Respiratory syncytial virus (RSV) is a seasonal, highly contagious virus that causes infections of the lungs and respiratory tract. RSV is a very common virus that infects most children by the age of 2.¹ 

RSV is commonly thought of as a virus that affects babies and young children. However, it can also affect adults. In most cases, infection with RSV will result in only mild, common cold symptoms, and will be easily managed with plenty of rest and fluids. 

However, sometimes it can lead to a more severe infection, in particular, in older adults, or adults who are immunocompromised or have pre-existing medical conditions. 

It’s important to understand what RSV is and what kind of complications it can cause to better manage and treat this infection.

What is RSV?

RSV is an enveloped RNA virus of the Paramyxoviridae family. Other members of this family include human parainfluenza viruses, mumps, measles, Nipah, and Hendra viruses.²

RSV can spread from an infected person to a healthy person via particles and droplets, which are released into the air when an infected person breathes, speaks, coughs, or sneezes. These are then inhaled by a healthy person, infecting that person. 

Additionally, it can also spread when the droplets land on surfaces that other people may touch, such as door handles or table tops. People can pick up the virus with their hands and get infected by touching their mouth, eyes, or nose.

RSV is a common respiratory virus, which causes common cold-like symptoms, such as:

• Cough
• Sneezing
• Fever
• Runny nose
• Wheezing
• Sore throat
• Headache
• Congestion
• Fatigue
• Disorientation
• Shortness of breath

However, some people can develop more severe infection. The people who are most at risk of developing a severe RSV infection are those over 65 and those with compromised immune systems. Pre-existing conditions, such as diabetes, heart disease, and lung disease, including chronic obstructive pulmonary disease (COPD) and asthma, also increase the risk..³ A more severe infection may result in symptoms, such as:

• Difficulty breathing
• Having to pause while breathing or short, shallow, and fast breathing
• Wheezing - a high-pitched noise that's heard when a person is breathing out
• Noisy breathing
• Blue or gray skin colour – due to lack of oxygen

It’s hard to know how many people are infected with RSV every year, as many people will never get diagnosed. 

However, it is estimated that RSV causes approximately 24.83 million lower respiratory tract infections and around 76600 deaths globally each year.⁴ In the EU, Norway, and the United Kingdom, RSV infection causes approximately 158000 hospitalizations every year. 

Furthermore, it is estimated that RSV infections lead to around 60,000-160,000 hospitalizations among adults, who are 65 years and older, in the United States each year.

Complications of RSV in adults

Most of the people who get infected with RSV will only have mild symptoms and will get better fast, within days. However, in some cases, people can develop a more severe illness, which can lead to certain complications. 

Some of the potential complications in adults include:

• Pneumonia – it is an infection of your lungs. Pneumonia leads to an inflammation of your lungs leading to the swelling of your lung tissues. Fluid and pus can build up in your lungs, which can make breathing more difficult
• Acute bronchitis – is irritation of your lungs that causes inflammation of your lungs. It can make your airways swollen and lead to mucus build up causing you to cough
• Bronchiolitis – it is an infection that causes the narrowing of the small airways (bronchioles) in your lungs. The bronchioles get swollen and filled with mucus, making breathing more difficult
• Worsening existing conditions such as asthma, congestive heart failure or COPD – RSV infection can make your pre-existing conditions get worse. It can lead to you having an asthma attack or make your COPD symptoms get worse
• Respiratory failure – this is a condition when there is not enough oxygen in the tissues of your body or when there is too much carbon dioxide in your blood. This is usually a medical emergency and you should seek immediate medical attention if you suspect that you are experiencing respiratory failure

Around 47.9% of people aged over 60, who attend a health clinic and have been diagnosed with RSV, develop one or more RSV-related complications within one month of initial diagnosis.⁵ The proportions of RSV-related complications are: pneumonia (24.0%), chronic respiratory disease (23.6%), hypoxia (low level of oxygen in your body tissues) or dyspnea (shortness of breath) (22.0%), congestive heart failure (18.4%), acute respiratory failure (15%) and developing other upper or lower respiratory infection, which is not caused by RSV directly (3.5%).⁵

What are the risk factors for developing complications?

In general, healthy adults younger than 60 will only experience mild symptoms when infected with RSV, however, some adults might develop more severe symptoms and complications. 

Some factors that increase your risk of developing RSV-related complications include:^5,6,7

• Age – people older than 65 are more likely to develop complications. The risk even further increases in adults over 80. As we age our immune systems become weaker, and it becomes harder to protect us from infection and associated complications
• Being frail – in medicine, frailty refers to older adults who are at the highest risk of falls, disabilities, admission to hospital, or the need for long-term care
• Living in a long-term care facility
• Having a previous diagnosis of RSV-related complications, such as hypoxia, dyspnea, pneumonia, acute respiratory failure or congestive heart failure
• Having a disability
• Diabetes – having diabetes might increase your chances of getting the infection and it might make the recovery process longer
• Chemotherapy treatment – this would weaken your immune system, making it harder to fight off the infection
• COPD
• Receiving a solid organ transplant – recipients are prescribed medication that suppresses their immune system, so that their bodies would not reject the transplant. This makes it harder for the immune system to fight off the infection
• Receiving hematopoietic cell transplant – this is also known as bone marrow transplant. In the initial period of receiving a transplant, you are more prone to infections
• Having blood cancer – this can stop your immune system from working properly and increase your chances of getting an infection

How can you prevent the RSV infection?

RSV is a very common virus, which is hard to avoid, however, there are some things you can do to reduce your risk of getting infected:

• Regularly disinfect commonly touched surfaces – this includes surfaces like tables and door handles. Disinfecting involves using a chemical (disinfectant), which destroys microorganisms, such as viruses and bacteria
• Practice good hygiene – wash your hands regularly with soap and water for at least 20 seconds, especially before you prepare your food or eat. If you cannot wash your hands, having an alcohol-based hand sanitizer is an alternative that you can use to kill pathogens on your hands
• Try to limit your exposure to microbes - RSV is most common from October through March. During this season, it might be best to avoid crowded events and gatherings. It also might be a good idea to wear a mask in public spaces
• Avoid close contact or sharing any personal items with people infected with RSV – this might involve avoiding hugging, kissing, handshaking, or sharing kitchen items, utensils, and dishes.
• Consider getting an RSV vaccine – if you are over 60, it might be a good idea to get the vaccine to lower your chances of developing an infection

Summary

RSV is a common, seasonal viral infection that usually causes only mild, common cold symptoms, like coughing, sneezing, fever, and runny nose. However, some people might develop a more severe illness with more severe symptoms, such as difficulty breathing and reduced amount of oxygen in the tissues. 

Furthermore, RSV infections can then lead to some additional complications. Some of the potential complications related to RSV are pneumonia, bronchitis, bronchiolitis, respiratory failure, and worsening of pre-existing conditions, such as COPD or asthma. 

Some things might increase your risk of developing complications, which include being over the age of 65, having a compromised immune system, which makes fighting infections harder, or having a pre-existing medical condition. 

As this virus is quite common, it’s hard to avoid it entirely, however, there are some measures that you can take to reduce your risk of contracting this virus. You should practice good hygiene, such as regular hand washing, disinfecting commonly touched surfaces regularly, and avoiding contact with sick people.