Who is commonly affected

Typhoid fever may occur at any age , but the commonest age is between 5-19 years. After, the age of 30 years, the incidence falls probably due to acquisition of immunity from clinical or subclinical infection.
More cases are reported among males than females. But carrier rate is more in females. Carrier can spread the disease.
Commonly occurs in low socio-economic group where water supply and sanitation facilities are poor.