The US is once again facing another COVID-19 wave, with the latest Omicron subvariant, BA.5, becoming the dominant strain nationally. Experts say that though it seems more transmissible than previous variants and the rise in cases has led to an uptick in hospitalizations (but not a dramatic one), the COVID death rate is relatively low compared to earlier surges in the pandemic.
BA.5 and its closely related subvariant, BA.4, have overtaken existing strains in 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 America and Europe, WHO Director-General Tedros Adhanom Ghebreyesus said in a July 6 briefing. But a decrease in testing levels in multiple countries obscures the real numbers and delays treatments, he cautioned.
In the US, those two strains accounted for 81.3% of cases the week ending July 9, with BA.5 — the more dominant of the two — making up 65% of that total, according to the CDC's estimates.
As cases climb, the emergence of a new, more contagious strain is a reminder that the pandemic is still very much ongoing. Here's 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 dramatically so," David Dowdy, an infectious disease epidemiologist and professor at Johns Hopkins University, told BuzzFeed News.
"I think the challenge is that every new strain, if compared to the old strain, the existing strain, is going to appear 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 subvariant, which was behind the massive winter wave — remember all those holiday parties that turned into superspreader events? — BA.5 has taken over at a slower rate.
"It's taken BA.5 over two months to get to this point, whereas with the original Omicron wave, it was a complete takeover in about one month," he said. "It's substantially more gradual than what we saw this past winter, and honestly, not faster than Delta either."
Peter Chin-Hong, an infectious disease specialist and professor in the University of California, San Francisco Health Division of Infectious Diseases, also said the rise of BA.5 has been a lot different from the original Omicron surge.
"There's still a lot of BA.2 in some places. But [BA.5] is moving — I would call it at a moderate pace," he said.
Being infected with BA.5 could also result in people testing positive for longer, and therefore being contagious for a longer time, said Dean Blumberg, chief of the division of pediatric infectious diseases at the University of California, Davis, School of Medicine. Because BA.5 appears to enter the cells more easily, he said, it results in a higher concentration of the virus in the body.
"That higher concentration tends to linger for a longer period of time, and that results in patients being positive for a longer period of time," Blumberg said.
If I had COVID recently, what are my chances of being infected by BA.5 now?
Because there are so many strains in the mix now, the immunity that you've built up from a previous infection may not protect you from a new subvariant.
"If you've got [an infection] that was not BA.5, we know that you're going to be susceptible to BA.5," Chin-Hong said.
"In the old days, there was just one thing in town, so if you got infected, you have a three-month period where you wouldn't get infected, likely," he said. "Whereas now with all these players jostling for power and flavors of Omicron, if there's no one dominant thing, you can get one of several things floating around. And that doesn't guarantee that you won't get infected [by a different strain] in the next few weeks."
But nobody knows what strain they're infected with, which makes it even more complicated. Typically, people are only testing for whether they have the coronavirus or not. Genome sequencing, the process that decodes the genetic makeup of the virus, is only done on a limited amount of positive tests that are anonymized, and that data is then used to estimate how the virus is moving in a community.
"It's going to be a very psychologically difficult time for people, because you don't know what you've got," he said. "We don't sequence variants when people get infected, so it could be one of a bunch of different things."
What are the symptoms?
Experts have said the symptoms from BA.5 are similar to that of previous Omicron subvariants.
"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 illness from BA.5 more severe than previous strains?
The difference with this wave of infections compared to early in the pandemic is that there are fewer hospitalizations and ICU admissions, which overwhelmed healthcare workers and facilities. That's partly because many people have some level of immunity at this point, Blumberg said.
"At this time, if people don't have complete immunity, at least they have partial immunity from prior infection or vaccination, or a combination of the two," he said. "So that when they do get these breakthrough infections, these repeat infections, they generally result in outpatient disease."
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 people who are vaccinated and boosted, being infected with BA.5 probably won't land them in the hospital.
"But being infected is so disruptive to your life, and, plus, it's not a walk in the park for everyone, either," he said.
Are people more likely to get long COVID with BA.5? Do we know that yet?
Experts said that there isn't enough data on long COVID from BA.5 to make any conclusions, given how new it is.
But there is a risk of long-term health consequences with every infection, especially repeat infections — even if you don't come down with a severe case, Blumberg said.
"There's emerging evidence that the more times that you're infected with COVID, this can result in generalized inflammation that can affect many organ systems and damage them," he said. "So it can result in long-term damage to the liver or the gastrointestinal system. It can result in 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 know instinctively what we can do to lower our chances of infection.
"Best practices are what they always have been," Dowdy said, like avoiding large indoor gatherings and getting your booster shots.
Anyone who's immunocompromised or at least 50 years old should also get their second booster shot, which the CDC recommended beginning in May 2022, if they haven't already.
"I know that people can get frustrated with the changing recommendations, but that's driven by the data that we have," Blumberg said, citing the CDC's guidance.
And if you're wondering whether you should wear a mask in crowded areas, the answer is still a resounding yes. High-quality, well-fitting masks have proven 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 OK to socialize, Blumberg said, as long as you're prudent about your behavior.
"Continue to mask if you're in really crowded settings, but enjoy yourself and socialize," he said. "I would still wear an N95 [mask] if I was going on a trip, but I would still go on a trip."
Those who are vaccinated, boosted, and have a healthy immune system should not necessarily worry about this strain more 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 to assess your risk tolerance. Someone in their 80s or 90s, or who has existing health issues, is more at risk of being seriously ill than a younger or nonimmunocompromised person if they catch the virus.
Where you socialize and who you're with matter too. Being outdoors lowers your risk of infection, and so does spending time with people who are vaccinated and boosted.
"If you're with people who take this seriously, so that they will test themselves if they might be symptomatic and then cancel plans, that's the responsible thing to do," Blumberg said. "And then you can have more confidence that you can get together with people more safely."
Every tool you use at your disposal — vaccines, masks, avoiding indoor crowds — 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 from a year ago," he said. "So you have to take a measured risk — you wear a seatbelt when you're driving, but that doesn't mean you wouldn't get into an accident. You're just decreasing your chances of getting injured."