Is anyone surprised that some folks are already talking about a coming twindemic, or the possibility of getting hit with both a COVID-19 and influenza pandemic at the same time?
What is a Twindemic?
First things first though.
It is very important to remember that flu epidemics are routine. They happen every single year. On the other hand, flu pandemics are very rare. In fact, there have only been five influenza pandemics, including the well known 1918 Spanish flu pandemic and the 2009 swine flu pandemic.
So the twindemic, if it happens, almost certainly won’t be twin-pandemics.
What else could a twindemic look like?
“Pandemic refers to an epidemic that has spread over several countries or continents, usually affecting a large number of people.”
Lesson 1: Introduction to Epidemiology
How about a continued COVID-19 pandemic with a flu epidemic?
As you can imagine, even that would cause a lot of problems, as both cause life-threatening disease, and they share many of the same symptoms.
In addition to the confusion of not knowing if someone has flu or COVID-19, what happens if someone gets both, or gets one while recovering from the other? Or if a health system already overburdened with COVID-19 patients has to suddenly start caring for a lot of sick people with the flu?
What Happened to Last Year’s Flu Season?
But don’t we already know what will happen? After all, we first started to see SARS-CoV-2 infections during last year’s flu season.
A flu season that started early, and ended as one of the deadliest, with 188 pediatric flu deaths.
A flu season that was ending as COVID-19 cases started to peak.
Which brings up an interesting question… Did all of the social distancing and mask wearing that we did to combat the SARS-CoV-2 virus also help put an end to last year’s flu season?
“Intuitively, it makes sense that wearing masks, social distancing, working from home, closing schools, and other strategies to minimize the spread of COVID-19 would lessen transmission of other respiratory infectious diseases as well.”
What Happens When COVID-19 Collides With Flu Season?
While it may have been ending anyway, there is evidence from other countries that mitigation strategies for COVID-19 can reduce the risk of a bad flu season.
Mitigation strategies like social distancing, mask wearing, and closing schools, etc.
Twindemic – Hype or Hazard
So what about this year’s flu season?
Can we count on everyone wearing masks and social distancing to help us avoid a flu season this year?
Of course not!
For one thing, many of those countries in the Southern Hemisphere that are seeing lower rates of flu because of social distancing, mask wearing, and other COVID-19 mitigation strategies have also been seeing lower rates of COVID-19!
If you are in an area with continued high rates of COVID-19, then you likely shouldn’t count on folks wearing masks or practicing social distancing to keep the flu away.
What can you count on instead?
Getting a flu vaccine!
“Our results suggest a reduction in COVID-19 mortality associated with higher influenza vaccination rates in the elderly population. Specifically, we found that overall, a 10% increase in vaccination coverage was associated on average with a statistically significant 28% decrease in the COVID-19 death rate.”
Zanettini et al on Influenza Vaccination and COVID19 Mortality in the USA
That’s especially important this year, as in addition to the usual benefits of a flu vaccine, several studies have shown a positive effect in relation to COVID-19.
“Influenza vaccination programs might need to adapt and extend the duration of vaccination campaigns to accommodate stay-at-home orders and social distancing strategies aimed at slowing the spread of SARS-CoV-2. These circumstances might necessitate consideration of starting vaccination campaigns earlier (i.e., as soon as vaccine is available, which can be as early as July or August) to allow sufficient time to vaccinate the population and avoid some persons going unvaccinated for influenza. When possible, such considerations should be balanced against the potential waning of protection from influenza vaccination, particularly for persons aged ≥65 years.”
Prevention and Control of Seasonal Influenza with Vaccines: Recommendations of the Advisory Committee on Immunization Practices — United States, 2020–21 Influenza Season
Let’s do everything we can to keep the case counts of both COVID-19 and flu down by social distancing, wearing masks, and getting our flu vaccine.
“Southern Hemisphere countries help “reseed” influenza viruses in the Northern Hemisphere each year, Dr. Jernigan said.”
Fears of a ‘Twindemic’ Recede as Flu Lies Low
Still, if there was no flu in the Southern Hemisphere this year, then hopefully we won’t have a big flu season this year either.
More on This Year’s Flu Season
- When Should I Get My Flu Shot?
- How Long Does It Take for the Flu Vaccine to Start Working?
- What Are the Benefits of the Flu Shot?
- Three Reasons to Skip a Flu Shot This Year
- What Makes the Flu So Deadly?
- Hosting a Flu Clinic During the COVID-19 Pandemic
- Fears of a ‘Twindemic’ Recede as Flu Lies Low
- MMWR – Prevention and Control of Seasonal Influenza with Vaccines: Recommendations of the Advisory Committee on Immunization Practices — United States, 2020–21 Influenza Season
- IAC – Ask the Experts about Flu Vaccines
- Lesson 1: Introduction to Epidemiology
- CDC – 2019-20 Season’s Pediatric Flu Deaths Tie High Mark Set During 2017-18 Season
- Seasonal Influenza Activity During the SARS-CoV-2 Outbreak in Japan
- What Happens When COVID-19 Collides With Flu Season?
- COVID-19 and the next influenza season
- COVID-19: Australia and the United States by the numbers
- Relative disease burdens of COVID-19 and seasonal influenza in New York City, February 1 – April 18, 2020
- Inactivated trivalent influenza vaccine is associated with lower mortality among Covid-19 patients in Brazil
- Influenza Vaccination and COVID19 Mortality in the USA
- How will COVID-19 affect the coming flu season? Scientists struggle for clues
- Fact Check: CDC has not stopped reporting flu deaths, and this season’s numbers are typical
I hope we have better flu vaccine uptake this year. I’m excited about some of the new flu vaccines being tested which have better efficacy and cross coverage, too.