Colds and Influenza

Colds and Influenza (flu) are both caused by a virus that is passed from one individual to another through the air. These two ailments also have common symptoms, which often leads to confusion of the two conditions. Colds and flu are not the same thing, flu is much more dangerous, and can be fatal. However, due to the similarity of the symptoms the treatments available are similar for both the flu and the common cold.
The flu has additional symptoms which make it identifiable from a cold. The symptoms of a cold, of which some or all may be present, include:
  • Headache
  • Runny/Blocked Nose
  • Sore Throat
  • Runny Eyes
  • Slight Fever
  • Dry Cough
The flu has the following additional symptoms:
  • Fever (High Temperature)
  • Lethargy
  • Sweating
  • Aching of the entire body (particularly) the joints
Another way to differentiate a bad cold from a case of flu is the duration of the infection and subsequent recovery. An individual will take longer to recover fully from the flu than they would from a common cold.
It is possible to vaccinate against flu by monitoring the slight changes in the virus each year. However, when faced with the massive variety of cold viruses it would be impossible to vaccinate against them all. This is why there is, as yet, no cure for the common cold.

Duration of InfectionOver 2 weeks7 to 10 days
Chance of catching the virusLowHigh
Chance of ReinfectionVery LowVery High
Vaccination AvailableYesNo
Epidemics/Pandemics occurYesNo
Can it be FatalYesNo

Definitions: An epidemic is the spread of the infection through a community (perhaps up to country size), a pandemic is the spread of the infection through the population of the world.


There are many products on the market which contain an even greater variety of active ingredients. These active ingredients can be categorised into 3 areas and all treat the symptoms associated with a cold and flu.
  • Analgesics
    Analgesics are included in cold and flu preparations to treat symptoms such as the headache, shivering, fever, aches and pains. Paracetamol (acetaminophen) is the most commonly used analgesic in these preparations with Aspirin and Ibuprofen making up the analgesic content of the other preparations. Many of these preparations also contain Caffeine which improves the analgesic effect of the painkiller and also helps with the feeling of lethargy in flu as it is a mild stimulant.

    Care with Analgesics
    Paracetamol is the the analgesic of choice since it is safer when taken at the recommended dose than any other analgesic. Paracetamol is the only recommended analgesic for use by children (those under the age of 12 years) since Aspirin can cause Reye's Syndrome.
    Care must be taken to avoid other forms of Paracetamol while taking cold and flu preparations. Examples of other sources of paracetamol include painkillers and other cold and flu preparations.
    Also, remember to take cold and flu preparations containing aspirin or ibuprofen with or after food to avoid the main side effect of these drugs, an upset stomach.

  • Decongestants
    Decongestants help to alleviate the symptoms associated with the nose and eyes. They reduce blood flow to the nasal lining and therefore slow the production of catarrh. This will help with a blocked and runny nose and also with running eyes as this symptom is connected with the catarrh in the nose.
    Decongestants must only be taken for short periods, up to a maximum of 7 days. Always follow the instructions that come with decongestants and never exceed the stated dose.
    Decongestants must also be avoided by people taking medication for blood pressure, thyroid dysfunction and diabetics. There is a range of decongestant free cold and flu preparations especially for these patient groups. Always check with your Pharmacist if you are unsure if a medication is suitable for you to use.

  • Cough Suppressants
    Cough Suppressants are included to relieve the symptoms of coughing and the sore throat. More information on cough suppressants can be found on the Dry Cough page.

Influenza Vaccines

The flu vaccine has been available for some time, however, it is not effective at halting epidemics or pandemics. For this reason it is only recommended for administration to those who are at most risk from the disease. The recommendations include those people suffering from:
  • Chronic Respiratory Diseases (eg. asthma, emphysema, chronic obstructive pulmonary disease)
  • Chronic Heart Failure
  • Chronic Renal Failure
  • Diabetes Mellitus
  • Immunosuppression (whether disease or drug induced)
  • Residents of Residential/Nursing Homes
  • Residents of other long-stay facilities
  • Healthcare workers with a high chance of exposure
The flu virus has two distinctive antigens or markers on its surface that make it readily distinguishable to our immune system, these are called haemagluttinin and neuramidase. The vaccines that are available make use of these. A safe form of these markers is injected into the person undergoing the vaccination. The markers are injected in one of two froms depending on the manufacturer of the vaccine.

Some vaccines use an inactivated viral particle, called a split virion, which would have been broken up into tiny fragments of the original virus, each piece will contain a sample of the markers and this will allow the vaccinated individual to gain resistance to the virulent strain of the virus.
The remaining vaccines work in the same way as the split virion but they purify the markers much more so that only the markers are injected. This type of vaccine has no benefit over the split virion method of vaccine manufacture and there is no price difference.

Both vaccines offer 70 to 80% protection from the wild virus although this level may be lower in the elderly. Vaccine usage should be avoided in those individuals who are pregnant and also by those who have an allergy to hens eggs since eggs are involved in the manufacturing process of the vaccine.

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