Has Covid-19 mutated? Virus may have become more contagious in Houston which saw two disease waves, says study
As Covid-19 cases are continuing to climb in the US, scientists have detected that the virus may have mutated to become more contagious in Houston, Texas. Tracking how the virus changes over time could have a bearing on vaccines and if it is needed to fine-tune them every year like flu shots.
The mutation has not made it more fatal or dangerous. Instead, it may have allowed it to spread better, according to a new pre-print study, which is not vetted for accuracy yet. Researches arrived at this conclusion after analyzing the genomes of over 5,085 Covid-19 virus strains causing two disease waves in Houston.
However, mutations are not unusual. In fact, viruses rapidly undergo changes in their genomes and most are inconsequential. "Mutation doesn't transform viruses into ninja turtles," Dr Angela Rasmussen, Virologist at Columbia University, tweeted, adding that mutations have not given the new coronavirus "imaginary mask-crushing superpowers". Rasmussen was not involved in the study.
The study's author James Musser of Houston Methodist Hospital Musser told The Washington Post: "We have given this virus a lot of chances. There is a huge population size out there right now." The findings suggest that the virus may have become more contagious as it moved through the population and that this "may have implications for our ability to control it."
"Although we don't know it yet, it is well within the realm of possibility that this coronavirus, when our population-level immunity gets high enough, will find a way to get around our immunity," Morens said. "If that happens, we'd be in the same situation as with the flu. We'll have to chase the virus and, as it mutates, we'll have to tinker with our vaccine."
In Houston, the virus moved in two waves, according to the study. In the first one, it hit wealthier and older individuals before spreading to the younger population and lower-income neighborhoods, especially among the Hispanic and Latino people in the second wave.
The genetic analysis showed that a strain that had acquired a particular mutation represented only 71% of samples in March. In May, the virus variant's prevalence reached 99.9%. Researchers observed that people infected with this variant had a higher viral load — the amount of virus — in their upper respiratory tracts. This led researchers to speculate that the virus has gained the means to spread better.
However, not everyone is convinced. Kristian Andersen, an immunologist at the Scripps Research Institute in California, who was not involved in the new research, downplayed the significance of the new study. He told The Washinton Post that the findings "just confirm what has already been described." As for the numerous other mutations the study finds, "they just catalog them, but we don't know if any of them have any functional relevance."
Study author Musser called for more sequencing studies to understand how the virus is mutating. "I think we need to be doing this pretty aggressively in multiple locations on a real-time basis," Musser said and added, "I think it's shameful that we're not doing that."