What is the BA.2 variant?
Should you be concerned?
Hi friends,
I’ve been getting a lot of questions about the BA.2 variant, and whether that is something to be concerned about. Here’s a summary of what we know so far.
It’s NOT a new variant
BA.2 is not a new variant. It is rather a descendant from Omicron (which is referred to as BA.1), and part of the Omicron family. Remember, viruses, including SARS-CoV-2 continue to mutate and form new variants, and BA.2 is just that, another variant. But it is not new.
How is BA.2 different from BA.1?
BA.2 is different from BA.1 (or the original Omicron) in that it doesn’t have some of the mutations that BA.1 does, and has a few additional ones that BA.1 doesn’t. Notably, unlike BA.1, BA.2 does not cause the S-gene target failure (SGTF), meaning that it is now harder to pick up on PCR tests. What are the implications of the other mutations? We don’t know yet.
Here's a great Twitter thread on BA.2
Does it spread faster than BA.1?
It seems that BA.2 has a growth advantage over BA.1. Some estimates put it at 1.5x as transmissible than BA.1. The UK’s public health agency noted that BA.2 probably has a growth advantage over BA.1 - a 30% transmission advantage when looking at transmission within households.
The vast majority of COVID cases diagnosed worldwide remain BA.1. However, BA.2 has been found in multiple countries across the world, including the United States, and it’s growing compared to BA.1. It seems to be rapidly growing in Denmark and the UK. Notably, in Denmark, which lifted ALL of its COVID restrictions, this variant is spreading rapidly, especially among children and young adults.
Here’s the questions that we still don’t have answers to when it comes to BA.2:
Is it deadlier compared to BA.1?
There is no evidence so far that BA.2 causes more severe illness than BA.1, although this might change over the next few weeks as more data comes in.
Does prior infection protect against BA.2?
More importantly, does infection from BA.1 (original Omicron) protect against BA.2? This also remains to be seen. However, we do know that prior infection provides little protection against BA.1, and I don’t see this suddenly changing with BA.2.
How do the vaccines work against BA.2?
This we actually have some data on from the UK (table 3 on page 15):
While 2 doses have limited protection against symptomatic disease from both BA.1 and BA.2, getting a booster shot significantly improves that protection for both BA.1 (63%) and BA.2 (70%). So yes, the vaccines continue to work against BA.2.
Bottom line?
BA.2 is not a “new” variant, rather it’s a sister variant of the original Omicron. It does spread more rapidly, but there is no evidence that it causes more severe illness. What this does mean is that the Omicron wave in many places is likely to be prolonged as BA.1 retreats and BA.2 takes over. Vaccines (especially getting boosted), provide strong protection against both BA.1 and BA.2. So if you’ve not been boosted yet and are eligible, please get your booster ASAP.
Remember, viruses continue to evolve and mutate. Omicron is probably not the last variant we’ll have to deal with. This pandemic is far from over. Continue to protect yourself and your family by getting vaccinated + boosted, wearing a mask, and social distancing.
Questions? Thoughts? Comment below!
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Thanks for the update. I did have Omicron and the only way I tested positive was when I did a throat swab with my at home test. 2 Rapid test and a PCR both negative...
Thank you for all the great information that you are very willing to offer the public. I appreciate it.