How Worrisome Is This U.K. Virus Variant?

Sam Fazeli, a Bloomberg Opinion contributor who covers the pharmaceutical industry for Bloomberg Intelligence, answered questions about the emergence in the U.K. of a mutant variant of the coronavirus, which has prompted strict lockdown measures across England and led neighboring countries to put up trade and travel restrictions to protect against its spread. The conversation has been edited and condensed.

How unusual is this virus mutation?

SF: As far as viruses go, it’s not unusual to see mutations like this. They happen all the time, even within the same person. In fact, there have already been some 4,000 different documented mutations in the Sars-Cov-2 virus that causes Covid-19 as it has spread around the globe. Until now, none have been a real cause for concern. But the latest one that has been discovered in the U.K. is potentially worrisome, and I believe the government’s action in imposing severe lockdowns in London and southeastern England is warranted until more information is available.

The U.K. government says it took its action on lockdowns in part because the new variant may be as much as 70% more transmissible than original strains. What evidence is there of that?

SF: There is little hard data to prove that the new variant is transmitted more easily. The rapid rise in the number of cases in southeastern England may simply be because the virus was at the right place at the right time, just as was the case with a variant -- so-called D614G -- that was subsequently shown not to have better transmission but still became the dominant version of the virus in the U.S. and Europe. Also, one of the mutations related to this new variant has previously been shown to actually reduce transmission. So it’s just too early to know whether the spread is just luck or the result of a biological property of the virus. Without more information, though, it’s best to take these added precautions.

Does this variant cause a more severe form of Covid-19?

SF: Again, there are no hard data to suggest one way or another, but it’s very early days. Data on overall case counts relative to hospitalizations and mortality will in the next few weeks be able to provide preliminary clues. But definitive answers will need deeper study as there are many other confounding drivers of hospitalizations, such as the fact that infections are occurring in a colder climate, which is generally associated with weaker immune systems. Again, the mutation now dominant in the U.S. and Europe was thought to have 50% higher mortality, but that has turned out not to be the case.