Why respiratory illnesses increase in winter: a guide for parents

Why respiratory illnesses increase in colder weather

A number of environmental and behavioural factors contribute to the marked rise in respiratory infections during winter:

Cold, dry air

During the colder months, the air is often much drier, particularly indoors. Dry air can irritate the lining of the nose and airways and reduce the effectiveness of the body’s natural defences that help trap and clear viruses. In these conditions, respiratory viruses are also able to survive and spread more easily, increasing the chance of infection when children are exposed.

Spending more time indoors

During winter, families often spend greater periods indoors, particularly in shared or crowded spaces. Close contact increases the likelihood of viruses spreading between individuals, including those that commonly affect children. Good ventilation is important, but this can be harder to maintain during colder weather.

Seasonal viral patterns

Several respiratory viruses are much more common during the colder months, and many families are seeing these illnesses circulate widely at the moment.

Respiratory syncytial virus (RSV), a leading cause of bronchiolitis in babies and young children, typically increases from autumn and continues through winter. Parainfluenza viruses, which commonly cause croup, also peak at this time of year. Seasonal influenza (flu) tends to rise during winter as well.

Together, these viruses account for a large proportion of coughs, colds, noisy breathing and fevers seen in young children during winter.

Reduced vitamin D levels

Natural sunlight is the main source of vitamin D for most people. During the winter months, children may have lower exposure to sunlight, which can affect vitamin D levels and potentially play a role in immune function.

Supporting children’s immunity during winter

While it is not possible to prevent every winter illness, there are several steps that parents can take to support respiratory health:

• Ensure your child receives adequate vitamin D supplementation in line with national recommendations.
• Encourage regular handwashing, especially after coughing, sneezing or blowing noses.
• Keep indoor spaces as well-ventilated as possible by opening windows briefly when safe and appropriate.
• Maintain consistent sleep routines to support overall immune function.
• Provide a balanced diet that includes a range of nutrients to help the immune system work effectively.

These measures will not stop all illnesses, but they can help reduce the impact and frequency of infections during peak winter months.

When to seek medical advice

Most winter coughs, colds and mild respiratory symptoms improve without medical intervention. However, it is important to be aware of signs that may suggest a more significant illness such as croup, bronchiolitis or another condition affecting breathing.

Seek medical advice if you notice any of the following:

• Noisy or difficult breathing, including wheezing or stridor
• A distinctive barking cough, which is characteristic of croup
• Fast or laboured breathing, including visible chest retractions
• Poor feeding or difficulty feeding, particularly in infants
• A high fever that persists for more than a few days
• Blue-tinged lips or skin, which requires urgent attention

If you are worried about your child’s breathing, symptoms, or general wellbeing don’t hesitate to contact a medical professional.

Further support

Winter can be a challenging time for families, particularly when respiratory illnesses are circulating widely. If you have questions about symptoms, seasonal infections or your child’s respiratory health, you are welcome to contact our team for clinical guidance and support. Additionally, information on the NHS website is readily available for parents who wish to read more about specific conditions - croup and bronchiolitis. 

Disclaimer: The information provided in this article is for educational purposes only and should not replace medical advice. Always consult with a healthcare professional for personalised guidance and treatment recommendations.