As the world tries to take a hold over the delta variant, we're all watching and waiting to see if the virus is going to evolve into something new. There are fears that natural selection could potentially yield a new variant that will completely escape all of our current vaccines. While these scenarios are hypothetical, experts discuss the need to be vigilant and prepared without unnecessary panic. Experts unpack the virus' evolution so far into delta and how that has impacted our goals for herd immunity. They talk about the possibilty for delta to change into a variant more transmissible or virulent, and how potentially leaky vaccines might impact or enhance the virus' evolutionary path. In August, Joe Rogan highlighted a paper on his podcast "The Joe Rogan Experience," which raised public concern that our current vaccines are potentially encouraging new potent variants to emerge. The author of that paper, Professor Andrew Read, comes on to clarify his research in chickens and where certain extrapolations can and can't be made. Meanwhile, experts discuss the possibility of vaccine pressure and the need for new vaccines and which types of vaccine development strategies might better help us get ahead of the virus' curve.

Expert Guests:

-- Dr Shabir Madhi Shabir Madhi is Dean of the Faculty of Health Sciences and Professor of Vaccinology at the University of the Witwatersrand, Johannesburg, South Africa. He is also the co-founder of the African Leadership Initiative for Vaccinology Expertise (ALIVE).

-- Dr Jeffrey Morris is Professor of Biostatistics and Director, Biostatistics Division at the University of Pennsylvania, US. His research focuses on developing quantitative methods to extract knowledge from biomedical big data and he set up a blog dedicated to issues concerning the Covid-19 pandemic.

-- Dr Nikolai Petrovsky is Professor of Medicine, Flinders University, Adelaide, Australia and vice-president and secretary-general of the International Immunomics Society. He is the founder of vaccine biotech, Vaxine, which has a protein based vaccine for Covid-19 in its pipeline.

-- Dr Monica Gandhi is Professor of Medicine and Associate Division Chief (Clinical Operations/Education) of the Division of HIV, Infectious Diseases, and Global Medicine at University California San Francisco/San Francisco General Hospital.