Flu, RSV, or COVID-19? Convergence of Three Viruses Creates Risk of Diagnostic Errors

Nov 02, 2023 at 06:17 pm by pjeter




As we transition into colder weather, it is possible that healthcare practitioners will again see a spike in influenza (flu), respiratory syncytial virus (RSV), and COVID-19 cases—particularly with the circulation of newer Omicron subvariants. Last year, RSV infection peaked unusually early, flooding primary care offices and hospital emergency departments while creating severe shortages of pediatric hospital beds.

Public health officials declared the three viruses as a public health “triple threat” in 2022/2023, but this year we have reason for good news: Vaccines are now readily available for all three viruses—flu, RSV, and COVID-19. In 2023, the FDA approved RSV vaccines for adults ages 60 and over and pregnant women during weeks 32 through 36 gestational age, providing protection for infants from birth through six months of age.



For unvaccinated patients manifesting illness, the bad news is that all three viruses have similar symptoms, and testing must be performed for each to effectively confirm a correct diagnosis. Understanding the differences between the flu, RSV, and COVID-19 will help prevent misdiagnosis or delayed diagnosis when patients present with respiratory symptoms.

The American Academy of Pediatrics offers information on differential diagnosis between the three viruses, and the CDC provides specific guidance on distinguishing between the flu and COVID. General information for practitioners about each virus is available from the CDC as follows: fluRSV, and COVID-19. The CDC addresses signs and symptoms, incubation periods, length of time for spreading the viruses, how the viruses spread, individuals at higher risk for severe illness, potential complications, and approved treatments.



During flu season, it is possible that all three of the viruses may spread at the same time and patients could become infected with one or all three of the diseases. To counter this possibility, it is important to continue offering appropriate screening, testing, and vaccinations. Refer to the CDC’s guidance on “Frequently Asked Influenza (Flu) Questions: 2022-2023 Season.” Note that according to the CDC, both flu and COVID vaccines may be given on the same day if patients are eligible and vaccines follow the appropriate administration schedule. Some infectious disease experts recommend, however, that the RSV vaccine be given separately.


Patient Safety Strategies

Enhance patient safety by taking the following actions:


Patient Care


Office Measures


Patient Education

  • Distribute or display the American Heart Association infographic “Flu Shot 411.” Flu shots reduce the risk of death for people with heart disease.
  • Use other infographics and print resources in your office for the fluRSV, and COVID-19.
  • Offer a free video in your waiting area to educate patients about getting vaccinated. For an example, see the Mayo Clinic Minute: “Why getting vaccinated for the flu is doubly important this season.”
  • Educate patients to stop the spread of germs:
  • Wash hands frequently.
  • Maintain respiratory etiquette (including masking when possible).
  • Avoid touching eyes, nose, and mouth.
  • Avoid close contact, particularly with those who are sick.
  • Disinfect frequently touched surfaces and objects.
  • Encourage self-isolation if sick.


Community Monitoring


For additional assistance, contact the Department of Patient Safety and Risk Management at (800) 421-2368 or by email.


Debra Kane Hill, MBA, RN, is a Senior Patient Safety Risk Manager for The Doctors Company.


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.