In an attempt to encourage people to get their flu shot, the Centers for Disease Control and Prevention have named this week “National Influenza Vaccination Week” and Tuesday in particular “Children’s Flu Vaccination Day.” Each year, the flu season which officially begins in late September continues to be a significant public health challenge.

For those that don’t know yet, the Centers for Disease Control and Prevention recommend that all kids aged 6 to 18 years get the flu shot needed for full protection against influenza, as well as pregnant women who will be pregnant during the flu season-October through mid-May, persons over 50 years old, people with certain chronic medical conditions and residents of nursing homes or other chronic-care facilities.

Unlike last year when a surprise new influenza strain emerged, the CDC said that this year’s vaccine, which contains one influenza B strain and two influenza A strains, is a good match and should offer plenty of protection. The U.S. has 145 million doses of flu vaccine available this year. However, experts warn that not enough people are getting vaccinated, including many individuals at high risk for contracting the flu.

The message for most people is get your flu shot! About two weeks after vaccination, antibodies that provide protection against virus infection develop in the body. The CDC says the vaccine is 90% effective in healthy adults. Older people and people with certain chronic illnesses might develop less immunity than healthy young adults after vaccination. However, even for these high-risk individuals, the vaccine still can provide protection against getting severe complications from the flu, the CDC says. Vaccination serves to protect both patient and health care provider from becoming infected with influenza, as well as transmitting the virus to others. Studies have shown that a person can infect others from about one day before becoming sick to about five days after developing symptoms.

According to data from the Centers for Disease Control and Prevention, one in five Americans get the flu every year. Of these, 200,000 are hospitalized and about 36,000 die from influenza-related complications. Up to 90% of them are seniors. Last year, 86 children between the ages of 15 and 17 died of influenza.

This year, the CDC’s recommendations, supported by the National Foundation for Infectious Diseases and the American Academy of Pediatrics, expand the number of children targeted by flu vaccinations to include all school-age children. School-age children, on average, miss five days of school a year due to influenza.

Influenza’s symptoms include chills and fever, sore throat, muscle pains, severe headache, coughing, weakness and general discomfort. The flu remains infectious for around one week within human body temperature. Serious flu cases can develop in pneumonia, which in young children and the elderly alike can be fatal, which is why the latter two categories are the most urged to get vaccinated against influenza.