The flu and COVID-19 have several overlapping symptoms and could cause a “twindemic” this winter. How can you protect yourself and family from both viruses?

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The onset of colder, fall weather is usually the first trigger for people to remember that flu season is around the corner. The typical flu seasons runs from October to April, with ample reminders in communities for folks to get their flu vaccinations, wash their hands, monitor their symptoms, and avoid work or school if ill. 

But this fall and winter pose a distinct new set of public health challenges and questions to be answered: How will the novel coronavirus, also known as SARS-CoV-2 or COVID-19, impact flu season? Can you get infected with the flu and COVID-19 at the same time? Can the flu shot protect you from COVID-19 infection? 

University of Alabama at Birmingham School of Medicine experts from the Department of Family and Community Medicine and Division of Infectious Diseases weigh in on common questions circulating this season.

What are the symptoms of flu and COVID-19?

COVID-19 and flu have several overlapping symptoms, including fever, chills, cough, difficulty breathing, fatigue, sore throat, runny nose, body aches, headache, vomiting and diarrhea. The notable symptom of COVID-19 that differs from the flu may include change in or loss of taste and smell.

However, it is important to note that people have varying degrees of signs and symptoms with flu and COVID-19, ranging from no symptoms to severe symptoms.

How can someone tell the difference between flu and COVID?

It can be difficult to tell the difference between flu and COVID-19 based on symptoms. For that reason, nobody can tell for sure what the infection is without laboratory testing. If you have any inclination that you have symptoms of flu or COVID, self-isolate immediately and call your doctor.

The incubation period, which is the time from getting the infection until experiencing symptoms, could be longer for COVID-19 than flu. Symptoms may occur anywhere from five days post-exposure to up to 14 days for COVID-19, while for flu one may notice symptoms one to four days after getting the infection. For some, recovery could be faster for flu. 

It is worth noting that a tremendous amount of COVID-19 spread and cases have been linked to asymptomatic carriers. Just because you or those around you are not experiencing symptoms does not mean that you are not at risk for contracting COVID-19 or the flu.

If someone starts feeling symptomatic, what should they do?

If you feel unwell with any symptoms, the first and the best thing to do is to self-isolate at home; this includes avoiding contact with other household members. Both viruses are highly contagious. Contact your primary health care provider for further guidance regarding testing and treatment. 

In addition, take care of yourself by getting rest and staying well hydrated. Many cases of both flu and COVID-19 can be safely treated at home; but keep close track of your symptoms and call your doctor if you develop any concerning symptoms such as trouble breathing, chest pain, new confusion, inability to stay awake, or bluish lips or face.

Will the flu shot prevent COVID-19?

No. COVID-19 is caused by infection from the novel coronavirus called SARS-CoV-2, and flu is caused by infection from influenza viruses. The flu vaccine will not give protection against COVID-19, only against the flu.

However, getting the flu vaccine can reduce the risk of flu illness, hospitalization and death. Getting a flu vaccine can also save health care resources for the care of patients with COVID-19.

Can you be infected with the flu and COVID-19 at the same time?

Yes. Hospitals are starting to see dual cases of flu and COVID-19 in patients as the spread of flu circulates in the community; some are referring to this as a “twindemic.”

If you do become infected with both, you could be fighting two respiratory viruses at one time. Our speculations on how a patient would fare is concerning, as we have only one viable medicine available and it is for flu. Furthermore, ICU beds are in limited number and support care for patients of both viruses. If we see large outbreaks of both flu and COVID-19, hospitals simply may not have enough space for care.

However, it has also been shown in other countries and communities that the COVID-19 mitigation efforts such as mask wearing, social distancing, handwashing, and disinfecting measures are helping to curb the spread of flu.

Experts who contributed to this story include Sameera Davuluri, M.D., assistant professor in Family and Community Medicine; Emily Staples, D.O., assistant professor in Family and Community Medicine; Stephen Russell, M.D., associate professor in Family and Community Medicine; Sumayah Abed, M.D., assistant professor in Family and Community Medicine; and Jeanne Marrazzo, M.D., MPH, director of the Division of Infectious Diseases.