From a public health point of view, flu epidemics spread rapidly and are very difficult to control.

The microbes were even put forward as an hypothesis for flu epidemics, literally a plague from space.

The first wave had resembled typical flu epidemics; those most at risk were the sick and elderly, while younger, healthier people recovered easily.

In fact, some researchers advise that vaccinating 3- and 4-year-olds against flu might help curb flu epidemics.

This rush is often aggravated by flu epidemics.

However, they happened at the same time as the flu epidemics that happen every year.

It causes yearly flu epidemics that are generally not deadly except to the very old or very young.

Officials in Houston and Dallas have already declared flu epidemics in those cities.

Type A and B viruses are responsible for the large flu epidemics.

Researchers find that the spread of yearly flu epidemics in an area within the US is closely connected with people going to and from work.