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The H1N1 vaccine contains fragments of the influenza A virus, which is a variant of the common flu virus, stimulating the action of the immune system to produce anti-H1N1 antibodies, which attack and kill the virus, protecting the person against the disease.
This vaccine can be taken by anyone, but some specific groups take priority, such as the elderly, children or people with chronic diseases, as they are at greater risk of serious complications that can be life-threatening. After taking the vaccine, it is common to have adverse reactions such as pain, redness or swelling at the injection site, which improve in a few days.
The H1N1 vaccine is made available by SUS free of charge to risk groups, being administered at he alth posts in annual vaccination campaigns. For people who do not belong to risk groups, the vaccine can be found in private vaccination clinics.
Who can take it
The H1N1 vaccine can be taken by anyone over 6 months of age to prevent infection caused by the influenza A virus, which is H1N1.
However, some groups have priority to get the vaccine:
- He alth care professionals;
- Pregnant women at any gestational age;
- Women up to 45 days after childbirth;
- Older people over 60 years old;
- People with chronic diseases such as kidney or liver failure;
- People with lung diseases such as asthma, bronchitis or emphysema;
- People with cardiovascular disease;
- Adolescents and young people aged 12 to 21 under socio-educational measures;
- Prisoners and professionals in the prison system;
- Children from six months to less than six years old;
- Indigenous population.
The protection offered by the H1N1 vaccine usually occurs from 2 to 3 weeks after vaccination and can last from 6 to 12 months, so it should be given every year.
Who cannot take it
The H1N1 vaccine should not be given to people who are allergic to eggs, as the vaccine contains egg proteins in its preparation, which can lead to severe allergic reaction or anaphylactic shock. Therefore, vaccines are always administered in he alth centers, hospitals or clinics that have equipment for immediate care in case of an allergic reaction.
Furthermore, this vaccine should not be taken by children under 6 months of age, by people with fever, acute infection, bleeding or clotting problems, Guillain-Barré syndrome, or in cases where the immune system is weakened as in HIV carriers or undergoing cancer treatment.
Main adverse reactions
The main adverse reactions in adults that can occur after taking the H1N1 vaccine are:
- Pain, redness or swelling at the injection site;
- Eye irritation;
- Muscle pain.
Usually, these symptoms are temporary and improve in a few days, however, if they do not improve, you should inform your doctor or seek emergency care.
In children, the most common adverse reactions, which should be reported to the pediatrician who regularly monitors the child, are pain at the injection site, irritability, rhinitis, fever, cough, loss of appetite, vomiting, diarrhea, muscle pain or sore throat.
How to know if the vaccine is safe
All vaccines administered in the private network or in hospitals and he alth centers by the SUS are approved by Anvisa, which has a strict quality control of vaccines and, therefore, are reliable and protect the person from various diseases.
The H1N1 vaccine is safe, but it is only effective if the person's immune system produces enough anti-H1N1 antibodies to prevent infection by the virus, so it is important to get the vaccine annually, especially for people who belong to the risk group to avoid complications that can be fatal.