Scientists Warn BA.3.2 'Cicada' Variant Shows Unusual Pattern, Primarily Affecting Children

A newly identified Omicron subvariant of Covid-19, dubbed BA.3.2 and nicknamed 'Cicada' for its pattern of vanishing and reappearing, is raising eyebrows among scientists—not for its severity, but for its unusual preference for infecting children. First detected in South Africa in November 2024, BA.3.2 has since been identified in wastewater samples from 25 U.S. states and 23 countries, according to the Centers for Disease Control and Prevention (CDC). Despite its 53 mutations to the spike protein—far outpacing typical variant evolution—BA.3.2 has not triggered widespread severe illness or hospitalization spikes, offering a puzzling contrast to the virus’s historical patterns.

• BA.3.2, nicknamed 'Cicada,' is a heavily mutated Omicron subvariant first detected in South Africa in November 2024.
• The variant has been found in 25 U.S. states and 23 countries, but testing limitations likely undercount its true spread.
• Children aged 3-15 are five times more likely to be infected by BA.3.2 than adults, though severe disease remains rare.
• Scientists believe the variant’s genetic mutations may help it evade immunity, but it lacks the binding efficiency to dominate globally.
• Current updated vaccines appear effective against BA.3.2, and experts see no urgent need for variant-specific boosters.

Why Scientists Are Watching the 'Cicada' Variant Closely

The emergence of BA.3.2 is more than a curiosity—it’s a reminder of how SARS-CoV-2 continues to evolve in unpredictable ways. Unlike the original Omicron variant, which surged globally in late 2021, BA.3.2 has followed a quieter path, earning its nickname from its habit of disappearing for extended periods before reemerging. This pattern mirrors the lifecycle of cicadas, insects that spend years underground before surfacing in hibernation-like cycles.

A Variant That Defies the Omicron Family Tree

When Omicron first dominated in late 2021, researchers identified five primary branches of its family tree. Four of these—including BA.1, BA.2, BA.4, and BA.5—drove significant waves of infection worldwide. BA.3, however, was the outlier. First detected in 2022, it vanished almost entirely, puzzling scientists. Dr. T. Ryan Gregory, an evolutionary biologist at the University of Guelph in Canada, suggests BA.3 may have persisted in a single immunocompromised individual for two years. Chronic infections in such hosts create prolonged evolutionary pressure, allowing the virus to accumulate mutations before re-emerging.

“It has to look like it will take off or will be of wider interest … or else we don’t see a nickname as being useful.” — Dr. T. Ryan Gregory, evolutionary biologist, University of Guelph

BA.3.2’s reappearance in November 2024—identified in a 5-year-old boy in South Africa—revealed a variant with 53 mutations to its spike protein compared to its parent BA.3 and roughly 70 mutations from the original 2019 coronavirus. This level of genetic divergence is rare and typically associated with variants capable of evading immunity or causing severe disease. Yet BA.3.2 has defied expectations on both fronts.

The Mystery of BA.3.2’s Preferential Infection of Children

One of the most striking observations about BA.3.2 is its tendency to infect children aged 3 to 15 at disproportionately high rates. Analysis of New York City data by variant sleuth Ryan Hisner found that children were about five times more likely to contract BA.3.2 than other circulating variants. While BA.3.2 remains a minority strain in most regions, its pattern is consistent enough to warrant concern.

How BA.3.2’s Mutations May Explain Its Unusual Behavior

The genetic makeup of BA.3.2 offers clues to its behavior. Unlike other highly mutated variants, BA.3.2 has lost parts of specific genes that play a role in activating the immune system. This genetic deletion may allow it to slip past immune defenses more easily, particularly in children whose immunity from vaccines and prior infections wanes faster than adults’. Dr. Tulio de Oliveira, director of the Center for Epidemic Response and Innovation in South Africa, noted that BA.3.2 shares this trait with the XBB variant, which also showed a similar predilection for pediatric infections.

The Role of Immune History in Variant Susceptibility

Dr. Alex Greninger, head of the Division of Infectious Disease Diagnostics at the University of Washington, suggests that children’s limited immune history may make them more vulnerable to BA.3.2. Each Covid-19 infection or vaccine dose broadens a person’s immune response, preparing it for future variants. Adults, having accumulated years of exposures, may have a more diversified toolkit to fend off new threats. Children, by contrast, have fewer exposures and thus a narrower range of defenses.

Environmental Factors: Why Schools and Daycares Matter

Greninger also points to environmental factors as a potential driver of BA.3.2’s spread among children. Schools and daycare settings are hotspots for respiratory virus transmission, where close contact and shared surfaces facilitate rapid spread. This dynamic mirrors the behavior of other seasonal viruses like influenza, which often peaks in children before spreading to older household members. BA.3.2’s current pattern—high infection rates in kids with minimal severe outcomes—aligns with this classic respiratory virus behavior.

Why BA.3.2 Hasn’t Dominated Globally—And What That Means

Despite its genetic advantages, BA.3.2 has not achieved global dominance. One critical factor is its reduced ability to bind tightly to ACE-2 receptors, the cellular doorways SARS-CoV-2 uses to infect humans. This inefficiency makes it a 'middling competitor' on the global stage, according to Dr. Marc Johnson, a molecular microbiologist at the University of Missouri. Johnson, who tracks BA.3.2 in U.S. wastewater data, believes the variant has a chance to become dominant but is unlikely to trigger sweeping waves like past variants.

Vaccine Efficacy and the Case Against Immediate Booster Updates

Current Covid-19 vaccines, particularly those updated for the 2024-25 season to target the KP.2 strain, appear to provide adequate protection against BA.3.2. A study by Dr. Florian Krammer and his team at Mount Sinai’s Icahn School of Medicine found that vaccine-generated antibodies effectively neutralized BA.3.2 in lab settings. The authors concluded that this may explain why the variant has not achieved high transmission rates globally.

“Our results may explain why this variant has not achieved high transmission rates globally.” — Dr. Florian Krammer, virologist, Mount Sinai’s Icahn School of Medicine

Public Health Response: Monitoring vs. Action

Experts agree that BA.3.2 warrants close monitoring but does not yet require urgent public health interventions. Dr. de Oliveira emphasized that while the variant is interesting from an evolutionary standpoint, there is no evidence of increasing hospitalizations or deaths. He also noted the public’s waning appetite for frequent vaccination campaigns against new variants. Instead, he advocates for sustained genomic surveillance to detect any shifts in BA.3.2’s behavior.

The Broader Implications of BA.3.2 for the Pandemic’s Future

The emergence of BA.3.2 underscores a critical phase in the Covid-19 pandemic: one where the virus is no longer a novel threat but continues to evolve in ways that challenge public health strategies. The focus has shifted from containment to monitoring for variants that could reignite severe outcomes or evade immunity. BA.3.2’s behavior—high infection rates in children with minimal severity—raises questions about how future variants may interact with different age groups, particularly as immunity wanes across populations.

Tracking BA.3.2: The Challenges of Modern Covid Surveillance

Detecting and tracking BA.3.2 is complicated by the reduced genetic sequencing of Covid-19 samples in the U.S. and globally. During the pandemic’s peak, sequencing efforts were robust, but as testing has declined, so has the ability to identify emerging variants. Wastewater surveillance, however, has emerged as a critical tool. Dr. Johnson, who tracks BA.3.2 in U.S. wastewater, notes that while the data suggests the variant is gaining traction, it is still at low levels. The CDC’s recent report on BA.3.2, though quietly published, highlights the need for continued investment in genomic surveillance to stay ahead of the virus’s next moves.

What’s Next for BA.3.2—and the Pandemic

For now, BA.3.2 remains a variant of interest rather than a cause for alarm. Scientists like Dr. Greninger describe it as 'adding grilled onions to your burger'—a minor but notable addition, but not a game-changer. The variant’s future trajectory depends on several factors: its ability to accumulate further mutations that improve its binding efficiency, the durability of population immunity, and the public health response. If BA.3.2 gains the ability to bind more effectively to ACE-2 receptors, it could yet pose a greater threat. Until then, experts urge vigilance but not overreaction.

Key Takeaways: What You Need to Know About BA.3.2

• BA.3.2 is a heavily mutated Omicron subvariant first detected in South Africa in November 2024, now found in 25 U.S. states and 23 countries.
• Children aged 3-15 are five times more likely to be infected by BA.3.2 than adults, though severe disease remains rare.
• The variant’s 53 spike protein mutations may help it evade immunity, but its reduced ACE-2 binding limits its global spread.
• Current vaccines, particularly those updated for 2024-25, appear effective against BA.3.2, and experts see no urgent need for variant-specific boosters.
• Wastewater surveillance is critical for tracking BA.3.2’s spread, as reduced genetic sequencing complicates variant detection.

Frequently Asked Questions About the BA.3.2 'Cicada' Variant