What you should know about BA.5, the dominant COVID strain right now

9 月 12, 2022World News

The US is once again facing another wave of COVID-19, with the latest Omicron sub-variant, BA.5, becoming the dominant strain nationally. Experts say that while it appears more transmissible than previous variants and the rise in cases has led to a rise in hospitalizations (but not a dramatic one), the death rate from COVID is relatively low compared to earlier surges in the pandemic.

BA.5 and its closely related subvariant, BA.4, have outcompeted existing strains in some parts of the world. COVID-19 cases reported to the World Health Organization in the last two weeks increased by nearly 30%, with BA.4 and BA.5 driving waves in the Americas and Europe, WHO Director-General Tedros Adhanom Ghebreyesus said at a briefing on July 6. But a drop in testing levels in several countries obscures the real numbers and delays treatments, he warned.

In the US, those two strains accounted for 81.3% of cases in the week ending July 9, with BA.5, the more dominant of the two, accounting for 65% of that total, according to the CDC estimates.

As cases rise, the emergence of a new, more contagious strain is a reminder that the pandemic is still raging. This is what you need to know about BA.5.

How infectious is it?

BA.5 is the most contagious strain we’ve seen so far, “but not that contagious,” David Dowdy, an infectious disease epidemiologist and professor at Johns Hopkins University, told BuzzFeed News.

“I think the challenge is that each new strain, when compared to the previous strain, the existing strain, is going to seem more contagious. Because that’s what allows that strain to take hold in the population,” Dowdy said. “Part of what causes that is that it’s not necessarily just that it’s better, it’s just that it’s different.”

Compared to the BA.1 Omicron sub-variant, which was behind the massive winter wave, remember all those holiday parties that became superspreading events? — BA.5 has taken over at a slower pace.

“It took BA.5 more than two months to get to this point, whereas with the original Omicron wave, it was a full acquisition in about a month,” he said. “It’s substantially more gradual than what we saw last winter and honestly not faster than Delta either.”

Peter Chin-Hong, an infectious disease specialist and professor at the University of California San Francisco Division of Infectious Disease Health, also said that BA.5’s rise has been very different from Omicron’s original rise.

“There’s still a lot of BA.2 in some places. But [BA.5] it’s moving, I would call it at a moderate pace,” he said.

Being infected with BA.5 could also result in people testing positive longer and thus being contagious longer, said Dean Blumberg, chief of the division of pediatric infectious diseases at the University School of Medicine. of Calif., Davis. Because BA.5 appears to enter cells more easily, he said, it results in a higher concentration of the virus in the body.

“That higher concentration tends to be more sustained over a longer period of time, and that results in patients being positive for a longer period of time,” Blumberg said.

If I recently had COVID, what are my chances of being infected with BA.5 now?

Because there are so many strains in the mix now, the immunity you’ve developed from a previous infection may not protect you from a new subvariant.

“If you have [an infection] that was not BA.5, we know you will be susceptible to BA.5,” Chin-Hong said.

“In the old days, there was only one thing in the city, so if you got infected, you had a three-month window where you probably wouldn’t get infected,” he said. “Whereas right now, with all these players competing for Omicron power and flavors, if there isn’t one dominant thing, you can have one of several things floating around. And that’s no guarantee that you won’t get infected.” [by a different strain] In the next weeks.”

But no one knows what strain they are infected with, which makes it even more complicated. People usually only test whether they have the coronavirus or not. genome sequencingthe process that decodes the genetic makeup of the virus is only done on a limited number of positive tests that are anonymous, and that data is then used to estimate how the virus is moving in a community.

“It’s going to be a very difficult time psychologically for people because you don’t know what you have,” he said. “We don’t sequence variants when people get infected, so it could be one of many different things.”

What are the symptoms?

Experts have said that the symptoms of BA.5 are similar to those of previous Omicron sub-variants.

“It’s actually very similar to BA.2: sore throat, scratchy throat, congestion, runny nose, headache, fatigue, muscle aches,” Chin-Hong said. “Less shortness of breath, less loss of taste and smell.”

Is BA.5 disease more severe than previous strains?

The difference with this wave of infections compared to earlier in the pandemic is that there are fewer hospitalizations and ICU admissions, overwhelming healthcare workers and facilities. That’s in part because many people have some level of immunity right now, Blumberg said.

“Right now, if people don’t have full immunity, they at least have partial immunity from previous infection or vaccination, or a combination of the two,” he said. “So when they get these advanced infections, these repeat infections, it usually results in an outpatient illness.”

Still, COVID-19 is no ordinary virus, and a “mild” case can still knock you out for a few days or even weeks.

Chin-Hong said he’s confident that for most vaccinated and boosted people, infection with BA.5 probably won’t land them in the hospital.

“But being infected is very detrimental to your life and also it’s not a walk in the park for everyone,” he said.

Are people more likely to have prolonged COVID with BA.5? We already know?

Experts said there isn’t enough data on prolonged COVID from BA.5 to draw any conclusions, given how new it is.

But there is a risk of long-term health consequences with each infection, especially repeated infections, even if a severe case does not occur, Blumberg said.

“There is emerging evidence that the more times you are infected with COVID, this can result in widespread inflammation that can affect and damage many organ systems,” he said. “So it can cause long-term damage to the liver or the gastrointestinal system. It can lead to strokes and heart attacks, and other long-term consequences can affect people’s health.”

How can I prevent getting COVID?

Two and a half years into the pandemic, most of us instinctively know what we can do to reduce our chances of infection.

“The best practices are what they’ve always been,” Dowdy said, like avoiding large gatherings indoors and getting booster shots.

Anyone who is immunocompromised or who is at least 50 years old should also get their second booster shot, which the CDC recommended as of May 2022, if they haven’t already.

“I know people may be frustrated with the changing recommendations, but that’s because of the data we have,” Blumberg said, citing CDC guidance.

And if you’re wondering if you should wear a mask in crowded places, the answer is still a resounding yes. High-quality, well-fitting masks have been shown to be extremely effective in preventing infection, and studies have shown that they can protect you even when you’re the only person wearing one.

Should I cancel my plans?

It’s okay to socialize, Blumberg said, as long as you’re cautious about your behavior.

“Continue with the mask if you are in very crowded places, but have fun and socialize,” he said. “I would still use an N95 [mask] if I went on a trip, but I would still go on a trip.

Those who are vaccinated, boosted and have healthy immune systems shouldn’t necessarily be more concerned about this strain than previous ones, Dowdy said, urging “respect for this contagious virus.”

Even if you have all your booster shots, your age and health are going to change how you assess your risk tolerance. Someone in their 80s or 90s, or who has existing health problems, is more at risk of getting seriously ill than a younger or non-immunocompromised person if they contract the virus.

Where you socialize and who you are with also matters. Being outdoors reduces the risk of infection, as does spending time with vaccinated and boosted people.

“If you’re with people who are taking this seriously, to test themselves if they can be symptomatic and then cancel plans, that’s the responsible thing to do,” Blumberg said. “And then you can be more confident that you can meet people more safely.”

Every tool you use at your disposal—vaccines, masks, avoiding crowds indoors—can help increase your protection against the virus. Chin-Hong also pointed to Paxlovid, an antiviral treatment that has been shown to significantly reduce hospitalizations and deaths in people with COVID-19.

“It’s a very different place than a year ago,” he said. “So you have to take a measured risk: You wear your seatbelt when you drive, but that doesn’t mean you won’t have an accident. You’re just lowering your chances of being injured.”

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