Common viral infections

Most infections are caused by viruses and the most common of these are colds, influenza (the flu) and flu-like illness. The common cold is caused by a group of viruses called rhinoviruses and influenza by ones called influenza viruses. It is much more likely complications can be serious with flu rather than a cold. There are other differences, explained in this topic, and some steps you can take when you have a cold or flu.

How are colds and flu similar?

Colds and the flu can cause symptoms such as sore throat, sneezing, a blocked, stuffy or runny nose, and dry, tickly or chesty cough. They may both leave you feeling tired or give you a headache.

How are colds and flu different?

The flu tends to come on strongly and suddenly (peaking in a day or two) whereas a cold may develop over a few days when you might feel ‘off colour’.

The flu has some symptoms which are less common with a cold, including:

• body (eg, back) and muscle aches
• shivers, chills and sweats
• fever (body temperature over 38°C) and headache
• exhaustion and weakness (may force you to bed)
• feelings of nausea
• poor appetite, vomiting or diarrhoea.

Influenza can mostly be prevented by annual vaccination (which currently includes the swine flu H1N1 variant), but there is no vaccine to prevent a cold.
TIP: Ask your GP about the annual influenza vaccine. It is free if you are over 65, pregnant or have certain long-term health conditions.

General cold symptoms - getting relief

General cold symptoms should last a few days then start to improve.

While you have a cold try to:

• get some rest – this helps speed your recovery
• drink plenty of fluids and avoid alcohol – this is important and it helps keep your mucus thin and loose and easier to blow out or cough up
• inhale steam or menthol/eucalyptus vapour for a blocked nose (put a towel over your head and the bowl of water) or try saline nasal drops or rinses
• suck lozenges or a teaspoon of honey for a sore throat
• take a pain relief medicine for headache, pains and fever and note the ingredients of any other remedies you are taking so as not to ‘double dose’ on things like paracetamol or ibuprofen, which is an easy but dangerous mistake
• ask a pharmacist for advice first before choosing products that may help with common lingering symptoms such as nasal congestion or a troublesome cough.
• IMPORTANT: Children under 16 years should not be given aspirin and children under six years should not use over-the-counter cough and cold remedies.

TIP: Visit the website www.pharmacylive.co.nz for general information on cough, cold and other pharmacy products.

Seek advice if symptoms persist

If you are usually fit and well but your symptoms do not start to improve in five to seven days, call Healthline free on 0800 611 116 or contact your doctor. If the person who is unwell has other health problems, or is a baby, child or an elderly person you should seek help at any time if you are worried or if they could be dehydrated.

Will antibiotics help me?

Antibiotics only treat bacterial infections. They do not cure cold or influenza viruses, or stop colds or the flu from getting worse. It takes a few days for your own immune system to start tackling these viruses, and within a week or two you should feel better.

Having a viral infection does, however, make it more likely to get a bacterial infection as well (called a secondary infection). This often affects the lung, sinuses, tonsils or ears.

Signs you might have a bacterial infection include:

• mucus becoming thick and green, yellow or bloody
• painful lungs, wheezing or being short of breath
• sore or painful ears, tonsils or sinuses.

If your doctor thinks you might have a serious secondary bacterial infection on top of your viral infection, antibiotics may be prescribed to kill off the bacteria.
TIP: Visit the website www.kickthatbug.co.nz to learn more about taking antibiotics.

What if I have the flu?

If you think you have the flu and become at all worried, phone your doctor. Influenza can lead to complications such as bacterial chest infection or pneumonia and can be much more serious for some people, including:

• older people
• people with long-term health problems (eg, cancer, kidney, heart or lung disease including asthma)
• pregnant women
• people who are very overweight (obese).

It is very important to avoid becoming dehydrated while you have the flu, particularly as you may be fatigued and not feel like drinking fluids. The ‘cold relief’ tips above may also help with the flu, particularly pain relief for aches.
TIP: An antiviral drug may shorten the flu but only if taken in the first 48 hours of symptoms – talk to your doctor.

Controlling spread of infection

If you have the flu it is important to not infect others, some of whom may suffer much more severe effects than you. Stay at home unless you must go out. Cover your coughs and sneezes (with your elbow sleeve if necessary) and dispose of used tissues in a bin. Wash or sanitise your hands with an alcohol gel and keep surfaces and handles at home wiped clean. 

Could it be something else?

It is not easy to tell the symptoms of a bad cold from a mild flu, and some symptoms are also much like those of other infections, some of which can be very serious.

The most urgent one to consider is meningococcal disease, an infection of the blood and/or brain, which first can appear like flu but worsens quickly and can kill. If you think a person might have this, it is vital to contact a doctor or hospital immediately, day or night. If treated early with antibiotics, death or disability can be avoided.

Symptoms of meningococcal disease

Having only a few of these signs should alert you.

Older children, teens and adults may:

• have a fever and severe headache
• vomit, have diarrhoea or cramps
• be sleepy, confused, delirious or unconscious
• have a stiff neck (can you touch your chin to your chest?)
• dislike bright lights
• have joint pain and aching muscles
• have a rash or spots (anywhere, no matter how small)

A baby or infant may:

• have a fever (perhaps also cold hands and feet)
• cry or be irritable, especially when picked up
• have a high-pitched, moaning cry
• refuse drinks or feeds
• vomit
• be sleepy or floppy or harder to wake
• have a stiff neck
• have a bulging fontanelle (top of the head in babies)
• dislike bright lights
• have skin that is pale, blotchy or turning blue
• have a rash or spots (anywhere, no matter how small).

Further information and support

You can phone Healthline on freephone (within New Zealand) 0800 611 116 for 24-hour advice, or call your GP. If you visit your GP let the receptionist know in advance if you have flu, or when you arrive.

Related topics

Also see: Influenza and Pneumococcal disease

Original material provided by everybody, November 2011.