Looks like a rough flu season ahead. Here are answers to ALL your flu questions

Enlarge / Influenza virus. Image produced from an image taken with transmission electron microscopy. Viral diameter ranges from around 80 to 120 nm. (credit: Getty | BSIP)

The 2017-2018 flu season is off to an early start, potentially hitting highs during the end-of-year holidays. Data so far suggests it could be a doozy. The predominant virus currently circulating tends to cause more cases of severe disease and death than other seasonal varieties. And the batch of vaccines for this year have some notable weaknesses.

To help you prepare—or just help you brush up on your flu facts—here are answers to every critical flu question you might ever have (well, hopefully). We’ll start off with the basics…

Table of Contents

• What is the flu?
• Why does flu strike in the winter each year, anyway?
• This is just the seasonal flu we’re talking about. It’s not that big of a deal, right?
• In general, how long is a person sick and contagious?
• Some flu viruses are worse than others, right? So, what are the different types of flu virus and what’s up with all those numbers and letters?
• I hear about the Hs and Ns the most. Why are they so important?
• Cut to the chase: What’s up with this year’s flu season?
• How do experts know what to expect and prepare vaccine in advance?
• How closely does that match with what experts are seeing in the US so far?
• So it sounds like a pretty good match. Shouldn’t this mean that the vaccines will work well?
• How do we make vaccines, and what went wrong with this one?
• Should I even bother getting vaccinated?
• Is one type of vaccine better than the others?
• It’s late in the game—should I still get vaccinated? What if I’m already sick or feel like I’m getting the flu?
• Man, what a pain all this is. Are we ever going to get better vaccines or—dare we ask—a single one that protects against all the possible kinds??

What is the flu?

The flu, or influenza, is a contagious respiratory infection caused by the influenza virus (not to be confused with Haemophilus influenzae, an opportunistic bacterium that can cause secondary infections following sicknesses, such as the flu). Symptoms of the flu include chills, fever, headache, malaise, running nose, sore throat, coughing, tiredness, and muscle aches.