What is BCG?

BCG or Bacillus Calmette-Guérin is a vaccine against tuberculosis. It is prepared from a strain of the attenuated live bovine tuberculosis bacillus, Mycobacterium bovis, which has lost its virulence in humans. The vaccine is 70-80% effective against the most severe forms of tuberculosis (TB). The World Health Organization (WHO) has classified Thailand as having a high incidence of tuberculosis and recommends the BCG vaccine to all newborns.

 

Who should receive the BCG vaccine?

• Babies born in Thailand should receive the vaccine at birth.
• Babies born to mothers infected with HIV (Human Immunodeficiency Virus).
• Person who living for three months or more in a country where is a high rate of tuberculosis.
• Person who being in close contact for a prolonged period with someone who has pulmonary tuberculosis.

 

How to give the BCG vaccine?

BCG vaccine is given by an injection just under the skin, usually on the upper arm as a single dose. If who have never received the BCG vaccine at birth, BCG vaccine can be given right away in every age and immunity against tuberculosis is most effective 2 months after the vaccine is administered.

 

Who should not receive the BCG vaccine or should wait?

• Persons with a history of allergic reactions to vaccines or the components of vaccines.
• Persons with an infectious skin disease or burn wound in the area where the vaccine must be administered.
• Persons with compromised immunity or those taking immunosuppressant drugs or undergoing radiation, with the exception of those infected with HIV (Human Immunodeficiency Virus) but exhibiting no symptoms who did not receive the vaccine as a newborn. The doctor may have to determine the suitability of each patient for the vaccine on a case-by-case basis.
• Pregnant women.
• hildren suffering from an acute infection or those who are severely ill. The vaccine may need to be delayed until they are well.

 

Vaccination reaction

After the vaccine is administered, a small lump will be seen on the skin, measuring approximately six to eight millimeters. After one hour the skin will flatten, while the injection site will remain red for two to three days. After two to three weeks of receiving the vaccine, blisters will form at the injection site and these may ooze some discharge. The blisters will break and a scar measuring four to five millimeters will form. This scar will fade and reappear for three to four weeks and will then heal, leaving a small scar.

 

Caring for the vaccination site

Keep the area clean and wipe as needed with boiled water or normal saline solution (NSS) and dry it carefully. Once a blister forms, do not pick on it or drain the blister. Once the blister breaks, do not apply any medication to it. Wipe it clean with boiled tap water or normal saline solution (NSS) as needed.

** If the wound does not dry up within 2 weeks, consult the doctor as soon as possible

 

What are the undesirable effects of BCG vaccine?

Possible side effects divided into 2 types

1. Common side effect (not severe) such as injection site irritation (90-95%)
2. Rare but severe;

 

Reaction	Onset	incidence (Per 1 million dose)
Enlarged or inflamed lymph nodes	2-6 months	100-1,000
BCG Osteitis	1-12 month(s)	1-700
Disseminated BCG	1-12 month(s)	2

 

Drug interactions

BCG vaccine is a live attenuated vaccine which can be given concurrently with other live attenuated vaccines. If not give at the same time, they should be given at least 4 weeks interval to minimize the potential risk for interference.
 


References

• Centers for Disease Control and Prevention. The Role of BCG VACCINE in the Prevention and Control of Tuberculosis in the United States. MMWR 45(RR-4):1996;1-18.
• Kulkanya Chokephaibulkit, Chonnamet Techasaensiri, Wirachai Watthanawiradet, Achara Tangsathaporpongs, Rudeewilai Samkoses (Editor). Textbook of Vaccines and Creating Immunity 2019. Bureau of General Communicable Diseases, Department of Disease Control, Ministry of Public Health. 2019. Page 91-95.
• University of Oxford. BCG Vaccine (TB vaccine). Available from: http://vk.ovg.ox.ac.uk/bcg-vaccine [Accessed 19 December 2022].