Blame virus evolution 101 if you’re getting a déjà vu feeling when it comes to the COVID-19 pandemic.
The rampaging COVID-19 Delta variant has life now is looking much like it did early in the pandemic; events are being postponed, masking and other rules and restrictions are creeping back.
What’s more, rising infections and hospitalizations threaten to undo much of the progress made over the last several months as vaccines led to a drop in hospitalizations.
It’s all about that word “variant.”
“Viruses like to reproduce but they need hosts to do it,” explains Ralph Baric, PhD. professor of Virology at the Gillings School of Global Public Health at the University of North Carolina at Chapel Hill. “And with much of the world’s population not yet vaccinated against COVID-19, the coronavirus has a lot of room to infect people, mutate, evolve and change over time as infections continue to spread. It’s just part of the natural history of evolution.”
Researchers say the Delta variant has mutations on its spike protein. That’s the crown-like piece of the virus that latches onto a person’s cell, creating the infection.
That mutation makes Delta stickier that the earlier coronavirus, so it’s able to infect the host cell more efficiently and with fewer viral particles. It makes you sicker, faster, and it creates a lot more virus in the body.
Scientists measure how contagious a disease is by how many people a patient could pass it too. That’s called the R-O number.
The CDC says a patient infected with the original COVID-19 virus could infect 2 ½ people. A patient with the Delta variant could infect eight people.
“Every time the virus gets transmitted from one person to another, it has an opportunity to mutate, to change,” explains Davod Montefiori, Ph.D., director of the Laboratory for Aids Vaccine Research and Development at Duke University. “The more we can shut this pandemic down and slow down the spread of the virus, the less opportunities it’s going to have to mutate and change and become more contagious. The mutation rate is dependent on the transmission rate, how many times the virus has transmitted from one person to another. “
But while the Delta variant has evolved to be more contagious, the good news is that it has not evolved the point where vaccines are ineffective.
“Whether the virus can evolve to where vaccines are not effective is still an open question that’s being studied extensively,” adds Montefiori, “But right now we need to be much more rigorous in our approach to vaccinating people. It’s the only way to shut the virus down.”
But for now, with so many unvaccinated people in the U.S. and around the world, the virus continues to mutate. Health officials are watching another variant called “Delta Plus,” which is another mutation of the now dominant delta variant.
“Delta Plus” was first spotted in India in June. So far, it’s been spotted in the United Kingdom, Portugal, Russia, China, South Korea and the U.S.
It’s too early to tell whether patients infected with the new variant are sicker or whether the new variant is more transmissible.
But it’s another sign of the importance of vaccines and going back to wearing masks and social distancing.
“I think we are all fatigued, but we have to understand we are watching evolution in progress,” said Cameron Wolfe, M.D., and infectious disease specialist and associate professor at Duke University School of Medicine. “Because of that, this is a new virus that will continue to ebb and flow in ways we can’t predict and we have to be prepared to be flexible and wear masks. We also have to get vaccinated to protect yourself, your family and your friends.”