Flu season is quickly approaching. We want you to be armed with information to help you understand the history of influenza, how it spreads, and what to watch for.
A Global Pandemic
Just over 100 years ago, at the start of 1918, the mother of all influenza pandemics broke out. Killing between 50 and 100 million people, it was the deadliest in history. Though it’s called the Spanish flu, epidemiologists don’t actually know where it originated.
Regardless of where the Spanish flu began, trade routes and war quickly spread the disease far and wide. In fact, the disease spread with such veracity, some speculated the Spanish flu was a form of biological warfare. When coupled with the stark reality of the time, that fear is easy to understand. In 1918, the Spanish flu infected an estimated 500 million people, or nearly a third of the world’s population. Of those afflicted, between 20 and 50 million lost their lives. An unprecedented number of which were 20 to 40 year olds, the age group which is usually the least vulnerable.
Influenza is a Clever Bug
Let’s talk about how influenza works. First off, it comes in four subtypes: A, B C and D, and of those four, influenza A is the culprit behind most pandemics. Every infectious pathogen takes a unique form, and in turn the immune system creates a very specific antibody to fight it off. Our immunity depends on the ability to recognize previous contagions. Unfortunately for us, that’s exactly why influenza has evolved to mutate so quickly.
While it’s a masterful shapeshifter, typically the flu only changes a little at a time. These slight mutations are called antigenic drifts. Following an antigenic drift, the immune system still recognizes a specific flu strain well enough to create the right antibodies. Sometimes, for reasons science still can’t identify or understand, influenza undergoes a major change. This is called an antigenic shift, and it changes the virus so much it becomes completely unrecognizable to the immune system. This lack of immunity leaves us very vulnerable, allowing pandemics to occur.
This is why so many young people died in 1918. As children, they were infected by the Russian flu (likely an H3N8 variant), which was the dominant strain of influenza at the time. This means their bodies recognized, and had antibodies for, H3N8. Then, in their early adulthood, there was a sudden antigenic shift, and the Spanish flu (or H1N1) became the new dominant strain. Young people had never been exposed to H1N1 before, so their bodies didn’t recognize it, and the antibodies they had for H3N8 were mostly useless against the new dominant strain. Some immune systems weren’t able to adapt quickly enough, and those people perished.
Getting a Flu Shot Matters
The earth has two hemispheres, each with their own winter. Due to this fact, the planet endures a flu season twice a year. In the northern hemisphere, flu season peaks December through February, and in the southern hemisphere it’s May through July. Because most viral mutations are small, the influenza strains that are dominant during one hemisphere’s flu season will likely be the same as (or very similar to) the dominant strains that will go on to infect the opposite hemisphere during its flu season.
Sometimes influenza strains mutate more than expected, and the vaccines aren’t as effective, but that doesn’t mean you shouldn’t take getting a yearly flu vaccine seriously. Science and medicine are constantly striving toward ever-better solutions. In recent news, researchers discovered an antibody called M-001, which works by targeting small segments of protein inside the influenza virus that never change despite frequent mutation. This promising new vaccine could potentially ward off all strains of influenza and is currently making its way through clinical trials.
It’s also important to remember that not everyone can receive a flu shot. Some people are too vulnerable to be exposed to even the trace amounts of virus inside a vaccine. So, it’s up to us, as a community, to protect those people with a thing called herd immunity. Herd immunity is based on individual immunity. When someone falls ill with a virus and survives, they can’t get infected by that virus again, unless it mutates significantly. If enough people have individual immunity, then a virus loses its mobility. Unable to spread from person to person, the virus can no longer penetrate the herd, thereby protecting the handful within a population who haven’t been vaccinated for one reason or another.
What to Do If You Get the Flu
Know if you have any risk factors that could interfere with your ability to fight the flu. The CDC lists the following as factors that could “increase the likelihood of developing serious flu-related complications.”
People 65 years of age or older
Those living with chronic medical conditions
Children under 5, but especially those younger than 2
If you find yourself ill with the flu, and you don’t have any risk factors, please stay home and take good care of yourself. Get lots of rest, stay hydrated, and treat any pain or fever. Humidifiers and steam can help alleviate congested breathing. Typically you are sick with the flu for about five days.
If you have risk factors mentioned previously and influenza, it’s important to see your doctor. Your primary care provider may decide it’s appropriate to give you an antiviral that can lessen the impact and longevity of your illness.