Quarantining people with virulent strains of a virus can help promote less deadly ones Christian Minelli/NurPhoto via Getty Images
SEVERAL weeks before the novel coronavirus became a serious issue in the UK, I attended a friend’s birthday party. Already, much of the conversation centred on the virus and the illness it causes, covid-19. While most people were talking about how to avoid catching it, one guest suggested that everybody “get infected to boost their immune system”.
As a student of evolutionary biology, the idea alarmed me. I became even more concerned when, in early March, the UK’s chief scientific adviser recommended that 60 per cent of the population be infected with the coronavirus to build up herd immunity. Of course, the government rapidly ditched the policy and put the UK into lockdown. However, now that infection rates seem to have plateaued in several countries and governments around the world are looking for “exit strategies” from lockdown, talk of exposing people to the virus to build up herd immunity has returned. It remains a dangerous idea.
To understand why, it is crucial to think about how the virus is changing as it jumps from host to host and circulates in the human population. As biologist Theodosius Dobzhansky said almost half a century ago: “Nothing in biology makes sense, except in the light of evolution.” It may not seem obvious, but evolutionary processes have profound implications for pandemics. As well as helping us think clearly about herd immunity, they can explain where new diseases come from and help predict where they are going. Yet, an evolutionary perspective has been lacking in the …
