in the united states the flu season usually occurs from about november until april. officials have decided each new flu season will start on oct. 4. typically activity is very low until december and peak activity most often occurs between january and march. ideally the conventional flu vaccine should be administered between september and mid-november. it takes about one to two weeks after vaccination for antibodies against influenza to develop and provide protection. the cdc has published a summary list of their current recommendations of who should get the 2010-2011 vaccine: summary of influenza vaccination recommendations 2010 all people 6 months and older should be vaccinated annually. protection of people at higher risk for influenza-related complications should continue to be a focus of vaccination efforts as providers and programs transition to routine vaccination of all people 6 months and older. when vaccine supply is limited vaccination efforts should focus on delivering vaccination to people who are 6 months to 4 years (59 months) of age are 50 years of age and older have chronic pulmonary (including asthma) cardiovascular (except hypertension) renal hepatic neurologic hematologic or metabolic disorders (including diabetes mellitus) are immunosuppressed (including immunosuppression caused by medications or by human immunodeficiency virus) are or will be pregnant during the influenza season are 6 months to 18 years of age and receiving long-term aspirin therapy and who therefore might be at risk for experiencing reye's syndrome after influenza virus infection are residents of nursing homes and other chronic-care facilities are american indians/alaska natives are morbidly obese (body mass index is 40 or greater) are health-care personnel are household contacts and caregivers of children aged younger than 5 years and adults aged 50 years and older with particular emphasis on vaccinating contacts of children aged younger than 6 months; and are household contacts and caregivers of people with medical conditions that put them at higher risk for severe complications from influenza as each flu season progresses and as the cdc refines its data from previous flu seasons and pandemics this summary may be modified. the cdc publishes routine updates about the flu at flu. gov and at <link>.
who should receive the flu vaccine? when should someone get the flu shot?