There is a rumor that has been circulating over the past few weeks that there are actually #2STRAINS of Covid-19, and one is deadlier than the other. Is there any truth to this rumor? I did a little research to find out. 🤓
So COVID-19 is an RNA virus, like influenza and the common cold, which means it uses ribonucleic acid to encode its genetic material instead of DNA. The constant mutations make RNA viruses more difficult to target which is why they require a new attempt at a vaccine every year.
Covid-19 was found by a few Chinese scientists to have 2 predominant strains: S strain and L strain. (And each of these strains has multiple variations as well). They originally published a paper the first week in March saying the S strain was more ancestral and the L strain was more “aggressive”. That language caused a frenzy and (incorrectly as it turns out) convinced people the L strain was more “deadly.”
In reality the word “aggressive” was meant to describe the rate of #replication of the L strain, NOT the severity of the virus or likelihood for it to do more harm or cause more deaths. But don’t take my word for it:
“Dr. Scott Weaver, director of the Institute for Human Infections and Immunity, said in a Q&A session organized by the Texas Medical Center “I think, in reality, there’s very little evidence so far that there’s any meaningful difference between those strains. […] It’s too early to know if… these two differences have any effect on the way the virus replicates and causes disease.”
“The differences between the two identified strains are tiny. In fact, they can’t really be considered to be separate ‘strains,’” virology professor Dr. Ian Jones of the University of Reading told The New Scientist. “In all practical terms, the virus is as it was when it originally emerged. There’s no evidence it is getting any worse.”
***Dr. Jones told Newsweek that many misinterpret “aggressive” to mean the L-Strain is more likely to kill, whereas the authors of the paper were actually describing an increased rate of transmission.***
“What they mean is that the virus transmits more easily, not that it causes worse disease,” he said. “From my own reading of Xialou’s paper, I see no mention of increased severity or mortality for the L-strain, but I do see explicit mention of increased transmissibility: “…our results suggest the L might be more aggressive than the S type due to the potentially higher transmission and/or replication rates.”
Some experts have now called for the retraction of the Chinese paper saying it causes unnecessary panic at a crucial time of the outbreak. One epidemiologist replied to the paper with his feedback:
“What is missing is discussion about the use of ‘aggressive’, which is not a standard epidemiological term. Any work on the subject of COVID-19 is going to draw attention, so we all need to be very mindful about the public health messaging. The way that I assume that they are using ‘aggressive’ is to imply transmission rate or fitness, as they are only looking at the frequencies of the lineages. Many in the public, however, see ‘aggressive’ and think severity or virulence. It’s this part that is drawing the most attention to the paper and in-sighting unnecessary fear. The press loves this as articles about fear generate more clicks. Now there are common threads all over twitter that suggest if you are infected with the “L” strain, you will be more likely to have severe disease and die. We now have to spend considerable energy undoing this misinformation. Much of the damage, however, is already done. Please think about the messaging around future papers to avoid confusion and unnecessary panic.”
So hopefully this answers some of your questions regarding the theory about the two strains—one which is mild and one that is “more deadly”. According to this data, that isn’t true. In fact, the strains are so similar that immunity to one is believed to create immunity to the other.
We will discuss this tonight on our FB LIVE Podcast event for Coronavirus-Night 2 with Dr. Bob Sears.