The University of Tennessee, Knoxville.

The Value of Flu Shots during the COVID-19 Pandemic

A Policy Brief by the Howard H. Baker Jr. Center for Public Policy in Partnership with the Coronavirus-19 Outbreak Response Experts (CORE-19)

September 29, 2020
Tennessee State Capitol and Flag
Using publicly available data from emerging research on COVID-19, this brief was written and reviewed by the Coronavirus-19 Outbreak Response Experts (CORE-19) at the University of Tennessee, Knoxville. The brief contains general information regarding the flu vaccine and explains the importance of the flu shot during the COVID-19 pandemic. 
In general, influenza vaccinations, or flu shots, are vital for prevention of seasonal flu, particularly in the elderly and people with health problems. Their importance is even greater during the COVID-19 pandemic. As we begin flu season, there are many questions about the flu vaccine and its relation to the COVID-19 pandemic. 

Essential Information Regarding Influenza

Influenza is a viral infection that affects the respiratory tract, from the nose to the lungs. Infection can be mild, moderate, or severe, and potentially deadly. Symptoms are fever, headache, muscle ache, runny nose, sore throat, cough, fatigue, and shortness of breath (Mayo Clinic). Certain groups are at greater risk for influenza-related complications including adults 65 years or older and those with chronic health conditions (e.g., asthma, heart disease, diabetes) (CDC). 
Flu is transmitted by droplets that are expelled during coughing, sneezing, and talking. The influenza virus is present throughout the year but with a peak of infections occurring from December to February (CDC).  According to the CDC, the approximate burden of influenza infection last year (October 1, 2019 to April 4, 2020) included 39 million – 56 million illnesses, 18 million – 26 million flu-related healthcare visits; 410,000 – 740,000 hospitalizations; and 24,000 – 62,000 deaths. However, the actual burden may be higher than these numbers reflect because influenza is not a reportable disease in most US states (CDC).  

Importance of the Influenza Vaccine

When it comes to influenza, “prevention is better than the cure” due to the possibility of complications and death. While medications are available for the treatment of influenza infection, they are expensive and must be administered 24 to 48 hours from the appearance of symptoms to be effective. Flu infection is stressful to bodies and can be complicated by secondary bacterial infections, which exhaust the body's immune system. The flu shot helps to reduce the risk of serious complications from influenza. And despite the varying effectiveness of vaccines from season to season, they have been shown to significantly reduce flu-related morbidity and mortality. According to two recent studies, the flu vaccine helps decrease the length of a hospital stay and the number of people who need hospitalization (CDC [1], [2]). During the 2018-2019 flu season, about 49% of Americans received the flu vaccine, which helped to prevent an estimated 4.4 million infections, 58,000 hospitalizations, and 3,500 deaths (CDC).   
The flu vaccine is very safe, cannot cause flu, and has generally mild and short-term side effects, if any (CDC). The flu vaccine is recommended for the following groups (CDC), with priority groups during times of vaccine shortage indicated: 
Age: all people, ages 6 months or older
  • Priority: children from 6 months up to 5 years old; adults aged 50 years and older; and children under 18 years of age taking aspirin or salicylate-containing medications
Pregnancy: pregnant females are more likely to develop complications in the 2nd and 3rd trimesters
  • Priority: women who will be pregnant or up to two weeks post-partum during flu season
Chronic health conditions: conditions that weaken the immune system can lead to complications, such as diabetes, chronic kidney disease, HIV/AIDS, cancer and chemotherapy, organ transplantation and medications to prevent organ rejection, autoimmune disease, immune suppressive medications, IV drug abuse, excessive alcohol use, and tobacco smoking
  • Priority: people with body mass index (BMI) 40 or greater (extreme obesity); people with specific chronic diseases of the pulmonary, cardiovascular, renal, hepatic, neurologic, hematologic, or metabolic systems; and people with HIV infection or other immunosuppressive conditions 
Residential and occupational considerations: jobs or living situations can place people at higher risk of infection or put them in contact with high-risk individuals
  • Priority: healthcare workers; household contacts and caregivers of high-risk individuals; and residents of nursing homes or long-term care facilities 
Only children under 6 months of age or those with
life-threatening allergies to the flu vaccine or its components should avoid vaccination.
The flu vaccine helps the immune system form antibodies that protect people against infection. Antibodies are formed two weeks after vaccination, so it is recommended to get the flu shot in September and October before the flu season begins in the US. The flu vaccine is recommended annually because influenza viruses change every year. Viruses change their structures and new viruses circulate, making the previous season’s vaccine less effective. New vaccines are developed each year against the types of flu viruses expected to be circulating. Flu vaccine types include inactivated flu vaccine, recombinant flu vaccine, and live attenuated flu vaccine. For more information about different types of vaccines, visit the CDC webpage on the flu shot. However, primary care physicians and other healthcare professionals are the best advisors on which type is suitable for your age and health condition.  

COVID-19 and Influenza Co-Infection

Both COVID-19 and influenza are contagious infections (American Society for Microbiology). They are transmitted via respiratory droplets, which are produced with coughing, sneezing, and talking. Both COVID-19 and influenza cause fever, cough, shortness of breath, fatigue, sore throat, runny nose, body aches, vomiting, and diarrhea. COVID -19 additionally may cause loss of taste and smell. Both COVID-19 and flu may cause serious illnesses such as pneumonia, respiratory failure, heart attack, stroke, multiple organ failure, and even death. However, each virus has different receptors required to enter the body, leaving people at risk for co-infection with influenza and COVID-19.
Co-infections may be difficult to identify, because if a patient tests positive for one they may not be tested for the other. Fortunately, tests for the diagnosis of co-infection with COVID-19 and influenza are available now. The FDA provided an emergency use authorization (EUA) for three tests to simultaneously diagnose COVID-19 and flu. These three tests are:
Health Impacts
The health impacts of co-infection are not yet clear. There is little available information about the impacts of co-infection on disease severity. One study in mice found that respiratory virus co-infection may reduce disease severity and alter the respiratory tract's pathological effect (National Library of Medicine). However, a recent study examined COVID-19 and influenza co-infection in humans in Wuhan, China, and found that co-infected patients were at greater risk for poor health outcomes (i.e., severe disease, complications, or death) (Journal of Medical Virology).  We do not currently have enough data on COVID-19 and the dynamics of co-infection. However, we do know certain people are at greater risk for severe complications or death from both viruses individually. Therefore, the potential for serious outcomes with co-infection increases the importance of flu shots.

COVID-19 and Flu Safety Guidelines

COVID-19 and Influenza "Twindemic" 

It is more important than ever to get the flu vaccine. Scientists expect that the 2nd wave of COVID-19 will occur this winter simultaneously with the peak of flu season, creating a concurrent influenza and COVID-19 epidemic situation or “Twindemic”. Such a situation will be stressful by further exhausting already taxed healthcare facilities and have additional negative impacts on the economy due to employee absenteeism and reductions in productivity.
The similarity of symptoms between COVID-19 and influenza is confusing for people and requires them to seek medical care and testing even with few symptoms. This rush to seek medical care drains resources from healthcare facilities which are already depleted due to the COVID-19 pandemic response. Having more people vaccinated for influenza will help to reduce this burden on medical personnel and facilities.  
A major hurdle to increasing flu vaccine coverage during this pandemic is limited access to or opportunity for vaccination. In fact, the US has seen an overall decline in all childhood vaccinations as a result of this pandemic (CDC). Routine healthcare visits have declined, and other opportunities for vaccination, like businesses, school-located vaccine clinics, and colleges/universities, have been eliminated as jobs and education have moved online. Alternative outreach locations, like pharmacies, are needed to ensure sufficient vaccine coverage in the US (Journal of the American Medical Association).
Fortunately, data emerging from the Southern Hemisphere suggests that influenza season in the US could be fairly mild this year. Lower than expected cases were reported, despite usual or even increased testing for flu in these countries (WHO). This may be a result of the COVID-19 prevention measures in place around the world (i.e., restricted travel, social distancing, use of face masks, increased hand washing and sanitizing, etc.). 
However, we should not let this information make us complacent – we need to continue to use these prevention measures and get vaccinated to ensure that flu season in the Northern Hemisphere is equally as mild.

Preventing the "Twindemic"

We all need to work together to mitigate the impacts of a possible “Twindemic” situation. Nationwide, colleges and universities are requiring flu shots for all workers and students this year, including the University of Tennessee (UTK News). The CDC has ordered 9.3 million doses of flu shots for uninsured individuals this year, compared to a half-million doses in previous years (American Medical Association); and vaccine manufacturers are expected to supply 194-198 million doses to the American market (CDC).
Keeping communities safer can be achieved by continuing social distancing, using face masks, frequently washing hands or using sanitizer, and disinfecting surfaces. And encourage your friends and family to get their flu shots, especially children over six months, adults aged 50 and over, and people with chronic health problems.

Where can I get a flu shot?

The Vaccine Finder website helps people quickly access flu shot locations. Local public health departments will offer flu shots free of charge and can be located through this directory of local health departments or at state health departments’ websites. Contact your primary care physician and make an appointment to receive your vaccination. Appointments help to prevent overcrowding in provider’s offices. Medical facilities are also providing vaccination clinics at various locations around communities, both indoors and outdoors to further reduce spread of COVID-19. Check your local news outlets for information on these opportunities. 
Send any additional questions to the CORE-19 team. | 865-321-1299

Coronavirus-19 Outbreak Response Experts (CORE-19) 

Policy Brief Authors
Elizabeth Molinet

Ola Elsakhawy MD, PhD

Ola is a Ph.D. student in Comparative and Experimental Medicine. She graduated from the Faculty of Medicine at Tanta University, Egypt. Her priorities are epidemiology and biostatistics of infectious diseases. She is currently a Graduate Research Assistant at Tennessee University, working with Dr. Kristina W. Kintziger.
Dr. Kristina Kintziger

Dr. Kristina W. Kintziger, PhD, MPH

Kintziger is an Assistant Professor in the Department of Public Health and the co-Director of the Doctoral Program. She has worked in academia and public health practice. Prior to coming to Tennessee, she served as an epidemiologist and biostatistician at the Florida Department of Health. She is an environmental and infectious disease epidemiologist. Kintziger is a member of the CORE-19 Steering Committee
Coronavirus Outbreak Response Experts (CORE-19)
Steering Committee
Dr. Kathleen Brown

Dr. Kathleen C. Brown, PhD, MPH

Brown is an Associate Professor of Practice in the Department of Public Health and the Program Director for the Master's in Public Health (MPH) degree. Her research focuses on the health and well-being of individuals and communities. She has experience in local public health in epidemiology, risk reduction and health promotion.
Dr. Katie Cahill

Dr. Katie A. Cahill, PhD

Cahill is the Associate Director of the Howard H. Baker Jr. Center for Public Policy. She also is the Director of the Center's Leadership & Governance program and holds a courtesy faculty position in the Department of Political Science. Her area of expertise is public health policy. She leads the Healthy Appalachia project. 
Dr. Matthew Murray

Dr. Matthew N. Murray, PhD

Murray is the Director of the Howard H. Baker Jr. Center for Public Policy. He also is the Associate Director of the Boyd Center for Business and Economic Research and is a professor in the Department of Economics in the Haslam College of Business. He has led the team producing Tennessee's annual economic report to the governor since 1995. 
Dr. Agricola Odoi

Dr. Agricola Odoi, BVM, MSc, PhD

Odoi is a professor of epidemiology at the University of Tennessee College of Veterinary Medicine. He teaches quantitative and geographical epidemiology and his research interests are in population health and impact of place on health and access to health services. He was a public health epidemiologist before joining academia. Odoi is a member of the CORE-19 Steering Committee. 
Dr. Marcy Souza

Dr. Marcy J. Souza, DVM, MPH

Souza is an associate professor and Director of Veterinary Public Health in the UT College of Veterinary Medicine.  Her teaching and research focuses on zoonotic diseases and food safety issues. 
Disclaimer: the information in this policy brief was produced by researchers, not medical or public health professionals, and is based on their best assessment of the existing knowledge and data available on the topic. It does not constitute medical advice and is subject to change as additional information becomes available. The information contained in this brief is for informational purposes only. No material in this brief is intended to be a substitute for professional medical advice, diagnosis or treatment, and the University of Tennessee makes no warranties, expressed or implied, regarding errors or omissions and assumes no legal liability or responsibility whatsoever for loss or damage resulting from the use of information provided.
Howard H. Baker Jr Center for Public Policy
1640 Cumberland Avenue
Knoxville, TN 37996
Phone: 865-974-0931
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