It’s almost impossible to get through the winter without hearing about the flu. While we often use the word flu to describe any miserable feverish head cold, a cold (rhinovirus) is NOT the same as the flu (influenza). A head cold is 10 days of misery. Flu will disable you for weeks, if not outright kill you.

Flu shots are a government conspiracy. I got the shot and still got the flu.

Preventing death and permanent disability is not a conspiracy. Complications of a cold include sinus and ear infections, asthma, or rarely pneumonia. The most common complication of the flu is pneumonia – the #4 killer world-wide, but can also leave you with organ damage or failure,  encephalitis, and even sepsis. If you get the flu shot and then feel lousy, it’s not flu; it’s your body charging up its antibodies. If you get a flu shot and then get a cold, it’s not the flu. Recombinant flu vaccines don’t even contain flu. CAN you get the flu after getting a flu shot? Of course you can, the same way you seem to get the same cold every year. Here’s why:

Is there more than one type of flu?

There are actually three flu viruses, A, B, and C. A is common, B less so, C mild and rare. Each type has two parts: the hemaglutinin protein (the H) and an enzyme to let it reproduce (the N, for neuraminidase). There are 18 types of H’s and 11 types of N’s – thousands of combinations of H1N1’s, H2N3’s, H6N4’s. Now, not all of these can be caught by people (some are limited to animals), but viruses can mutate and change very rapidly. With all those combinations, the Centers for Disease Control have to make a best guess at what flu will prevail that winter, and make enough vaccine a year in advance. If your shot is for N1H1, and you catch H2N3 – you’ve got flu. Better flu shots (called trivalent or quadravalent) will give you immunity to the top three or four likely flus, quadrupling your chances of staying healthy. Even if you do manage to get a flu, your partial immunity will give you a much milder case.

What are the odds I will get the flu?

What are your chances? In the winter of 2016-17, more than 2500 Connecticut residents showed up at the Emergency Department for flu-like illnesses. 80% of those were type A, and of those , 98% of them were of the H3N2 variety (the others were the old H1N1). Sixty-five of them died. That’s not a total of reported cases; that’s just how many wound up hospitalized. If you have diabetes, heart problems, take immune suppressors, pregnant, sickle cell disease, cancer treatment, are over 65 or under 2, you are considered high risk. If someone in your family or workplace fits these categories, you are placing them at risk.

Now, of course, some years are worse for flu than others. The biggie was 1918, when the H1N1 (yes, that same one you’re getting vaccinated for right now) had a new mutation to a form no one had ever had before, and it became a world-wide pandemic for two years, killing as many as 50 million people. Fifty. 5-0. Million. The next major flu was 1957 Asian flu (H2N2), which killed two million people. The 1968 Hong Kong flu (H3N2) killed more than a million. That’s not counting disabled, or lost 30 days from work, or sick as a dog. That’s the number dead.

Why do so many flus start in Asia?

Many flu strains are animal-only. They’re limited to birds, or horses, or pigs. In Asia, people, chickens, and pigs are often living in close or crowded conditions, and many Asian cities are very densely populated. Pigs are very similar to people in their genetic makeup (surgeons can use pig organs in people for short times). A bird flu can mutate and jump to pigs, and from pigs it doesn’t take a lot of mutation to become a Human flu. This is why scientists worry every time there’s a breakout of swine flu or bird flu, and millions of animals may be slaughtered to keep it from spreading. All it takes is a new mutation to start a mega-deadly 1918-style pandemic.

Should everyone get a flu shot?

So who should NOT get a flu shot? Check with your doctor first if you’ve got Guillain-Barre Syndrome, if you have immune disorders such as HIV, children on aspirin therapy, severe egg allergies, people with certain metabolic disorders, if you have kidney disease or severe respiratory issues. Sometimes it’s worth the risk, sometimes it’s not, depending on the year.

Washing your hands constantly remains the next-best flu preventative. And while you’re avoiding the flu, or perhaps recovering from it, check out these really awesome books on the flu (I’ve read them!) – and some excellent (scary) novels on flu (check for movie versions, too!) :