The H1N1 flu: Will there be a second surge?

Many countries are bracing for a second wave of swine-flu infections that could sicken millions of people and hospitalize thousands, including many children and young adults. While flu viruses are notoriously capricious, making firm predictions impossible, a second wave could hit some countries and lead to major disruptions in schools, workplaces, and hospitals, according to international health officials. “The virus is still around and ready to explode,” said William Schaffner, a Vanderbilt University School of Medicine influenza expert.

It was in April 2009 when the news broke that a new flu had shown up in Mexico, California, and Texas. By June, the outbreak had become a pandemic, meaning it was spreading rapidly throughout the world. Though initially referred to as swine flu, the never-before-seen virus — officially called H1N1 influenza — actually contains genes from viruses that circulate in pigs, birds, and humans.

As the first flu pandemic in 41 years spread around the world, scientists found that the pandemic overall hadn’t been worse than an average seasonal flu — just more widespread. No signs have emerged that the microbe had mutated into a more dangerous form, and most infected people seem to experience relatively mild illness.

Many experts suspect the second wave, however, could be more severe than an average flu season. Because the virus is new, most people have no immunity against it. “This epidemic will transmit faster than usual, because the population is more susceptible,” said Mark Lipsitch, a Harvard School of Public Health professor of epidemiology who has been helping the US Centers for Disease Control and Prevention (CDC). “We have to be worried about our ability to handle a surge of severe cases,” he added.

Perhaps more important, the virus continues to affect children and young adults much more commonly than typical flu viruses. Most of those who developed serious illness and died had other health problems. But those include many common conditions, such as diabetes, asthma, and obesity. Pregnant women appear to be especially at risk. And the virus can cause severe illness and death in otherwise healthy people in perhaps one-third of cases.

To protect yourself against this and other potential pandemics, it’s important to arm yourself with the facts about H1N1 influenza.

What Is H1N1?

Lab testing of the virus revealed a unique combination of gene segments. The new virus looked very different from the flu viruses that normally circulate in pigs. H1N1 is what epidemiologists call a “triple-reassortment” virus because it combines genes from different flu viruses — viral strains that normally affect pigs, along with birds and human flu strains.

People, particularly those under age 65, have little or no natural immunity against a novel flu strain such as H1N1. As a result, the virus can affect large numbers of people. In addition, the virus could mutate and lead to more severe cases.

• How it spreads. H1N1 influenza spreads the same way as does a typical seasonal flu —from person to person, mainly through coughing or sneezing. The virus can also be transmitted if you touch something contaminated with it, such as a desk or phone, and then touch your mouth or nose. You can’t get H1N1 flu from eating or preparing pork or from tap water or swimming pools.

One thing different about this flu is that it has affected younger people more commonly. Last year, the majority of people who were infected were age 18 or younger. The CDC estimates that about one-third of people over age 60 may have cross-antibodies that could protect them from the illness.

• Signs and symptoms. Signs and symptoms of H1N1 influenza are similar to those of regular flu. These include fever, cough, sore throat, headache, body aches, fatigue, and runny nose. Diarrhea and vomiting occurred in about 25 percent of cases. Most people infected with the virus experience a mild to moderate illness and recover quickly without medical treatment. But the flu can also be severe and cause complications or even death.

Deaths from influenza often result from complications, such as viral or bacterial pneumonia or the worsening of a chronic condition, such as asthma or diabetes. About half the people who were hospitalized with H1N1 influenza had underlying health conditions or weak immune system. Pregnant women and very obese people seem to face a higher risk of serious illness.

How can you prevent it?

Each year, a vaccine against the expected strains of seasonal flu becomes available. The vaccine for this year’s seasonal flu won’t work against H1N1 flu. At present, however, a limited supply of H1N1 flu vaccine is already available in the Philippines. Ask your doctor about the need to have it for you or your family.

But even if you aren’t vaccinated against H1N1, you can take simple steps to prevent infection:

• Clean your hands often. Wash thoroughly with soap and warm water for at least 15 to 20 seconds, and dry your hands completely. If you don’t have access to soap and water, use an alcohol-based hand sanitizer.

• Avoid touching your nose and mouth. Also cover your nose and mouth with a tissue when you cough or sneeze, and throw the tissue away.

• Avoid close contact with people who might be sick. If flu is widespread in your community, stay away from crowded settings when possible.

It is not necessary to wear a facemask in public to avoid H1N1 flu. If you’re caring for someone with flu, you can wear a mask when in close contact. Throw the mask away as soon as you’re done, and wash your hands thoroughly.

What if you get the flu?

If you develop symptoms of influenza, follow these precautions:

• Stay home. Don’t venture out until your fever is gone for 24 hours.

• Cover your mouth and nose when coughing or sneezing. Wash your hands afterwards.

• Rest and drink plenty of fluids. Most people recover from H1N1 flu with supportive care at home, including rest, fluids, and pain relievers for aches.

• Keep your home clean with household disinfectant.

• Don’t give aspirin to children or teens. Use acetaminophen instead.

• When to seek medical care? You probably won’t be able to tell the difference between regular seasonal flu and H1N1 since symptoms are similar. Still you don’t have to contact your physician unless you develop more severe symptoms or are at high risk of flu complications. You may be at higher risk of complications if you’re pregnant, 65 years old or older, or have a weakened immune system or a chronic condition such as asthma, heart disease, obesity or diabetes.

In adults, the following warning signs require urgent medical attention: difficulty breathing or shortness of breath, pain or pressure in your chest or abdomen, sudden dizziness, fever that lasts more than three days, confusion, severe or persistent vomiting, flu symptoms that improve and then return with fever and a worse cough.

If you have a severe bout of influenza or at risk of complications, your doctor may recommend that you take an anti-viral drug such as oseltamivir (Tamiflu), to help prevent or treat the illness. This prescription drug keeps flu viruses from reproducing in your body.

Be Informed, Be Prepared

As the first pandemic of the 21st century, H1N1 influenza will likely continue to pose a threat for some time. By being well-informed, you can stay on top of this flu.

“There’s only so much that can be done to get ready,” said Eric Toner of the University of Pittsburgh’s Center for Biosecurity. “Flu, like a hurricane, is a force of nature. You can’t stop it. You can’t make it less severe than it would be otherwise. All you can do is try to be prepared to deal with the consequences.”

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For more up-to date information, please log on to www.pandemicflu.gov.