Compare symptoms
Influenza, a cold, and stomach upset are different illnesses
The chart below shows the differences between influenza, a cold and a stomach upset. It also notes the differences of pandemic H1N1 influenza.| Type of infection | Respiratory infection |
Gastrointestinal infection | |
| Description / symptoms |
Influenza |
Common cold |
Stomach upset* |
| Virus involved | Influenza A or B Note: Pandemic H1N1 influenza virus is a type of influenza A. |
Many different kinds of viruses such as rhinovirus, coronavirus, adenovirus, etc. | Norovirus (Norwalk-like viruses) is the most common. |
| Fever | Usually high, beginning suddenly and lasting 3–4 days. | Sometimes | Rarely |
| Headache | Usually, can be severe. | Rarely | Sometimes |
| Chills, aches, pain | Usually, and often severe. | Rarely | Common |
| Loss of appetite | Sometimes. Pandemic H1N1 influenza symptoms may also include nausea, vomiting and diarrhea. |
Sometimes | Frequently – usually nausea, vomiting and diarrhea occur as well. |
| Cough | Usually | Sometimes | Rarely |
| Sore throat | Sometimes | Sometimes | Rarely |
| Sniffles or sneezes | Sometimes | Usually | Rarely |
| Extreme tiredness | Usually – tiredness may last 2–3 weeks or more. | Rarely | Sometimes |
| Involves whole body | Usually | Never | Stomach and bowel only. |
| Symptoms appear quickly | Yes | More gradual | Yes |
| Possible Complications (Health problems) |
Pneumonia, kidney failure, swelling of the brain and death. | Sinus infection or ear infection. | Dehydration (losing more fluid than you take in). |
| Vaccine | Yearly vaccine provides protection against two influenza A strains and one influenza B strain. Vaccine for Pandemic (H1N1) 2009 influenza is now available. |
No vaccine available. | No vaccine available. |
* Note: A stomach upset is sometimes incorrectly called the "stomach flu" – there is no such illness as "stomach flu." As noted in the chart, stomach upsets are caused by viruses and other micro-organisms but not by the influenza virus.
