The BCG vaccine is one of the most important vaccinations in countries in which people have a medium to high risk of contracting tuberculosis (also known as TB). Below are the full answers about BCG Vaccines.

Tuberculosis is a potentially serious infectious disease that affects the lungs. The challenge lies in getting treated, and most TB strains resist the drugs meant to provide treatment. People suffering from TB end up taking months of medications to get well. The BCG vaccine appears to be the most viable means to deal with the disease worldwide. Prevention is better than cure.

Naturally, there are many misconceptions and queries regarding the various aspects of the vaccine, the disease per se, its symptoms, treatment and recovery. Therefore, this write-up aims to shed light on some frequently asked questions (FAQs) on the BCG vaccine and give you a thorough and comprehensive outlook.

Q: What is BCG vaccine?

A: The BCG, or the Bacillus Calmette-Guérin vaccine, is a vaccine against tuberculosis (TB). The BCG vaccine is formulated using live bacteria that do not cause disease in healthy people. It is used to prevent tuberculosis in those who haven’t been infected by the disease but are at high risk of contracting it. The BCG vaccine is about 70-80% effective against the most severe TB forms, such as meningitis.

The BCG vaccine, currently the only vaccine for TB, has been available for more than 80 years and is one of the most widely used of all current vaccines. In addition, this vaccine is relatively inexpensive, safe, and readily available in most cases.

Q: How well does the BCG vaccine work?

A: The weakened strain of bacteria in the BCG vaccine helps to build immunity and fights tuberculosis if one is infected with it. The weakened strain does not cause TB per se and provides up to 80% protection against TB meningitis.

The vaccination is primarily given to babies and young children to offer effective protection against TB; it is less effective in adults. While the vaccine is not too effective in adults, it is still provided to adults aged 35 if their job profile involves a high risk of TB.

Overall, the BCG vaccine is still the primary vaccination for TB even after eight decades since its inception.

Q: What is the BCG vaccine made of?

A: The typical BCG vaccine contains a weakened strain of the bacterium closely associated with the one that causes TB in humans. To be more precise, the bacterium particularly used for the vaccine is Mycobacterium bovis, which is responsible for tuberculosis in cows.

In addition to the bacterium, the vaccine also consists of the following ingredients:

Antigens
Citric acid
Sodium, potassium and magnesium salts
Glycerol

Q: What are the side effects associated with the BCG vaccine?

A: Common side effect

Soreness at the site of injection, accompanied by a reddish blister

Uncommon side effects

Throbbing headache
Fever
Painful ulcer resulting from the blister at the injection site, around 2-6 weeks after the administration
Swollen or enlarged lymph nodes that may or may not become infected

Rare side effects

Severe skin reactions such as rashes
Inflammation of the bones
Skin infection such as an abscess at the site of injection

Very rare side effect

Severe allergic reactions that can also be life-threatening. Most GPs ensure that this is avoided.

Q: What are the various BCG vaccine age groups?

A: The BCG vaccination is meant for babies, children and adults up to 35 who run a risk of contracting tuberculosis. This vaccine is administered only once in a lifetime.

For babies

The vaccination is given to babies as soon as possible after birth or up to 1 year who:

Is born in a place where TB rates are high
Lives in close quarters with someone who has TB
Has a parent or grandparent with TB

Children between 1 to 16 years of age

The BCG vaccination is provided to young children who are at risk of TB, including:

Children with risk of TB who were not vaccinated as babies
Any child under 16 who resides in a place where the risk of TB is high
Any child under 16 who is in close contact with someone who has TB

People aged between 16 and 35 who should get the vaccine:

The vaccination is provided to people aged between 16 and 35 who run the risk of TB in their occupations. This includes:

Medical workers who have direct contact with TB patients or samples/materials linked with TB
Veterinary professionals or staff who come in direct contact with animals with TB

In addition, the BCG vaccine is also given to people that include:

Prison staff
Hostel staff for the homeless
People who work in asylum facilities

Q: Which travellers should have the BCG vaccine?

A: The BCG vaccine is recommended for travellers under the age of 16 who will live for more than three months in a place with a high risk of TB.

Q: What is BCG vaccine scar?

A: It is a common situation to develop a raised blister at the injection site, which may disappear in a short time.

However, after 2 to 6 weeks, one can expect a small and reddish spot to appear at the same site. Gradually, this develops into a prominent scab that tends to ooze.

The area should be left uncovered and give it air to heal. Furthermore, this leaves behind a small and harmless scar called the BCG vaccine scar.

This scar is common and not of concern. However, if it develops into an infection, you should consult your GP.

Q: I have an allergy. Should I be worried about the BCG vaccine?

A: No. This vaccine is safe

No. The BCG vaccine is safe for allergies such as:

Latex
Penicillin
Dairy products, eggs or nuts

If you have concerns about your allergies, feel free to talk to your GP before taking the vaccination.

Q: My child did not develop a BCG vaccine scar or blister after the injection. Did the vaccine work?

A: Yes, it did work. Not everyone develops a blister or scar on the administration of the vaccine. Furthermore, there is no need to opt for another vaccination.