Flu season is in full swing in the U.S., with 36 states reporting widespread influenza activity. This year’s predominant flu strain — H3N2 — tends to produce severe outbreaks, with higher rates of influenza-related morbidity and mortality. Already, the number of flu-related deaths has reached an epidemic level, and experts say we could be in for a long season ahead.
“Flu always has a potential to be serious, but H3N2 viruses tend to be associated with more severe seasons,” Dr. Thomas Frieden, M.D., M.P.H., director of the U.S. Centers for Disease Control and Prevention (CDC), said at a press conference earlier this year. “[W]hen H3 viruses predominant, we tend to have seasons that are the worst flu years, with more hospitalizations from flu and more deaths from the flu.”
With the virus getting to more people and causing worse illness than usual, it’s even more important that we all know what we’re up against this winter. With that in mind, here are 10 things you should know as we approach the peak of flu season:
1. How long will the flu season last?
Flu activity most commonly peaks in the U.S. between December and February, the CDC says. However, seasonal flu activity can begin as early as October and continue to occur as late as May. Influenza viruses constantly change from week to week, and even day to day, so making predictions can be difficult, but health officials seem to agree that this year’s flu season has not yet peaked.
2. How do I know if I have the flu?
The symptoms of influenza infection generally include: fever* (or feeling feverish), chills, cough, sore throat, runny or stuffy nose, muscle or body aches, headaches, fatigue, and/or vomiting and diarrhea in some patients (most commonly children), according to the CDC. Although the severity varies with patients and strains of the virus, flu symptoms tend to be more severe than the common cold and usually come on very suddenly.
*The CDC points out that not everyone with the flu will have a fever.
3. What should I do if I have the flu?
Most flu illnesses are mild to moderate in severity and don’t need medical treatment or drugs, other than rest at home, according to the CDC. However, there are high-risk groups – very young children, people over the age of 65, people with weakened immune systems or poor health, and pregnant women – who need to be extra careful if they think they’re getting sick. Those patients may need to see a doctor, or even travel to the emergency room if severe vomiting, dizziness, trouble breathing, or skin discoloration occurs.
Research shows that early antiviral treatment (most commonly with Tamiflu) can shorten the duration of fever and illness symptoms, and may reduce the risk of complications from influenza (e.g., otitis media in young children, pneumonia, and respiratory failure). The CDC recommends antiviral drug treatment as early as possible for any patient with confirmed or suspected influenza who: a) is hospitalized; b) has severe, complicated, or progressive illness; or c) is at higher risk for influenza complications (including children under the age of 2, pregnant women, adults aged 65 years and older, nursing home residents, and other high-risk individuals).
4. Flu shots: is it too late to get one? Is it recommended for everyone? Is there enough supply left?
An estimated 151 million to 156 million doses of flu vaccine have been distributed this year, beginning in October, according to the CDC. The most recent guidelines from the federal agency call for everyone over the age of 6 months get vaccinated – and for some young children, two doses (administered at least 4 weeks apart) are recommended to provide the best protection. While it’s best to get vaccinated early — by September or October — experts say it’s never too late, particularly since flu season likely hasn’t reached its peak yet.
“With flu activity continuing to increase and the warnings about a possible severe flu season, this would actually be a very good time to get your family a flu vaccine if you haven’t yet,” pediatrics experts Dr. Vincent Iannelli wrote this week.
5. What type of vaccine should I get? Where do I get it?
This year, the types of flu vaccines being offered include an injectable vaccine for people 3 years and older, a live nasal mist for healthy people 2 to 49 years of age, and a high-dose vaccine for those 65 years and older. The high-dose vaccine has been shown to improve the production of antibodies, thus providing a stronger immune response against the flu. Both the injectable and nasal mist flu vaccines are quadrivalent, which means they contain four influenza strains — two influenza A and two influenza B strains. The high-dose flu shot is available only as a trivalent vaccine. The CDC does not recommend one over the other; however, recent studies suggest that the nasal spray flu vaccine works better than the flu shot in healthy children aged 2 years to 8 years of age.
Flu shots are available from your physician or at many local pharmacies and stores. For help locating a flu clinic near you, click here to go to Flu.gov’s vaccine locator.
6. How does the vaccine this year match up with the prevalent strains?
The ingredients for seasonal flu vaccines — and thus the strains they will cover — are selected by scientists months ahead of the start of flu season, generally by analyzing the most dominant strains from the previous year. The most common strains of flu viruses that have been circulating this year are so-called “drift variants” of A H3N2 viruses that are genetically different from the strains used to make this season’s vaccine. As a result, CDC officials have acknowledged that the protection probably won’t be as good as if the vaccine strains were a match — but that doesn’t mean you should skip the flu shot.
Even during a season when the vaccine only partially protects against one flu virus, it can still protect against the others and, importantly, will likely offer protection against other flu strains that may become more common later in the season. According to a recent CDC report, a third of the H3N2 samples tested in late December matched with the strain contained in this year’s flu shot, suggesting the vaccine is still an effective method in fighting the flu. Additionally, even you do get the flu, you’re more likely to experience a milder illness if you are vaccinated.
7. How does the flu spread?
People with flu can spread it to others up to about 6 feet away. According to the National Institute of Allergy and Infectious Disease, most flu viruses are thought to be spread by droplets made when people with flu cough, sneeze or talk. These droplets can land in the mouths or noses of people who are nearby or possibly be inhaled into the lungs. You can also become infected by touching a surface or object that has flu virus on it and then touching your own mouth or nose, although this route of infection is less common.
8. How can I avoid catching the flu? And spreading it to others?
The CDC recommends several commonsense measures to reduce your risk of catching the flu virus and/or spreading it to others. First, avoid close contact with sick people and stay home if you are sick. It’s also important to wash your hands regularly with soap and water. If soap and water are not available, use an alcohol-based hand rub. Linens, eating utensils, and dishes belonging to those who are sick should not be shared without washing thoroughly first. Eating utensils can be washed either in a dishwasher or by hand with water and soap and do not need to be cleaned separately. Additionally, frequently touched surfaces should be cleaned and disinfected at home, work and school, especially if someone is ill.
9. What’s the period of contagiousness?
Most healthy adults may be able to infect other people beginning 1 day before symptoms develop and up to 5 to 7 days after becoming sick. Children may pass the virus for longer than 7 days. Symptoms start 1 to 4 days after the virus enters the body. That means that you may be able to pass on the flu to someone else before you know you are sick, as well as while you are sick. Some people can be infected with the flu virus but have no symptoms. During this time, those persons may still spread the virus to others. To avoid bringing the virus to work with you, the CDC recommends remaining home a full 24 hours after the flu fever subsides; before that, germs are more likely to be spread.
10. What about other influenza strains, like swine flu and avian flu?
The H1N1 flu virus — also known as “swine flu” — caused a global pandemic in 2009, the first year the strain was detected in humans. By the end of flu season, the virus had claimed more than 12,000 lives in the U.S. and up to 203,000 worldwide. That strain is now part of the seasonal viral mix, causing symptoms that mirror those of other flu viruses and spreading through the same routes of transmission. According to Flu.gov, this current flu season is the first since 2009 that H1N1 has been so predominant in the United States.
Confirmed cases of human infection from several subtypes of avian influenza infection have been reported since 1997. In the past decade, more than 600 sporadic cases of human infection with highly pathogenic avian influenza (HPAI) A (H5N1) virus with high mortality have been reported, primarily by 15 countries in Asia, Africa, the Pacific, Europe and the Near East. On January 8, 2014, the first case of a human infection with H5N1 in the Americas was reported in Canada. Another strain of avian flu (H7N2) was detected in New York in 2003. Most cases of avian influenza infection in humans have resulted from contact with infected poultry (e.g., domesticated chicken, ducks, and turkeys) or surfaces contaminated with secretion/excretions from infected birds. The spread of avian influenza viruses from one ill person to another person has been reported very rarely, with limited transmission. Just last week, Hong Kong confirmed the season’s first case of the deadly H7N9 strain of avian influenza.