"And if both tests are positive, infection most probably occurred more than six months earlier."

Such infections generally occur later in life through sexual activity.

Most patients are aged 2 to 5 years, but infection may occur in any age group.

But infections can occur with no particular pattern throughout the year.

Most infections occur in those who are middle-aged or older.

Frequent infections may occur over the course of the disease.

At what point, during pregnancy or birth, does infection occur?

This means that few new infections would occur in a study group whether or not its members took the vaccine.

Infection does not occur often and can be treated with antibiotics.

Infections can occur without a known injury to the affected area.