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Background: The 2022–23 US influenza season peaked early in fall 2022. Methods: Late‐season influenza vaccine effectiveness (VE) against outpatient, laboratory‐confirmed influenza was calculated among participants of the US Influenza VE Network using a test‐negative design. Results: Of 2561 participants enrolled from December 12, 2022 to April 30, 2023, 91 laboratory‐confirmed influenza cases primarily had A(H1N1)pdm09 (6B.1A.5a.2a.1) or A(H3N2) (3C.2a1b.2a.2b). Overall, VE was 30% (95% confidence interval −9%, 54%); low late‐season activity precluded estimation for most subgroups. Conclusions: 2022–23 late‐season outpatient influenza VE was not statistically significant. Genomic characterization may improve the identification of influenza viruses that circulate postinfluenza peak. [ABSTRACT FROM AUTHOR]

Sesame (Sesamum indicum L.) is an annual plant known as one of the first domesticated oilseed crops. It is cultivated worldwide, mostly in Asia, Africa, and the Americas (Singh, 2006). In August 2022 and September 2023, dark angular necrotic spots on leaves and stems (100% incidence), blights, and severe defoliation were observed in a 4-acre rainfed sesame field located in the Colleton County of South Carolina, USA (Fig. S1). Bacterial streaming from cut leaf lesions was observed from diseased plants in both years. Two plants were collected for pathogen isolation in 2023. Symptomatic leaves were surface sterilized with 70% ethanol for 1 min and dried in a laminar flow hood. For each isolate, four sterile toothpicks were used to poke lesion margins and stirred in 300 µl of sterile distilled water in a 2-ml sterile microcentrifuge tube and soaked at room temperature (c. 21 °C) for 10 min. Each bacterial suspension (10 µl) was streaked on nutrient agar (NA) in a Petri dish. Convex and mucoid yellow colonies formed after a 48-h incubation at 28°C in the dark. Two isolates (S813 and S814), one from each plant, were obtained by transferring single colonies to new NA plates. Both isolates were preliminarily identified as Xanthomonas [S813: X. campestris (P = 0.53); S814: X. campestris (P = 0.77)] using a Biolog Microbial Identification System (GEN III Microplate; Identification Database v.2.8.0.15G). PCR amplification of the atpD and dnaK genes was performed for both isolates using the conditions described in Félix-Gastélum et al. (2019). The sequences of both amplicons are 100% identical for each gene between the two isolates. PCR and sequencing of the gyrB gene was also done for S813 with the primers from Young et al. (2008). The atpD (S813/S814), dnaK (S813/S814), and gyrB (S813) sequences (GenBank accessions: PP507118 to PP507120) showed the best match with 100% identity to the corresponding gene sequences [GenBank accessions: KJ491167 (100% coverage), KJ491257 (99% coverage), EU285201 (100% coverage)] of the X. euvesicatoria pv. sesami (=X. campestris pv. sesami) type strain LMG865 (Constantin et al. 2015, Parkinson et al. 2009). A neighbor joining tree with the concatenated sequences of these three genes (2,210 nt) showed that S813 and LMG 865 had the closet relationship with X. euvesicatoria pv. alfalfae (CFBP3836, Fig. S2). To fulfill Koch's postulates, three healthy sesame plants (cultivar Shirogoma) were spray inoculated separately with each suspension of S813 and S814 in sterile tap water until runoff (approx. 5×108 CFU/ml). Two sesame plants were sprayed with sterile tap water and served as negative control. All plants were maintained in a greenhouse at approximately 28/20°C (day/night) with natural photoperiod. Dark leaf spots and leaf yellowing were observed on inoculated plants 7 to 14 days after inoculation. No disease symptom was observed on the control plants. Bacteria were reisolated from leaf spots of the inoculated plants and confirmed to be X. euvesicatoria pv. sesami based on atpD and dnaK sequences. The disease was first reported in Sudan (Sabet and Dowson, 1960), after which it was reported in USA (Isakeit et al., 2012) and Mexico (Félix-Gastélum et al. 2019). To the best of our knowledge, this is the first report of this disease in South Carolina, USA. Since the interest of sesame to the farmers is increasing in the southeastern USA, it is necessary to perform further research to examine the disease distribution and its economic impact.

Competing Interests: All authors have completed and submitted the International Committee of Medical Journal Editors form for disclosure of potential conflicts of interest. No potential conflicts of interest were disclosed.

Influenza viruses continually evolve new antigenic variants, through mutations in epitopes of their major surface proteins, hemagglutinin (HA) and neuraminidase (NA). Antigenic drift potentiates the reinfection of previously infected individuals, but the contribution of this process to variability in annual epidemics is not well understood. Here we link influenza A(H3N2) virus evolution to regional epidemic dynamics in the United States during 1997-2019. We integrate phenotypic measures of HA antigenic drift and sequence-based measures of HA and NA fitness to infer antigenic and genetic distances between viruses circulating in successive seasons. We estimate the magnitude, severity, timing, transmission rate, age-specific patterns, and subtype dominance of each regional outbreak and find that genetic distance based on broad sets of epitope sites is the strongest evolutionary predictor of A(H3N2) virus epidemiology. Increased HA and NA epitope distance between seasons correlates with larger, more intense epidemics, higher transmission, greater A(H3N2) subtype dominance, and a greater proportion of cases in adults relative to children, consistent with increased population susceptibility. Based on random forest models, A(H1N1) incidence impacts A(H3N2) epidemics to a greater extent than viral evolution, suggesting that subtype interference is a major driver of influenza A virus infection dynamics, presumably via heterosubtypic cross-immunity., Competing Interests: Competing interests The WHO Collaborating Centre for Reference and Research on Influenza in Melbourne has a collaborative research and development agreement (CRADA) with CSL Seqirus for isolation of candidate vaccine viruses in cells and an agreement with IFPMA for isolation of candidate vaccine viruses in eggs. SGS reports honoraria from CSL Seqirus, Moderna, Pfizer, and Evo Health. The Icahn School of Medicine at Mount Sinai has filed patent applications relating to influenza virus vaccines, SARS-CoV-2 serological assays, and SARS-CoV-2 vaccines which list FK as co-inventor. Mount Sinai has spun out companies, Kantaro and Castlevax, to market the SARS-CoV-2 related technologies. FK has consulted for Merck and Pfizer (before 2020), and is currently consulting for Pfizer, Seqirus, 3rd Rock Ventures, GSK and Avimex. The Krammer laboratory is also collaborating with Pfizer on animal models of SARS-CoV-2 and with Dynavax on universal influenza virus vaccines. All other authors declare no competing interests.

Importance: The COVID-19 pandemic was accompanied by an unprecedented surveillance effort. The resulting data were and will continue to be critical for surveillance and control of SARS-CoV-2. However, some genomic surveillance methods experienced challenges as the virus evolved, resulting in incomplete and poor quality data. Complete and quality coverage, especially of the S-gene, is important for supporting the selection of vaccine candidates. As such, we developed a robust method to target the S-gene for amplification and sequencing. By focusing on the S-gene and imposing strict coverage and quality metrics, we hope to increase the quality of surveillance data for this continually evolving gene. Our technique is currently being deployed globally to partner laboratories, and public health representatives from 79 countries have received hands-on training and support. Expanding access to quality surveillance methods will undoubtedly lead to earlier detection of novel variants and better inform vaccine strain selection., Competing Interests: The authors declare no conflict of interest.