BCG vaccine is one of the first vaccines given after birth to a newborn. BCG vaccine protects against TB or tuberculosis.
TB is one of the most prevalent infections in our country. In India, Every year, more than2.5 million people get this disease, 10% of which are children. More than 4 lac people lose their lives to TB each year. TB can affect most of our organ systems. Chest TB is the most common, but TB can also cause infection in brain, spine, bones, LN, intestine, uterus etc.
Tuberculosis occurs most commonly in children less than 5 years. While pulmonary TB is the predominant form of TB in children, around 30–40% have extrapulmonary TB. Children, who develop TB disease, usually do so within 1 year following infection. Infants especially <2 years are at risk of developing severe widespread TB, also brain TB associated with a high risk of death. Tuberculosis frequently spreads in poor, crowded, and poorly ventilated settings. HIV infection and malnutrition also increase risk of TB. Adolescents are at increased risk of TB, also they may be the source of transmission to others.
BCG is the only vaccine effective against TB. BCG means Bacillus Calmette Guerin, its almost a 100 yr old vaccine. It’s a live attenuated vaccine, made from bovine strain of TB bacteria, which is harmless to humans, but gives protection.
BCG vaccination should be done at birth or as soon as possible after birth. It can also be given to low birth weight and preterm infants between 32-36 weeks of gestation. It is given intradermally, that is in the superficial layers of skin, on the left upper arm, as a convention. It is not advised to begiven in thigh or buttocks, because more chances of side effects. Initially, there is small wheal at the injection site, it is important not to rub, or touch the injection site for 2 days. After 2–3weeks, a small boil or papule develops which increases to a size of 4–8 mm by the end of 5–6 weeks. This papule then breaks down, sometimes discharging pus, and results in a scar after 6–12 weeks. It is important not to apply anything or bandage the area when BCG boil bursts.
Around10% of children do not develop a scar and that does not mean that protection has not been achieved. Older children who have missed their BCG vaccine can also get this vaccine if their TST or IGRA TB test is negative.
Side effects of BCG vaccine are rare and usually include injection site abscess, or lymph node enlargement locally. These are treatable and recover well.
Protection by BCG against pulmonary TB is variable, from 44-90% according to different studies. More importantly, it reduces severe form of TB like brain TB by 85%. Vaccine given in new born period is more effective. Thus, we can see that TB is an important and dangerous illness prevalent in India. Therefore, we should all vaccinate our children with BCG vaccine to protect against this disease.