Facts about the flu vaccine (Ⅰ)

chinacdc.cn | Updated: 2023-10-26
Q1 Why should people get an influenza vaccine?
Influenza, unlike the common cold, is an acute respiratory infection caused by the influenza virus. According to the World Health Organization, influenza can result in three to five million severe cases worldwide each year, with 290,000 to 650,000 respiratory-related deaths. Getting the vaccine is an effective measure to prevent influenza and reduce the risk of severe cases and deaths associated with it.
Q2 How many types of influenza vaccines do we have?

Available influenza vaccines include inactivated vaccines (including split virion vaccines and subunit vaccines), live attenuated vaccines, and recombinant vaccines. Inactivated vaccines are administered by intramuscular injection, while live attenuated vaccines are administered by intranasal spray. These vaccines can be categorized as trivalent or quadrivalent based on the components they contain. Compared to trivalent influenza vaccines, quadrivalent influenza vaccines include an additional lineage of influenza B strain.

Q3 When to get an influenza vaccine?
Usually, it takes 2 to 4 weeks for the antibody levels to reach protective efficacy after receiving the influenza vaccine. It is recommended that individuals receive the influenza vaccine one month before the onset of the flu season. If vaccination is not completed before the flu season begins, it can still be administered throughout the entire flu season.

Q4 Where to get an influenza vaccine?
Influenza vaccines are usually available at community health centers or hospitals. The availability of vaccination sites may vary by region, so it is advisable to consult the local health administration department for specific information.
Q5 Who should get an influenza vaccine?
People aged ≥6 months and without contraindications should receive the influenza vaccines.
The following priority and high-risk groups are recommended to get vaccinated in a timely manner:
1.Healthcare workers, including those involved in clinical care, public health, and health quarantine.
2.Individuals aged ≥60.
3.Individuals with one or more chronic diseases.
4.Vulnerable individuals and staff in nursing homes, long-term care facilities, and welfare institutions.
5.Pregnant women.
6.Children aged 6-59 months.
7.Household members and caregivers of infants aged <6 months.
8.Individuals in key locations such as daycare centers, primary and secondary schools, and regulatory facilities.

Q6 Who should not receive an influenza vaccine?
1.Individuals who are allergic to any component of the vaccine, including excipients, formaldehyde, splitting agents, or antibiotics, and those who have a history of severe allergic reactions to any influenza vaccine should not receive the vaccine.
2.Individuals with acute illnesses, severe chronic illnesses, or in the acute phase of a chronic illness, as well as those with a fever, are advised to wait until they have recovered or their condition is stable before receiving the vaccine.
3.Patients who have developed Guillain-Barré syndrome within six weeks after a previous influenza vaccination should consult a doctor before considering vaccination.
It is important to note that the following groups should not receive live attenuated vaccine:
1.Individuals with compromised immune function due to medications, HIV infection, or any other reason.
2.Children and adolescents who are on long-term treatment with medications containing aspirin or salicylic acid.
3.Children aged 2-4 with asthma.
4.Pregnant women.
5.Individuals with a history of Guillain-Barré syndrome.
6.Individuals who have used antiviral medications such as oseltamivir or zanamivir within 48 hours before vaccination, peramivir within 5 days before vaccination, or baloxavir within 17 days before vaccination.