Viral Infections In Premature Babies

Overview

Infections can occur at any stage of pregnancy, from the first stages of foetal development through to the delivery of the baby. When a baby is born prematurely (before the 37th week of gestation)¹ they are significantly susceptible to infections compared to babies born at full term. 

The increased susceptibility is due to numerous factors, one of which is an underdeveloped immune system or due to unsanitary hospital equipment. 

Virus microorganism induces these risk factors and produces a reaction known as infection. Viruses are known to cause a range of illnesses in premature babies with varying rates of morbidity and severity. Since viruses cannot be killed by antibiotics, different therapies are used to fight the infection. 

The early recognition of viral infections can drastically improve the outcomes for both the mother and newborn. 

Causes and risk factors

There are several types of infection and these can occur at any point in the baby’s development:

• Intrauterine infections: is acquired, when the membrane is infected in the womb.
• Antepartum infections: are acquired before  childbirth
• Postpartum infections: is acquired after birth and lasts 6 to 8 weeks.⁷

Causes of these infections include:

• The infection migrates from the mother to the foetus via the placenta, the amniotic fluid or membranes surrounding the new newborn. 
• Being in labour with an infected birth canal. 
• After the membrane of the womb is ruptured, the infection ascends to the vagina before labour.^{8, 9}
• Medical equipment being contaminated during a Caesarean section process.
• Close contact with an infected mother, medical professionals, family or visitors after childbirth
• Breastfeeding from an infected mother
• Use of unclean equipment (IV lines, ventilation tubes, catheters etc.)
• Unclean hospital environment
• Airborne droplets travel and infect others

Common viral infections in premature babies

Respiratory syncytial virus (RSV)

 Respiratory syncytial (sin-SISH-ul) virus is a common viral infection (RSV). The virus belongs to the same family as mumps and measles viruses² and most people will contract it in the first two years of life. 

RSV is transmitted through droplets released into the air or coming into contact with contaminated surfaces. Typically, RSV will present as a mild upper respiratory illness and alter to Bronchitis in children.⁵

However, high-risk groups such as premature babies may develop severe complications and will require to seek medical attention. 

Symptoms of RSV in babies include:

• Runny nose
• Fever
• Coughing
• Decreased appetite
• Breathing difficulty
• Wheezing cough (can indicate the virus has spread to the lower respiratory tract)
• Pneumonia (in severe cases)¹⁰

Diagnosing RSV

Most cases of RSV will present symptoms like the common cold and will usually require no testing due to lack of investigation. A medical expert may initiate tests to confirm a diagnosis. A physical examination will involve using a stethoscope to hear wheezing and abnormal sounds.¹⁵

If symptoms are extreme, further tests may be carried out to rule out other conditions. Tests can include the following:

• Blood test
• Chest x-rays
• Mouth swabs

Treatment and prevention of RSV

The kind of treatment will depend on the severity of the baby’s infection. Generally, increasing fluid intake (Intravenous fluid) and taking over-the-counter painkillers are advised for mild RSV cases. 

A nasal saline spray can relieve congestion in a baby if needed. If RSV becomes severe, a baby may need extra medical attention such as oxygen masks and mucus suctioning.¹⁶

To prevent RSV, regular hand washing and disinfecting surfaces is advised. Limiting a baby’s exposure to the virus by preventing close contact with other children or large crowds is also advised, especially for premature babies. 

 RSV can be neutralised to better protect them during the RSV  season (November to April). For premature babies especially, a monthly injection of palivizumab is recommended.¹⁵

Influenza

Influenza (IN-floo-EN-za) is a respiratory illness that affects the nose, throat and lungs.⁶ The influenza virus is transmitted from person to person through droplets, coughing or talking and can also be transmitted through contact with contaminated surfaces, similar to RSV.

Babies and children are particularly at risk from the flu, but prioritising premature babies as it gets serious. Influenza can share similar symptoms to the common cold but can progress into a more serious condition. 

Symptoms of influenza in babies include

• Fever with  38°C and above
• Runny nose
• Sneezing
• Fatigue
• Chills or shakes, the process of killing the virus by increasing the temperature
• Diarrhoea, the flu causes to vomit 
• Sore throat

Symptoms typically last for approximately 1 or 2 weeks. In rare cases, more serious symptoms can develop:

• Constantly being fussy or uncomfortable
• Blue colour on the lips or face
• Trouble breathing
• Seizures
• Dehydration (not making urine for 8 hours or a dry mouth can be a sign)¹⁷

Diagnosing influenza

Generally,  a baby with the flu can be a clue to having influenza and enough to diagnose the virus, especially if it is known that influenza is circulating in the community. Expressing symptoms of a fever, aches and cough strongly indicate influenza. 

To confirm the presence of influenza, a nasal swab may be taken from a baby. The swab may be tested using a rapid influenza diagnostic test (RIDT) or other lab tests.⁶

Treatment and prevention of influenza:

An increase in water intake and rest are recommended to assist in a baby’s recovery. If needed, a medical expert l may prescribe an antiviral medicine to treat the flu that is tailored to babies. 

Antivirals can help reduce the symptoms of influenza, speed up to recovery and prevent serious flu complications, such as pneumonia, from developing. These medications are best used within two days of having signs and symptoms and should be used as soon as symptoms start developing in premature babies.¹¹

Children aged six months and older as well as their family caregivers are recommended to get the annual flu vaccine to prevent the contraction of influenza. The vaccine is usually in the form of a nasal spray meaning it’s quick and painless.⁶

However, the vaccine is not approved for use in children under six months, so increased caution is needed to prevent influenza from spreading. If a child or caregiver shows flu symptoms, keeping them away from others is recommended. As with all types of infections, covering the nose and mouth and regularly washing hands with soap is recommended as well.

Human immunodeficiency virus (HIV)

Human Immunodeficiency Virus (HIV) is a virus that targets the body’s immune system, specifically white blood cells called T helper cells (CD4). The virus kills and lowers the number of CD4  in the blood, weakening the immune system and making it more difficult to fight off infections.¹² Without treatment, an HIV infection will gradually advance and lead to acquired immunodeficiency syndrome (AIDS) which refers to a series of life-threatening illnesses. 

HIV can be transmitted from mother to baby at any stage of the pregnancy and can increase the risk of premature birth. HIV is transmitted to babies through various ways:

• During the pregnancy, an infected mother may pass HIV infection onto the foetus through the placenta
• During childbirth, the baby may be exposed to blood (shared with the mother) and other body fluids containing HIV.
• After birth, breast milk may contain HIV and can transmit HIV to the baby through breastfeeding. Exposing the baby to infected blood from the mother and other bodily fluids can also pass on HIV.¹³

HIV transmission to premature babies is particularly dangerous as the baby’s immune system is less complex and effective than that of adults, leaving it at risk of contracting diseases or death.

Symptoms of an HIV infection in babies can include

The symptoms of HIV can vary greatly as the following symptoms  are  potential for HIV infection:

• Recurrent infections (3 or more episodes of bacterial infection in a year)
• Slowed growth due to immune cells fighting the virus 
• Oral thrush is a white-coated tongue
• Enlarged lymph nodes
• Persistent fever of 38°C and above
• Diarrhoea 

Some symptoms are very specific to HIV

• Pneumocystis pneumonia (a fungal infection that causes inflammation and fluid buildup in the lungs)
• Esophageal candidiasis (also known as oesophagal thrush)
• Lymphoid interstitial pneumonia (the presence of lymphocytes, a type of immune cell, in certain areas of the lungs)
• In girls, acquired recto-vaginal fistula (an abnormal connection between the rectum and vagina)⁵

Diagnosis of HIV

Diagnosing HIV at the earliest key point is to ensure the best quality of life for a child. The most common test available to diagnose HIV infection is an antibody test such as an ELISA or rapid test. 

Treatment and prevention of HIV:

Currently, there is no cure for HIV though there are ways to prevent a baby from contracting HIV. When an HIV-positive mother gives birth, the baby should receive post-exposure prophylaxis (PEP) which is a medication used to reduce HIV transmission. The medication given is known as antiretroviral treatment (ART). The only approved treatment for premature babies is zidovudine, which is administered orally for up to 6 weeks to significantly decrease the risk of HIV transmission.¹⁴

A mother can also pass HIV through her breast milk. If a mother is taking HIV medication and the HIV is declared ‘undetectable’ then breastfeeding is considered safe. If the virus is detected in a mother’s blood, they will be encouraged to use formula milk.

Conclusion

Viral infection can occur at any stage of development, with each virus having its own unique set of symptoms. Special attention must be given to premature babies as their underdeveloped immune system leaves them more likely to contract an infection and develop serious complications. 

Viruses can spread in different ways, from airborne droplets to the exchange of infected bodily fluids. Generally, there will be preventative strategies and treatments available to help keep the child safe, such as regular hand washing, vaccinations and antivirals. If a child’s condition starts to worsen or a caregiver simply needs advice, medical services should be contacted for further assistance.