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The H3N2 vaccine is the influenza vaccine, which protects against type B and type A influenza, which includes subtypes H1N1 and H3N2. This vaccine should be applied every year, as the Influenza virus is quite changeable, so its composition is updated every year to provide more protection against circulating variants.
Currently, the H3N2 variant in circulation is known as Darwin variant and, although the Influenza vaccine administered in 2021 was not produced taking this variant into account, it was verified that the vaccine is capable of conferring a cross protection. That is, the current flu vaccine helps to neutralize this variant in circulation and reduce the risk of infection.
The flu vaccine is indicated for everyone from 6 months of age, being mainly indicated for the elderly and children, who have a more fragile immune system, in addition to he alth professionals.
When to get the vaccine
The flu vaccine, which protects against H3N2, is indicated for all people over 6 months of age, however it is mainly recommended for people who have a weaker immune system and/or who are more likely to enter in contact with the virus, for example:
- He althcare professionals;
- Chronic diseases such as diabetes, asthma or bronchitis;
- Immunocompromised people due to illnesses such as HIV infection and cancer;
- Carriers of genetic alterations, such as trisomy 21, characteristic of Down Syndrome;
- Carriers of cardiac, renal, neurological, hepatic and/or chronic respiratory disorders;
- Pregnant women and women up to 45 days after childbirth;
- Primary and higher education teachers;
- Indigenous population.
The vaccine is made available free of charge by the SUS at he alth centers, especially during the months of the flu vaccine campaign or in emergency situations, such as in the case of an epidemic, for example. In addition, it is also possible to find the vaccine for H3N2 in private clinics.
I have flu or COVID symptoms, can I get the vaccine?
In the presence of flu symptoms, such as headache, fever, runny nose, body ache and headache, it is recommended not to vaccinate, and wait about 7 days after the symptoms disappear. If there is only fever as a symptom, you should wait 48 hours after the fever has disappeared before taking the flu vaccine.
If a coronavirus infection is suspected, testing for COVID-19 is indicated to rule out this infection. If the test is positive for COVID-19, it is recommended to wait 14 days after the symptoms disappear before taking the flu vaccine.
Is it necessary to get a flu shot every year?
Yes, because the Influenza virus undergoes several mutations throughout the year, so the vaccine may not have the same effect or provide the same level of protection against the new variants in circulation the following year.
In this way, an annual update of the vaccine is carried out, taking into account the characteristics of the viruses circulating in the place, so that it is possible to obtain a more effective protection.
Can I get the H3N2 and COVID-19 vaccine on the same day?
It is possible to take both vaccines on the same day, with no risk of interfering with the action of the two immunizers. Vaccines can be applied to different muscle groups, that is, one in each arm, or in the same arm with a distance of at least 2.5 cm, so that it is possible to differentiate the local reactions that may occur. Clarify other doubts about the vaccine for COVID-19.
Possible side effects
Reactions to the H3N2 vaccine are infrequent, but some people may report pain, redness, and hardening of the area where the vaccine was applied, and these symptoms can last up to 48 hours. In some cases, it is also possible to have fever, malaise, body pain and headache. Learn about other possible flu vaccine symptoms.
When not indicated
The H3N2 vaccine is not indicated in case of allergy to egg protein or latex, nor for people younger than 6 months or who have had a severe allergic reaction to the previous dose of vaccine.