What to Know About BA.5 (and All the Other COVID Subvariants)

As expected, the virus that causes COVID-19 is still mutating, and newer versions or subvariants of omicron have been circulating in recent months, keeping cases of COVID-19 high compared to the March and April dip in cases.

The first subvariant of omicron (the original is called BA.1) to cause concern was BA.2, or “stealth omicron,” which quickly gave way to BA.2.12.1. Both subvariants were slightly different than the original and more contagious. Now omicron has evolved to BA.5, which has quickly become the dominant version of COVID-19 in the US — it’s responsible for more than half of COVID-19 cases, according to an estimate by the US Centers for Disease Control and Prevention .

More research and time is needed to see how BA.5 acts in the US, but analyzes now point to BA.5 being the most contagious version of the virus yet, and one that will further chip away prior immunity from past infections and likely vaccination . In an effort to target the most relevant strain of virus causing COVID-19, vaccines based on the BA.5 subvariant (along with BA.4) will be the first choice for COVID-19 booster shots this fall.

Here’s what we know about BA.5 and new versions of omicron.

What is BA.5? Is it more contagious or severe?

BA.5 is a subvariant of omicron, which means it’s different than the “original” omicron, but not different enough to constitute its own variant status. (Delta is a different variant from omicron and beta, for example.) BA.5 is understood to be the most contagious version of the virus yet, however, and it’s evading immunity. This means more people will get reinfected with COVID-19, which can put them at risk of complications and long-term COVID symptoms, even if the infection itself was mild.

Experts are particularly concerned about BA.5. In an analysis of a preliminary report from the Kirby Institute in Australia, Dr. Eric Topol, a professor of molecular medicine at Scrips Research, wrote that BA.5’s ability to infect cells might be more similar to the delta variant than other versions of omicron. He also writes that changes in BA.5 might explain reports of people taking longer to test negative compared to illnesses with earlier omicron subvariants.

Like other versions of omicron that whittled down our immunity, the vaccines and boosters available are still expected to provide protection against severe disease and death. Boosters — including a second booster — have been particularly important for protecting older adults and other people more vulnerable to severe disease in the age of omicron. But more research and time is needed to see how the subvariant will act in the US population.

Paxlovid, an effective antiviral medication, is still being prescribed to treat COVID-19 in people at high risk of severe disease in the current variant landscape. One monoclonal antibody therapy, bebtelovimab from Eli Lilly, is still authorized to treat COVID-19 caused by the omicron variants.

As the variants that cause COVID-19 evolve and change, however, the FDA may take back its authorization of certain treatments if research shows they’re no longer effective.

What are the symptoms?

There isn’t information available now to suggest a difference in COVID-19 symptoms between different types of omicron — including BA.5. For many people who become sick with COVID-19 these days (particularly those who are fully vaccinated and boosted), symptoms resemble cold symptoms such as sore throat, runny nose and fatigue. Back pain is a peculiar new symptom of COVID-19 that some people with omicron have reported, and the once common loss of taste or smell appears to be much less common with omicron variants than with older strains.

If you have symptoms and are wondering whether it’s COVID-19, taking a test and staying home while you’re sick will help protect people more vulnerable to severe COVID-19 disease.

Read more: Is It Allergies or COVID? How to Tell the Difference

Understanding omicron, variants and subvariants

Variants are made up of multiple lineages and sublineages. Each variant has a “parent” lineage, according to the CDC, followed by other lineages, which you can think of like a family tree. As the virus spreads between people, mutations occur, but not all of them change the characteristics of the virus in meaningful ways.

The omicron variant and its sublineages made the virus much more contagious and capable of infecting more people, but it led to less severe disease, on average, than the delta variant.

Genomic surveillance can detect variants and sublineages. Scientists in South Africa were able to quickly identify omicron as a new variant because of the way it presents through PCR tests. The original omicron causes a dropped signal or marker on the test that sets it apart from delta, which was the dominant variant prior to omicron. BA.2, however, did not have the same signal, called an S gene target failure. This made it more “stealthy” and gave it its name. But genomic sequencing will detect all omicron subvariants and coronavirus variants in general.

However, detecting new variants or subvariants may be becoming more difficult as the number of sequences shared across the world have “dropped precipitously,” Dr. Maria Van Kerkhove, an infectious disease specialist with the World Health Organization, said in June. While the impact was still enormous, having real-world data available quickly after scientists detected omicron was a benefit during the worldwide surge last winter.

The information contained in this article is for educational and informational purposes only and is not intended as health or medical advice. Always consult a physician or other qualified health provider regarding any questions you may have about a medical condition or health objectives.