SAIS/Immunopaedia Webinar on BCG & COVID-19


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This webinar, co-hosted by South African Immunology Society (SAIS) and Immunopaedia featured talks by Prof Christine Benn on “BCG for COVID-19 – hope or hype?” & Prof Gerhard Walz on “BCG trials for COVID-19 in SA – progress and promise.”

Studies have shown that in addition to BCG providing protection against Tuberculosis in children, it also have non-specific effects which are associated with a reduction in all-cause infant mortality* (Kristensen et al., 2020) and reduction in upper respiratory tract infections in revaccinated individuals (Nemes et al., 2019; Wardhana et al., 2020). These non-specific responses have been attributed to trained immunity# (Read more: Have you heard of trained immunity?) which are induced upon vaccination and contribute to a decrease in systemic inflammation.

Prof Christine explained two main hypotheses around BCG & COVID-19: (1) BCG-at-birth protects against COVID-19 & Recent BCG protects against COVID-10. Currently, no direct evidence for either is available, however, a plethora of ecological studies have suggested that the first hypothesis is responsible for low COVID-19 prevalence in some countries (Read: BCG & COVID-19). Realistically, this may not be possible because trained immunity is short lived < 2 years, suggesting that it may not be the sole reason for reduced burden in countries where BCG is still give. For hypothesis 2, trials are currently investigating are on-going, in the meantime observation studies provide evidence that recent BCG vaccination is associated with lower the risk of COVID-19 (Moorlag et al., 2020; Amirlak et al., Pre-print)

 

Prof Gerhard Walzl then presented his talk on “BCG trials for COVID-19 in SA: progress and promise”. He highlighted challenges the SA healthcare system expriences which include high burden of TB, HIV and more recently non-communicable diseases like diabetes, and also inadequate intensive care facilities among others see below. He then described why BCG re-vaccination was “trailed”, and some challenges they experienced which included: funding challenges “poor buy in from govt”, PPE shortages, lockdown etc.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Notes:

  • *: this is not only associated with BCG but also other live-attenuated vaccines such measles and polio
  • #: Trained immunity is the non-specific resistance to infection that is conferred by innate immune cells. Mechanistic studies have attributed trained immunity to epigenetic re-programming that occurs when innate immune cells are activated by infection or vaccination (Netea et al.,  2016).

Summary by Cheleka Mpande

 
 
 
 
 
 
International Union of Immunological SocietiesUniversity of South AfricaInstitute of Infectious Disease and Molecular MedicineScience Education PrizesElizabeth Glazer Pediatric Aids Foundation