Is the BA.2 wave coming to the United States?

About three weeks ago, the rate of covid cases in the United Kingdom skyrocketed, triggered by a more contagious omikron submarine called BA.2. (So ​​far, there is no reason to believe that the new submarine is the cause of a more serious disease.) Given that BA.2 already exists in the United States, The Washington Post Reports that epidemiologists and public health leaders suspect that North America will be next. After all, the paper says, “In the last two years, a widespread outbreak like the one in Europe has followed a similar wave in the United States a few weeks later.”

It is true that seeing the delta and omikron waves in Europe last year was like peeking into a crystal ball of the American epidemic future. Cases in the UK began to rise in early June, peaked about a month later and dropped in early August. In the United States, the wave started in July, peaked in September, and peaked in October. Cases in the UK, which started on 10 December, have risen again and peaked on 4 January; The United States follows December 18 and January 10, respectively. Britain hit its post-Omicron True at the end of February. If the pattern continues, we should hit … right now.

But these relationships are not always maintained. If, in the last two years, some upheavals in European countries have been followed by the United States, others simply have not. And the wave we see now abroad may end in the latter. Differences in the level of variance, previous infections and epidemiological policies between the United States and European countries may keep our case rates on a different track. “There are things that take the US experience away from the European experience,” Bill Hanez, an epidemiologist at Harvard, said in a press conference yesterday.

The fact that Europe is sometimes two steps ahead of us may come down to chance. By far the most influential variants — Alpha, Delta, and Omicron — each identified in the first place — the United Kingdom, India, and South Africa — which were more connected by traveling to Europe than the United States, have reached the United States, but that trend could easily be reversed. Graham Medley, an infectious-disease model at the London School of Hygiene and Tropical Medicine, told me, “If the next form starts in Brazil, it is much more likely to go to the United States before coming to Europe.” “We’re all following each other.”

Johns Hopkins epidemiologist Shawn Trulov said vaccination rates, the type of vaccine used, and the type of previous infection may also have influenced European-American trends. The AstraZeneca vaccine, for example, which was commonly used in the early stages of the vaccine rollout in the United Kingdom, does not protect against infections as well as Pfizer and Modern Jabs, which were the most popular shots in the United States from the beginning. “It’s a very complex system, so it’s hard to say exactly,” Trulov told me.

Differences in policy and behavior can also drive trends over time, and at the moment, policies and practices in Europe, what we call them, are everywhere. In England, those who test positive for the virus are no longer asked to isolate themselves; Meanwhile, Spain and Italy have recently been eliminated Outdoor Order the mask. “The restrictions that have been lifted in many European countries include restrictions that have never been in place in many parts of the United States,” Hanez said, which could mean that Europeans’ lives have changed more rapidly in the last few years than Americans. Weeks In the United States, overall, there haven’t been many Covid restrictions since last summer.

Surprisingly, America’s recent licensing-fire approach to epidemics has made it easier to predict case rates here. Throughout the epidemic, the hardest part of modelers’ jobs has been calculating how policy and behavior of Americans will change, says Lauren Ansel Meyers, who runs the COVID-19 Modeling Consortium at the University of Texas at Austin. During the winter, however, the schools were largely open, and the Americans made their living. Suddenly, the assumptions made by Meyers and his team were spot-on. “We’re not used to that being right,” he told me.

But that doesn’t mean the models are ready to say exactly what will happen to America. “What we’ve gotten over the last two years is that models have fought these important turning points,” Trulov told me. We will know if we have entered a wharf, he said, after it is over and if the case rate goes up again. Meyers said he hopes to get a better forecast in a week. In some parts of the United States, cases are starting to grow or escalate on the plateau, and he wants more time to learn more about how long people are protected from infection or disease after fighting Omicron. He also wants to know how easily BA.2 can infect people who have survived either BA.1 and BA.1.1 submarines, which have been responsible for American lawsuits since December.

BA.2 is considered to be slightly more transmissible than BA.1, and it already exists in the United States which may seem inauspicious considering what is happening in Europe and according to the pattern set it may also suggest that a US wave is coming soon Delta and By Omicron. Hanez has assured me that BA.2 will almost certainly beat the other variants here, but that does not mean that the US will suffer a single wave. When BA.2 enters Europe, it closes almost immediately. In the United States, Hanez says its rise has been slow, probably because it is competing with both BA.1 and BA.1.1. Even if BA.2 starts taking responsibility with sincerity tomorrow, it will do so in times of much less traffic and possibly less virus-friendly weather than when faced with bidding for dominance in the UK.

That may mean that BA.2 will have less impact here than in Europe. This has happened before: in the last weeks of 2020, the Alpha variant started driving in the UK for the most part and contributed to a devastating increase. (The United States also experienced a devastating wave at the same time, with the highest death toll from the epidemic, but Alpha was not a major player; if it had, the winter wave would probably have been worse.) Alpha became dominant in the United States until spring. The weather was warm and the Americans were vaccinated. This may help explain why the United States has not had much experience with alpha bumps; If anything, the curve of that period looks like a plateau. “We’d rather avoid a bullet with that,” Hanez said.

If we were lucky, we could have cheated another one with BA.2. Hanez says his best guess for the next few months is that parts of the United States will continue their downward trend, albeit at a slower pace. Other regions are likely to experience a bump – wastewater data indicates that it may be coming soon. For now, however, the size of those bumps is anyone’s guess.

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