To help put Omicron in perspective, I caught up with Boghuma Kabisen Titanji, an infectious-disease physician, virologist, and global-health expert at Emory University. Our conversation has been lightly edited for clarity and length. [...]

Wu: Could we have seen the arrival of Omicron coming?

Titanji: Viruses are going to evolve regardless of what we do. There are things we can do to slow that down: barrier measures [such as masking], vaccinating. And there are things that we can do that can maybe speed up or aid the evolution of the virus. One is if we're not doing what we need to do to prevent spread of the virus within the population. Every time a virus spreads, it gets another opportunity to infect a new host, and it gets another opportunity to evolve and change and adapt.

All of this means that it is worth having a conversation about whether the slow rollout of vaccines globally has had an impact. In certain parts of the world, not enough people have been given a measure of protection to allow them to be able to withstand infection, and to slow down transmission of the virus. Are we actually giving the virus an opportunity to spread unrestricted in certain places and drive its evolutionary trend? It's basically exposing ourselves to the emergence of more variants. So this was predictable. If the virus has the opportunity to spread unchecked in the population, then we're giving it multiple ways in which to evolve and adapt.

If we had ensured that everyone had equal access to vaccination and really pushed the agenda on getting global vaccination to a high level, then maybe we could have possibly delayed the emergence of new variants, such as the ones that we're witnessing.