High demand for BCG vaccine may leave newborns vulnerable to TB, experts warn

A spike in demand for BCG vaccines after research suggested it could protect people from Covid-19 is putting supplies under strain, South African TB experts and paediatricians have warned.

They said those demanding the vaccine included health workers “requesting revaccination as protection for themselves and vaccination of their non-BCG-vaccinated dependents, especially older children”.

In a letter published in the International Journal of Tuberculosis and Lung Disease,  infectious disease experts, mostly from Stellenbosch University, said responsible stewardship of BCG in the context of Covid-19 was “urgently needed”.

Though manufacturer and supply chain issues were largely resolved, they said, “supply remains fragile due to the limited number of production facilities available globally”.

A shortage could leave newborns, who receive the vaccine to protect them from TB, vulnerable.

Scientists in New York recently compared countries with and without universal BCG policies, and found that countries that give the vaccine have lower Covid-19 infection rates.

The Stellenbosch experts said while the research provided interesting circumstantial evidence, “it does not confirm causality”.

However, the sudden demand could result in an acute shortage of BCG, which has been in short supply in recent years, they said.

Their letter highlighted “the critical need to sustain newborn BCG, especially in settings with high TB and HIV burden,” such as SA.

“Outside of a clinical trial, health-care workers or other individuals should therefore not receive BCG vaccination for protection against Covid-19,” they said.

“Health-care workers, many of whom are at high risk of Covid-19 disease, should consider enrolling in trials, including those where BCG is used as an intervention.

“Their participation would generate much-needed data regarding any potential benefit or risk of BCG vaccination in the context of Covid-19.

“Importantly, the BCG vaccines used for such trials should be sourced specifically for clinical research and not from the limited supply available for children in low-income settings.”

BCG inoculation modulates the body's immune response and has been proven effective against severe forms of TB.

The Stellenbosch experts, including Prof Simon Schaaf, said the New York research should be treated with “extreme caution” because it displayed potential bias in its selection of countries for analysis and its failure to take into account the fact that different countries may be at different stages of the Covid-19 epidemic.

The exclusion of countries that contradicted the authors’ conclusions was unexplained, they added.