Health Affairs [ASD(HA)].

“DoD has always taken all infectious diseases seriously because any has the potential to affect our ability to conduct our mission,” he said. “We have a really robust surveillance system to make sure that doesn’t happen. DoD has been responsible for seasonal flu vaccines since the 1940s, working with our civilian counterparts, because we recognized even seasonal influenza could be a showstopper for the military.

“We’re engaged in one form or another with almost all federal agencies – CDC [Centers for Disease Control and Prevention], and Health & Human Services, obviously but also those not necessarily linked to a medical response so much as a pandemic response – the departments of Homeland Security, Transportation, Education, and Commerce, the intelligence community, etc. In the past, government agencies were somewhat stovepiped, but while getting ready for what we expected would be a bird flu pandemic, all of those agencies did some real sharing in terms of needs and resources; a pandemic is not just a medical response, but needs the engagement of all sectors of government.”

There are two kinds of influenza surveillance – lab-based and syndromic. Lab-based captures select populations within DoD, as well as overall sampling across the military, primarily through the Navy and Air Force facilities in San Diego and San Antonio.

“That system has more than 200 contributing sites to create a global snapshot of what is happening with influenza throughout the year,” Hachey said. “Because of that unique perspective, the lab data we submit each year to CDC is the largest lump of data it has in determining each year’s flu vaccine.”

With syndromic surveillance, if a service member or dependent shows up at a medical facility with flu-type symptoms, a record is begun. As others appear with the same diagnosis, any increase or spread of that particular illness can be tracked by state, installation, or even ZIP code, allowing them to be targeted geographically and by commands, both in the United States and abroad.

“We have a number of DoD research facilities around the world engaged not only with the host nation but with surrounding nations in infectious disease surveillance activities,” Hachey said. “Because those samples are processed by that hub or with it closely engaged, the validity of the information should be comparable to anything we have domestically.”

Those facilities are part of the Global Emerging Infections Surveillance and Response System (GEIS). The network currently has specimens from more than 490 sites in more than 70 nations, including three Navy labs in Egypt, Indonesia, and Peru, and Army labs in Kenya and Thailand. “It is very valuable to have this scientifically credible presence in these countries and regions, working with their hosts and building an increasingly robust network for the benefit of the countries in those regions and the U.S.,” DeFraites said.

Dealing with any serious disease outbreak among deployed troops in combat can be a problem, especially one easily passed through personal contact in stressful, crowded environments. In a peacetime civilian setting, those who are ill and might be contagious may be isolated, while those who are not sick but may have been exposed could be quarantined.

“Isolation is a real problem for combat casualty care facilities, which are not optimally set up for that; quarantine also has been a challenge,” DeFraites said. “The speed with which this spread has made separating the sick from those who are not very difficult, so just using isolation and quarantine has limited results.”

Isolation, quarantine, and evacuation concerns also have changed significantly with the shift from bird flu to swine flu as the primary threat.

“The current plan is to treat in place as much as possible, especially with something like H1N1, which lasts about seven days, after which folks should be able to return to at least limited duty,” Hachey said. “When we were looking at H5N1, however, almost everyone who caught that got very, very ill, so there were evacuation plans in place. But at this point in time, given the natural course of this particular flu, our overall goal is to try to keep people in place rather than mount any large-scale evacuation.”

AFHSC was established by the ASD(HA) in February 2008 with the merger of two existing organizations – GEIS and the Army Medical Surveillance Activity, which operated the DoD Serum Repository (DoDSR). That reorganization culminated nearly a decade-and-a-half of developing responses to lessons learned from the first Gulf War in terms of a single DoD center for epidemiological excellence – in essence, a small DoD version of CDC.

“The Army is the executive agent for the SECDEF [Secretary of Defense] and responsible for AFHSC. We also have staff officers from the Army, Navy, and Air Force medical departments, and the Public Health Service,” DeFraites said. “We have a collaborative relationship with CDC in the sense we host a vaccine analysis unit that is jointly operated to look for any adverse effects of vaccines. We also sit on several joint committees, such as the Joint Influenza Laboratory Working Group, for which we share responsibility with CDC.”

In addition to GEIS and DoDSR, AFHSC also operates the Defense Medical Surveillance System (DMSS) and the Defense Medical Epidemiology Database (DMED). DMED provides remote access to selected anonymous data within the DMSS, whose database contains up-to-date and historical data on diseases and medical events – hospitalizations, reportable diseases, health-risk appraisals – and longitudinal data on personnel and deployments.

Since 1989, DoDSR has stored serum taken during mandatory HIV testing of service members, as well as serum specimens collected before and after operational deployments worldwide, enabling AFHSC to link serum specimens to health-related data and perform vital seroepidemiologic investigations related to the overall health of the armed forces. It is the world’s largest serum repository, with 46 million specimens, drawn almost entirely from active duty military since the late 1980s. Since the early 2000s, DoD has had an additional requirement that service members being deployed overseas have a blood specimen drawn before and after every deployment.

“This asset has led to answering very important questions about the prevalence of infectious diseases and their impact on the military,” DeFraites said. “We provide the surveillance capability for DoD, which translates mainly to tracking illnesses and injuries in different populations at risk and, with the analysis of that data, trying to determine trends and early warnings whenever possible.

“So our scope is well beyond infectious diseases, but because of their nature and impact on military forces, especially now with the focus on pandemic influenza since 2006, a large part of our effort has gone into influenza surveillance, especially since the onset this spring of the novel H1N1, but not to the neglect of the other missions.”

Before 2006, DoD invested about $10 million a year across a variety of programs. That has now been raised to about $40 million a year for influenza alone and $12 million for other infectious diseases. With that has come a continued emphasis on partnerships, both international and interagency.

“We are always looking for other data sources to associate with [DMSS] so, whatever operationally relevant question senior leadership may ask – such as what are the major causes of disease or injury according to location, age, assignment, etc. – we can quickly assemble a group population of any size to do the group analysis,” DeFraites said.

“We also are the unique repository for all pre- and post-deployment health assessments. We have been able to track all service members who have participated in major deployments since 1990, fulfilling one of our major tasks – to monitor the health of that group and determine health outcomes.”

The DMED is a small extract of DMSS data – with all personal identifiers removed – used primarily by public health officers, epidemiologists, and researchers interested in such things as the number of malaria cases reported by one or more services in the past 15 years.

Insofar as health problems such as influenza are concerned, the top priority is areas of active combat operations.

“Influenza is transmitted very effectively by personal contact, so the concern is especially high in areas where there is crowding, such as ships and training camps,” DeFraites said. “Similarly, on deployments, if you take long airplane flights and then are housed in a marshaling area, it can enhance the spread of infectious diseases. In places like Iraq, a continuing concern is suspended particles in the air, which gets back to our origins and oil fire explosions in the first Gulf War.

“One constraint of the operating environment is some of this immediately relevant data is not readily available. For example, if you need to know what was suspended in the air at a particular location, we don’t have sensors everywhere a service member might be. There has been a lot of sampling in Southwest Asia at forward operating areas, so we have some data regarding typical conditions, but that does not expand itself to the entire road network or every town or village.”

That is one area where the serum repository may be useful by determining biomarkers.

“Rather than having an air sample, you could have some type of protein or marker in the individual that would indicate exposure. Those types of markers are just at the beginning of the science, so it is good to have that repository now so, as the science develops, we can expand its usefulness. And having biomarkers from people rather than sensor data from everywhere around the world is far more practical.”

Eight years of combat operations in Afghanistan and Iraq have created new demands on AFHSC, including a dramatic increase in the volume of individuals tracked, and data and serum stored.

“Our data system is fairly robust and was able to expand for volume, so that was not an issue. The expansion of the serum repository, however, has put a strain on our available freezer space and I hope in the next several weeks to have a lease to double that capacity in the future,” DeFraites said. “That is one result of an ops tempo that has grown faster than was anticipated 10 years ago. We also have increased our staff analysts commensurate with the mission and the Air Force and Navy have been very supportive in assigning skilled individuals to join our Army professional staff.”

The growth in military health monitoring and data collection, combined with new science and technologies, has created a far more knowledgeable and prepared military today than the one that faced the Spanish Flu pandemic nine decades ago.

DoD also is preparing for perhaps the biggest – but publicly perhaps least recognized – lesson learned from the 1918 pandemic: About half of all military deaths then were due to secondary pneumonias; the victims survived the flu, but their systems were so weakened they could not fight off secondary infections. As a result, military treatment facilities have stockpiled antibiotics against a possible supply shortage. The military also is acquiring enough novel H1N1 vaccine to cover all military personnel and dependents.

“The overall DoD response is layered – no one measure will be 100 percent effective every time. Like Swiss cheese, each has holes, but if you layer the response, the holes will be covered,” Hachey said. “So our response includes both drugs and non-pharmaceutical measures, such as clinical guidance, based in part on current CDC guidance, modified for more austere deployed settings.”

From identifying seasonal flu strains and developing vaccines to combat them to preparing to keep combat troops healthy or able to make a quick recovery, AFHSC and its components and partners are key to combating the current swine flu pandemic or any future influenza outbreak.

“Our surveillance system is essentially a national treasure,” Hachey said. “No one, including the CDC, has as much of a global footprint, especially in many austere areas of the world that provide a true global snapshot of what is happening with any emerging infectious disease. We can always use more funding to increase our communications and warehouse portfolios, but DoD has been planning for a pandemic, at least on the medical side, for more than a decade. So we were ready for this.”

Even so, he added, they cannot afford to be overconfident.

“Our surveillance is as robust as it is so we have as much warning as possible for emerging diseases,” Hachey concluded. “From what we can predict, I think we are well-positioned. But there is always an unknown virus that could appear tomorrow and make all our pharmaceuticals ineffective. That’s why we always have non-pharmaceutical measures to fall back on.”

This article was first published in The Year in Veterans Affairs and Military Medicine: 2009-2010 Edition.