World Health Organization
As of 2016, the World Health Organization (WHO) recommends seasonal influenza vaccination for:First priority:

Pregnant womenSecond priority (in no particular order):

Children aged 6–59 months
Elderly
Individuals with specific chronic medical conditions
Health-care workers

Canada
The National Advisory Committee on Immunization (NACI), the group that advises the Public Health Agency of Canada, recommends that everyone over six months of age be encouraged to receive annual influenza vaccination, and that children between the age of six months and 24 months, and their household contacts, should be considered a high priority for the flu vaccine. Particularly:

People at high risk of influenza-related complications or hospitalization, including people who are morbidly obese, healthy pregnant women, children aged 6–59 months, the elderly, aboriginals, and people with one of an itemized list of chronic health conditions
People capable of transmitting influenza to those at high risk, including household contacts and health care workers
People who provide essential community services
Certain poultry workersLive attenuated influenza vaccine (LAIV) was not available in Canada for the 2019–2020 season. European Union
The European Centre for Disease Prevention and Control (ECDC) recommends vaccinating the elderly as a priority, with a secondary priority people with chronic medical conditions and health care workers.The influenza vaccination strategy is generally that of protecting vulnerable people, rather than limiting influenza circulation or eliminating human influenza sickness. This is in contrast with the high herd immunity strategies for other infectious diseases such as polio and measles. This is also due in part to the financial and logistics burden associated with the need of an annual injection.
Universal flu vaccines
A "universal vaccine" that would not have to be designed and made for each flu season in each hemisphere would stabilize the supply, avoid error in predicting the seasons variants, and protect against escape of the circulating strains by mutation. Such a vaccine has been the subject of research for decades.One approach is to use broadly neutralizing antibodies that, unlike the annual seasonal vaccines used over the first decades of the 21st century that provoke the body to generate an immune response, instead provide a component of the immune response itself. The first neutralizing antibodies were identified in 1993, via experimentation. It was found that the flu neutralizing antibodies bound to the stalk of the Hemagglutinin protein. Antibodies that could bind to the head of those proteins were identified.