Respiratory Viruses Unleashed: The Interplay between Influenza, SARS-CoV-2, and Respiratory Syncytial Virus

An important aspect of the lockdown period is its potential impact on immunity. Although isolation measures were intended to reduce the spread of COVID-19, they may have unintentionally reduced exposure to other seasonal viruses such as influenza and respiratory syncytial virus (RSV).

Manuela Băbuș
Medical Writer
Respiratory Viruses Unleashed: The Interplay between Influenza, SARS-CoV-2, and Respiratory Syncytial Virus

This reduced exposure may have led to a decline in population immunity to these viruses, potentially increasing the risk of severe disease and transmission once these viruses once again begin to circulate more widely.

Influenza, COVID-19, and infection with respiratory syncytial virus (RSV) are all highly contagious respiratory infections caused by viruses. Influenza is caused by the influenza virus, COVID-19 by the SARS-CoV-2 virus, and RSV by the respiratory syncytial virus. 

RSV is a respiratory virus that can infect individuals of all ages but poses a greater risk to vulnerable populations such as infants and the elderly

While symptoms of RSV infection can be mild in adults and older children, they can be more severe in infants and the elderly, including fevers and wheezing. Hospitalization may be required for some cases, although most infections typically resolve within 1 to 2 weeks.

Infants with RSV infection require close monitoring and may need significant attention until they recover. It is crucial to be aware of potential signs of serious illness that may require emergency medical attention, such as rapid breathing, fatigue, and bluish discoloration of the skin or nails. If these symptoms are present, immediate medical care should be sought to ensure prompt and effective treatment.

COVID-19 has had a significant impact on cases of respiratory syncytial virus (RSV). 

The hygiene and sanitation measures implemented to control the spread of the virus have limited contact between children and adults, thereby reducing the incidence of common infections, including RSV infection.

However, the lack of exposure to seasonal viruses has had other indirect effects, such as the reduction of population immunity. This has resulted in more severe or frequent seasonal infections than before. According to the American Academy of Pediatrics, children's hospital beds in the United States were almost full by the end of 2022 due to the increasing number of RSV infections.

It is possible for an individual to be infected with multiple viruses simultaneously.

The coexistence of SARS-CoV-2 with influenza viruses presents an unpredictable evolution, commonly known as "Flurona," whereby both viruses coexist simultaneously in the same organism.

Individuals can be infected with COVID-19 and influenza at the same time. 

Both are respiratory viruses and may present similar symptoms, including:

  • cough, 
  • sneezing, 
  • sore throat, 
  • fever,
  • headache, 
  • Fatigue
  • Muscle soreness

A symptom that seems to be unique to COVID-19 is loss of taste or smell

It can take longer for people infected with SARS-CoV-2 to show symptoms and people stay infectious longer than with the flu. 

COVID-19 and influenza are transmitted through droplets and aerosols when an infected person breathes, coughs, sneezes, talks, or sings

These droplets and aerosols can enter the eyes, nose, or mouth of nearby individuals, and the risk of transmission is higher in crowded or poorly ventilated areas. People can also become infected with COVID-19 and influenza by touching contaminated surfaces and then touching their eyes, nose, or mouth with dirty hands.

Each of these viruses can cause asymptomatic forms of the disease or, conversely, severe and potentially fatal forms.

How do I prevent the flu, COVID-19, and RSV?

We can decrease the risk of contracting the flu by getting a flu shot. There are many types of influenza vaccines, developed using various technologies, which are updated every flu season according to the circulating strains, as recommended by the World Health Organization.

The available COVID-19 vaccines have demonstrated efficacy in protecting individuals from severe illness, hospitalization, and death.

Long COVID and Long Flu 

Long COVID and Long Flu are two conditions that can affect individuals who have experienced COVID-19 or influenza, respectively. 

Long COVID, also known as post-acute sequelae of SARS-CoV-2 infection (PASC), is a condition where individuals continue to experience symptoms and complications after recovering from the acute phase of COVID-19. The symptoms can range from fatigue, brain fog, and shortness of breath, to chest pain, joint pain, and depression. 

Long COVID can affect individuals of all ages, regardless of the severity of the initial COVID-19 infection. While the exact mechanisms of long COVID are still being studied, it is believed to be related to persistent inflammation and autoimmune reactions triggered by the initial infection.

Long flu refers to a condition where individuals continue to experience symptoms after recovering from the acute phase of influenza. The symptoms of long flu can include fatigue, weakness, and coughing, and may last for weeks or even months. However, the long-term effects of flu are less well-documented than those of long COVID, and the exact mechanisms underlying long flu are still not well understood.

Both long COVID and long flu have been the focus of intense research in recent years, as they can significantly impact the quality of life of affected individuals. In addition, these conditions have implications for public health policy, as they underscore the importance of preventing and controlling the spread of COVID-19 and influenza.

To prevent long COVID and long flu, it is important to take steps to reduce the risk of infection in the first place. This includes getting vaccinated against COVID-19 and influenza, practicing good hand hygiene, wearing masks when appropriate, and practicing social distancing in crowded spaces. 

By taking these precautions, individuals can help protect themselves and others from the potentially severe and long-lasting effects of these conditions.

In conclusion, it is crucial for individuals who have been diagnosed with the flu, COVID-19, or respiratory syncytial virus (RSV) to follow the recommendations of their doctor throughout the course of their illness and beyond. This includes: 

  • adhering to any prescribed medications, 
  • getting plenty of rest, 
  • staying hydrated, 
  • monitoring symptoms closely.

Moreover, as these infections can result in long-term complications or sequelae, individuals should remain vigilant about any new or persistent symptoms that may develop following the acute phase of the illness. 

By working closely with their doctor and staying vigilant about their health, individuals can increase their chances of a successful recovery and reduce the risk of long-term health consequences.

Article Citations & Bibliography
  1. Chow E.J. The effects of the COVID-19 pandemic on community respiratory virus activity. Nature Reviews-Microbiology  volume 21, March 2023
  2. Nalbandian, Armand, et al. "Post-acute COVID-19 syndrome." Nature Medicine, vol. 27, no. 4, April 2021, pp. 601-615, doi: 10.1038/s41591-021-01283-z.
  3. Greenhalgh T, Knight M, A’Court C, Buxton M, Husain L. Management of post-acute Covid-19 in primary care. BMJ. 2020;370:m3026. doi: 10.1136/bmj.m3026 

Please note that the information provided on this blog is for educational and informational purposes only. It is not intended to be used as a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified healthcare provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on this blog.

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Manuela Băbuș.
Medical Writer