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Dear Dr Jennifer: Can leaving the doors and windows open in school be harmful for kids in winter?

Ask the Doctor


Schools have been advised to ensure good ventilation in classrooms

Schools have been advised to ensure good ventilation in classrooms

Schools have been advised to ensure good ventilation in classrooms

Question: I am hearing a lot of talk about leaving the doors and windows open in schools as a good way of reducing risk of contracting coronavirus.

Is this going to harm the kids in the winter? What is the truth about cold draughts and illness?


Answer: Human-to-human transmission of the coronavirus is primarily through coughing/sneezing or even talking/singing in a confined space as this allow the spread of respiratory droplets or aerosols.

Typically the inhalation of aerosols/droplets into the upper respiratory tract (nose/mouth) and lungs causes onset of symptoms within a few days.

Some limited scientific data has recorded aerosolised Covid-19 particles that remain suspended in the air for hours and can be transported over short distances.

In theory, by leaving windows and doors open, these particles may be more likely to be transported but in what direction? Towards the people in the room or towards the great outdoors?

And what is the likely risk of causing infection?

That depends on the inoculum (amount or dose) of Covid-19 present in the first instance, the diameter of the particles, the direction of airflow within the room, to name but a few variables.

I’m afraid there are so many variables and basically there is a paucity of scientific data.

There is also indirect spread, which can occur by touching a contaminated surface/object. Some studies have shown the coronavirus can live up to 72 hours on surfaces depending on the surface, the inoculum of the virus shed, etc.

The real difficult part in preventing the spread of Covid-19 lies in addressing the three great areas of delay.

Firstly, the delay between becoming infected and the onset of symptoms; secondly, the time taken to get a Covid-19 test; and thirdly relying on individual to go into self-isolation immediately pending test results.

That’s why adhering to the strict guidance on preventative measure such as wearing masks, hand hygiene, cough etiquette and social distancing is so important.

Another big factor is the fact that symptoms vary greatly from person to person, with many carriers remaining asymptomatic but unknowingly causing spread.

Fever may be absent. The spectrum can range from what seems like a common head cold to more severe diseases such as bronchitis, pneumonia, severe Acute Respiratory Distress Syndrome (ARDS), multi-organ failure and even death.

Some of these symptoms may occur at various stages of the illness.

Flu-like muscle aches and pains, fatigue, headache, sore throat, nausea, vomiting, diarrhoea, cough, nasal congestion, viral conjunctivitis, sneezing, increased breathing rate or difficulty breathing, chest pain, reduced or complete loss of sense of smell (hyposmia or anosmia) and/or taste are all potential symptoms.

In answer to your question about cold draughts making people more prone to infection, it is fair to say that we all know to ‘wrap up well’ in the winter or to make sure to dry off well if you come in from the outdoors in cold and/or wet state.

From my understanding, there is no evidence to suggest that we are more prone to catching infection from exposure to cold weather, or from getting chilled.

Moreover, there is no scientific evidence to support the concept that exposure to moderately cold temperatures depresses our immune function thereby making us more susceptible to infection.


If you have any queries, email askthedoctor@independent.ie; Dr Jennifer Grant is a GP with Beacon HealthCheck

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