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Flu or COVID-19? Convergence of Two Viruses Creates Risk of Diagnostic Errors

Susan Shepard, MSN, CPHRM, Senior Director, Patient Safety and Risk Management Education, The Doctors Company

Updated March 1, 2021: As both the flu and COVID-19 are contagious respiratory illnesses, the guidance for controlling the spread of COVID-19 can also work for minimizing the spread of influenza. The good news is that there is a vaccine for influenza. The problem for healthcare providers is that the symptoms of both are similar and testing will need to be used to confirm the correct diagnosis. Understanding the differences between the flu and COVID-19 will help to prevent misdiagnosis or delayed diagnosis of either disease. One of the key differences noted by the Centers for Disease Control and Prevention (CDC), for example, is those suffering from COVID-19 may experience new loss of taste or smell, while this is not a symptom of the flu.

As the country experiences the new COVID-19 variants and continues to battle the pandemic, refer to the CDC guidance on Frequently Asked Influenza (Flu) Questions: 2020-2021 Season. To enhance patient safety and conserve scarce medical resources for the care of patients with COVID-19, the following actions are recommended:

  • Encourage your patients (6 months and older), especially those at high risk, to get an annual flu vaccine. Flu shots reduce the risk of death for people with heart disease.
  • Ensure all staff members are vaccinated for the flu and offer it at no cost to the employee, which will increase vaccination rates.
  • Follow the guidelines for COVID-19 prevention to stop the spread of germs through:
    • Frequent handwashing.
    • Respiratory etiquette (including masking when possible).
    • Avoiding touching eyes, nose, and mouth.
    • Avoiding close contact.
    • Disinfecting frequently touched surfaces and objects.
    • Encouraging self-isolation if sick.
  • Adhere to local government or public health department recommendations for additional precautions to be taken in the context of the COVID-19 pandemic.
  • Prescribe flu antivirals as necessary to prevent complications.
  • Distribute or display the American Heart Association infographic COVID-19 and the Flu: Avoiding Double Trouble.

Diagnostic Risks

The potential risks of flu and COVID-19 convergence may occur due to delayed treatment or diagnosis. It is important that appropriate screening, testing, and vaccinations are available. For patients who are at high risk for flu who do not want to get the flu vaccine, physicians should take a shared decision-making approach to ensure the patient understands the risks of not being vaccinated. Learn more about this process with The SHARE Approach: Shared Decision-making Tools and Training. This consent discussion should be well documented.

A second risk is diagnostic errors due to the thinking process. It would be an unfortunate occurrence to diagnose influenza when it is actually COVID-19. To understand thinking processes, physicians should explore implicit bias and Dual Process Thinking (DPT).

Implicit Bias

Implicit bias could be identified as a provider factor that impacts the diagnosis (or missed diagnosis) of flu versus COVID-19, as well as treatment and referral. The Ohio State University Kirwan Institute defines implicit bias as “attitudes or stereotypes that affect our understanding, actions, and decisions in an unconscious manner.” Implicit bias is dangerous in healthcare. Studies have identified that patients for whom the provider is biased experience lower referrals to specialists, less than preferred treatment, poor pain management, and delayed follow-up response. Patients are often aware that the provider is biased and leave the appointment feeling that they have not been listened to and wondering if the care they received is appropriate. These patients are more likely to be dissatisfied with their care and less likely to adhere to the treatment plan, including failure to fill prescriptions and obtain diagnostic studies and follow up. In studies of malpractice claims, dissatisfied patients are more likely to bring a suit against the physician.

No one is immune to implicit biases, as they are subconscious. However, they can be addressed, managed, and changed. The most important step to address implicit bias is mindfulness. Healthcare providers should ask themselves if they may have any bias before treating patients. They should consider whether their approach may need to be adjusted. Learn more about implicit bias at Quick Safety 23: Implicit Bias in Health Care and in Physicians and Implicit Bias: How Doctors May Unwittingly Perpetuate Health Care Disparities.

Dual Process Thinking

Another error in misdiagnosis can be explained by DPT. This serves as a framework to describe how clinicians think when reasoning through a patient’s case. Adapted from research in psychology, dual processes—known as System 1 and System 2—join forces to enable a clinician to think fast and slow when considering a patient’s clinical presentation. Both systems are active when we are awake. System 1 (“fast” thinking) is fast, effortless, intuitive, emotional, and largely unconscious. System 2 (“slow” thinking) is slow, effortful, requires rational conscious attention, and is important for deliberative decision-making. However, System 1 is the dominant mode, and we spend only a fraction of our day in System 2 mode. System 1 is characterized by cognitive shortcuts or heuristics that allow for rapid problem solving to arrive at a provisional diagnosis based upon assumptions, “rules of thumb,” or past experiences. While very useful, a clinician may incorrectly apply heuristics that result in several types of cognitive errors. Learn more about DPT at JGIM: Dual Process Theory Overview.

Scenario Example

In cases of flu versus COVID-19, implicit bias may occur when a young adult patient who did not have the flu vaccine presents with symptoms that started occurring within the last 3-4 days. As the patient is young and presumably healthy other than the current symptoms, the physician may be biased into thinking the individual would more likely have the flu. This example also outlines System 1 thinking as the physician jumped to the conclusion rather than eliciting more evidence, e.g., the young person had attended a big party two weeks earlier.

Patient Safety Strategies

Additional recommendations for practices include:

  • Ensure that standard documentation relative to the possible contraction of the flu and/or COVID-19 is included.
  • Maintain, date, and document all changes in office policies as it relates to PPE or other covered countermeasures.
  • Appoint someone in the office to maintain all COVID-19 and flu-related processes and procedures so that they are centrally located.
  • Designate a person to speak on behalf of the facility with respect to the steps taken to ensure patient safety.

The guidelines suggested here are not rules, do not constitute legal advice, and do not ensure a successful outcome. The ultimate decision regarding the appropriateness of any treatment must be made by each healthcare provider considering the circumstances of the individual situation and in accordance with the laws of the jurisdiction in which the care is rendered.


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