IMPORTANCE People who have been infected with or vaccinated against SARS-CoV-2 have reduced risk of subsequent infection, but the proportion of people in the US with SARS-CoV-2 antibodies from infection or vaccination is uncertain.OBJECTIVE To estimate trends in SARS-CoV-2 seroprevalence related to infection and vaccination in the US population. DESIGN, SETTING, AND PARTICIPANTSIn a repeated cross-sectional study conducted each month during July 2020 through May 2021, 17 blood collection organizations with blood donations from all 50 US states; Washington, DC; and Puerto Rico were organized into 66 study-specific regions, representing a catchment of 74% of the US population. For each study region, specimens from a median of approximately 2000 blood donors were selected and tested each month; a total of 1 594 363 specimens were initially selected and tested. The final date of blood donation collection was May 31, 2021. EXPOSURE Calendar time.MAIN OUTCOMES AND MEASURES Proportion of persons with detectable SARS-CoV-2 spike and nucleocapsid antibodies. Seroprevalence was weighted for demographic differences between the blood donor sample and general population. Infection-induced seroprevalence was defined as the prevalence of the population with both spike and nucleocapsid antibodies. Combined infection-and vaccination-induced seroprevalence was defined as the prevalence of the population with spike antibodies. The seroprevalence estimates were compared with cumulative COVID-19 case report incidence rates. RESULTS Among 1 443 519 specimens included, 733 052 (50.8%) were from women, 174 842 (12.1%) were from persons aged 16 to 29 years, 292 258 (20.2%) were from persons aged 65 years and older, 36 654 (2.5%) were from non-Hispanic Black persons, and 88 773 (6.1%) were from Hispanic persons. The overall infection-induced SARS-CoV-2 seroprevalence estimate increased from 3.5% (95% CI, 3.2%-3.8%) in July 2020 to 20.2% (95% CI, 19.9%-20.6%) in May 2021; the combined infection-and vaccination-induced seroprevalence estimate in May 2021 was 83.3% (95% CI, 82.9%-83.7%). By May 2021, 2.1 SARS-CoV-2 infections (95% CI, 2.0-2.1) per reported COVID-19 case were estimated to have occurred. CONCLUSIONS AND RELEVANCEBased on a sample of blood donations in the US from July 2020 through May 2021, vaccine-and infection-induced SARS-CoV-2 seroprevalence increased over time and varied by age, race and ethnicity, and geographic region. Despite weighting to adjust for demographic differences, these findings from a national sample of blood donors may not be representative of the entire US population.

Abstract. Melioidosis is a bacterial infection caused by Burkholderia pseudomallei, a gram-negative saprophytic bacillus. Cases occur sporadically in the Americas with an increasing number of cases observed among people with no travel history to endemic countries. To better understand the incidence of the disease in the Americas, we reviewed the literature, including unpublished cases reported to the Centers for Disease Control and Prevention. Of 120 identified human cases, occurring between 1947 and June 2015, 95 cases (79%) were likely acquired in the Americas; the mortality rate was 39%. Burkholderia pseudomallei appears to be widespread in South, Central, and North America.

Taken together, isolation of B. pseudomallei from a soil sample and high seropositivity among patient contacts suggest at least regional endemicity of melioidosis in Puerto Rico. Increased awareness of melioidosis is needed to enable early case identification and early initiation of appropriate antimicrobial therapy.

Five laboratory-acquired brucellosis (LAB) cases that occurred in the United States between 2008 and 2011 are presented. The Centers for Disease Control and Prevention (CDC) reviewed the recommendations published in 2008 and the published literature to identify strategies to further prevent LAB. The improved prevention strategies are described.

1.21-2.18), and 0.37 vs 0.16 for diagnoses on hospital day 15 or later (RR, 2.31; 95% CI,. The increase in hospital-onset infections during the Omicron wave vs the prior winter wave mirrored similar increases in community and health care worker case numbers during these same periods (Figure).

Abstract. A fatal case of melioidosis was diagnosed in Ohio one month after culture results were initially reported as a Bacillus species. To identify a source of infection and assess risk in patient contacts, we abstracted patient charts; interviewed physicians and contacts; genetically characterized the isolate; performed a Burkholderia pseudomallei antibody indirect hemagglutination assay on household contacts and pets to assess seropositivity; and collected household plant, soil, liquid, and insect samples for culturing and real-time polymerase chain reaction testing. Family members and pets tested were seronegative for B. pseudomallei. Environmental samples were negative by real-time polymerase chain reaction and culture. Although the patient never traveled internationally, the isolate genotype was consistent with an isolate that originated in Southeast Asia. This investigation identified the fifth reported locally acquired non-laboratory melioidosis case in the contiguous United States. Physicians and laboratories should be aware of this potentially emerging disease and refer positive cultures to a Laboratory Response Network laboratory.

Background There are limited data on the risk of SARS-CoV-2 infection in the U.S. by occupation. We identified occupations at higher risk for prior SARS-CoV-2 infection as defined by the presence of infection-induced antibodies among U.S. blood donors. Methods Using a nested case-control study design, blood donors during May–December 2021 with anti-nucleocapsid (anti-N) testing were sent an electronic survey on employment status, vaccination, and occupation. The association between previous SARS-CoV-2 infection and occupation-specific in-person work was estimated using multivariable logistic regression adjusting for sex, age, month of donation, race/ethnicity, education, vaccination, and telework. Results Among 85,986 included survey respondents, 9,504 (11.1%) were anti-N reactive. Healthcare support (20.3%), protective service (19.9%), and food preparation and serving related occupations (19.7%) had the highest proportion of prior infection. After adjustment, prior SARS-CoV-2 infection was associated with healthcare practitioners (adjusted OR [aOR] 2.10, 95% CI 1.74-2.54) and healthcare support (aOR 1.83, 95% CI 1.39-2.40) occupations compared with computer and mathematical occupations as the referent group. Lack of COVID-19 vaccination (aOR 16.13, 95% CI 15.01-17.34) and never teleworking (aOR 1.17, 95% CI 1.05-1.30) were also independently associated with prior SARS-CoV-2 infection. Protective service occupations had the highest proportion of unvaccinated workers (30.0%). Conclusions Workers in healthcare, protective services, and food preparation had the highest prevalence of prior SARS-CoV-2 infection. Occupational risks for SARS-CoV-2 infection remained after adjusting for vaccination, telework, and demographic factors. These findings underscore the need for mitigation measures and personal protection in healthcare settings and other workplaces.

We describe a periprosthetic Brucella abortus infection in a case-patient undergoing hip replacement revision surgery, and the subsequent investigation of laboratory and surgical staff exposures. Although exposures are rare, it is important to have infection prevention recommendations for surgical procedures among patients with suspected or unidentified Brucella spp. infection.