Less than six months after the omicron wave hit its peak in the United States, public health officials are once again warning of an other potentially dramatic wave of COVID-19, this one driven by two omicron offshoots—Ba.4 and especially Ba.5.
According to the latest estimates from the Centers for Disease Control and Prevention (CDC), those two variants now make up more than half of all cases as Ba.2 and Ba.212—the two variants that drove prior waves—decline in prevalence. The newer variants have already caused waves in South Africa and Portugal, and are currently driving up cases in the U.K. and other parts of Europe.
Ba.5, in particular, is expected to spread far and wide, according to a detailed tweet thread from Bob Wachter, chair of UCSF’s Department of Medicine, who predicts that this offshoot will outcompete Ba.4. Meanwhile, in a recent edition of his Ground Truths newsletter, medical researcher Eric Topol published an extensive deep dive into Ba.5, calling it the “worst version of the virus that we’ve seen.” The newsletter also comes with a helpful map of Ba.5’s lineage, showing how dramatically it differs from even the other variants in the omicron family. In a nutshell, this is not your December COVID.
What makes Ba. 5 especially concerning is that it appears to not only be ultra-contagious, but it comes with a significant amount of immune escape potential, meaning that even if you’ve been vaccinated, boosted, and previously infected with an earlier subvariant of omicron, you may still have less protection against infection with this current strain. That’s why you’ve likely been hearing more anecdotal accounts of people getting reinfected with COVID after recovering from the virus only a few months ago.
This doesn’t mean the vaccines have stopped working. One piece of good news here is that hospitalizations and deaths are still far below their omicron peak, and vaccines and boosters are still providing protection against severe disease. With luck, those numbers will stay relatively low as the newest variant spreads.
What symptoms should I look out for?
It’s still too early to know for certain if Ba.5 causes dramatically different symptoms than its predecessors. One small omicron-specific study from the CDC, released in December, showed cough (89%), fatigue (65%), congestion or runny nose (59%), and fever (38%) were the most commonly reported symptoms, while loss of taste and smell—a prominent feature of earlier COVID waves—was relatively uncommon. Another study, published in the BMJ in April, showed that sore throat and a “hoarse voice” were more common with omicron than with the previous delta variant.
However, there’s no guarantee that a Ba.5 will act or feel like previous omicron strains, or even the strains that came before them. Until researchers can collect more data about symptoms, it’s probably a good idea to keep an eye out for any symptom associated with COVID-19. The CDC currently lists those as the following:
- Fever or chills
- Shortness of breath or difficulty breathing
- Muscle or body aches
- New loss of taste or smell
- Sore throat
- Congestion or runny nose
- Nausea or vomiting
Importantly, as the CDC points out, the above list is not complete, which means it’s not a bad idea to get tested if you’re feeling any unusual symptoms at all. One thing we’ve learned about COVID over the last two and a half years is that it will continue to be unpredictable.