This type of preparation is usually associated with fewer side effects than whole-virus preparations. This group includes physicians and health care workers in hospitals, outpatient clinics and other institutions, as well as other employees in these workplaces who have contact with patients. The third group for whom influenza vaccination may be considered is people providing essential community services. Protection against influenza would minimize the disruption of routine activities during epidemics. Children younger than 9 years of age who have never been vaccinated for influenza before should be given a second dose 4 weeks after the first.
Intramuscular administration is preferred for all age groups.
The vaccines currently available are not very effective for infants under 6 months of age, and vaccination is therefore not recommended for this age group. Influenza vaccines are safe and associated with only minimal side effects. Allergic responses are rare. Vaccine should not be given to people who have had an anaphylactic reaction to a previous vaccine or who have shown anaphylactic hypersensitivity to eggs. Vaccination should be postponed for those with an acute febrile illness.