Introduction

Respiratory Syncytial Virus (RSV) is a common, and often harmless virus that causes a respiratory infection (throat, sinuses, airways). For most who are infected, they will experience mild, classic cold-like symptoms such as runny nose, coughing, and sneezing. And these often clear up in a couple of weeks. 

The virus can affect all and is most commonly spread by airborne transmission. Although most do not become significantly ill when infected with the virus, serious illness can occur in those who are very young, very old, or those with a weakened immune system. This can lead to hospitalisation and, in rarer cases, mortality. When pregnant, the body undergoes so many changes, including some to the immune system. This means pregnant women are at a slightly higher risk of catching RSV and could experience slightly more severe symptoms than if they were in ‘normal’ health. Additionally, although RSV does not increase the risk of miscarriage or stillbirth, it is linked to increased odds of preterm delivery.¹ This article will walk you through the specifics of how RSV may affect you and your pregnancy and how best to prevent catching the disease.

Transmission and prevalence of RSV

How is the virus transmitted? 

RSV is most commonly spread indirectly through small contaminated droplets that are released when an infected person coughs or sneezes. Other forms of indirect transmission can come about from contact with RSV on surfaces. This includes dried mucus from an infected individual on materials such as bed sheets or clothes. On hard surfaces, the virus can remain infectious for several hours. When touching these surfaces the virus may be passed to the skin where it can remain infectious for between 30 to 60 minutes. Within this time, and without proper hygiene, the virus may be passed on when touching your face, particularly the eyes and nose. 

Additionally, direct contact such as kissing can also lead to the spread of the illness. Direct contact such as this is the most efficient way for the virus to spread. 

How common is RSV?

In the general population RSV is most prevalent during the winter months, from November through to March. Incidence is common, with most infants having been infected by the virus by the age of 2.² The exact prevalence of RSV is not known as many people infected will not seek any form of medical treatment or test. An estimate for this figure however is somewhere between 0.09% to 17.9%.³ In the United States around 2.1 million children under the age of 5 are brought to receive outpatient treatment for the disease with 58,000 to 80,000 hospitalisations, and 100-300 deaths seen in this age group.⁴ Although there is no validated estimation for incidence among pregnant women, it is thought to be in line with or slightly higher than the average healthy population.

Symptoms of RSV

What symptoms might I experience?

If you are infected with RSV while pregnant, you may experience a range of cold-like symptoms. These will probably occur 2-8 days after exposure and may emerge in a staggered way. For example, the illness may start with sneezing which leads to a cough. Mild symptoms include:

• Running nose
• Coughing
• Sneezing
• Wheezing
• Decreased appetite 
• Mild fever (37.5॰C to 38.0॰C)
• Sore throat 
• Headache

However, in some more severe cases the infection may spread lower into the respiratory system to the airways and lungs. Symptoms that require immediate medical attention include:

• Shortness of breath
  • Includes rapid breathing and difficulty taking in air
  • May get worse when lying down 
• High fever (above 38.0॰C) 
• Bluish tint to the skin
  • Caused by lack of oxygen (cyanosis) 
  • Seen particularly in the lips and nail beds 
• A wheezing or worsening cough 

These symptoms can be indicative of pneumonia (infection within the lung) or bronchiolitis (inflammation of the airway passages). 

RSV and pregnancy

Complications for the pregnant person

RSV, although mostly harmless to pregnant individuals, can cause complications which may lead to hospitalisation. It’s been suggested that pregnant women are more likely to develop severe symptoms due to changes to the immune system and decreases in heart and lung capacity that occur during pregnancy. Additionally, if you have any other pre-existing conditions including asthma or a condition, you may be more likely to develop severe symptoms. If you experience any of the severe symptoms listed above, or something doesn’t feel right, then ensure to contact your healthcare provider immediately. 

Risks to the foetus

 Fortunately, unlike other viruses, contracting RSV does not increase the risk of miscarriage. Additionally, RSV does not increase the risk of birth defects in the unborn child. 

However, other risks may occur if the foetus is exposed to the virus. If a pregnant woman contracts RSV during pregnancy, the foetus can come into contact with the virus as it is able to pass from the bloodstream and through the placenta. This may lead to the following complications:

• Preterm birth
  • This is when a baby is born prior to 37 weeks
  • Women who experience RSV during pregnancy are around 3 times more likely to deliver their baby preterm¹
  • Preterm babies are more susceptible to infection
  • As well as this, they may experience issues breathing, problems with vision or hearing, and developmental delays
  • This is most likely to occur if you have RSV during the third trimester of pregnancy
• Lower birth weight (LBW)
  • This is defined as a baby who is born weighing less than 2.5 kg (5lb 8oz)
  • LBW can lead to a baby being more likely to develop certain health conditions later in life such as diabetes and high blood pressure. It can also mean the baby is more susceptible to infection in infancy
  • The link between LBW and RSV is tenuous with the mother’s reported cases having coinciding health issues
  • Some studies have not found a significant link¹

Of course, contracting RSV during pregnancy does not automatically mean a woman will give birth preterm, however, it is definitely something to be aware of. If you contract RSV during pregnancy be sure to discuss this with your healthcare provider. 

Diagnosis and treatment

How is RSV diagnosed in pregnancy?

RSV is diagnosed by a conversation with your healthcare provider who will be able to assess if your symptoms are in line with RSV. This will most likely be the case if you are only experiencing a mild form of the illness. 

If you develop a more severe reaction to the virus which requires closer monitoring or hospitalisation then a laboratory test will most likely be issued to positively identify the virus and rule out other illnesses. The laboratory test involves either a mouth swab or a blood sample. The laboratory technicians will then be able to see if the sample contains RSV protein which will identify the virus. 

How is RSV treated?

In mild cases of RSV then symptomatic management will be the only required. This mainly includes getting plenty of fluids and rest. Some over-the-counter cold medicines may help ease symptoms but make sure to check packaging or with the pharmacist to ensure it is safe to take during pregnancy. 

If the case of RSV is more severe or develops into pneumonia or bronchitis, hospitalisation may be required for closer monitoring. Hospitalisation may include the following:⁵

• Intravenous fluids
  • To prevent dehydration 
• Humidified oxygen 
• Mechanical ventilation
  • To assist in breathing
  • This is only in very rare cases 
• Clearance of nasal obstruction
  • Suction to remove mucus that may prevent the patient from breathing properly.

Ribavirin is an antiviral medicine approved for RSV treatment, however, this is not often used due to lack of proven effectiveness for the virus. Furthermore, it cannot be used on pregnant individuals. 

Prevention strategies

General prevention

There are various general practices you can engage with to minimise the risk of contracting the virus (as well as other infectious diseases) when pregnant. These include:

• Good hand hygiene
  • Washing hands frequently with soap and water or using an alcohol-based hand sanitiser can significantly reduce the risk of infection
• Avoid close contact with sick individuals
  • Especially those showing symptoms of respiratory infections, such as coughing or sneezing. 
• Disinfecting commonly touched surfaces
  • For example; doorknobs, countertops, and mobile devices can help prevent the spread of the virus 
• Additionally, staying away from crowded places, especially during peak RSV seasons can minimise exposure

Vaccination 

Vaccination against RSV is a great way of preventing RSV infection while additionally protecting the baby. RSV vaccines, designed to be administered during pregnancy, aim to boost the mother's immunity, which is then passed to the baby through the placenta. This passive immunity can provide critical protection for the infant during the first few months of life, a period when they are most vulnerable to severe RSV infections. By vaccinating pregnant women, not only is the mother's risk of contracting RSV reduced, but the newborn also gains immediate protection against the virus, which can help prevent hospitalizations and serious health complications. This approach is particularly beneficial as it provides a safe and effective means to shield the youngest and most at-risk populations from RSV, contributing to better overall maternal and infant health outcomes.

Furthermore, making sure you are updated with other vaccines such as the annual Influenza vaccine will prevent co-infection which can lead to more severe symptoms. 

Conclusion

In conclusion, while Respiratory Syncytial Virus (RSV) is generally mild and akin to a common cold, it poses a greater risk to pregnant women and their unborn children due to the unique changes in the immune system during pregnancy. Understanding the modes of transmission, recognizing symptoms, and knowing the potential complications can help manage and mitigate these risks. Preventive measures such as maintaining good hygiene, avoiding contact with sick individuals, and disinfecting surfaces are essential. Additionally, RSV vaccination for pregnant women is a significant advancement, offering protection not only to the mother but also to the infant during the critical early months of life. By following these strategies and maintaining close communication with healthcare providers, pregnant women can better safeguard their health and that of their babies against RSV.