Tracking the subtle changes to the virus’ RNA is like global detective work, requiring health officials around the world to sequence a selection of viral samples and share them broadly. Without that, scientists are flying blind.
“A lot of places that have had big outbreaks are places where we do not have good sequencing, and the only way to monitor for new variants is through sequencing,” [molecular ebidemiologist Emma] Hodcroft said.
[Hodcroft:] More recently, we’ve had another problem with bias in that everyone is super interested to find which sequences might be the variants of concern, and so they’re preferentially sequencing samples that might have a travel history or have a particular signature on PCR tests. What we lose in the process is the actual surveillance and monitoring — well, what else is going on? What other variants might be out there?
Mutations arise randomly, they’re typos… But whether a mutation goes on to spread and become prominent in a population, that depends on whether that mutation gives the virus an advantage… You can imagine now in some parts of the world, where a lot of people have been infected and have at least some partial immunity, there might be an advantage for the virus now to reinfect people.