All you need to know about your child’s cold, flu and immune system

Your child’s nose is running, they’re all clogged up and just want to go to sleep. Parents will tell any concerned parties that their little one has the flu – but do they? There is a lot of confusion around the differences and similarities between a cold and the flu, as they cause similar symptoms. If you want a family of healthy kids and adults though, it is important to know the difference as flu is generally more serious and can cause further complications.

By Dr Rabeen Lutchman

There are over 200 types of viruses that can cause a ‘cold’...

What is a ‘cold’

A ‘cold’ is a viral infection of the upper respiratory tract. The upper respiratory tract includes the nose, throat, larynx, Eustachian tube (the connection between the throat and the middle ear) and sinuses.

There are over 200 types of viruses that can cause a ‘cold’ and they occur at different times of the year (this is called seasonal variation). The most common cause is Rhinovirus.

The common symptoms of a ‘cold’ are stuffy nose, sneezing, sore throat, and less commonly, a cough. It has a more gradual onset, and one experiences mild body aches and fatigue. It is rarely associated with a fever. The exact cause of a ‘cold’ does not necessarily need to be established and the symptoms can be managed conservatively.

What is the flu?

The term ‘flu’ is derived from an infection with the Influenza Virus, which can cause similar symptoms to a cold, but Influenza can cause a more serious infection.

Flu symptoms, unlike a ‘cold,’ have a more sudden onset and are associated with a fever. One can experience quite prominent body aches, fatigue, and headache. The cough can be more prominent and there may be some chest discomfort.

Three types of influenza viruses are responsible for the disease: Influenza A or B or C.

What is the immune system?

When a baby is born at full term (9 months), they have all the essential components of the immune system, but this immune system is still maturing.

Immunoglobulins are essential components of the immune system and are produced by the body to fight infection. There are different types of immunoglobulins – Immunoglobulin G (IgG), Immunoglobulin M (IgM), Immunoglobulin A (IgA), etc. Each have a different role and function in the immune system.

At birth, the baby has a high level of IgG which has been transferred from the mom to the baby via the placenta. Breast milk also contains high levels of IgG.

These levels of IgG slowly decline over the first 3-5 months and the infant will need to start making his own immunoglobulins. The levels will start to rise again reaching about 60% of adult level at one year old, and only achieve levels that of an adult by 6-10 years of life.

Children under five years of age are thus susceptible to repeated infections until their immune system matures to produce the same amount of immunoglobulins as an adult.

When a child has his first infection with that specific virus or bacteria, the immune system first sends out immunoglobulin G (IgG), while the body makes immunoglobulin M (IgM) and other components of the immune system to finally control the disease.

Upon repeat infection with the same virus or bacteria, the body already has Immunoglobulin M (IgM), and this helps to fight and contain the disease before it becomes too serious.

This is the basis of immunisations and why it is so important to vaccinate your child. Vaccination allows their immune system to be equipped to fight off harmful viruses and bacteria when exposed to it in the future.

Children at day-care are susceptible to more infections because their immune system is still developing, and they are simply exposed to more infections. Due to increased secretions and mucous in the airways, secondary bacterial infections are common. Children are not able to effectively clear these secretions, as adults are able to do with a strong cough or blowing of their nose, and this provides a favourable environment for bacteria to grow – often leading to a secondary infection in children.

These secretions can block the Eustachian tube (the connection between the throat and the middle ear) and can cause a secondary infection in the middle ear (otitis media) or can collect in the lower airways and cause a pneumonia or bronchitis.

The dangers of a viral infection of the upper respiratory tract are the possible complications of secondary infections and these include otitis media, bronchitis, pneumonia, etc.

Children with other illnesses, such as asthma or diabetes or who are on chronic medication that suppress their immune system, are more likely to have complications.

Visit a doctor if your child experiences any of the following (danger) signs:

• fever for more than three days • breathing fast • breathing noisily • experiencing difficulty breathing • not feeding • persistent vomiting • difficult to wake up • lethargic • inconsolable crying • loose stools/ bloody stools

Dr Rabeen Lutchman is a Paediatrician working at the Paediatric Unit at Life Kingsbury Hospital. He runs a multifaceted paediatric practice with a wide range of paediatric services. He is dedicated to providing a paediatric service that upholds the best interests of the child. T +27 (0)21 685 0336 E paedrabeen@gmail.com W www.paediatrician-capetown.co.za

Prevention is better than cure:

• make sure immunisations are up to date • good nutrition and healthy diet • avoid contact with someone with the flu • keep children at home if they are sick to prevent the spread of germs and outbreaks • cover mouth and nose when sneezing • dispose of tissues after use • practice good hand hygiene – wash hands with soap and water where possible 