CDC raises alarm after new Covid variant from South Africa is found in dozens of samples in US
A new, highly mutated Covid variant is quietly spreading across the US, prompting the CDC to take notice.
The variant, known as BA.3.2, first appeared in South Africa in November 2024 and scientists are concerned that it could be significantly more adept at sidestepping immune defenses, particularly the protection provided by the 2025-2026 Covid vaccines.
The variant’s spike protein, which vaccines train the body to recognize and fight, has undergone about 75 mutations. That makes it look like an entirely new threat to the immune system compared to other recent strains.
As of mid-March 2026, BA.3.2 has turned up in six travelers, three airplane wastewater samples, over two dozen patients and 260 wastewater sites across 29 states and Puerto Rico. Overall, it accounts for a small fraction, about half a percent, of recent virus sequences, according to the latest CDC data.
Wastewater surveillance is often the first clue that a virus is gaining a foothold in the community. In this case, it detected BA.3.2 weeks before doctors saw it in patients.
Detections of BA.3.2 started climbing in Europe last fall, reaching roughly 30 percent of cases in Denmark, Germany, and the Netherlands. It has not yet taken over in the US, but its ability to spread alongside other more dominant variants suggests it has been mutating for a while.
Two lab studies found that BA.3.2 does not bind as well to human cells as other variants do, and that weakness may be holding it back from spreading faster.
The CDC is monitoring the spread of BA.3.2 by testing international travelers, sampling airplane wastewater and monitoring sewers nationwide. These systems captured the variant’s arrival in the US in June 2025, months before it appeared in hospitals.
On June 27, 2025, BA.3.2 was identified for the first time in the US at San Francisco International Airport in California, from a respiratory specimen collected from someone returning from the Netherlands
While BA.3.2 may be better at evading immunity, the current vaccines still offer protection against severe disease.
BA.3.2 was first detected in a five-year-old boy in South Africa in November 2024. It then appeared in Mozambique and a few European countries in early 2025.
Detections were sparse at first but began climbing that September, peaking in December.
BA.3.2 first reached the US on June 27, 2025, when a traveler flying from the Netherlands tested positive at San Francisco International Airport.
Reports started ticking up in September 2025, but because many countries lack the sophisticated surveillance tools necessary to closely track variants, ‘these detections likely underrepresent the actual geographic extent of spread,’ according to the CDC.
Wastewater surveillance in the US picked it up in Rhode Island that November, months before clinical cases appeared.
The first patients were reported in early January 2026 — two older hospitalized adults with underlying conditions and a young child. All of them survived.
By February 2026, BA.3.2 had appeared in a handful of international travelers, a few clinical patients and over 130 wastewater samples across two dozen states.
To track Covid variants, the CDC pulls data from three main sources: national lab testing, travelers arriving at airports, including volunteer nasal swabs and airplane wastewater, and a nationwide wastewater surveillance system that monitors about 1,450 sewer sites.
When scientists find a BA.3.2 sample, they analyze its genetic code, comparing it to current vaccines to see what has changed. They use software to line up sequences side by side, building family trees that show how different versions are related.
Every detection is logged by location and date, allowing the CDC to map where it first appeared and how quickly it moves, giving officials a real-time view of the evolving variant.
According to the agency, BA.3.2 is genetically distinct from the JN.1 family of variants that have dominated in the US since early 2024.
Compared to the strain used in current vaccines, BA.3.2 has about 70 to 75 mutations on its spike protein.
Of those, 20 are in the part that grabs onto human cells, 35 are in a nearby region that also helps the virus infect cells and evade immunity and the remaining changes are scattered elsewhere on the spike.
By February 11, 2026, BA.3.2 had been identified in at least 23 countries. Among them, four U.S. travelers tested positive through the TGS program after returning from Japan, Kenya, the Netherlands and the United Kingdom
The current Covid vaccine, updated for the 2025–26 season, works well against the dominant JN.1 strains still circulating.
In a lab study comparing seven variants, it performed worst against BA.3.2. That means the vaccine may offer less protection against this particular variant, though real-world data is still needed to know for sure.
Covid has gone from being a consistent viral threat to a seasonal public health concern alongside the flu and respiratory syncytial virus (RSV).
In 2020 and 2021, the country would often experience waves of such severe disease transmission that thousands of patients were dying each day.
Now, the virus follows a predictable seasonal rhythm with far shorter peaks thanks to highly effective vaccines and the antiviral drug Paxlovid.
Like the flu, Covid now tends to spike during the colder months, from late fall through early spring, when people gather indoors and the virus spreads more easily. In the summer, cases typically drop.
Most of the population now has some protection from a combination of vaccination, prior infection, or both. That does not stop everyone from getting sick, but it does mean most people who catch it will not end up in the hospital.
