Dr. Toshi Is In! "COVID-19 is still going strong, but will we have a regular flu season this fall and winter, too?"

Dear Dr. Toshi,  

COVID-19 is still going strong, but will we have a regular flu season this fall and winter, too?

Yes, we will have a season of influenza (the flu) again, just like any other year. Unfortunately, having COVID-19 is a different virus, so it doesn't make our regular flu season go away.

COVID-19 is caused by a virus called SARS-CoV-2, while the seasonal flu is caused by any of several types of influenza (flu) viruses. You might have heard your doctor mention "Influenza A" and "Influenza B" before. Flu vaccines usually immunize you against three or four types of Influenza A and B viruses. Every year, American scientists and doctors of Infectious Disease who study influenza make an educated guess about which viruses are most likely to hit us in the coming flu season, and then we develop and manufacture the vaccine to immunize us against those viruses, and that process usually takes several months.

According to the CDC (the Centers for Disease Control and Prevention, which is part of the US government), the flu kills 12,000 to 56,000 Americans every year. That may not seem like many people compared to how many people were killed by COVID-19, so you might think the flu isn't as bad. You might also think that the flu season is, well, seasonal. It usually peaks between December and February (although the flu season is longer than that). But remember: SARS-CoV-2 and influenza viruses are different kinds of viruses, so they can invade your body at the same time! Unfortunately, viruses don't care about our well-being!

It already sounds bad to have COVID-19 AND influenza at the same time.

But here's another fact: sometimes there are completely new types of Influenza A viruses that have never been seen on Earth before. If one of them spreads widely enough, and if it's severe enough, it can become a pandemic, which is much worse than the seasonal flu. A pandemic is when a disease spreads worldwide, resulting in many people becoming very sick. A large number of those people also die. COVID-19 is a pandemic.

There have been 4 influenza pandemics during the last 120 years. The famous 1918 Flu (sometimes called the "Spanish Flu") is one, but there was another one in 1957, another in 1968, and, most recently, there was the H1N1 pandemic in 2009! Thankfully, pandemics are fairly rare. But the bad thing is that we don't know another one is coming until it actually happens. Health organizations such as the CDC and WHO (World Health Organization) are always watching for potential pandemics in order to try to contain them before they begin, but like in the case of COVID-19, their efforts are sometimes unsuccessful.

So, protection becomes very important on our part whenever it's available. You might have seen the news saying that some drug stores have already started to get influenza vaccines from manufacturers this year. But the CDC is still recommending that people get immunized in September or October, just like they recommend every year. Influenza vaccines only protect you for a few months, so you want to make sure you're well covered during the peak season (December to February). At the same time, you don't want to delay getting one, because it takes about two weeks for your immune system to make antibodies against the viruses after you're vaccinated.

Recently you may have been hearing the phrase, "herd immunity." Herd immunity is when people who haven't been vaccinated against a disease (like the flu) are protected against it because most of the other people in their community are immune to it, either because they were vaccinated or they actually had the disease and recovered. Either way, those community members have been immunized against it and don't get sick, and that protects those who don't get vaccinated. So, the "herd" of community members who don't get sick are protecting those who don't get vaccinated. There are some people who may not be able to get certain vaccinations due to their age or health conditions, so herd immunity is important for them. Vaccines can provide heard immunity if enough people are vaccinated. Some American Infectious Disease scientists estimate that up to 70% of the population (more than 200 million Americans) would have to get COVID-19 and recover from it for us to have herd immunity against COVID-19 here in the US! As for influenza, the percentage varies every year, but some studies have shown that at least 80% of healthy people (and 90% of high-risk people) should be vaccinated to achieve herd immunity. Last year, I did a small study and found out that only about 40% of people get the flu shot in our community, so we don't have herd immunity against the flu, which is why so many people here get the flu every year.

According to the Johns Hopkins Coronavirus Resource Center, as of August 25, 2020, the U.S. has had a total of 5,764,304 confirmed cases of COVID-19 and 178,065 deaths directly caused by COVID-19. Scientists around the world have started testing vaccines for it, but creating a vaccine for any disease is a very complicated process, so we don't have one yet, unfortunately.

So, currently in the U.S., less than 6 million people may be immune, and of course that's far less than the 200 million required for herd immunity. Until we have a vaccine, we can't safely develop herd immunity against COVID-19. And we definitely don't want to get COVID-19 with influenza on top of it. I can't imagine how terrible it would be to be sick with both! So, all the experts have been emphasizing the importance of flu shots, especially this year more than any year, and they are manufacturing more than usual to cover us.

So, I definitely recommend getting your flu shot this fall! This is one simple, effective way to help protect yourself and the people you care about!

Dr. Toshiko (Toshi) Luckow, MD is a Family Medicine physician at the West River Health Services hospital and clinics.