Flu season is far from over. The winter months are peak time for flu activity, typically from December through February, with continued activity through April or May, according to the Centers for Disease Control and Prevention (CDC). As of February 1, 2020, up to 31 million people have become sick and 12,000 to 30,000 people have died of the flu. Health experts say current circulating strains of the flu include A, B, C, and D, but the most predominant strain, B, could lead to severe cases, especially in children and the elderly—even if they’re already vaccinated. (Here’s more information on whether it’s too late to get a flu shot.)
Two highly dominant flu strains
For the 2019-2020 flu season, not one but two strains of influenza have been highly prevalent: influenza A and influenza B. Doctors encourage patients to receive a flu vaccine because, as James Wantuck, MD, a San Francisco-based physician, chief medical officer and co-founder of the telehealth urgent care provider PlushCare points out, the vaccine always protects against at least one strain of flu type B in addition to two strains of flu type A.
“Flu B has been more predominant in the early flu season this year,” says Dr. Wantuck. “As is also typical, because there are two strains circulating, you can get the flu twice. This means you should be cautious even if you’ve already been sick once, and it’s also a reminder that it’s never too late to get the vaccine.” (Check out these flu “myths” that are actually true.)
“According to the CDC, so far this year about 24 out of every 100,000 people in the US have had the flu,” says Dr. Wantuck. “To date, more than 60 percent of cases have been from flu B.”
However, these numbers are always in flux as flu season moves along. Richard J. Webby, PhD, infectious disease expert at Jude Children’s Research Hospital in Memphis, says most of the activity he’s seen this year has revolved around the flu type B virus, but in the last few weeks, there has been a notable uptick in flu type A (H1N1). Webby now sees the landscape as more of a 50/50 split between the two strains. (This is why it’s time to take the flu seriously.)
If you’re curious about what separates these strains, it boils down to A, B, and C viruses which are classified by the way in which their proteins are composed, according to the World Health Organization.
Flu type A vs. flu type B: What’s the difference?
Symptom-wise, how do you know if you have flu type A or flu type B? You may not, as our health experts say the two are mostly indistinguishable.
“The symptoms of influenza are commonly felt in a progression and begin with a sneeze, sore throat, fever, delirium, and then chest congestion,” explains Michael Hall, MD, a family medicine physician at Hall Longevity Clinic in Miami Beach. “With an incubation period of around five to seven days, the respiratory system is the target of the virus.”
Dr. Hall says the symptoms can come fast, leaving you feverish and with body aches that emerge within a few hours of developing a sore throat.
“It is not uncommon to have a fever of 104 degrees Fahrenheit and to feel like you have been hit by a train, feeling completely zapped and bed bound for days,” he says. “Most of the symptoms end within a week or so, but the chest congestion and cough can last up to a month or longer.”
A 2014 study published in the journal Clinical Infectious Diseases found adults who developed flu type A or B had a similar duration of hospital stays and rates of death and intensive care admission. While flu type B has been thought to be milder than flu type A, a 2016 study, published in the journal Pediatrics, found it poses a significant disease burden, specifically in children. In the study, the researchers found flu type B led to more deaths than flu type A among children who were hospitalized due to the flu. Healthy children hospitalized with flu type B, those 10 years and older, had a higher risk of being admitted to the intensive care unit. (If you avoid shots in general, here’s how to make the flu shot hurt less.)
FotoDuets/Getty ImagesFlu type B, children, and the elderly
Children and the elderly tend to bear the brunt of influenza B. Webby admits that the reason why is not completely known, but there is a theory that makes a great deal of sense.
“The influenza B virus doesn’t change as much as the influenza A,” says Webby. “It helps people build up immunity to the B virus a bit over a lifetime. As the virus doesn’t change as much you can build up quite a bit of immunity to that as a healthy adult. But that’s probably not the whole story.”
While the elderly may have been healthy as younger adults, the immune system begins to weaken around age 65, according to Medline Plus, which means the body becomes more susceptible to getting sick. For example, flu shots or other vaccines may not work the same in regards to protection or duration.
How to cope with the flu
Regardless of whether you have influenza A or B, doctors recommend the same treatment for both.
“Besides prescription antivirals, I would recommend plenty of rest and drinking lots of fluids,” says Dr. Wantuck. “When you are sick, you lose a lot of body water more quickly because you are breathing, sweating, and secreting it out. Ibuprofen or other over the counter anti-inflammatories are also a good measure, as they can reduce the inflammation making you feel so miserable.”
In terms of medication, he encourages patients to get on an antiviral, like Tamiflu, Xofluza, or Relenza, as soon as possible.
“These drugs can shorten your time being sick and the quicker you take them the more powerful their effect,” says Dr. Wantuck. “You can even get a prescription online via an online doctor like PlushCare, which can help you get medication fast.”
The CDC recommends antiviral medication for anyone who has been hospitalized for flu, is at high risk of complications, or has “severe, progressive, or complicated illness.” (Here’s everything you need to fight the flu at home.)
How to prevent the flu
You may hear friends or family proudly announce they’ve never had a flu shot in their adult life and haven’t gotten the flu, but if that’s true, it’s a lot of luck on their part. Dr. Wantuck says the vaccine is the best line of defense against the virus, even if it only offers partial protection and even if you’re getting it later in the flu season.
“Some protection is always better than none,” he says.
Dr. Wantuck also explains that hand washing is the most effective method to prevent you from getting sick.
“Personally, I advise patients they should wash their hands at least 10 times a day,” he says. “This sounds like a lot, and it is. If you count every time you eat and use the bathroom in a day, you are almost to 10 before you throw in a few extra for good measure.”