Cold, Flu, COVID-19 & RSV: What’s the Difference?

A cough, runny nose and fever can point to several respiratory infections. Does your child have an ordinary cold, or could it be influenza, COVID-19 or respiratory syncytial virus, commonly known as RSV?

It can be difficult to tell because these infections share many of the same symptoms. While symptom patterns may provide clues, they alone may not confirm the cause of the illness.

Here is a simple guide to the differences, what you can do at home and when your child should receive medical attention.

What Is the Difference Between a Cold, Flu, COVID-19 and RSV?

Colds, influenza, COVID-19 and RSV are all caused by viruses that can affect a child’s respiratory system. However, as they are different viruses, they may affect children differently.

The table below presents a quick overview of the key differences.

These are general patterns rather than diagnostic rules. A child may not experience every symptom, and different infections can present very similar symptoms. A medical assessment or test will be the most accurate form of diagnosis.

Common Cold

What It Is:

The common cold is a viral infection affecting the upper respiratory tract. It is one of the most common infections, with minor symptoms including a stuffy or runny nose, sore throat, and cough. Serious health problems are uncommon, and colds are typically treated with home remedies and over-the-counter pharmaceuticals.

Causes:

The common cold is caused by viruses, with rhinoviruses responsible for approximately 30–50% of cases. Other viruses, including coronaviruses and adenoviruses, can also cause the common cold. Rhinoviruses usually cause mild symptoms but can lead to worsening of preexisting bronchial asthma or more severe sickness in those with compromised immune systems or underlying disorders.

When a Cold May Need Medical Attention

Most colds are not serious. However, seek medical advice if your child's symptoms are worsening over time, or if they experience difficulty breathing, have poor appetites, are unable to eat or drink, are dehydrated or have other concerning symptoms.

Flu (Influenza)

What it is:

The flu is a contagious respiratory illness caused by influenza viruses, which affects people of all ages and can trigger seasonal outbreaks. It attacks the human respiratory tract (nose, throat, and lungs), causing inflammation of the membranes. The flu typically strikes suddenly, with severe symptoms that can disrupt daily activities. In Singapore, influenza occurs all year, with peak seasons typically occurring from May to August and December to March. The timing of these peaks may vary from year to year.

Causes:

Influenza is caused by influenza viruses, primarily types A and B, which are responsible for seasonal outbreaks. The viruses spread mainly through infectious respiratory particles released when an infected person coughs, sneezes or talks. Transmission can also occur through contact with contaminated surfaces, followed by touching the eyes, nose or mouth.

Why Flu Can Be More Serious

Although many children recover without complications, influenza can sometimes lead to pneumonia, dehydration or ear infections. Young children and children with certain underlying health conditions may have a higher risk of complications.

Annual or biannual influenza vaccination is an important way to reduce the risk of influenza and its complications. In Singapore, influenza vaccination is recommended for young children in specified age and risk groups under the National Childhood Immunisation Schedule.

COVID-19

What It Is:

COVID-19 is an infectious disease caused by the SARS-CoV-2 virus. It was discovered in late 2019 and has since caused a global pandemic. It typically affects the respiratory system but can also affect other organs. Symptoms can range from mild to severe, such as major breathing difficulties and hospitalisation.

Causes:

The virus spreads mainly through infectious respiratory particles released when an infected person coughs, sneezes, talks or sings. Transmission can also occur through contact with contaminated surfaces, followed by touching the eyes, nose or mouth. Infected individuals can transmit the virus before developing symptoms or without developing symptoms.

Testing and Prevention

A rapid antigen test or molecular test may be used to diagnose whether a child has COVID-19. Following current vaccination recommendations, practising good hand and cough hygiene (e.g. covering coughs and sneezes with a tissue or your elbow and washing hands afterwards), maintaining good ventilation at home, and keeping children home when unwell can help reduce the spread of COVID-19 and other respiratory infections.

RSV (Respiratory Syncytial Virus)

What It Is:

RSV is a common respiratory virus that affects the lungs and breathing airways. It is more severe in infants and young children, particularly those with underlying medical conditions, resulting in serious respiratory problems. Severe cases may require hospitalisation for supportive care, such as oxygen therapy.

Causes:

RSV spreads through respiratory droplets and through contacting infected surfaces. It is highly contagious and can quickly spread to young children and newborns.

Why RSV Can Be More Concerning in Young Children

Young infants have smaller airways, so inflammation and mucus caused by RSV can make breathing more difficult. In Singapore, an RSV vaccine is licensed for use during weeks 32–36 of pregnancy to help protect infants against RSV disease from birth through six months of age. Long-acting RSV monoclonal antibodies[JK1.1], including nirsevimab (Beyfortus) and clesrovimab (Enflonsia), are also licensed for eligible newborns and infants. Unlike vaccines, they provide ready-made antibodies that help prevent RSV lower respiratory tract disease.

What Should You Do If Your Child Is Unwell?

1. Manage Symptoms at Home

Children with mild symptoms, and are able to breathe relatively comfortably, are drinking adequately and behaving reasonably normally can often be cared for at home.

• Encourage rest and fluids

Let your child rest and offer fluids regularly. Babies should continue to be breast or formula fed as usual. If nasal congestion makes it difficult for a baby to finish a feed, smaller and more frequent feeds may help.

• Use saline nasal drops or sprays

Plain saline, as nasal drops or sprays, can help loosen mucus and relieve nasal congestion. For babies, saline drops may be followed by gentle suction using a nasal aspirator. Avoid excessive or forceful suction, as this may irritate the inside of the nose.

• Use a cool mist humidifier

A cool mist humidifier may provide some comfort if the air is dry. Change the water daily and clean the humidifier according to the manufacturer’s instructions to prevent mould or bacteria from growing.

• Use medicines safely

Age-appropriate fever or pain medicine may help your child feel more comfortable. Follow the product instructions or advice from a doctor or pharmacist. For colds and mild flu symptoms, age-appropriate over-the-counter medicines such as pain relievers and topical decongestants may help ease discomfort. Check that the product is suitable for your child’s age and follow the labelled dose or advice from a doctor or pharmacist. Over-the-counter cough and cold medicines are not recommended for children younger than two.

2. Monitor Symptoms and Seek Medical Advice if Necessary

If your child’s symptoms worsen or new, severe symptoms develop, consult a healthcare provider. Seek medical attention if your child has any of the following symptoms:

• Difficulty Breathing: Rapid or laboured breathing, flaring nostrils, or blue-tinged lips or face. Seek emergency help for severe breathing difficulties.
• High Fever: A fever of 38°C or higher in babies younger than 3 months requires urgent medical assessment. For older children, seek medical advice if the fever is persistent or accompanied by concerning symptoms.
• Dehydration: Reduced urination, dry mouth, or a lack of tears when crying.
• Persistent Pain: Chest pain or severe abdominal pain that does not go away.
• Unresponsiveness or Severe Fatigue: Unusual drowsiness, difficulty waking up, or unresponsiveness.

3. Seek Emergency Care

Seek emergency medical care if your child exhibits any of the following:

• Severe Breathing Problems: Severe difficulty breathing or blue-tinged lips or face.
• Convulsions or Seizures: A seizure, especially a first seizure or one lasting 5 minutes or longer.
• Severe Weakness: Sudden severe weakness, inability to move, or unresponsiveness.
• High-Risk Medical Conditions: Children with underlying conditions, such as asthma, chronic lung disease or heart disease, may be at higher risk of severe illness and should receive medical advice promptly if symptoms worsen.

By managing mild symptoms at home and monitoring changes, you can help keep your child comfortable and recognise when medical care is needed. When in doubt, consult a healthcare professional.

How Can You Reduce the Risk of Respiratory Infections?

It is not possible to prevent every respiratory infection, especially in young children. However, the following measures may reduce the risk of infection or serious illness.

1. Consider Prevention Through Vaccination

• Flu vaccine: Recommended annually or biannually for children aged 6 months to under 5 years, and older children with certain medical conditions.
• COVID-19 vaccine: Recommended for medically vulnerable children aged 6 months and above. For first-time vaccination, children aged 6 months to 4 years require 2 doses, 8 weeks apart; those aged 5 years and above require 1 dose.
• RSV prevention: Pregnant women may receive the RSV vaccine at 32–36 weeks of pregnancy to protect their babies from birth to 6 months. Long-acting RSV monoclonal antibodies, including nirsevimab (Beyfortus) and clesrovimab (Enflonsia), provide ready-made antibodies that help prevent RSV lower respiratory tract disease.

2. Practise Good Hand Hygiene

• Handwashing: Encourage frequent handwashing with soap and water, especially before eating and after coughing or sneezing.
• Avoid touching face: Teach your child to avoid touching their face, particularly their eyes, nose, and mouth.

3. Reduce Exposure

• Stay home when unwell: Keep your child home to rest and reduce the spread of infection.
• Avoid close contact: Keep young infants and medically vulnerable children away from people who are unwell, where possible.
• Wear a mask when unwell: If your child needs to go out while symptomatic, have them wear a mask if they are old enough to do so safely.
• Cover coughs and sneezes: Teach your child to use a tissue or the inside of their elbow, dispose of used tissues promptly, and wash their hands after.

4. Maintain a Healthy Environment

• Clean surfaces: Regularly clean and disinfect frequently touched surfaces, such as doorknobs, light switches, and toys.
• Ventilation: Ensure good ventilation in your home by opening windows or using air purifiers to reduce the concentration of airborne viruses.

Conclusion

Colds, flu, COVID-19 and RSV can cause similar symptoms, so it may not always be possible to tell them apart based on symptoms alone.

For mild symptoms, focus on rest, fluids and keeping your child comfortable. Continue monitoring your child’s breathing, feeding, fluid intake and overall condition, and seek medical advice if they are becoming more unwell.

If you are concerned about your child’s symptoms, an SBCC Baby & Child Clinic paediatrician can assess your child and advise on the appropriate care.

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