These two adjectives both describe diseases, referring to the way in which a person can get a disease.
Contagious means “can be spread from person to person.”
Infectious means “can give a person an infection; can infect someone.”
Practically speaking, these are almost the same thing, but technically there is a great difference.
Contagious refers only to the ability of a disease to spread from one living thing to another. So, for example, food poisoning is not contagious. Cancer is not contagious. Viruses and colds are the most usual contagious diseases.
An infection is the event in a body, where a virus or bacteria is reproducing itself. When part of your body becomes red, swollen, and painful, you may have an infection. You can have a virus or bacteria in your body, without having an infection—but if you become ill from bacteria or a virus, you do have an infection.
So, contagious and infectious have different meanings, although practically speaking they often happen together:
Many infectious diseases are contagious because contagion is a convenient way for an infection to spread.
Thank goodness that infections from insect bites are not usually contagious.
When you carry a contagious disease, without having an infection, you are called a carrier.
Keep reading for more examples of how to use these oft-confused words in a sentence.
More Examples of How to Use "Contagious" in a Sentence
- Mary’s positive attitude is definitely contagious, so you should try being around her more often.
- The energy at the concert was contagious and I found myself dancing even though I don't usually dance.
- His laughter was so contagious that I couldn't help but laugh along with him.
- How did this virus become so contagious?
- The disease is highly contagious, which poses a serious public health threat.
- The flu is contagious, so please stay home from work if you're sick
- Effective prevention of contagious diseases requires vigilance on the part of everyone in a community or workplace.
- Widespread panic is contagious and can quickly spread through a group of people.
More Examples of How to Use "Infectious" in a Sentence
- The infectious disease specialist had been asked to consult on the patient's case.
- Infectious diseases can be extremely serious and even deadly if not treated quickly.
- I'm afraid that this virus is highly infectious—and deadly.
- Prevention is the best way to avoid getting an infectious disease.
- The infectious laughter of the children caused the entire cafeteria to erupt in laughter of their own.
- The World Health Organization (WHO) has published a global strategy for the control of infectious diseases.
- Some infectious diseases can be cured, while others are incurable.
- The new virus variant is more infectious than the previous one.