Viruses and Colds

Catching a virus or cold is a common occurrence. Such infections are self-limiting and will settle within one to two weeks. Most people do not require any treatment, since the body is very good at fighting off coughs, colds and viruses. Unfortunately, there is very little that modern medicine can do to help against such conditions, and antibiotic prescribing is generally not appropriate.

Viral vs. Bacterial Infections

Viral infections are much more common than bacterial infections. The typical symptoms of a viral infection include:

  • Raised temperature (though it may be normal)
  • Cough (including yellow or green sputum)
  • Runny nose
  • Earache
  • Sore throat
  • Achy joints
  • Low appetite
  • Feeling ‘under the weather’

You may have some or all of these symptoms, and they may come and go at different times.

An infection is more likely to be viral if others in the family are similarly affected, since bacterial infections are not easily passed from one person to another.

A bacterial infection is more likely if a person suffers from asthma or COPD (though infections can still be viral).

Treatment of Viral Infections

Unfortunately there is no specific treatment available for viral infections. Any treatment given is generally supportive in nature. This may include regular paracetamol or ibuprofen and fluids. Mouthwash can be given for sore throats.

Antibiotics do not work against viral infections, only against bacterial infections. Therefore, they should not be prescribed since they will have no effect. Furthermore, they can cause side-effects of diarrhoea, vomiting and rash; as well as causing antibiotic resistance, which is a growing problem.

Throat Infections

Most sore throats are caused by a viral infection and are often accompanied by the symptoms listed above. Management for viral infections is also as detailed above. About 50% improve in 3 days5 and 85% resolve in one week.1,4

Rarely, infections can be caused by bacteria, giving rise to tonsillitis. The Centor Criteria help distinguish whether a throat infection is likely to be viral or bacterial.4 If a person has three or more of the following, the infection is likely to be bacterial and would benefit from a course of penicillin antibiotics:

  1. Pus on the tonsils
  2. Painful lymph nodes/glands in the neck
  3. Absence of cough
  4. Fever (usually with sweats and shivers)

If you have three or more of the above symptoms, you should see the doctor in an ‘emergency appointment’ as you may have tonsillitis and may need a course of antibiotics.


Cough can be very troublesome and is usually worse at night (due to lying flat). It  can cause dizziness, headache, chest pain (from a pulled muscle), sickness or leakage of urine (more likely in women). Unfortunately, there is generally nothing that can be done to make a cough go away any faster. It will go of its own accord when the time is right.

Cough can last up to 6-8 weeks before it goes away. You do not need to see a doctor during this time unless you are short of breath, are coughing up blood or are losing weight. If the cough is still present after 6-8 weeks, you should see the doctor and have a routine chest x-ray.

Cough medicine is generally not recommended (for both children and adults), since there is a lack of evidence to suggests it has any beneficial effect. Furthermore, both the Food and Drug Administration (USA) and the Medicines and Healthcare products Regulatory Agency (UK) have recommended that cough medicine not be sold to or used for children under two years of age.2,3

Usual Duration of Viral Infections

Infection Duration
Otitis media (ear infection) 4 Days
Sore throat (including tonsillitis) 1 Week
Common Cold 1½ Weeks
Rhinosinusitis (runny nose) 2½ Weeks
Cough 3 Weeks

When do I need to see the doctor?

People in the following groups should make an ‘emergency appointment’ to see the doctor, since they are likely to benefit from antibiotics and may require further investigation or management.

  • Children <2 years with earache on both sides
  • Children with earache and ear discharge
  • People with tonsillitis (see separate article)
  • People who are very unwell (e.g. fevers, rigors, shaking, drowsy, dehydrated, poor urine output, etc)
  • People with significant heart, lung, kidney, liver or neuromuscular disease
  • People with immunosuppression and cystic fibrosis
  • Young children who were born prematurely
  • People over 65 years with cough and two or more of:
  • People over 80 years with cough and one or more of:
    • Diabetes
    • Heart failure
    • Hospitalisation in the previous year
    • Currently taking steroids


  1. NICE Guidance CG67 (Quick reference guide) – Respiratory tract infections – Prescribing of antibiotics for self-limiting respiratory tract infections in adults and children in primary care (July 2008)
  2. Food and Drug Administration. Nonprescription Drug Advisory Committee Meeting. Cold, cough,
allergy, bronchodilator, antiasthmatic drug products for over-the-counter human use.(accessed 6 Oct 2008)
  3. Medicines and Healthcare products Regulatory Agency. Updated advice — ver-the-counter cough
and cold medicines for young children. (accessed 6 Oct 2008).
  4. MeReC Bulletin 2006;17(3):12-14
  5. Del Mar C et al. Antibiotics for sore throat. Cochrane Database Syst Rev 2004;(2): CD000023 (cited from GP Notebook 2008)