Respiratory Diseases Roundup

COVID-19 Research Roundup: Surveillance and Risk

Edited by:
Kate Young

Key highlights

  • CDC reported that SARS-CoV-2 variant BA.3.2 had been identified in 23 countries by February 11, 2026, including U.S. detections in travelers, clinical samples, and wastewater.1
  • A Communications Medicine analysis estimated that Long COVID years lived with disability in U.S. adults approximate those of Alzheimer disease and asthma, while NIH funding reached 14% of disability-commensurate levels.2
  • A Nature Communications modeling study found that postpandemic SARS-CoV-2 infection and vaccination have likely reduced the probability that a related zoonotic sarbecovirus would successfully emerge in humans.3
  • In a cohort of 379,144 VA outpatients with COVID-19, severe outcome risk rose as risk factors accumulated, with 239 significant combinations identified and the highest-risk patterns including older age, cardiopulmonary and neurologic disease, smoking, hypertension, and not being up to date on vaccination.4

BA.3.2 detected across multiple surveillance streams1

In a Morbidity and Mortality Weekly Report, published on March 19, 2026, the CDC described the emergence and spread of SARS-CoV-2 variant BA.3.2, a lineage first identified from a respiratory sample collected in South Africa on November 22, 2024. The report noted that BA.3.2 is genetically distinct from the JN.1 lineages that have circulated in the United States since early 2024 and carries approximately 70 to 75 spike substitutions and deletions relative to JN.1 and LP.8.1, the antigens used in the 2025-2026 COVID-19 vaccines. Relative to LP.8.1, BA.3.2 has 20 receptor-binding domain differences and 35 N-terminal domain differences, with additional deletions and an insertion, findings that underscore its antigenic distance from recently circulating strains.

The CDC said its multimodal surveillance approach detected BA.3.2 internationally and in the United States through traveler-based genomic surveillance, clinical sequencing, and wastewater monitoring. The first U.S. detection occurred on June 27, 2025, in a traveler arriving from the Netherlands, and the first U.S. clinical specimen was reported on January 5, 2026. As of February 11, 2026, BA.3.2 had been reported in at least 23 countries and in the United States had been identified in 4 traveler nasal swabs, 3 airplane wastewater samples, 5 clinical samples, and 132 wastewater samples from 25 states. Weekly detections rose beginning in September 2025 and reached about 30% of reported sequences in Denmark, Germany, and the Netherlands during November 2025 through January 2026, although overall COVID-19 incidence was not substantially higher than in previous years. CDC said continued genomic surveillance is needed to monitor whether BA.3.2 could reduce protection from prior infection or vaccination.

Long COVID burden outpaces funding2

A Communications Medicine study quantified the disability burden of long COVID in U.S. adults and compared that burden with NIH funding across 68 comparator conditions. Investigators derived long COVID prevalence from U.S. Census Bureau Household Pulse Survey data collected from September 2022 through August 2023 and applied Global Burden of Disease disability weights to estimate years lived with disability, or YLDs. They reported that Long COVID YLDs approximate those of Alzheimer disease and asthma, placing the condition among major causes of nonfatal health loss in adults. The authors also wrote that nearly 4 million U.S. adults have long COVID that significantly limits daily activity and that about half are younger than 50 years.

Against that burden, the study found that Long COVID received an average of $106 million in NIH funding across fiscal years 2022 through 2024, compared with an estimated $739.8 million in disability-commensurate funding, or about 14% of the expected level. The paper also reported that ME/CFS received less than 1% of disability-proportionate funding. In sex-stratified analyses, 7 of the 12 conditions that were above the median in YLDs but below the median in funding were female-predominant, and none were male-predominant. Median funding per YLD was 5.2 times higher for male- than female-predominant conditions, at $7.03 versus $1.29 per YLD. The authors concluded that long COVID remains a major source of disability without established treatments and said the most pressing research need is well-designed therapeutic trials with standardized outcomes.

Cross-immunity may blunt new sarbecovirus spread3

In Nature Communications, investigators examined whether immunity generated during and after the COVID-19 pandemic may affect the likelihood that a related zoonotic sarbecovirus could emerge in humans. The study combined empirical cross-neutralization data with mathematical modeling focused on a hypothetical virus termed SARS-CoV-X. According to the abstract, sera from individuals with different COVID-19 immunologic histories contained cross-neutralizing antibodies against spike proteins from multiple zoonotic sarbecoviruses, suggesting that prior infection and vaccination may provide at least partial protection beyond SARS-CoV-2 itself.

To translate those findings into population-level risk, the researchers built an age-stratified stochastic SEIRS model parameterized to resemble Scotland’s vaccination patterns, SARS-CoV-2 trajectory, and projected demographics from 2020 through 2028. The model incorporated waning immunity, booster programs, co-circulating SARS-CoV-2, and varying assumptions for SARS-CoV-X transmissibility and cross-protection. The authors reported that postpandemic cross-immunity significantly reduced the modeled likelihood that a novel sarbecovirus would reach endemicity, with outcomes depending on the new virus’ basic reproduction number and the degree of cross-protection. They also found that preventive vaccination with currently available COVID-19 vaccines could help resist emergence even when SARS-CoV-2 remains in circulation. By contrast, they said a hypothetical vaccine highly specific to SARS-CoV-2 could paradoxically increase emergence probability by lowering SARS-CoV-2 prevalence and, in turn, reducing naturally acquired cross-protection. Overall, the study suggests that contemporary population immunity may function as an immunologic barrier to sarbecovirus emergence, although the findings are model based.

Stacked risks identify highest-risk outpatients4

An Infectious Diseases and Therapy study evaluated whether combinations of established risk factors identify outpatients at especially high risk for severe COVID-19. The retrospective cohort included 379,144 high-risk adults receiving care through the Veterans Affairs health system who had a positive SARS-CoV-2 test or COVID-19 diagnosis between April 1, 2022, and August 21, 2024. Severe COVID-19 was defined as COVID-19-related hospitalization or all-cause mortality within 30 days. Investigators assessed 14 dichotomous risk factors selected on the basis of prevalence and CDC criteria, including age 50 years or older, chronic lung disease, cancer, neurologic or cerebrovascular disease, chronic kidney or liver disease, diabetes, heart conditions, mental health conditions, obesity, smoking, immunosuppression, hypertension, and not being up to date on COVID-19 vaccination.

Overall, 1.5% of patients, or 5801 individuals, experienced a severe outcome within 30 days. Risk rose steadily with each additional factor present, from an adjusted odds ratio of 2.10 for 2 risk factors to 43.49 for 14 risk factors, each compared with 1 risk factor. The investigators identified 239 significant risk-factor combinations. Hypertension appeared in 82.0% of those combinations, not being up to date on vaccination in 72.4%, smoking in 70.3%, and heart conditions in 64.4%. The single combination associated with the highest risk included age 50 years or older, chronic lung disease, neurologic or cerebrovascular disease, diabetes, heart conditions, smoking, hypertension, and not being up to date on vaccination, with an adjusted odds ratio of 35.25. The authors concluded that severe COVID-19 risk in outpatients increases with risk stacking and that patients with multiple overlapping conditions who are not vaccinated represent a particularly high-risk group for targeted vaccination and timely antiviral treatment.

References

  1. Shakya M, Ma KC, Hughes LJ, et al. Early detection and surveillance of the SARS-CoV-2 variant BA.3.2—worldwide, November 2024-February 2026. MMWR Morb Mortal Wkly Rep. 2026;75(10):130-137.
  2. Bonuck K, Gao Q, Congdon S, Kim RS. Long COVID disability burden in US adults. Commun Med (Lond). 2026;6(1):177. Published 2026 Mar 31. doi:10.1038/s43856-026-01516-7
  3. Imrie RM, Bissett LA, Raveendran S, et al. Post-pandemic changes in population immunity have reduced the likelihood of emergence of zoonotic coronaviruses. Nat Commun. 2026;17(1):2248. Published 2026 Mar 24. doi:10.1038/s41467-026-69988-8
  4. Appaneal HJ, Lopes VV, Puzniak L, Allen KE, Zasowski EJ, Caffrey AR. Impact of Risk Factor Combinations on Severe COVID-19 Outcomes Among Outpatients. Infect Dis Ther. Published online March 25, 2026. doi:10.1007/s40121-026-01328-1