The highly mutated SARS-CoV-2 BA.3.2 variant, which has been reported by at least 23 countries as of February 11, has been detected in nasal swabs collected from four US travelers, clinical samples from five patients, three airplane wastewater samples, and 132 wastewater surveillance samples from 25 states, per a study published last week in Morbidity and Mortality Weekly Report.

First identified in a respiratory sample in South Africa in November 2024, the strain has roughly 70 to 75 substitutions and deletions in the gene sequence of its spike protein relative to the JN.1 variant and its descendant, LP.8.1, the antigens used in the latest COVID-19 vaccines. 

“BA.3.2 represents a new lineage of SARS-CoV-2, genetically distinct from the JN.1 lineages (including LP.8.1 and XFG) that have circulated in the United States since January 2024,” wrote the authors, led by Centers for Disease Control and Prevention (CDC) researchers. The CDC uses digital public health surveillance to monitor SARS-CoV-2 variants around the world.

30% prevalence in 3 European countries

Detections of BA.3.2 began rising in September 2025. The first US identification of the strain was on June 27, 2025, through the CDC’s Traveler-Based Genomic Surveillance program in a person traveling to the United States from the Netherlands. 

Continued genomic surveillance is needed to track SARS-CoV-2 evolution and determine its potential effect on public health.

From November 2025 to January 2026, weekly BA.3.2 detections increased to about 30% of sequences in Denmark, Germany, and the Netherlands. The first US instance of BA.3.2 in a clinical specimen was documented on January 5, 2026. As of February 11, the strain’s prevalence among 2,579 total genetic sequences in national surveillance collected starting on December 1, 2025, was 0.19%.

“Because many countries have limited genomic detection and surveillance capacities, these detections likely underrepresent the actual geographic extent of spread,” the researchers wrote. “Phylogenetic analyses have identified the emergence of two BA.3.2 sublineages (BA.3.2.1 and BA.3.2.2), indicating ongoing viral evolution.”

As BA.3.2 mutations in the spike protein could reduce protection from a vaccination or infection, “continued genomic surveillance is needed to track SARS-CoV-2 evolution and determine its potential effect on public health,” they added.

Sepsis is a fast-moving, life-threatening condition that occurs when the body overreacts to an infection, sometimes causing permanent organ damage and death.

A new study, published yesterday in JAMA, identified sepsis in 1.3% of hospitalized US children ages one month to 17 years old. The study, which included data from nearly four million admissions from 2016 through 2023, found that 10% of children with sepsis died while in the hospital. 

Overall, 18% of deaths in hospitalized children were related to sepsis, the study showed. Based on those rates, researchers calculated that more than 18,000 cases of sepsis and 1,800 deaths in 2022 among children in this age group.

Findings based on electronic health records

In an accompanying editorial, physicians from Australia, Singapore and Switzerland commended the study authors for developing a standardized way to measure sepsis cases and deaths in children. Previous reports have been based on diagnostic codes, which can vary by hospital and over time. Annual estimates of pediatric cases have varied dramatically, ranging from 33,000 illnesses a year to 75,000.

The new study is based on electronic health records, including laboratory results, use of antibiotics, and markers of organ dysfunction, such as the use of mechanical ventilation.

Children with sepsis, which can cause permanent disabilities, stayed in the hospital an average of 24 days, far longer than the average length of stay of four days. About 79% of children with sepsis were treated in intensive care units, compared to fewer than 1% of other children.

“These findings underscore the substantial burden of pediatric sepsis and its major contribution to childhood morbidity and mortality,” the study authors wrote.

US maternal syphilis case detection rose 26% in the first quarter after screening opportunities were mandated in the third trimester of pregnancy and at delivery, although the confidence intervals were very wide, and the effect fell off and became insignificant in the next year, Harvard researchers write in JAMA Health Forum.

For the study, which included 16.3 million live births and 20,961 syphilis cases from 2012 to 2022, the investigators analyzed birth certificate data from 33 states from 2012 to 2022. They compared maternal syphilis case detections in Arizona, Georgia, Louisiana, and Michigan, all of which enacted expanded mandates for third-trimester and/or delivery screening, with 29 control states without such mandates during this period. 

All four states required offering pregnant women third-trimester screening, while three mandated that high-risk patients be offered testing again at delivery, and one required universal screening at delivery. To determine whether expanded mandates were tied to changes in screening uptake, the team analyzed hospital release records from Georgia.

“Congenital syphilis rates in the US have surged nearly 12-fold over the last decade (from 8.7 to 105.8 cases per 100 000 live births between 2013 and 2023) since reaching historically low rates in the early 2000s,” the researchers wrote. “Transmitted from mother to child during pregnancy, congenital syphilis increases the risk of stillbirth, neonatal death, low birth weight, and infant death, and can confer lifelong medical complications.”

Complementary efforts needed

Expanded screening mandates were linked to a 26% (95% confidence interval [CI], 3% to 53%) increase in maternal syphilis case identification in the first quarter of enactment. But the increase attenuated and was no longer significant within one year (11%; 95% CI, −17% to 48%).

Congenital syphilis increases the risk of stillbirth, neonatal death, low birth weight, and infant death, and can confer lifelong medical complications.

The waning impact may reflect falling adherence to mandates among expansion states, the study authors said. “In this study, expanded prenatal syphilis screening mandates may improve syphilis case detection in the near-term but are unlikely to have sustained impact without complementary efforts, such as those that facilitate clinician adherence and ensure patient access to and completion of treatment,” they wrote.

• A meningitis outbreak associated with the University of Kent in England now has 20 confirmed cases and 9 probable cases of invasive meningococcal disease, down from 34 reported over the weekend. Several suspected cases were downgraded after further testing, and the death toll remains at two. All patients have been hospitalized, and 19 of the 20 confirmed cases involve meningococcal group B. All patients are young adults, with many having a shared exposure at a popular university nightclub in Canterbury in early March. Invasive meningococcal meningitis or sepsis may begin with flu-like symptoms but can rapidly become more serious, the UK Health Security Agency said.
• Two adults in Missouri have contracted clade 1 mpox, according to a statement from the Missouri Department of Health & Senior Services. This is the more virulent strain of mpox that was first identified in 2024 and has caused major outbreaks in central Africa. These detections mark Missouri’s first cases of clade 1 mpox cases and raises the nation’s total to 14. According to Missouri officials, the two infections are unrelated to one another and are not believed to be connected to any locally acquired mpox cases.
• Diphtheria poses a moderate risk to African nations, after 29,000 suspected cases with 1,420 deaths (case-fatality rate, 4.9%) have been reported in eight countries since January 2025, according to a new report from the World Health Organization. The countries are Algeria, Chad, Guinea, Mali, Mauritania, Niger, Nigeria and South Africa, and the data represent a 67% increase in suspected cases (11,749 additional cases) and a 59.4% increase in deaths since October 2025. Nigeria has had the most cases in the past year, accounting for 62.6% of all illnesses. Children aged 5 to 14 years represent 57% of cases, and 84% to 95% of patients are unvaccinated or under-vaccinated or have an unknown vaccination status.