Thread by @NathanGrubaugh

During disease outbreaks 🦠, like #COVID19 (#SARSCoV), there is often a lot of speculation about mutations 😱.

@edwardcholmes, @MaryPetrone10, and I argue that we shouldn't worry.

Here's why👇
@NatureMicrobiol
nature.com/articles/s4156…

@edwardcholmes @MaryPetrone10 @NatureMicrobiol 2/n Mutation to many implies a significant transformation. See the X-Men or just about any outbreak movie. This pushes some to view mutations in the fictional context rather than a natural state of evolution.

@edwardcholmes @MaryPetrone10 @NatureMicrobiol 3/n With the competitive online journalism market, we get bombarded with stories about dangerous mutations and doomsday scenarios for the current #COVID19 outbreak.

For example
telegraph.co.uk/global-health/…

@edwardcholmes @MaryPetrone10 @NatureMicrobiol 4/n Misinterpretations about mutations can have some serious consequences. See the 2018 #Zika outbreak in India where the government concluded that they did not find the "microcephaly mutation" and thus incorrectly thought the viruses were not harmful.

cell.com/trends/microbi…

@edwardcholmes @MaryPetrone10 @NatureMicrobiol 5/n Rather, RNA viruses, like #SARSCoV2, mutate all of the time. Its a central part of being a virus. Most of these changes do nothing. Only when there is a strong selective pressure do the mutations mean more.

@edwardcholmes @MaryPetrone10 @NatureMicrobiol 6/n Selection does not necessarily mean that the virus will become more virulent. It could become less virulent, or do nothing to virulence. Selection acts to help perpetuate the virus, but we don't often see any real epidemiological impacts of this.

@edwardcholmes @MaryPetrone10 @NatureMicrobiol 7/n How do we know if there is a real impact? We can't just look at a series of virus genomes and determine if it is changing the virus in a meaningful way. This takes a lot of time to confirm with experimental and epidemiological data.

@edwardcholmes @MaryPetrone10 @NatureMicrobiol 8/n And finding positive selection or host adaptation is an interesting line of research, but it may not help with public health decision making.

@edwardcholmes @MaryPetrone10 @NatureMicrobiol 9/n E.g. during the Ebola epidemic in West Africa, we found a mutation (GP-A82V) that increased infection of human cells. But! we didn't find differences in viral titers or mortality rates. Knowing this during the outbreak would not have changed anything.

sciencedirect.com/science/articl…

@edwardcholmes @MaryPetrone10 @NatureMicrobiol 10/n Since #SARSCOV2 is naturally found in bats and maybe other mammals, is it possible for it to also adapt to humans? Yes.

Will adaptive mutations lead to more deaths? Unlikely.

@edwardcholmes @MaryPetrone10 @NatureMicrobiol 11/n In fact, virus mutations allow us to track the spread of the virus, constructing phylogenetic relationships similar to family trees. A great example of this can be found on @nextstrain.

nextstrain.org/ncov

@edwardcholmes @MaryPetrone10 @NatureMicrobiol @nextstrain 12/12 Lets not spend time fretting and speculating about virus mutations during outbreaks. It's at best a distraction and at worst the misinformation can influence bad policies.

@edwardcholmes @MaryPetrone10 @NatureMicrobiol @nextstrain P.S. I also unlocked an achievement by referencing work by Stan Lee and Michael Crichton in a published scientific article.

@edwardcholmes @MaryPetrone10 @NatureMicrobiol @nextstrain P.P.S. We were trying to get this out quickly, so I farmed out a lot of my background research to twitter. Thanks folks!

https://twitter.com/NathanGrubaugh/status/1225080153367351296

@edwardcholmes @MaryPetrone10 @NatureMicrobiol @nextstrain We included many of you in the acknowledgements. Sorry in advance if I left some out.

@edwardcholmes @MaryPetrone10 @NatureMicrobiol @nextstrain P.P.P.S Follow @marypetrone10, she's an awesome PhD student in our group that was instrumental in taking our collection of ideas and putting them into a story. She'll have some excellent #dengue papers coming out soon!