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BCG is a vaccine indicated against tuberculosis and is usually administered shortly after birth and is included in the child's basic vaccination schedule. This vaccine does not prevent infection or the development of the disease, but it does prevent it from evolving and prevents, in most cases, the most serious forms of the disease, such as miliary tuberculosis and tuberculous meningitis. Learn more about tuberculosis.
The BCG vaccine is composed of bacteria from the Mycobacterium bovis(Bacillus Calmette-Guérin), which have an attenuated viral load and, therefore, help to stimulate the body, leading to the production of antibodies against this disease, which will be activated if the bacteria enters the body.
The vaccine is available free of charge by the Ministry of Health, and is usually administered at the maternity ward or at the health center soon after birth.
How it is administered
The BCG vaccine should be administered directly to the top layer of the skin, by a doctor, nurse or trained health professional. Generally, for children under the age of 12 months the recommended dose is 0.05 mL, and over the age of 12 months is 0.1 mL.
This vaccine is always applied to the child's right arm, and the response to the vaccine takes 3 to 6 months to appear and is noticed when a small raised red spot appears on the skin, which develops into a small ulcer and, finally, a scar. The scar formation indicates that the vaccine was able to stimulate the baby's immunity.
Care after the vaccine
After receiving the vaccine, the child may have an injury at the injection site. In order for the healing to be done correctly, one should avoid covering the lesion, keeping the place clean, not applying any type of medication, or dressing the area.
Possible adverse reactions
Usually the tuberculosis vaccine does not lead to side effects, in addition to the occurrence of swelling, redness and tenderness at the injection site, which gradually changes to a small blister and then to an ulcer in about 2 to 4 weeks.
Although it is rare, in some cases, swollen lymph nodes, muscle pain and sore at the injection site can occur. When these side effects appear, it is recommended to go to the pediatrician to have the child evaluated.
Who should not take
The vaccine is contraindicated for premature babies or those weighing less than 2 kg, and it is necessary to wait for the baby to reach 2 kg before the vaccine is administered. In addition, people with allergies to any component of the formula, with congenital or immunodepressive diseases, such as generalized infection or AIDS, for example, should not get the vaccine.
How long is the protection
The duration of protection is variable. It is known that it has been decreasing over the years, due to the inability to generate a sufficiently robust and long-lasting amount of memory cells. Thus, it is known that protection is superior in the first 3 years of life, but there is no evidence that protection is greater than 15 years.
Can the BCG vaccine protect against coronavirus?
According to the WHO, there is no scientific evidence to show that the BCG vaccine is capable of protecting against the new coronavirus, which causes the COVID-19 infection. However, investigations are underway to understand whether this vaccine could actually have any effect against the new coronavirus.
Due to a lack of evidence, the WHO recommends the BCG vaccine only for countries where there is an increased risk of contracting tuberculosis.