Myths vs. Facts: A Look at Seasonal and H1N1 Flu Facts

In April, the 2009-10 flu season changed dramatically with the first reports of a novel strain that was proving virulent in Mexico. That we are now in the midst of a pandemic has created more questions than answers and has added a new layer of myths that healthcare providers have already been faced with addressing for their patients regarding seasonal flu vaccine. The media attention has had the positive effect of educating the public about the seriousness of the seasonal flu, however despite the ramp up in communication, the general public is still uncertain about the seriousness of this double threat.

The same misconceptions surrounding the seasonal flu also appear to be taking hold with the new H1N1 flu, for which vacccine should soon be available. Not only do many people think the seasonal flu is not that serious, but they also believe that reports about how serious and widespread the H1N1 flu will become are overblown. What’s worse, many are afraid of the new H1N1 vaccine, and according to early estimates, have no intention of becoming vaccinated. If these early indications prove true, more people will become infected with the flu — seasonal, H1N1 or both — this year because they are unprotected. And, each preventable case will result in numerous others due to the highly contagious nature of the disease. That’s why it’s more important than ever to communicate the true facts about seasonal and pandemic H1N1 influenza and the vaccines that can help to prevent them.

Seasonal Flu

Myth: The seasonal flu isn’t that serious.

Fact: The seasonal flu is highly contagious. Each year, more than 200,000 individuals are hospitalized and approximately 36,000 die from flu-related complications.¹ The flu can disrupt your work, school and social life for up to two weeks, with symptoms that include fever, headaches, cough, sore throat, nasal congestion, extreme tiredness and body aches.² And, because it can easily be passed from a low-risk individual to a high-risk individual, it can lead to serious complications, including pneumonia and worsening of chronic conditions.³

Myth: The seasonal flu vaccine doesn’t protect against getting the flu.

Fact: The seasonal influenza vaccine prevents the disease in approximately 70 to 90 percent of healthy people under age 65. The reason the vaccine doesn’t prevent some individuals from being infected with the flu is due to several variables. First, the vaccine’s effectiveness will vary due to a person’s age and health status. In addition, the effectiveness will depend upon the match between virus strains in the vaccine and virus strains in circulation.⁴ The virus strains in the vaccine are determined through extensive monitoring conducted throughout the year to determine which are the most prevalent to circulate among the population. While the vaccine protects against these most common strains, it is possible for individuals to contract a different strain of the flu that is not included in the vaccine.

Myth: In some years, the seasonal vaccine isn’t effective even against the major strains.

Fact: A decreased effectiveness level of the flu vaccine in a given year (notably, the 2007-2008 year) is a phenomenon that happens only every 15 to 20 years, when the best guess of serotypes ends up being incorrect because of a genetic shift of the viruses. Even if a vaccine is not as effective in a particular year, in most cases, it still can provide cross-protection benefits. For instance, in 2007, the vaccine’s overall effectiveness was a good match; it was 58 percent effective against circulating influenza A viruses.⁵

Myth: The seasonal flu vaccine will give me the flu.

Fact: A flu vaccine will not cause the flu. Because the viruses in the flu shot are killed (inactivated), it is biologically unable to cause illness.¹ However, it is possible for some side effects to occur soon after the shot, usually lasting one to two days. These include soreness, redness or swelling where the shot was given, a low-grade fever and aches.

Myth: People don’t need a seasonal flu shot every year.

Fact: Influenza strains change each year. If you had an influenza vaccine last year, your body built up antibodies to those strains to protect you against infection. And while those antibodies provide a natural immunity to the strains they were developed to protect against, they will not protect you from each year’s new circulating strains.⁶

Myth: Failing to get a flu shot is a personal choice that doesn’t affect anyone else.

Fact: Getting the flu means also becoming a carrier. Flu symptoms don’t start until one to four days after the virus enters the body, so even the most conscientious individuals may unknowingly spread the virus.⁷ Everyone, then, has a responsibility for doing what they can to halt the spread of the influenza virus, especially those who come into contact with young children and individuals with compromised immune systems.

Myth: The seasonal flu vaccine is necessary only for the old and very young.

Fact: The flu vaccine is for everyone who is over 6 months old, especially those who don’t want to be sick with the flu or inadvertently spread the virus to others if they become infected. The Centers for Disease Control and Prevention recommend certain groups of people be vaccinated each year:1

• Children ages 6 months up to their 19th birthday
• Pregnant women • People 50 years of age and older
• People of any age with certain chronic medical conditions
• People who live in nursing homes and other long-term care facilities
• People who live with or care for those at high risk for complications from flu, including healthcare workers; household contacts of persons at high risk for complications from the flu; and household contacts and out-of-home caregivers of children younger than 6 months of age (these children are too young to be vaccinated).

Myth: It’s too late in the season.

Fact: October and November are the recommended months for vaccination. However, getting a flu shot later in the season, from December through March, can still protect individuals. Flu season begins in the fall, but it usually peaks after January 1st.¹

Pandemic H1N1 (Swine) Flu

Myth: The H1N1 flu isn’t much different from the seasonal flu.

Fact: The H1N1 flu is both a completely different strain of flu from the seasonal flu and it is pandemic. The H1N1 strain is a new, mutated strain of an influenza A virus subtype H1N1 (a virus type that causes the yearly seasonal flu), and is referred to as the “novel H1N1.” Commonly called the “swine flu,” it is thought to be a reassortment of four known strains of influenza A virus: one endemic in (normally infecting) humans, one endemic in birds, and two endemic in pigs (swine).⁸ The World Health Organization declared the H1N1 flu a pandemic in May because it is a new, mutated strain for which there is no built-up immunity. In addition, the H1N1 flu spread globally, and until this month, there was no vaccine to prevent it.

Like seasonal flu, symptoms include fever, cough, sore throat, nasal congestion, headache, chills and fatigue. However, additional symptoms in H1N1 flu include vomiting and diarrhea. Conjunctivitis is rare, but has been reported.

Myth: The H1N1 flu isn’t that serious.

Fact: Just like the seasonal flu, the H1N1 flu is very serious. Since the first reported case of H1N1, almost 2,000 deaths have occurred worldwide. Based on the effects of H1N1 in the Southern Hemisphere, the estimates of how widespread this flu will become have increased substantially. It is now thought that the H1N1 flu could infect half the U.S. population this fall and winter, hospitalize up to 1.8 million people and cause as many as 90,000 deaths.9 (See the H1N1 Swine Flu Update on page 44.)

Considering past pandemics, there is definitely a need for concern. There have been three previous pandemics: the 1918 pandemic, known as the Spanish flu, which killed approximately 50,000 people; the 1957 pandemic, known as the Asian flu, which killed two million individuals worldwide; and the 1968 Hong Kong flu pandemic, which killed one million people globally. In August, Homeland Security Secretary Janet Napolitano said that, while the H1N1 pandemic would not likely be the world’s worst, it would likely mirror the 1957 pandemic, which killed 70,000 people in the U.S.¹⁰

Myth: There is no way to prevent the H1N1 flu.

Fact: Like seasonal influenza, H1N1 is a vaccine-preventable disease. Vaccine manufacturers have spent months developing a vaccine that, through clinical testing, has shown to be effective in preventing the H1N1 flu. The vaccine, scheduled to be available to the public beginning in mid-October, has recently shown to be effective with a single dose, just like the seasonal flu vaccine.

Myth: An H1N1 flu vaccine isn’t needed if an antiviral drug is taken.

Fact: Antiviral drugs are not intended to be used to prevent the flu; they are a treatment once someone has been exposed to the virus. The first line of defense against any flu is vaccination. A flu vaccine exposes the body to inactivated (killed) strains of the flu virus, which helps the body to build up immunity to the flu. Antiviral drugs, on the other hand, are a class of medication used specifically to treat viral infections.¹¹ Antiviral drugs do not destroy their target pathogen (in this case, the H1N1 virus) as the vaccine does, but rather inhibits its development. Individuals who have been infected with the H1N1 flu should use antiviral drugs to help minimize the effects of the flu; they can make symptoms milder and may prevent serious flu complications. In addition, individuals who have been exposed to the H1N1 virus should consider taking an antiviral as a pre-symptom measure of treatment.

Myth: The seasonal flu vaccine will protect me against the H1N1 flu.

Fact: The H1N1 flu is a new strain of influenza, and it will require a separate vaccine in addition to the seasonal flu vaccine. Each year, the seasonal flu strains mutate to create new strains. This means individuals have to be revaccinated each year with the new seasonal flu vaccine to help protect them from infection against the mutated strains. However, the H1N1 flu virus strains causing the current outbreak are novel and are not the mutated strains found in seasonal flu. In fact, the H1N1 flu strains are very different from human H1N1 viruses found in seasonal flu; therefore, vaccines for this past human seasonal flu provide no protection from these H1N1 flu viruses.¹²

Myth: The H1N1 flu vaccine will make me sick.

Fact: The injectable vaccines that have been created to help prevent the H1N1 flu are inactivated, meaning they are killed. Inactivated vaccines are different from live vaccines that are made from live viruses or bacteria that have been weakened. Live vaccines have a slight possibility of causing the disease itself. Inactivated vaccines, on the other hand, are made from viruses or bacteria that have been killed, and therefore, cannot cause the disease that it is given to prevent.¹³ As such, the injectable H1N1 flu vaccine cannot make individuals sick.

Myth: The H1N1 flu vaccine isn’t safe because it hasn’t gone through long-term clinical trials.

Fact: Clinical trials by manufacturers of the H1N1 vaccine began in mid-August and are still ongoing. These trials are being conducted at multiple sites throughout the U.S. and worldwide, and are using the same study methodologies as all other clinical drug trials. To date, thousands of individuals, both adults and children, have been inoculated with the H1N1 vaccine, and all trials have produced positive results to protect against he H1N1 strain with no adverse effects.

Myth: Only older adults and children are most in need of the H1N1 flu shot.

Fact: Nearly everyone needs to be vaccinated with the H1N1 vaccine. While children and older adults have been most at risk from serious complications from seasonal flu, this is not the case for H1N1 flu. The Centers for Disease Control and Prevention has tracked individual cases and has found that individuals ages 5 through 24 are those at highest risk from H1N1 flu, followed by children ages 0 to 4. Also at high risk are pregnant women and those with chronic diseases.¹⁴ However, even if individuals don’t fall within a high-risk category, they are still potential carriers of H1N1 flu, and should they become infected, they risk infecting those with whom they come in contact.