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adults average only 2 or 3 a year. The principal cause of the common cold is a group of 50 to 60
different viruses known as rhinoviruses. In addition to rhinoviruses, which seem to account for
the majority of common colds, certain other viruses have also been associated with the disease.
Since so many viruses cause the common cold, it is unlikely that artificial immunization, that is
any medication to prevent it, will be probable for some time. A natural form of immunity does
exist; but an individual must be infected with all of the many cold-producing viruses before he
is truly immune to the disease. Evidence of natural immunity is the fact that colds occur less
frequently in older persons. This is the result of immunity acquired from cold infections in the
past. It also reflects their lessened contact with small children, a major source of infection.
16. The common cold is more usually seen in................
a) people who are artificially immunized
b) people who become naturally immune to disease
c) parents with small children
d) small children
17. Artificial immunization to common cold will not protect a person from it all his life
as.................
a) the common cold is not cause by one specific virus
b) there is no medication to fight against common cold
c) common cold is a very contagious virus infection
d) he or she will be now and then in contact with others with common cold
18. "The disease is also more prevalent among certain age
groups" refers to.................
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