Seasonal Flu Vaccination Is Vital for Employees During the COVID-19 Pandemic

Michelle Hopkins

The economic burden of seasonal flu is an estimated $11.2 billion annually, including 20.1 million lost workdays.1 Supporting employee health has always been the motivation behind employer-sponsored seasonal flu (flu) vaccination campaigns and working with an occupational health expert like Concentra®. This year, with the lingering COVID-19 pandemic already a major challenge to workforces and business continuity, there is greater urgency for promoting flu vaccination programs to try to keep influenza infections low.

Vaccination stimulates the immune system against a vaccine-preventable disease like the flu. Getting a flu vaccine is the most recommended step to help avoid the flu. When many employees get a flu shot, it may help protect everyone vis-à-vis a concept called “herd immunity.” This means, even if a few employees don’t get a flu shot, they may be less likely to get the flu; vaccination of a majority of others at the same location reduces the likelihood of “community spread” of the flu virus.

Flu vaccine at Concentra, while supplies last

Concentra utilizes the Flucelvax Quadrivalent flu vaccine2, which protects against four strains of the flu virus. This vaccine is produced through cell-based technology and has the potential to offer better protection than other flu vaccines that are egg-based.3 Concentra medical centers will have the flu vaccine as long as supplies last. This aligns with the recommendation from the Centers for Disease Control and Prevention (CDC), which said:

“Getting vaccinated in July or August is too early, especially for older people, because of the likelihood of reduced protection against flu infection later in the flu season. September and October are good times to get vaccinated. However, as long as flu viruses are circulating, vaccination should continue, even in January or later.”4

The question everyone is asking

Mention flu shots in your next team meeting and you can bet dollars to donuts that someone will ask, “Will getting the flu shot help protect me from COVID-19?”

The official answer from the CDC is no, the flu shot will not help protect you from COVID-19.5 Wonder why? While it’s true that seasonal flu and COVID-19 are both contagious respiratory illnesses, the flu shot is designed to help protect against the two main types of influenza viruses, A and B viruses. COVID-19 is caused by infection with the coronavirus, a new virus also called SARS-CoV-2, which is different than the influenza viruses.

Should an employee suspected or confirmed with COVID-19 get a flu shot?

This is, perhaps, the second most common question you’re likely to hear. The CDC recommends people suspected or confirmed with COVID-19 (whether showing symptoms or not) postpone getting a flu shot “until they have met the criteria to discontinue isolation.”6

Is it COVID-19 or is it the flu?

The third question that rounds out the trifecta of top questions about flu during the COVID-19 pandemic – and one you will likely ask if an employee calls in sick this fall and winter – is “Is it COVID-19 or the flu?” There are similarities and differences between COVID-19 and the flu, so the best advice is to familiarize yourself and your employees with the comparisons below. This information is from the CDC.7

Signs and Symptoms

With both COVID-19 and flu, adults may experience fevers (with or without chills), cough, shortness of breath, sore throat, fatigue, runny or stuffy nose, muscle pain or body aches, headache, and sometimes vomiting or diarrhea.

COVID-19 also may be associated with loss of smell or taste.

Period from Infection to Showing Symptoms

It may take longer for symptoms to appear with COVID-19 than with the flu. With COVID-19, the time from infection to first symptoms may be anywhere from two days to 14 days.

Flu symptoms generally appear one to four days after infection.

Period of Contagiousness

We are still learning about COVID-19 but it’s believed a person can spread the virus from two days before symptoms appear to 10 days after symptoms first appeared or until 10 days after testing, if the employee was asymptomatic when tested and has remained without symptoms. A longer period of infectiousness may occur for people who are severely immunocompromised or hospitalized with severe COVID-19.

With flu, an adult may be contagious from one day before showing symptoms for about seven days after symptoms appear.

How the virus spreads

COVID-19 and flu spread among people in close proximity, mainly through droplets produced by speaking, coughing, and sneezing. The virus that causes COVID-19 appears able to “quickly and easily spread to a lot of people and result in continuous spreading among people as time progresses,” according to the CDC.


Flu and COVID-19 can both potentially result in a long list of complications: pneumonia, respiratory failure, acute respiratory distress syndrome, heart attack and stroke, multiple organ failure, worsening chronic medical conditions, inflammation of the heart, brain, or muscle tissues, and secondary bacterial infections.

COVID-19 also may lead to blood clots in the veins and arteries of the lung, heart, legs, and brain. Again, there is much about COVID-19 that we still do not know.

A COVID-19 RNA test is the best way to determine if an employee has the coronavirus and not the flu. Contact Concentra about COVID-19 RNA testing at Concentra medical centers.

It is possible to have the flu and COVID-19 or other respiratory illnesses at the same time.8 Health officials do not yet know the likelihood of having both viruses simultaneously.

Concentra has protocols in place that follow all official guidelines to safeguard employees from COVID-19 when they come into a Concentra medical center to get a flu shot (or for any other health service).

Benefits of the flu vaccine

With any virus – seasonal flu or COVID-19 – there is a tendency to focus on the number of infections, hospitalizations, and deaths. But thanks to the development of the flu vaccine, there are other important statistics to celebrate each flu season: the numbers of flu cases, hospitalizations, and deaths prevented by the flu shot. For example, at the end of 2019, the CDC updated calculations for the 2017-2018 flu season.

“Flu vaccination prevented an estimated 6.2 million influenza illnesses, 3.2 million influenza-associated medical visits, 91,000 influenza-associated hospitalizations and 5,700 influenza-associated deaths,” said the CDC. “The flu vaccine has been shown to reduce the risk of having to go to the doctor (with the flu) by 40 to 60 percent.”9

Talk to your employees about this fact: Getting a flu shot will reduce the probability your employees will need to seek medical care for a flu-like illness; this is advantageous because seeking medical care may possibly increase their exposure to COVID-19. This is why getting a flu shot is especially important during a pandemic.

The CDC also says the flu shot is especially important for employees with chronic heart and lung conditions, as well as diabetes, because it can help reduce any worsening and hospitalization for these conditions.10

Effectiveness of the flu vaccine

Imagine how difficult it would be to predict the season outcome of your favorite sports team if the roster of players continually changed. This is not so different than deciding the composition of a flu vaccine weeks before the flu season begins and with viruses that are continually changing.

Surveillance data and forecasts are used to determine vaccine production. More than 100 national influenza centers in more than 100 countries are involved. The Food and Drug Administration makes the final decision about vaccine viruses for influenza vaccines sold in the United States.11 Before and after the final determination is made for the upcoming flu season, flu viruses continually change. “Antigenic drift” is a phrase that describes a gradual change, seen in both influenza A and influenza B viruses, and “antigenic shift” is an abrupt, major change that occurs in A viruses.12 An example would be when a virus jumps from animal populations to people (such as in the 2009 “swine flu” pandemic).

A flu vaccine can continue to be effective when small changes occur in the flu viruses’ surface proteins/antigens but the virus is still recognized by the immune system. When the changes are such that the immune system no longer recognizes the virus, an individual may get the flu again or get the flu after getting the vaccine (leading to the myth that the flu shot gave the individual the flu).

Given influenza viruses’ continual changes, it should come as no surprise that 15 years of CDC calculations show that the effectiveness of the seasonal flu vaccine has ranged from a low of 10 percent in 2004-2005 to a high of 60 percent in 2010-2011.13 The interim estimate for the 2019-2020 season is that the flu vaccine was 45 percent effective overall.14 Most people buy insurance for their homes or vehicles when the odds of a vehicle accident or house fire may be very low. Getting a flu shot – even when its effectiveness is not 100 percent – is still the best “insurance” to stay well.

Protecting your employees as best you can

Influenza may be viewed as commonplace and no more threatening than the common cold but that’s not a sound conclusion. Health officials cannot predict from year-to-year how serious the seasonal flu will be and which age groups will be most affected. For example, the 2017-2018 flu season, with 45 million cases reported, had the highest hospitalization rate since the 2009 pandemic and the highest infection rate across all age groups since 2005. The 2019-2020 flu season had potentially the lowest rate of hospitalization since 2015-2016. In 2015-2016, the flu season started later and peaked later than in any of the three prior years. 15 The takeaway is this: No one can predict the extent and severity of the flu season. Best to be prepared by getting flu shots for your entire workforce.

When employees get the flu, they cannot – and should not – report to work. This means a severe and widespread influenza season may create a substantial burden on businesses to find replacement workforce. Productivity could take a hit while work responsibilities are shifted over to healthy employees or replacement staff.

Let Concentra prepare your employees for flu season

You can keep your workforce healthier this flu season by sending your employees to Concentra medical centers beginning in September for the cell-based Flucelvax Quadrivalent flu vaccine. The flu vaccine is also provided for the workforces of employers with Concentra onsite clinics and, when possible, through episodic workplace health events. Contact Concentra to make plans for your seasonal flu vaccination program.

1 Putri Wayan CWS, Muscatello DJ, Stockwell MS, Newall AT. Economic burden of seasonal influenza in the United States. Vaccine. June 2018; 36(27); 3960-3966. 
2 Flucelvax Quadrivalent Influenza Vaccine. Food and Drug Administration (FDA).
3 Cell-based Flu Vaccines. Centers for Disease Control and Prevention.
4 Centers for Disease Control and Prevention. Frequently Asked Influenza (Flu) Questions: 2020-2021 Season.   
5 ICenters for Disease Control and Prevention. Frequently Asked Influenza (Flu) Questions: 2020-2021 Season.
6 ICenters for Disease Control and Prevention. Frequently Asked Influenza (Flu) Questions: 2020-2021 Season.
7 Similarities and Differences between Flu and COVID-19. Centers for Disease Control and Prevention. Reviewed July 10, 2020.
8 Centers for Disease Control and Prevention. Frequently Asked Influenza (Flu) Questions: 2020-2021 Season.
9 What are the benefits of flu vaccination. Centers for Disease Control and Prevention. Reviewed December 3, 2019.
10 What are the benefits of flu vaccination. Centers for Disease Control and Prevention. Reviewed December 3, 2019.
11 Selecting Viruses for the Seasonal Influenza Vaccine, Centers for Disease Control and Prevention. Reviewed September 4, 2018.
12 How the Flu Virus Can Change: “Drift” and “Shift”. Centers for Disease Control and Prevention. Last reviewed October 15, 2019. 
13 Past Season Vaccine Effectiveness Estimates. Centers for Disease Control and Prevention. Last reviewed January 29, 2020.
14 Interim Estimates of 2019-2020 Seasonal Influenza Vaccine Effectiveness – United States, February 2020. February 21, 2020 Morbidity and Mortality Weekly Report. Centers for Disease Control and Prevention.
15 Past Seasons Estimated Influenza Disease Burden. Centers for Disease Control and Prevention. Last reviewed January 9, 2020.