It's the worst.
Okay, maybe not the literal worst, but it's still pretty terrible. And it can really derail you this time of year. Like many things, prevention is the best option, but sometimes we just can't avoid it.
First off, is it really the flu? In the early stages it might be difficult to know if it's really the flu and not just a cold. This link from the Cleveland Clinic gives some clues. If it's a cold, there's not much to do except stay hydrated, rest, and wait it out. Antibiotics won't help, and could make the problem worse later on. If it is the flu, there are some treatments that might help shorten the duration, but time is of the essence. Many of those treatments are only effective if they are taken within the first couple of days of the onset of symptoms. Otherwise, you can treat the symptoms to try to stay comfortable. If you are prescribed any medications or decide to use over the counter things to treat symptoms, check out this link from the National Center for Voice and Speech, which lists many types of herbs, vitamins, prescriptions, and over the counter medications and their known vocal side effects. If your drug has some known side effects, you might be able to request another drug, or you can take action to reduce your risk for those side effects. Ask your doctor or pharmacist for info. Then, go home, rest, stay hydrated, and binge watch some Great British Baking Show until you're feeling better. And please, STAY HOME! Please be kind to your neighbors and keep the bugs to yourself.
To prevent catching or spreading the flu, wash your hands often with actual soap (sing the alphabet through in your head twice to make sure you do it long enough), get enough sleep, eat good food, and regularly clean off surfaces that get touched often, like doorknobs, cell phones, and steering wheels. Consider carrying your own pen instead of borrowing the one at the bank. The fewer things you can touch, the better.
Of course, preventing all kinds of illnesses follows the same kind of guidelines, so making these prevention practices a part of your daily life can go a long way to keeping you healthy. In addition, some things you can try include removing your shoes before you walk into your house, covering coughs and sneezes with your elbow instead of your hands, and make preventative visits to your primary health care person.
If you do catch the flu, give your voice a bit of extra time to heal, even after your body is feeling better. Many people have a lot of coughing and drainage with the flu, and that can really irritate the vocal tissues. Drink some extra water, do gentle vocal exercises, and limit your phonation time. If you find that your voice is still not back to normal after a couple of weeks, seek out a voice professional for some advice.