INDIANAPOLIS - The number of flu-related deaths in Indiana jumped to 21 on Monday, state health officials said.

Two children are among those who have succumbed to the illness, which has infected thousands across the country.

An earlier-than-usual flu season is hitting harder than in recent mild seasons, with the illness widespread across much of the country.

Officials with the Indiana State Department of Health said no official shortages of the influenza vaccine have been reported, but noted that it may be more difficult to find the vaccine with the current high demand.

This year's vaccine protects against the three most common strains of influenza -- H3N2, H1N1, and Influenza B. The H3N2 strain appears to be the most prominent this season.

Those 6 months and older are urged to get vaccinated.

Symptoms of the flu include a fever of 100 degrees or higher, headache, fatigue, cough, muscle aches and sore throat.

More: Flu information