Risk factors and titers of COVID-19 infection in a longitudinal statewide seroepidemiology cohort.

BACKGROUND: Virginia is a large state in the USA, yet it remains unclear what percentage of the population has had natural COVID-19 infection and whether risk factors for infection have changed over time. METHODS: Using a longitudinal cohort, from December 2021-July 2022 we performed follow up serology and a questionnaire on 784 individuals from across Virginia who had previously participated in a statewide COVID-19 seroepidemiology study in 2020. Children were also invited to participate and an additional 62 children also completed the study. Serology was performed using Roche nucleocapsid and spike serological assays. RESULTS: The majority of participants were white (78.6%), over 50 years old (60.9%), and reported having received COVID-19 vaccine (93.4%). 28.6% had evidence of prior COVID-19 infection (nucleocapsid positive). Reweighted by region, age, and sex to match the Virginia census data, the seroprevalence of nucleocapsid antibodies was estimated to be 30.6% (95% CI: 24.7, 36.6). We estimated that 25-53% of COVID-19 infections were asymptomatic. Infection rates were lower in individuals > 60 years old and were higher in Blacks and Hispanics. Infection rates were also higher in those without health insurance, in those with greater numbers of household children, and in those that reported a close contact or having undergone quarantine for COVID-19. Participants from Southwest Virginia had lower seropositivity (16.2%, 95% CI 6.5, 26.0) than other geographic regions. Boosted vaccinees had lower infection rates than non-boosted vaccinees. Frequenting indoor bars was a risk factor for infection, while frequently wearing an N95 mask was protective, though the estimates of association were imprecise. Infection rates were higher in children than adults (56.5% vs. 28.6%). Infection in the parent was a risk factor for child infection. Spike antibody levels declined with time since last vaccination, particularly in those that were vaccinated but not previously infected. Neutralizing antibody positivity was high (97-99%) for wild type, alpha, beta, gamma, delta, and omicron variants. Neutralizing antibody levels were higher in the follow-up survey compared to the first survey in 2020 and among individuals with evidence of natural infection compared to those without. CONCLUSIONS: In this longitudinal statewide cohort we observed a lower-than-expected COVID-19 infection rate as of August 2022. Boosted vaccinees had lower infection rates. Children had higher infection rates and infections tracked within households. Previously identified demographic risk factors for infection tended to persist. Even after the omicron peak, a large number of Virginians remain uninfected with COVID-19, underscoring the need for ongoing vaccination strategies.

Histotripsy for the Treatment of Uterine Leiomyomas: A Feasibility Study in Ex Vivo Uterine Fibroids.

Uterine fibroids (leiomyomas), the most common benign tumors in women of reproductive age, are a frequent cause of abnormal vaginal bleeding and other reproductive complaints among women. This study investigates the feasibility of using histotripsy, a non-invasive, non-thermal focused ultrasound ablation method, to ablate uterine fibroids. Human fibroid samples (n = 16) were harvested after hysterectomy or myomectomy procedures at Carilion Memorial Hospital. Histotripsy was applied to ex vivo fibroids in two sets of experiments using a 700-kHz clinical transducer to apply multicycle histotripsy pulses and a prototype 500-kHz transducer to apply single-cycle histotripsy pulses. Ultrasound imaging was used for real-time treatment monitoring, and post-treatment ablation was quantified histologically using hematoxylin and eosin and Masson trichrome stains. Results revealed that multicycle histotripsy generated diffuse cavitation in targeted fibroids, with minimal cellular ablative changes after treatment with 2000 pulses/point. Single-cycle pulsing generated well-confined bubble clouds with evidence of early coagulative necrosis on histological assessment in samples treated with 2000 pulses/point, near-complete ablation in samples treated with 4000 pulses/point and complete tissue destruction in samples treated with 10,000 pulses/point. This study illustrates that histotripsy is capable of fibroid ablation under certain pulsing parameters and warrants further investigation as an improved non-invasive ablation method for the treatment of leiomyomas.