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A mutated, more contagious coronavirus that Houston scientists reported was the primary strain circulating in the area in the pandemic’s early days is now virtually the only one infecting people here, according to the team. In a new study released Wednesday, Houston Methodist scientists reported that more than 99 percent of samples of the virus they’ve sequenced since mid-May contained the mutation that allows it to infect more people, up from about 70 percent the previous two months. (Ackerman, 9/23)

The new report, however, did not find that these mutations have made the virus deadlier or changed clinical outcomes. All viruses accumulate genetic mutations, and most are insignificant, scientists say. Coronaviruses such as SARS-CoV-2 are relatively stable as viruses go, because they have a proofreading mechanism as they replicate. But every mutation is a roll of the dice, and with transmission so widespread in the United States — which continues to see tens of thousands of new, confirmed infections daily — the virus has had abundant opportunities to change, potentially with troublesome consequences, said study author James Musser of Houston Methodist Hospital. (Mooney, Achenbach and Fox, 9/23)

The study, which has not yet been reviewed by outside experts, found that nearly all strains in the second wave had a mutation, known as D614G, which has been shown to increase the number of “spikes” on the crown-shaped virus. The spikes are what allow the virus to bind to and infect cells, increasing the ability of the mutated virus to infect cells. The Houston researchers said patients infected with the variant strain had significantly higher amounts of the virus on initial diagnosis. (Beasley, 9/23)

The longer the COVID-19 pandemic goes on, the younger its victims get. A new study from the Centers for Disease Control and Prevention reports that the median age of people with COVID-19 in the U.S. has declined over the spring and summer, with Americans in their 20s now accounting for more cases than people in any other age group. The findings suggest that if the U.S. wants to get its coronavirus outbreak under control, it will need more cooperation from young adults. (Kaplan, 9/23)

Younger people are more likely to believe false claims related to the novel coronavirus than older people, according to a new survey released Tuesday by a team of researchers at Harvard University, Rutgers University, Northeastern University and Northwestern University. The survey of nearly 22,000 individuals from all 50 states comes as a slew of misinformation surrounding COVID-19 is spreading online as the pandemic rages on, and as health officials express worry over rising cases among younger Americans. (Thorbecke, 9/23)