A new CDC report shows how traveler screening and wastewater monitoring detected the emerging BA.3.2 variant early, offering a clearer view of its spread, immune-evasion potential, and public health significance.
Key takeaways
BA.3.2 spread internationally after first being identified in South Africa in November 2024, with detections rising from September 2025 and reports from at least 23 countries by 11 February 2026.
U.S. surveillance picked up BA.3.2 early through traveler-based genomic surveillance and wastewater monitoring, with detections in travelers, airplane wastewater, patients, and 132 wastewater samples from 25 states by 11 February 2026.
The variant is highly divergent, with about 70-75 spike-protein substitutions and deletions relative to JN.1 and LP.8.1, raising concern that it could better evade immunity from prior infection or vaccination.
Despite that immune-evasion potential, BA.3.2 had not rapidly overtaken other circulating variants at the time of the report, so the main public health message was continued genomic surveillance rather than evidence of a new dominant or clearly more severe strain.
Report: Early Detection and Surveillance of the SARS-CoV-2 Variant BA.3.2 - Worldwide, November 2024–February 2026. Image Credit: Jezper / Shutterstock
The latest Morbidity and Mortality Report (MMWR) from the CDC highlights the global spread of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) BA.3.2 variant. First identified in South Africa in November 2024, the variant has been reported in 23 countries, with detections rising steadily since September 2025.
In the United States (U.S.), the Centers for Disease Control and Prevention (CDC) has detected BA.3.2 from four travelers' nasal swabs, clinical specimens from five patients, and 132 wastewater surveillance samples across 25 states, plus three airplane wastewater samples, highlighting its continued global spread and public health relevance.
SARS-CoV-2 Evolution and Spike Protein Mutations
As SARS-CoV-2 has continued to circulate, the virus has accumulated spike protein mutations that may affect transmissibility, immune escape, and vaccine effectiveness. The CDC tracks these changes through a multimodal genomic surveillance system that integrates international reports with U.S.-based wastewater, traveler, and clinical sampling.
BA.3.2 Variant Genetic Characteristics and Mutations
The BA.3.2 variant, a descendant of BA.3, carries approximately 70-75 substitutions and deletions in the spike protein gene sequence relative to JN.1 and its descendant, LP.8.1, the antigens used in the 2025-26 COVID-19 vaccines, including receptor-binding and N-terminal domain (NTD) differences.
Monitoring its spread across countries and U.S. states provides insight into immune evasion and informs prevention strategies and vaccine composition decisions.
Global and U.S. Genomic Surveillance Study Design
This report summarizes the detection and dissemination of the SARS-CoV-2 BA.3.2 strain and its sublineages globally and in the U.S. from November 2024 through February 2026.
Internationally, the CDC tracked BA.3.2 by analyzing digital population health data. Data included sequences uploaded in open-access databases, including the National Center for Biotechnology Information (NCBI) and the Global Initiative on Sharing All Influenza Data (GISAID). The team also analyzed preprint databases, media reports, GitHub, and online platforms.
The US CDC integrated data from the traveler-based genomic surveillance (TGS), national SARS-CoV-2 genomic surveillance, and national wastewater surveillance system (NWSS). The national program combines National SARS-CoV-2 Strain Surveillance (NS3) sequencing data with data from other repositories to determine variant proportions over time.
TGS tested airplane wastewater and traveler nasal swabs. NWSS and WastewaterSCAN monitored approximately 1,300 U.S. wastewater sites and 150 sites, respectively, to detect SARS-CoV-2 and characterize variants.
The CDC investigated BA.3.2 sequences to confirm lineage assignments. They evaluated wastewater sequences computationally for variant detection. The team analyzed selected sequences for spike glycoprotein mutations and phylogenetic relationships using multiple sequence alignment (MSA) and unrooted maximum-likelihood methods.
The CDC team calculated spike protein differences relative to the LP.8.1 antigen, which has been used to formulate vaccines between 2025 and 2026. They aggregated BA.3.2 infection cases by epidemiologic week and country, mapped by earliest collection date, and estimated prevalence using statistical methods. The data represent information collected through 11 February 2026.
Global Detection Trends and Geographic Spread
BA.3.2 was first identified in a respiratory sample from a five-year-old in South Africa on 22 November 2024. This variant was designated as lineage BA.3.2.1. Scientists next identified the strain in Mozambique (17 March 2025), the Netherlands (12 April), and Germany (29 April).
Following initial sporadic reports, global detections increased from September 2025, peaking on 7 December 2025. As of 11 February 2026, the BA.3.2 variant has been reported across 23 countries.
In Europe, weekly detections accounted for nearly 30% of the variant sequences documented in the Netherlands, Germany, and Denmark. However, the overall incidence of SARS-CoV-2 infections has remained stable.
United States Detection and Surveillance Findings
In the U.S., BA.3.2 was first detected on 27 June 2025 through the TGS program in a participant traveling from the Netherlands to the United States. Wastewater surveillance identified the strain in Rhode Island on 11 November 2025.
The first clinical samples were collected from patients between 4 December 2025 and 4 January 2026. Detected cases included a young outpatient child and two older adults who were hospitalized with comorbidities; all patients survived.
As of 11 February 2026, researchers have identified BA.3.2 in five respiratory samples, four traveler nasal swabs, three samples from airplane sewage, and 132 wastewater surveillance samples across 25 states.
Phylogenetic analysis revealed two subvariants, BA.3.2.1 and BA.3.2.2, reflecting ongoing evolution. By 12 March 2026, detections included six travelers, 29 patients, three airplane sewage samples, and 260 wastewater samples collected from across 29 U.S. states plus Puerto Rico.
Prevalence among sequences has increased from 0.19% to 0.55% between 1 December 2025 and 12 March 2026.
Public Health Implications and Variant Monitoring
The emergence and international spread of the SARS-CoV-2 BA.3.2 variant underscores the virus's evolving evolution and the critical role of comprehensive genomic surveillance.
While laboratory studies indicate that BA.3.2 can evade antibodies induced by previous infection or current vaccines, clinical outcomes to date, including U.S. cases, do not yet indicate a clear signal of increased severity, with all patients surviving.
Wastewater and traveler-based surveillance have proven effective for early detection, often preceding clinical case identification.
Although BA.3.2 has not rapidly replaced other circulating lineages, its continued circulation and ongoing spike mutations warrant close monitoring.
Sustained genomic surveillance, combined with observational studies on vaccine and antiviral effectiveness, remains essential to guide public health strategies, vaccine composition decisions, and timely responses to variants affecting transmissibility, immune escape, and COVID-19 outcomes.
Journal reference:
- Shakya, M., Ma, K.C., Hughes, L.J., et al. (2026). Early Detection and Surveillance of the SARS-CoV-2 Variant BA.3.2 - Worldwide, November 2024-February 2026. MMWR Morb Mortal Wkly Rep;75:130-137. DOI: 10.15585/mmwr.mm7510a1, https://www.cdc.gov/mmwr/volumes/75/wr/mm7510a1.htm
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