I feel like it gets a little daunting and is tedious to go through some of the sections in order so I decided to jump from section to section, covering what I felt like were the higher yield sections and mixing up the categories so that the information didn’t start to blur in my memory.  Having a solid understanding of travel medicine diseases, treatments, preventive measures and vaccines seemed the most relevant.  So, today I’m covering the next section under vaccines, which is the BCG, or Bacille Calmette-Guerin, but then we’ll move on and readdress vaccinations every so often so they aren’t all jumbled up to try to remember.

02. IMMUNOLOGY/VACCINOLOGY (20%)

03. Bacille Calmette-Guerin

“BCG, or bacille Calmette-Guerin, is a vaccine for tuberculosis (TB) disease. Many foreign-born persons have been BCG-vaccinated. BCG is used in many countries with a high prevalence of TB to prevent childhood tuberculous meningitis and miliary disease. However, BCG is not generally recommended for use in the United States because of the low risk of infection with Mycobacterium tuberculosis, the variable effectiveness of the vaccine against adult pulmonary TB, and the vaccine’s potential interference with tuberculin skin test reactivity. The BCG vaccine should be considered only for very select persons who meet specific criteria and in consultation with a TB expert.” ¹

• Indications/contraindications
  • “Indicated in children: BCG vaccination should only be considered for children who have a negative tuberculin skin test and who are continually exposed, and cannot be separated from, adults who
    • Are untreated or ineffectively treated for TB disease (if the child cannot be given long-term treatment for infection); or
    • Have TB caused by strains resistant to isoniazid and rifampin.
  • Indicated in health care workers: BCG vaccination of health care workers should be considered on an individual basis in settings in which
    • A high percentage of TB patients are infected with M. tuberculosis strains resistant to both isoniazid and rifampin;
    • There is ongoing transmission of such drug-resistant M. tuberculosis strains to health care workers and subsequent infection is likely; or
    • Comprehensive TB infection-control precautions have been implemented, but have not been successful.
    • Health care workers considered for BCG vaccination should be counseled regarding the risks and benefits associated with both BCG vaccination and treatment of Latent TB Infection (LTBI).
  • Contraindicated in immunosuppression: BCG vaccination should not be given to persons who are immunosuppressed (e.g., persons who are HIV infected) or who are likely to become immunocompromised (e.g., persons who are candidates for organ transplant).
  • Contraindicated in pregnancy: BCG vaccination should not be given during pregnancy. Even though no harmful effects of BCG vaccination on the fetus have been observed, further studies are needed to prove its safety.” ¹
• Routes of administration
  • “BCG vaccination is given as an injection into the left upper arm.
  • The vaccination usually leaves a small scar.” ²
• Dosing regimens
  • “The BCG vaccine should only be given once in a lifetime.” ²
• Duration of protection
  • I wasn’t able to readily find a specific answer to this question on the government sites but they both mention that immunity wanes over time.  Additionally, it is designed to protect children from severe disease, with the understanding that immunity is expected to wane.  I think that probably is sufficient as an answer.
• Immunogenicity
  • “The tuberculin skin test (TST) and blood tests to detect TB infection are not contraindicated for persons who have been vaccinated with BCG.
  • Tuberculin Skin Test (TST). BCG vaccination may cause a false-positive reaction to the TST, which may complicate decisions about prescribing treatment. The presence or size of a TST reaction in persons who have been vaccinated with BCG does not predict whether BCG will provide any protection against TB disease. Furthermore, the size of a TST reaction in a BCG-vaccinated person is not a factor in determining whether the reaction is caused by LTBI or the prior BCG vaccination. (See below for specific guidance on skin test results.)
  • TB Blood Tests. Blood tests to detect TB infection, unlike the TST, are not affected by prior BCG vaccination and are less likely to give a false-positive result.” ¹
• Efficacy
  • “The BCG vaccine is made from a weakened strain of TB bacteria. Because the bacteria in the vaccine is weak, it triggers the immune system to protect against the infection but does not give you TB.
  • It provides consistent protection against the most severe forms of TB, such as TB meningitis in children.
  • It’s less effective in preventing TB that affects the lungs in adults, so has limited impact on the spread of TB.” ²
• Potential adverse reactions and medical management of adverse reactions
  • “Like all vaccines, the BCG vaccine can cause side effects, but they’re uncommon and generally mild.
  • Some common side effects may include:
    • soreness or discharge from where the injection was given
    • a high temperature (fever)
    • headache
    • swollen glands under the armpit in the arm where the injection was given
  • More serious complications, such as abscesses, bone inflammation and widespread TB are rare.
  • Most children develop a sore at the injection site. Once healed, the sore may leave a small scar. This is normal and nothing to worry about.

Serious side effects from the BCG vaccine, such as a severe allergic reaction (anaphylaxis), are very rare.” ²

References:

Centers for Disease Control and Prevention. (2016, May 4). Fact sheets. Centers for Disease Control and Prevention. https://www.cdc.gov/tb/publications/factsheets/prevention/bcg.htm

NHS. (2019, April 26). NHS choices. https://www.nhs.uk/conditions/vaccinations/bcg-tuberculosis-tb-vaccine/#:~:text=BCG%20vaccination%20is%20given%20as,usually%20leaves%20a%20small%20scar