Why are some COVID variants worse than others?

Viruses are always mutating. That’s a problem as health experts work to stop the spread of SARS-CoV-2, the virus behind COVID-19.

Most mutations are minor. Some are even harmful to the virus. But every once in a while, a mutation gives a virus a slight edge in its fight to reproduce. That seems to be the case in three variants of the novel coronavirus that have been uncovered by scientists.

The so-called B.1.1.7 strain of SARS-CoV-2 may be 56% more transmissible than the strain we’re used to. It quickly became the dominant strain in certain areas of the U.K. in recent months and has already been discovered in Michigan. Two other variants are also causing concern: P.1 popped up in Brazil and has already been discovered in the U.S., and B.1.351, which was spotted in South Africa, has led to the U.S. president issuing restrictions on travel from there.

All three strains employ the same change in SARS-CoV-2’s spike protein – the part that latches onto cells in the human body. Experiments suggest that change allows it grab on more readily, giving it a better chance of infecting the cells.

Unfortunately, there isn’t much time for studying the virus’s mutations or transmission as it sweeps through the world infecting millions. That means scientists have scant data with which to make recommendations.

Nonetheless, the old methods of limiting transmission are still the best ones. That means social distancing, wearing masks, and avoiding indoor gatherings.

You can read the full story on National Geographic.