Yellow fever vaccine: most common adverse reactions and what to do

Yellow fever vaccination is the most effective way to prevent and control the disease and is a drug considered safe and effective, although in some cases it can cause side effects, such as reactions at the injection site, fever, headache and muscle pain and, in more severe cases, anaphylaxis and neurological problems, in the liver or kidney.

The vaccine has in its composition live attenuated viruses, which stimulate the immune system to produce protective antibodies against the virus, which appear between the seventh and tenth days after the administration of the vaccine and, therefore, the vaccination should be performed about 10 days before the person travels to the risk region of the disease.

This vaccine is safe and effective from 9 months of age, and should be administered to people who are residents or who intend to travel to areas with vaccination recommendations. In the case of babies, the pediatrician may recommend a booster dose at age 4, to ensure more effective protection.

1. Pain, erythema and induration

The most common adverse reactions that can occur with the administration of the yellow fever vaccine are pain, erythema and induration at the application site. These reactions occur in about 4% of people, about 1 to 2 days after vaccination.

What to do: To relieve pain, erythema and inflammation, ice should be applied to the area. If there are very extensive injuries or limited movement, see a doctor immediately.

2. Fever, muscle and headache

Side effects such as fever, muscle pain and headache may also manifest, which can occur in about 4% of people, usually from the 3rd day after vaccination.

What to do: To relieve fever, the person can take painkillers and antipyretics, such as paracetamol or dipyrone, for example.

3. Anaphylaxis

Anaphylaxis is a very serious allergic reaction, which although rare, can occur in some people who receive the vaccine. Some of the characteristic symptoms of a severe allergic reaction are low blood pressure, shock and respiratory, cardiac and skin manifestations. These reactions usually occur in the first 30 minutes up to 2 hours after vaccination and, in these cases, you should immediately go to the emergency department. Know what to do in case of anaphylactic shock.

What to do: In view of these symptoms, you must urgently go to the medical emergency. In addition, revaccination is contraindicated.

4. Neurological problems

Neurological manifestations, such as meningism, seizures, motor disorders, changes in the level of consciousness, stiff neck, intense and prolonged headache or numbness are very rare, but also very serious reactions, which can occur about 7 to 21 days after vaccination. Intense and prolonged headache is a frequent symptom and can occur soon after vaccination, being a warning sign for possible neurological complications.

What to do: If you experience any of these symptoms, you should go to the doctor as soon as possible, who should investigate other serious neurological syndromes.

5. Acute viscerotropic disease

Also defined as acute multiple organ dysfunction, it is also a very rare but serious side effect that can occur after vaccination, which is characterized by the development of hepatitis, kidney failure or bleeding, along with symptoms such as fever, headache, fatigue, muscle and joint pain, nausea, vomiting, diarrhea and abdominal pain similar to the characteristic symptoms of yellow fever disease. These symptoms can occur in the first 10 days after vaccination.

Know how to recognize the symptoms of yellow fever.

As the disease progresses, jaundice, decreased platelets, elevated liver transaminases, total bilirubins and creatinine may occur. The most severe condition is characterized by low blood pressure, hemorrhage, acute renal failure and respiratory failure.

What to do: In case of acute viscerotropic disease, the person should receive intensive care and undergo dialysis.