Has Omicron evolved to become more dangerous? – Hot air

Short answer: Probably not.

Longer answer: probably not, and even if it were, it might not be dangerous enough to do any real harm given the amount of immunity the population now has.

A few weeks ago I wrote some new sub-variants of Omicron, BA.4 and BA.5. The first indications are that they are more contagious than the current dominant sub-variant in the United States, BA.2.12.1, which is more contagious than the original Omicron, which was itself insanely contagious. Worse still, as natural immunity from Omicron appears to last only a few months, a previous infection is not a real defense against BA.4 and BA.5. In fact, the two are so immune that they may be able to pierce immunity even in someone who has had a recent infection.

The bottom line is that people will have COVID again and again and again in the Omicron era. There isn’t even a short-term prospect of a vaccine that will prevent this: Although mRNA vaccines do a great job of conferring immunity to serious diseases, a vaccine that will confer immunity against infections like the smallpox vaccine seems a long way off.

So we’re all bound to catch some Omicron sub-variant or another eventually. In that case it is important to know if those sub-variants are becoming more virulent.

You may recall that following the eruption of the Omicron in Africa last winter, scientists were quick to understand why people infected with it seemed to exhibit milder symptoms than previous strains of the coronavirus. The answer according to some researchers has to do with where the virus took root. The previous strains replicated in the lungs, causing lethal pneumonia that killed millions of people. However, the Micron did not replicate in the lungs efficiently. It replicated in the upper respiratory tract. Since it did not afflict the major organs, more people could shrug off without major damage.

Researchers in Japan say they have evidence that BA.4 and BA.5 spread better in the lungs than their grandparents.

According to preliminary data from Kei Sato of the University of Tokyo and colleagues, BA.4, BA.5 and BA.2.12.1 may have evolved to favor infection of lung cells, rather than upper respiratory tract tissue, making them more like previous variants, such as Alpha or Delta …

Professor Sato’s experiments indicate that BA.4, BA.5 and BA.2.12.1 replicate more efficiently in human lung cells than BA.2, while further experiments in hamsters suggest that BA.4 and BA.5 they can cause more serious diseases.

“These things appear to be returning to their more dangerous form of infection, thus going further down the lung,” said Dr Stephen Griffin, a virologist at the University of Leeds.

Game over, man. Game over.

Or is it? Let’s take a look at some numbers. According to this site, BA.4 and BA.5 account for a significant majority of cases over the past 60 days in South Africa, the country most affected by the new sub-variants. Over the past 60 days, BA.4 accounts for 63% of confirmed cases while BA.5 accounts for 20% more. Sixty days is also a lot of time for a wave of deaths to appear in the data, as the typical period from infection to death due to COVID is about a month. Are we seeing a recent spike in mortality in South Africa due to the threatening prevalence of BA.4 and BA.5?

We do not:

South African researcher Tulio de Oliveira, who raised the global alarm on Omicron last year, reports that the BA.4 and BA.5 wave was the * least * deadly wave the country has experienced so far.

It is more difficult to draw firm conclusions about the US and UK as BA.4 and BA.5 are not yet dominant or have not been dominant long enough for us to draw a conclusion on how deadly they could be. Scientists in England believe the two sub-variants are spreading rapidly there, likely fueled by the recent jubilee celebrations for Queen Elizabeth. Cases have increased by more than 30% in the past seven days, as have hospitalizations, in particular. This is interesting circumstantial evidence that there may be something in the Japanese data about increased virulence. But how much greater? Here’s what the death curve looks like:

It could be that many of the recently inpatients will die in the next few weeks or two, sending the curve upward, but there is still no evidence that the tide England is experiencing right now is particularly deadly. Maybe it’s because BA.4 and BA.5 aren’t as virulent as feared, but it could also be that medicine has caught up with the virus and is turning COVID cases that would have been fatal a year ago into short hospital stays. It combines extended population immunity with better therapies like Paxlovid and a much broader knowledge base among doctors and nurses on how to treat disease in the emergency room and even a virulent sub-variant may not be as virulent in practice. The two sub-variants might be dangerous enough to send you to the hospital more often than Omicron would, but perhaps not dangerous enough to send you to the morgue. However, not at this stage of the pandemic.

Another look at the data. Look back at the excerpt above and you will see that Japanese researchers have found that BA.2.12.1, not just BA.4 and BA.5, appears to reproduce more efficiently in the lungs than the original Micron. Well, according to the CDC, there has been a lot of BA.2.12.1 in the US since the beginning of May:

We experienced the same phenomenon in England over those six weeks, with not only cases on the rise, but hospitalizations as well. In fact, the number of people hospitalized with COVID is now twice as high as in mid-April, more circumstantial evidence that Omicron’s sub-variants are indeed more virulent. But what do we see when we look at the death curve?

No peak. In fact, according to Drudge, we had fewer deaths from COVID yesterday (293) than we did the same date a year ago (301) even though we had nearly * nine times * confirmed cases – and probably many more times that in reality, if we could include all the people who tested positive for rapid tests yesterday but never bothered to confirm their contagion with a laboratory. Even in the era of the Omicron sub-variants, the virus is killing far fewer people as a percentage of infections than in the past. There is still no good reason to think that BA.4 and BA.5 are particularly threatening.