Health experts agree that a worldwide influenza epidemic (pandemic) is inevitable. The only unknown is when it will occur and how severe it will be.
A pandemic could already be underway. Or, it might not happen for years. A pandemic could be fairly mild, or it could be severe, causing schools to close and workshops to empty, overwhelming hospitals and possibly killing millions across the globe. There’s no way to predict.
There’s also no way to predict what might happen with the A(H1N1) virus, a novel flu virus that resulted from the reassortment of four viruses from pigs, humans, and birds, that has been the focus of so much recent attention. Although there are a number of reasons why experts are particularly concerned about this virus, no one knows what may occur with this — or any other influenza virus — in the future.
What’s Known
In the past 90 years, there have been three pandemics. The most severe was the 1918 Spanish flu, which is estimated to have killed 100 million people around the world in 18 months. Milder flu pandemics occurred in 1957 and 1968.
Pandemics tend to occur when organisms that cause diseases that typically affect only animals adapt so that the organism can infect humans — then further adapt to pass easily from human to human. The human population has little or no immunity to this virus, so person-to-person spread could occur rapidly. Birds, especially domesticated birds such as chicken and ducks, are a common source of viruses. Domestic pigs often serve as a genetic stepping stone for viruses that evolve to infect humans, such as the A(H1N1) virus. Of course, viruses can also jump directly from birds (animals) to humans. Researchers discovered a few years ago that the 1918 pandemic began this way.
Indeed, the Spanish flu pandemic of 1918 serves as a chilly reminder to everyone of just how catastrophic a pandemic can be. It is believed to have infected more than 30 percent of the world’s population. In just 24 weeks, it took more lives than AIDS has in 24 years. “It was a perfect storm for a terrible epidemic,” says Dr. Howard Markel, a medical historian at the University of Michigan.
But is it a storm that can happen again? In a worst case extrapolation from the toll of the 1918 pandemic, a new pandemic could kill 150 million people — 2.5 percent of the world’s population. Epidemiologist Michael Osterholm of the University of Minnesota calls that scenario “the single greatest risk to our world today.”
However, when public health officials warn that a flu pandemic could take millions of lives, they’re assuming the return of the 1918-strength virus. It wasn’t just the enormous death toll that made 1918 stand out though, but who died and how. While flu usually kills only the very young or old, in 1918, those aged 20 to 40 were the most vulnerable. That may have been because the Spanish flu, unlike the weaker flus, could apparently trigger a fatal overreaction on the body’s own defenses. Immune cells would tear apart infected tissue in an effort to destroy the virus, a process called cytokine storm, and blood and other fluid carrying those cells would pour into the lungs, triggering acute respiratory distress syndrome (ARDS). The pandemic viruses of 1957 and 1968, by contrast, were about as transmissible as the 1918 strain but were much weaker. Paul Edward, an evolutionary biologist at the University of Louisville, says, “I think we will never again see a pandemic with a mortality like 1918.” Some scientists disagree. Says Malik Peiris, a virologist at the University of Hongkong, “Nothing in influenza is surprising to me, because the one thing you can be sure of about influenza is its unpredictability.”
Questions, Questions
All over the world, people are asking two questions: Is the government doing everything it can? What can I do to protect my family? And the answers are: Not yet to the first question and only so much to the second.
Dr. Margaret Chan, director general of the World Health Organization, notes, “In history, no human intervention has managed to stop a pandemic once it starts.” Dr. Chan believes that the key factors that will determine success are surveillance, the authority to impose and enforce a quarantine, and the state of readiness in hospitals — and in all of these, the world has a long way to go. Take surveillance, the ability to detect an outbreak at the source. It is only now that something has been started in this regard. With funding from companies like Google, a group called the Global Viral Forecasting Initiative (GVFI) has teams in Africa and Asia surveilling wild animals and the people who live in proximity to them for new pathogens. These “sentinel populations” can provide early warning when a new virus emerges. It is only when a dangerous disease is discovered early once it crosses from animals to people that it can be contained effectively. Right now, there is not enough of these teams around the world, but it is a good beginning and a move in the right direction.
What about the surveillance done in our airports? Throughout Asia, governments have pulled their old SARS-epidemic thermal monitors out of the mothballs, and are scanning people for evidence of fever. That worked for SARS control because the SARS virus was almost exclusively contagious when people were running fevers. This is not, however, true with flu: Influenza can be very contagious before the individual carrier may have any symptoms at all, much less a fever.
At the first sign of human-to-human transmission and in a pandemic situation, the WHO Plan calls for an immediate quarantine, freezing all traffic in and out of an area that could be as large as an entire city. Schools and businesses would be closed and public gatherings banned. Of course, these measures could be implemented only by the national government — and the success of this plan would depend on how strictly it can be enforced and implemented.
Antiviral drugs are an important part of the WHO’s plan to combat flu. There are only two available, Tamiflu and Relenza, and they both work the same way, by interrupting the virus’ ability to replicate within the body. (Tamiflu, which is taken orally, is in wider use than Relenza, which is usually given by inhalation.) If taken at the very onset of symptoms, they are believed capable of reducing the severity and length of the disease. But their real value in public health, says Dr. Ann Miscoma, an influenza expert at New York Presbyterian Hospital/Weill Cornell Medical Center, would be to help contain an outbreak by treating healthy people in a “ring of prophylaxis” around it. The WHO recommends that nations stockpile enough to cover 10 percent of their population. However, some public health experts feel that a more desirable stockpile is a range of 20 to 30 percent of the population.
The best weapon against A(H1N1) would be a vaccine. But there’s a catch-22 in vaccine production: The virus now in circulation is not the one we have to worry about. It will have to mutate to cause a human pandemic, and the existing vaccine may or may not be completely effective against the new strain. [It presumably would offer at least some protection, but the standard vaccine now being given for the year’s seasonal flu variety offers no protection at all against A(H1N1) virus.] At any rate, a vaccine for the A(H1N1) strain will not be available until at least a few months from now — probably in July, at the earliest..
The final line of defense against a pandemic is the hospital. The points of entry in many cases will be emergency rooms that would have trouble coping with even a bad regular flu season. Many of these patients will probably be extremely sick, with respiratory and multi-organ failure and in need of intensive care. Many hospitals will simply be unable to handle a surge in medical admissions, resulting in a pandemic. Some experts even think that a virulent flu pandemic would cause the health-care systems to crash like an overloaded website.
What You Can Do
The truth is, it’s impossible to know how a pandemic might take shape. Should a flu epidemic occur — whether mild or severe, doctors recommend the following:
• Be knowledgeable. Look to reliable news sources for up-to-date news and recommendations from health experts. In the event of a pandemic, information will be available from sources such as our Department of Health, call (02) 711-1001 or 711-1002; the US Department of Health and Human Services (www.pandemicflu.gov http://www.pandemicflu.gov/) ; the US Centers for Disease Control (www.cdc.gov http://www.cdc.gov/); and the World Health Organization (www.who.int/en http://www.who.int/en).
• Get the standard influenza vaccine. Your flu shot won’t protect you from a pandemic flu virus, but it’s still protective against the most common flu viruses that health experts expect to be present during the flu season. It’s also a precaution against the possibility of having simultaneous infections.
• See your doctor within two days of the beginning of flu signs and symptoms. If you have cough, sore throat, fever of 38°C, and muscle aches, your doctor may be able to prescribe an antiviral drug. Occasionally, the flu may also cause diarrhea.
• Frequently wash hands or use alcohol-based hand sanitizers. Either method can help prevent the spread of infections of all kinds. It’s especially important to do this after likely exposure, and before handling food or touching your nose, mouth or eyelids. When you wash, use warm water and soap, and scrub for at least 10 to 15 seconds.
• Stay healthy. A healthy body means a strong immune system that can help you fight off infection. A few basic tips include eating a healthy diet, getting adequate sleep, and exercising.
• Consider wearing a face mask in public. A face mask may prevent you from inhaling airborne particles from an infected person’s cough or sneezes. The snug-fitting N95 face mask is the gold standard for infection protection. Ask your doctor where to get one.
• Be cautious with social contact. If you’re sick, avoid settings such as work, church or public places where you’ll likely to infect others. If you’re not sick, try to avoid such things as handshaking, being close to others who are sick, and taking part in public gatherings.
• Use good respiratory etiquette. Cough or sneeze into facial tissue, wash your hands often, and stay at home if you are ill.
Now that we have the first confirmed case of Influenza A(H1N1) in the Philippines, we need to be more aware of all the necessary precautions to avoid the spread of this potentially dangerous disease. –Tyrone M. Reyes, M.D., Philippine Star
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