Should Bacillus Calmette–Guérin (BCG) vaccine be used in the prophylaxis of COVID-19?

Abstract

At present, there is insufficient evidence to support the use of BCG vaccine as prophylaxis for COVID-19.

• Bacillus Calmette Guerin (BCG) vaccine is an attenuated microorganism derived from bovine tubercle bacillus and

is being given to prevent severe tuberculosis.

• BCG vaccination may enhance production of antibodies and pro-inflammatory cytokines such as interleukin

(IL)-1β and tumor necrosis factor (TNF). BCG may lead to increased CD4 and CD8 T-cell activity on subsequent

viral infection.

• Ecological studies on the effect of BCG vaccination policy on COVID-19 outcomes have conflicting results and

are prone to bias from confounders.

• There is insufficient evidence on the efficacy and safety of BCG vaccine for COVID-19 prophylaxis.
• Thirteen clinical trials are ongoing among high-risk groups (healthcare workers, elderly, police officers) to evaluate

the efficacy and safety of BCG vaccine in preventing COVID-19 and its severe symptoms.

• WHO does not recommend the use of BCG vaccine as prophylaxis against COVID-19.
• Adverse events of BCG vaccine range from mild local cutaneous reactions to systemic adverse events such as

abscess, lymphadenopathy and osteomyelitis.