This year’s influenza outbreak is already the most widespread on record since health officials began keeping track about a dozen years ago, with millions of people being infected by emerging and current strains such as the dominant H3N2.
Alfred Tallia, chair of the Department of Family Medicine and Community Health at Rutgers Robert Wood Johnson Medical School, discusses this year’s flu season and how you can protect yourself.
What strains are prevalent this year? This year, we are seeing the H3N2 influenza virus – one of three predominate subtypes of the Influenza A RNA virus that causes disease in humans – as the predominant cause of influenza virus–caused illness. Influenza RNA viruses have the capacity to mutate rapidly, and each year we tend to see a different variant or group of variants that predominate. Influenza B virus and its variants also can cause illness, but this year the A virus is causing most of the outbreaks.
Does H3N2 cause more severe symptoms than other flu strains? Influenza A strains such H3N2 and other subtypes causing this year’s illnesses tend to be the strains that cause more severe illness. Most epidemics are due to Influenza A strains. Many influenza A strains originate in other animals, mutate and infect humans. Influenza B strains mostly affect and reside in humans and are generally less severe.
What is the effectiveness of this year’s flu vaccination? For the 2017–2018 season, there are three-component vaccines that contain an H1N1 component, an H3N2 component and a B/Victoria lineage component, and four-component vaccines that protect against these strains and a second Influenza B strain. This year’s vaccination is estimated to be between 10 percent to 30 percent effective.
The method for developing vaccinations, which are currently manufactured using fertilized chicken eggs, explains why it’s difficult to match vaccinations to a particular season’s strains: First, scientists must predict how the virus will change from one year to the next, then the vaccine needs to be manufactured, which can take six to nine months. So, if the predictions on the prevalent strains are wrong, there is insufficient time to modify the vaccine. Vaccine producers are proposing changing the methodology of production from chicken eggs to cell cultures, which would shorten the production process.
Should people still get vaccinated? It is recommended that people still get the flu vaccination if they have not already. Even though it is not as effective as it has been in previous years, the vaccination can reduce symptoms and duration even if people get the flu. Most family physicians, pediatrician offices, primary care clinics and pharmacies offer the influenza vaccine. You cannot get the flu from the flu shot, but immunity usually takes about two weeks to develop.
People should also continue to practice good hygiene, like washing your hands, coughing into your sleeve, disposing used tissues and staying home if you’re sick. If you are sick, avoiding people who are hospitalized, undergoing cancer treatment or who have diabetes or other chronic illnesses is a good idea.
What complications can accompany the flu? Common symptoms include fever, chills, cough, sore throat, runny or stuffy nose, muscle or body aches, headaches, fatigue, vomiting and diarrhea. The last two are more common in children than adults.
Sinus and ear infections are examples of moderate complications of flu, but a frequent serious complication, particularly in people with chronic lung disease, is pneumonia. In addition to pneumonia, serious complications include inflammation of the heart, brain or muscle tissues, and multi-organ failure, such as respiratory and kidney failure.
When should you call your doctor? Call your physician if you have persistent fever, weakness, diarrhea, difficulty breathing or chest pain, persistent muscle or body aches, or if you have an underlying chronic illness like diabetes or heart disease. If your child experiences an inability or failure to feed, fever, rapid breathing or persistent diarrhea, call your doctor immediately. Elderly people with the flu who experience confusion or weakness likewise require medical attention. If you are in good underlying health, your symptoms are limited, fever and body aches are well controlled with antipyretics like acetaminophen and you are maintaining adequate hydration and nutrition, you can choose to ride it out. However, when sick and in doubt, it is always reasonable to call and seek medical attention.
Who is most vulnerable to the flu? While children and people over 65 are most vulnerable, the flu can have complications or be fatal to people of all ages. Women who are pregnant and people with diabetes and other chronic illnesses are also as vulnerable as children and the elderly. Fortunately, with vaccination, many people can be spared the misery associated with this disease, and vaccination is recommended for all ages.
How long is the flu season and when will it peak? Flu afflicts people worldwide year-round, but is most prevalent in locations during winter seasons. This means if you are travelling to southern hemisphere countries during their winter months, you will find yourself in the middle of peak flu season there. Our season peaks between December and the end of February.