Unmasking the mysteries of the flu (influenza)
October 2, 2019
Every year, the flu returns like clockwork spreading viruses through different populations, activating new and old controversies (hand-washing, mask use, flu shots), and, yes, causing people to miss work or even end up in the hospital.
Some people get into heated debates over whether they should or shouldn’t get a flu shot. (You should.)
Others argue there’s no difference between the flu and a bad cold. (There is.)
Even among medical professionals, there is a long-running dispute about the most effective masks (or respirators) to wear to protect health care workers from the spread of flu and other respiratory viruses. Do they need the more expensive respirator masks, or is the common surgical mask sufficient?
My colleagues and I recently conducted extensive research that addresses that last question. Our study, published in the Journal of the American Medical Association, found “no significant difference in the effectiveness” of common medical masks, which cost about a dime, vs. N95 respirators, which cost about $1, for prevention of influenza or other viral respiratory illness.
A little background: During the 2009 outbreak of H1N1, or swine flu, the U.S. Centers for Disease Control and Prevention (CDC) recommended health care workers use the tighter-fitting N95 respirators, which were designed to filter out at least 95 percent of airborne particles, rather than the more commonly used, looser-fitting surgical masks. But some facilities had trouble replenishing N95s as supplies were used, and health care workers were less vigilant about wearing them because they are less comfortable.
As the largest study ever done on this issue in North America, our research supports the assertion that in the outpatient setting there is no difference in protection provided between the two tested mouth coverings. The finding is important from a public policy standpoint because it informs health care facilities what kind of protective apparel to have available for outbreaks.
For patients, the question of whether they should wear a mask during flu season is a bit more complicated.
I’ll answer that one in a minute, but first let’s take a look at some of the most commonly asked questions about influenza and see if we can clear up some of the congestion and confusion.
1. Do I really need to get a flu shot? I’ve heard it isn’t even that effective.
The flu shot is the best way to protect yourself and your loved ones from influenza. Even when it’s not completely effective, the flu vaccine can decrease the risk of acquiring influenza, the severity of the virus and the risk of developing complications. It can also reduce the probability of you transmitting the virus to other people who may be vulnerable, such as a friend with leukemia or an elderly grandparent.
The flu vaccine tends to frustrate people because it only prevents flu 40% to 60% of the time, according to the CDC, and you have to get it every year. The effectiveness of the vaccine varies annually, depending on the dominant strains of flu and a few other factors:
- Your age: It’s less effective in children 0-6 months, and adults 65 and older.
- Your health: It doesn’t work as well for people with weakened immune systems, which is why we suggest vaccinating people around these people — we call it cocooning. A family cocoons a newborn baby and protects them by being protected.
- Type of vaccine: There are many types of vaccines and the choice of vaccines depends on the setting. We have high dose vaccines for those over 65, the nasal spray is commonly used in children, and the “egg free” vaccines are designated for patients with serious egg allergies.
- The strain of the flu: Every year, researchers monitor viruses worldwide and update the vaccine to combat what they think will be the dominant circulating strains that will cause flu that year. The predictions of these experts are pretty accurate, but not perfect.
Bottom line: The vaccine isn’t perfect but it’s your best protection against the flu.
2. Is there a 'best time' to get a flu shot?
In the northern hemisphere, the 12-16 week influenza season typically falls between November and February. So the best time to get your flu shot is between now and Thanksgiving. In general, we suggest October.
"Influenza actually occurs year-round, but here it peaks in the winter because cold and dry weather create optimal conditions for transmission. Also, people tend to stay inside and are crowded together, which may provide a perfect storm."
The vaccine needs two weeks to take full effect, so that timeframe will mean you are prepared for peak flu months.
Some pharmacies began offering flu shots in July or August, and it’s OK if you got your vaccine early. It typically lasts at least six months. You shouldn’t need a second shot unless there is a late wave of flu and then you can talk to your doctor. If you procrastinate, you should still get the vaccine because flu viruses begin circulating at different times every year.
Last year, we had a 21-week season with two waves of influenza A — (H1N1) began causing illness in October 2018 through mid-February 2019, then (H3N2) circulated between February and May 2019.
Influenza actually occurs year-round, but here it peaks in the winter because cold and dry weather create optimal conditions for transmission. Also, people tend to stay inside and are crowded together, which may provide a perfect storm.
3. Can you really tell the difference between cold and flu?
It is very difficult. Both are respiratory illnesses, and they share many symptoms such as cough, sore throat and fatigue. Because of this, we test patients for flu, preferably within the first two days of illness, to help treat them with proper medication.
If you push your voice when you have a cold, the flu, or allergy symptoms, you’re risking permanent damage to your vocal cords. Voice care expert Dr. Lesley Childs explains how to care for your voice during cold and flu season.
Here are some subtle differences between cold and flu symptoms, according to the CDC:
- Flu comes on quickly; a cold takes hold more gradually
- Flu is often accompanied by fever, chills and body aches
- Cold symptoms are milder and often include sneezing and/or a runny nose.
- Colds are less likely to result in serious illnesses such as pneumonia, bacterial infections or hospitalization.
4. Can you die from the flu? How dangerous is it?
Flu causes a spectrum of symptoms and can be very mild or cause life-threatening infections. Every year in the United States, at least 40,000 people die from flu.
Older adults and very young children are most at risk. But healthy adults should not be cavalier about the flu. Most cases resolve after about a week, but some symptoms, such as excessive coughing, can lead to inflammation of the lungs and difficulty breathing. If you experience shortness of breath, sudden dizziness, or ongoing vomiting, contact your doctor instead of trying to tough it out.
5. Should I wear a mask during flu season? What are the best ways to avoid getting the flu?
- The best way to avoid the flu is to get vaccinated. (See question No. 1 above.)
- Good, effective and frequent hand washing/hygiene reduces transmission of respiratory viruses including flu by 30%. So wash your hands and keep alcohol hand gel with you.
- Masks can help protect you from catching the flu, which is generally spread by tiny droplets made when people with flu cough, sneeze or talk. If you have the flu and wear a mask, you reduce the risk of spreading the infection.
- Avoid touching your mouth, eyes, and nose, especially after you’ve been out in public or at work during flu season.
In many ways, influenza doesn’t get the respect it deserves, likely because we live through a flu season every year. Influenza is highly contagious and easily transmitted, which is why it’s so important to get vaccinated and reduce the risk of an outbreak.
Researchers at the National Institutes of Health and labs overseas are hard at work to develop a universal flu vaccine that would protect against multiple strains for up to 10 years. But that breakthrough may be years away. For now, there is no debate: the flu vaccine is our best defense.