Age-group associations of schistosomiasis prevalence from trial data, Côte d'Ivoire, Kenya and the United Republic of Tanzania.

Objective: To determine if the prevalence of schistosomiasis in children aged 9-12 years is associated with the prevalence in 5-8-year-olds and adults after preventive chemotherapy in schools or the community. Methods: We combined data from four community-randomized, preventive chemotherapy trials in treatment-naïve populations in Côte d'Ivoire, Kenya and the United Republic of Tanzania during 2010-2016 according to the number of praziquantel treatments and the delivery method. Schistosoma mansoni infection was sought on two slides prepared from each participant's first stool using the Kato-Katz technique. We assessed associations between S. mansoni prevalence in 9-12-year-olds and 5-8-year-olds and adults in the community before and after treatment using Bayesian regression models. Findings: Stool samples from 47 985 5-8-year-olds, 81 077 9-12-year-olds and 20 492 adults were analysed. We found associations between the prevalence in 9-12-year-olds and that in 5-8-year-olds and adults after preventive treatment, even when only school-age children were treated. When the prevalence in 9-12-year-olds was under 10%, the prevalence in 5-8-year-olds was consistently under 10%. When the prevalence in 9-12-year-olds was under 50%, the prevalence in adults after two or four rounds of preventive chemotherapy was 10%-15% lower than before chemotherapy. Post-chemotherapy age-group associations were consistent with pre-chemotherapy associations in this analysis and previous studies. Conclusion: The prevalence of S. mansoni infection in 9-12-year-olds was associated with the prevalence in other age groups and could be used to guide community treatment decisions.

Effectiveness of Bivalent mRNA COVID-19 Vaccines in Preventing COVID-19-Related Thromboembolic Events Among Medicare Enrollees Aged ≥65 Years and Those with End Stage Renal Disease - United States, September 2022-March 2023.

COVID-19 has been associated with an increased risk for thromboembolic events, including ischemic stroke, venous thromboembolism, and myocardial infarction. Studies have reported lower rates of COVID-19-related thromboembolic events among persons who received the COVID-19 vaccine compared with persons who did not, but rigorous estimates of vaccine effectiveness (VE) in preventing COVID-19-related thromboembolic events are lacking. This analysis estimated the incremental benefit of receipt of a bivalent mRNA COVID-19 vaccine after receiving an original monovalent COVID-19 vaccine. To estimate VE of a bivalent mRNA COVID-19 dose in preventing thromboembolic events compared with original monovalent COVID-19 vaccine doses only, two retrospective cohort studies were conducted among Medicare fee-for-service enrollees during September 4, 2022-March 4, 2023. Effectiveness of a bivalent COVID-19 vaccine dose against COVID-19-related thromboembolic events compared with that of original vaccine alone was 47% (95% CI = 45%-49%) among Medicare enrollees aged ≥65 years and 51% (95% CI = 39%-60%) among adults aged ≥18 years with end stage renal disease receiving dialysis. VE was similar among Medicare beneficiaries with immunocompromise: 46% (95% CI = 42%-49%) among adults aged ≥65 years and 45% (95% CI = 24%-60%) among those aged ≥18 years with end stage renal disease. To help prevent complications of COVID-19, including thromboembolic events, adults should stay up to date with COVID-19 vaccination.

Influenza vaccine effectiveness against influenza-A-associated emergency department, urgent care, and hospitalization encounters among U.S. adults, 2022-2023.

BACKGROUND: The 2022-2023 United States influenza season had unusually early influenza activity with high hospitalization rates. Vaccine-matched A(H3N2) viruses predominated, with lower levels of A(H1N1)pdm09 activity also observed. METHODS: Using the test-negative design, we evaluated influenza vaccine effectiveness (VE) during the 2022-2023 season against influenza-A-associated emergency department/urgent care (ED/UC) visits and hospitalizations from October 2022-March 2023 among adults (age ≥18 years) with acute respiratory illness (ARI). VE was estimated by comparing odds of seasonal influenza vaccination among case-patients (influenza A test-positive by molecular assay) and controls (influenza test-negative), applying inverse-propensity-to-be-vaccinated weights. RESULTS: The analysis included 85,389 ED/UC ARI encounters (17.0% influenza-A-positive; 37.8% vaccinated overall) and 19,751 hospitalizations (9.5% influenza-A-positive; 52.8% vaccinated overall). VE against influenza-A-associated ED/UC encounters was 44% (95% confidence interval [95%CI]: 40-47%) overall and 45% and 41% among adults aged 18-64 and ≥65 years, respectively. VE against influenza-A-associated hospitalizations was 35% (95%CI: 27-43%) overall and 23% and 41% among adults aged 18-64 and ≥65 years, respectively. CONCLUSIONS: VE was moderate during the 2022-2023 influenza season, a season characterized with increased burden of influenza and co-circulation with other respiratory viruses. Vaccination is likely to substantially reduce morbidity, mortality, and strain on healthcare resources.

Relative Effectiveness of Coronavirus Disease 2019 Vaccination and Booster Dose Combinations Among 18.9 Million Vaccinated Adults During the Early Severe Acute Respiratory Syndrome Coronavirus 2 Omicron Period-United States, 1 January 2022 to 31 March 2022.

BACKGROUND: Small sample sizes have limited prior studies' ability to capture severe COVID-19 outcomes, especially among Ad26.COV2.S vaccine recipients. This study of 18.9 million adults aged ≥18 years assessed relative vaccine effectiveness (rVE) in three recipient cohorts: (1) primary Ad26.COV2.S vaccine and Ad26.COV2.S booster (2 Ad26.COV2.S), (2) primary Ad26.COV2.S vaccine and mRNA booster (Ad26.COV2.S+mRNA), (3) two doses of primary mRNA vaccine and mRNA booster (3 mRNA). METHODS: We analyzed two de-identified datasets linked using privacy-preserving record linkage (PPRL): insurance claims and retail pharmacy COVID-19 vaccination data. We assessed the presence of COVID-19 diagnosis during January 1-March 31, 2022 in: (1) any claim, (2) outpatient claim, (3) emergency department (ED) claim, (4) inpatient claim, and (5) inpatient claim with intensive care unit (ICU) admission. rVE for each outcome comparing three recipient cohorts (reference: two Ad26.COV2.S doses) was estimated from adjusted Cox proportional hazards models. RESULTS: Compared with two Ad26.COV2.S doses, Ad26.COV2.S+mRNA and three mRNA doses were more effective against all COVID-19 outcomes, including 57% (95% CI: 52-62) and 62% (95% CI: 58-65) rVE against an ED visit; 44% (95% CI: 34-52) and 54% (95% CI: 48-59) rVE against hospitalization; and 48% (95% CI: 22-66) and 66% (95% CI: 53-75) rVE against ICU admission, respectively. CONCLUSIONS: This study demonstrated that Ad26.COV2.S + mRNA doses were as good as three doses of mRNA, and better than two doses of Ad26.COV2.S. Vaccination continues to be an important preventive measure for reducing the public health impact of COVID-19.

Estimating the early impact of the US COVID-19 vaccination programme on COVID-19 cases, emergency department visits, hospital admissions, and deaths among adults aged 65 years and older: an ecological analysis of national surveillance data.

BACKGROUND: In the USA, COVID-19 vaccines became available in mid-December, 2020, with adults aged 65 years and older among the first groups prioritised for vaccination. We estimated the national-level impact of the initial phases of the US COVID-19 vaccination programme on COVID-19 cases, emergency department visits, hospital admissions, and deaths among adults aged 65 years and older. METHODS: We analysed population-based data reported to US federal agencies on COVID-19 cases, emergency department visits, hospital admissions, and deaths among adults aged 50 years and older during the period Nov 1, 2020, to April 10, 2021. We calculated the relative change in incidence among older age groups compared with a younger reference group for pre-vaccination and post-vaccination periods, defined by the week when vaccination coverage in a given age group first exceeded coverage in the reference age group by at least 1%; time lags for immune response and time to outcome were incorporated. We assessed whether the ratio of these relative changes differed when comparing the pre-vaccination and post-vaccination periods. FINDINGS: The ratio of relative changes comparing the change in the COVID-19 case incidence ratio over the post-vaccine versus pre-vaccine periods showed relative decreases of 53% (95% CI 50 to 55) and 62% (59 to 64) among adults aged 65 to 74 years and 75 years and older, respectively, compared with those aged 50 to 64 years. We found similar results for emergency department visits with relative decreases of 61% (52 to 68) for adults aged 65 to 74 years and 77% (71 to 78) for those aged 75 years and older compared with adults aged 50 to 64 years. Hospital admissions declined by 39% (29 to 48) among those aged 60 to 69 years, 60% (54 to 66) among those aged 70 to 79 years, and 68% (62 to 73), among those aged 80 years and older, compared with adults aged 50 to 59 years. COVID-19 deaths also declined (by 41%, 95% CI -14 to 69 among adults aged 65-74 years and by 30%, -47 to 66 among those aged ≥75 years, compared with adults aged 50 to 64 years), but the magnitude of the impact of vaccination roll-out on deaths was unclear. INTERPRETATION: The initial roll-out of the US COVID-19 vaccination programme was associated with reductions in COVID-19 cases, emergency department visits, and hospital admissions among older adults. FUNDING: None.

Effectiveness of Up-to-Date COVID-19 Vaccination in Preventing SARS-CoV-2 Infection Among Nursing Home Residents - United States, November 20, 2022-January 8, 2023.

Nursing home residents have been disproportionately affected by the COVID-19 pandemic; their age, comorbidities, and exposure to a congregate setting has placed them at high risk for both infection and severe COVID-19-associated outcomes, including death (1). Receipt of a primary COVID-19 mRNA vaccination series (2) and monovalent booster doses (3) have been demonstrated to be effective in reducing COVID-19-related morbidity and mortality in this population. Beginning in October 2022, the National Healthcare Safety Network (NHSN) defined up-to-date vaccination as receipt of a bivalent COVID-19 mRNA vaccine dose or completion of a primary series within the preceding 2 months.* The effectiveness of being up to date with COVID-19 vaccination among nursing home residents in preventing SARS-CoV-2 infection is not known. This analysis used NHSN nursing home COVID-19 data reported during November 20, 2022-January 8, 2023, to describe effectiveness of up-to-date vaccination status (versus not being up to date) against laboratory-confirmed SARS-CoV-2 infection among nursing home residents. Adjusting for calendar week, county-level COVID-19 incidence, county-level social vulnerability index (SVI), and facility-level percentage of staff members who were up to date, up-to-date vaccine effectiveness (VE) against infection was 31.2% (95% CI = 29.1%-33.2%). Nursing home residents should stay up to date with recommended age-appropriate COVID-19 vaccination, which now includes an additional bivalent vaccine dose for moderately or severely immunocompromised adults aged ≥65 years to increase protection against SARS-CoV-2 infection.

Preliminary Estimates of Effectiveness of Monovalent mRNA Vaccines in Preventing Symptomatic SARS-CoV-2 Infection Among Children Aged 3-5 Years - Increasing Community Access to Testing Program, United States, July 2022-February 2023.

On June 18, 2022, the Advisory Committee on Immunization Practices (ACIP) issued interim recommendations for use of the 2-dose monovalent Moderna COVID-19 vaccine as a primary series for children aged 6 months-5 years* and the 3-dose monovalent Pfizer-BioNTech COVID-19 vaccine as a primary series for children aged 6 months-4 years,† based on safety, immunobridging, and limited efficacy data from clinical trials (1-3). Monovalent mRNA vaccine effectiveness (VE) against symptomatic SARS-CoV-2 infection was evaluated using the Increasing Community Access to Testing (ICATT) program, which provides SARS-CoV-2 testing to persons aged ≥3 years at pharmacy and community-based testing sites nationwide§ (4,5). Among children aged 3-5 years with one or more COVID-19-like illness symptoms¶ for whom a nucleic acid amplification test (NAAT) was performed during August 1, 2022-February 5, 2023, VE of 2 monovalent Moderna doses (complete primary series) against symptomatic infection was 60% (95% CI = 49% to 68%) 2 weeks-2 months after receipt of the second dose and 36% (95% CI = 15% to 52%) 3-4 months after receipt of the second dose. Among symptomatic children aged 3-4 years with NAATs performed during September 19, 2022-February 5, 2023, VE of 3 monovalent Pfizer-BioNTech doses (complete primary series) against symptomatic infection was 31% (95% CI = 7% to 49%) 2 weeks-4 months after receipt of the third dose; statistical power was not sufficient to estimate VE stratified by time since receipt of the third dose. Complete monovalent Moderna and Pfizer-BioNTech primary series vaccination provides protection for children aged 3-5 and 3-4 years, respectively, against symptomatic infection for at least the first 4 months after vaccination. CDC expanded recommendations for use of updated bivalent vaccines to children aged ≥6 months on December 9, 2022 (6), which might provide increased protection against currently circulating SARS-CoV-2 variants (7,8). Children should stay up to date with recommended COVID-19 vaccines, including completing the primary series; those who are eligible should receive a bivalent vaccine dose.

Early Estimates of Bivalent mRNA Booster Dose Vaccine Effectiveness in Preventing Symptomatic SARS-CoV-2 Infection Attributable to Omicron BA.5- and XBB/XBB.1.5-Related Sublineages Among Immunocompetent Adults - Increasing Community Access to Testing Program, United States, December 2022-January 2023.

The SARS-CoV-2 Omicron sublineage XBB was first detected in the United States in August 2022.* XBB together with a sublineage, XBB.1.5, accounted for >50% of sequenced lineages in the Northeast by December 31, 2022, and 52% of sequenced lineages nationwide as of January 21, 2023. COVID-19 vaccine effectiveness (VE) can vary by SARS-CoV-2 variant; reduced VE has been observed against some variants, although this is dependent on the health outcome of interest. The goal of the U.S. COVID-19 vaccination program is to prevent severe disease, including hospitalization and death (1); however, VE against symptomatic infection can provide useful insight into vaccine protection against emerging variants in advance of VE estimates against more severe disease. Data from the Increasing Community Access to Testing (ICATT) national pharmacy program for SARS-CoV-2 testing were analyzed to estimate VE of updated (bivalent) mRNA COVID-19 vaccines against symptomatic infection caused by BA.5-related and XBB/XBB.1.5-related sublineages among immunocompetent adults during December 1, 2022­January 13, 2023. Reduction or failure of spike gene (S-gene) amplification (SGTF) in real-time reverse transcription­polymerase chain reaction (RT-PCR) was used as a proxy indicator of infection with likely BA.5-related sublineages and S-gene target presence (SGTP) of infection with likely XBB/XBB.1.5-related sublineages (2). Among 29,175 nucleic acid amplification tests (NAATs) with SGTF or SGTP results available from adults who had previously received 2­4 monovalent COVID-19 vaccine doses, the relative VE of a bivalent booster dose given 2­3 months earlier compared with no bivalent booster in persons aged 18­49 years was 52% against symptomatic BA.5 infection and 48% against symptomatic XBB/XBB.1.5 infection. As new SARS-CoV-2 variants emerge, continued vaccine effectiveness monitoring is important. Bivalent vaccines appear to provide additional protection against symptomatic BA.5-related sublineage and XBB/XBB.1.5-related sublineage infections in persons who had previously received 2, 3, or 4 monovalent vaccine doses. All persons should stay up to date with recommended COVID-19 vaccines, including receiving a bivalent booster dose when they are eligible.

Coverage with Influenza, Respiratory Syncytial Virus, and Updated COVID-19 Vaccines Among Nursing Home Residents - National Healthcare Safety Network, United States, December 2023.

Nursing home residents are at risk for becoming infected with and experiencing severe complications from respiratory viruses, including SARS-CoV-2, influenza, and respiratory syncytial virus (RSV). Fall 2023 is the first season during which vaccines are simultaneously available to protect older adults in the United States against all three of these respiratory viruses. Nursing homes are required to report COVID-19 vaccination coverage and can voluntarily report influenza and RSV vaccination coverage among residents to CDC's National Healthcare Safety Network. The purpose of this study was to assess COVID-19, influenza, and RSV vaccination coverage among nursing home residents during the current 2023-24 respiratory virus season. As of December 10, 2023, 33.1% of nursing home residents were up to date with vaccination against COVID-19. Among residents at 20.2% and 19.4% of facilities that elected to report, coverage with influenza and RSV vaccines was 72.0% and 9.8%, respectively. Vaccination varied by U.S. Department of Health and Human Services region, social vulnerability index level, and facility size. There is an urgent need to protect nursing home residents against severe outcomes of respiratory illnesses by continuing efforts to increase vaccination against COVID-19 and influenza and discussing vaccination against RSV with eligible residents during the ongoing 2023-24 respiratory virus season.

Effectiveness of Monovalent and Bivalent mRNA Vaccines in Preventing COVID-19-Associated Emergency Department and Urgent Care Encounters Among Children Aged 6 Months-5 Years - VISION Network, United States, July 2022-June 2023.

On June 19, 2022, the original monovalent mRNA COVID-19 vaccines were approved as a primary series for children aged 6 months-4 years (Pfizer-BioNTech) and 6 months-5 years (Moderna) based on safety, immunobridging, and limited efficacy data from clinical trials. On December 9, 2022, CDC expanded recommendations for use of updated bivalent vaccines to children aged ≥6 months. mRNA COVID-19 vaccine effectiveness (VE) against emergency department or urgent care (ED/UC) encounters was evaluated within the VISION Network during July 4, 2022-June 17, 2023, among children with COVID-19-like illness aged 6 months-5 years. Among children aged 6 months-5 years who received molecular SARS-CoV-2 testing during August 1, 2022-June 17, 2023, VE of 2 monovalent Moderna doses against ED/UC encounters was 29% (95% CI = 12%-42%) ≥14 days after dose 2 (median = 100 days after dose 2; IQR = 63-155 days). Among children aged 6 months-4 years with a COVID-19-like illness who received molecular testing during September 19, 2022-June 17, 2023, VE of 3 monovalent Pfizer-BioNTech doses was 43% (95% CI = 17%-61%) ≥14 days after dose 3 (median = 75 days after dose 3; IQR = 40-139 days). Effectiveness of ≥1 bivalent dose, comparing children with at least a complete primary series and ≥1 bivalent dose to unvaccinated children, irrespective of vaccine manufacturer, was 80% (95% CI = 42%-96%) among children aged 6 months-5 years a median of 58 days (IQR = 32-83 days) after the dose. All children should stay up to date with recommended COVID-19 vaccines, including initiation of COVID-19 vaccination immediately when they are eligible.

Lessons learned from the implementation of integrated serosurveillance of communicable diseases in the Americas.

Objective: Systematize the experience and identify challenges and lessons learned in the implementation of an initiative for integrated serosurveillance of communicable diseases using a multiplex bead assay in countries of the Americas. Methods: Documents produced in the initiative were compiled and reviewed. These included concept notes, internal working papers, regional meetings reports, and survey protocols from the three participating countries (Mexico, Paraguay, and Brazil) and two additional countries (Guyana and Guatemala) where serology for several communicable diseases was included in neglected tropical diseases surveys. Information was extracted and summarized to describe the experience and the most relevant challenges and lessons learned. Results: Implementing integrated serosurveys requires interprogrammatic and interdisciplinary work teams for the design of survey protocols to respond to key programmatic questions aligned to the needs of the countries. Valid laboratory results are critical and rely on the standardized installment and roll-out of laboratory techniques. Field teams require adequate training and supervision to properly implement survey procedures. The analysis and interpretation of serosurveys results should be antigen-specific, contextualizing the responses for each disease, and triangulated with programmatic and epidemiological data for making decisions tailored to specific population socioeconomic and ecologic contexts. Conclusions: Integrated serosurveillance as a complementary tool for functional epidemiological surveillance systems is feasible to use and key components should be considered: political engagement, technical engagement, and integrated planning. Aspects such as designing the protocol, selecting target populations and diseases, laboratory capacities, anticipating the capacities to analyze and interpret complex data, and how to use it are key.

Diagnostic Performance of Loop-Mediated Isothermal Amplification and Ultrasensitive Rapid Diagnostic Tests for Malaria Screening Among Pregnant Women in Kenya.

BACKGROUND: Screen-and-treat strategies with sensitive diagnostic tests may reduce malaria-associated adverse pregnancy outcomes. We conducted a diagnostic accuracy study to evaluate new point-of-care tests to screen pregnant women for malaria at their first antenatal visit in western Kenya. METHODS: Consecutively women were tested for Plasmodium infection by expert microscopy, conventional rapid diagnostic test (cRDT), ultra sensitive RDT (usRDT), and loop-mediated isothermal amplification (LAMP). Photoinduced electron-transfer polymerase chain reaction (PET-PCR) served as the reference standard. Diagnostic performance was calculated and modelled at low parasite densities. RESULTS: Between May and September 2018, 172 of 482 screened participants (35.7%) were PET-PCR positive. Relative to PET-PCR, expert microscopy was least sensitive (40.1%; 95% confidence interval [CI], 32.7%-47.9%), followed by cRDT (49.4%; 95% CI, 41.7%-57.1), usRDT (54.7%; 95% CI, 46.9%-62.2%), and LAMP (68.6%; 95% CI, 61.1%-75.5%). Test sensitivities were comparable in febrile women (n = 90). Among afebrile women (n = 392), the geometric-mean parasite density was 29 parasites/µL and LAMP (sensitivity = 61.9%) and usRDT (43.2%) detected 1.74 (95% CI, 1.31-2.30) and 1.21 (95% CI, 88-2.21) more infections than cRDT (35.6%). Per our model, tests performed similarly at densities >200 parasites/µL. At 50 parasites/µL, the sensitivities were 45%, 56%, 62%, and 74% with expert microscopy, cRDT, usRDT, and LAMP, respectively. CONCLUSIONS: This first-generation usRDT provided moderate improvement in detecting low-density infections in afebrile pregnant women compared to cRDTs.

Effectiveness of Coronavirus Disease 2019 (COVID-19) Vaccines Among Incarcerated People in California State Prisons: Retrospective Cohort Study.

BACKGROUND: Prisons and jails are high-risk settings for coronavirus disease 2019 (COVID-19). Vaccines may substantially reduce these risks, but evidence is needed on COVID-19 vaccine effectiveness for incarcerated people, who are confined in large, risky congregate settings. METHODS: We conducted a retrospective cohort study to estimate effectiveness of messenger RNA (mRNA) vaccines, BNT162b2 (Pfizer-BioNTech) and mRNA-1273 (Moderna), against confirmed severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections among incarcerated people in California prisons from 22 December 2020 through 1 March 2021. The California Department of Corrections and Rehabilitation provided daily data for all prison residents including demographic, clinical, and carceral characteristics, as well as COVID-19 testing, vaccination, and outcomes. We estimated vaccine effectiveness using multivariable Cox models with time-varying covariates, adjusted for resident characteristics and infection rates across prisons. RESULTS: Among 60 707 cohort members, 49% received at least 1 BNT162b2 or mRNA-1273 dose during the study period. Estimated vaccine effectiveness was 74% (95% confidence interval [CI], 64%-82%) from day 14 after first dose until receipt of second dose and 97% (95% CI, 88%-99%) from day 14 after second dose. Effectiveness was similar among the subset of residents who were medically vulnerable: 74% (95% CI, 62%-82%) and 92% (95% CI, 74%-98%) from 14 days after first and second doses, respectively. CONCLUSIONS: Consistent with results from randomized trials and observational studies in other populations, mRNA vaccines were highly effective in preventing SARS-CoV-2 infections among incarcerated people. Prioritizing incarcerated people for vaccination, redoubling efforts to boost vaccination, and continuing other ongoing mitigation practices are essential in preventing COVID-19 in this disproportionately affected population.

Evaluation of the Performance of Ortho T. cruzi ELISA Test System for the Detection of Antibodies to Trypanosoma cruzi.

The serologic diagnosis of chronic Chagas disease, caused by infection with the parasite Trypanosoma cruzi, is challenging and lacks a gold-standard assay. To overcome the problem, CDC uses an algorithm that uses two tests on different platforms and applies a third test as a tiebreaker. The Ortho T. cruzi ELISA Test System from Ortho Diagnostics was cleared by FDA for clinical diagnosis usage. We evaluated this test against the CDC algorithm for chronic Chagas disease. We tested several sets of serum specimens: 104 specimens tested positive for T. cruzi specific antibody and 283 (including 30 specimens positive for antibody to Leishmania spp.) tested negative based on the current CDC chronic T. cruzi infection diagnostic testing algorithm. Concordance of the Ortho T. cruzi ELISA Test System with the CDC algorithm result was 90% (95% CI 87 to 93%) overall and 92% (95% CI 89 to 95%) when excluding Leishmania spp. antibody positive specimens. The cross-reactivity of the Ortho T. cruzi ELISA Test System was 37% to Leishmania spp. serologically positive specimens, 1% to specimens from patients diagnosed with other parasitic infections, and 0% against specimens from a US noninfected population. In conclusion, the Ortho T. cruzi ELISA Test System compares well against the CDC diagnostic algorithm for chronic Chagas disease. The availability of this FDA-cleared assay will improve the chronic Chagas disease diagnosis.

Effectiveness of Bivalent mRNA Vaccines in Preventing Symptomatic SARS-CoV-2 Infection - Increasing Community Access to Testing Program, United States, September-November 2022.

On September 1, 2022, bivalent COVID-19 mRNA vaccines, composed of components from the SARS-CoV-2 ancestral and Omicron BA.4/BA.5 strains, were recommended by the Advisory Committee on Immunization Practices (ACIP) to address reduced effectiveness of COVID-19 monovalent vaccines during SARS-CoV-2 Omicron variant predominance (1). Initial recommendations included persons aged ≥12 years (Pfizer-BioNTech) and ≥18 years (Moderna) who had completed at least a primary series of any Food and Drug Administration-authorized or -approved monovalent vaccine ≥2 months earlier (1). On October 12, 2022, the recommendation was expanded to include children aged 5-11 years. At the time of recommendation, immunogenicity data were available from clinical trials of bivalent vaccines composed of ancestral and Omicron BA.1 strains; however, no clinical efficacy data were available. In this study, effectiveness of the bivalent (Omicron BA.4/BA.5-containing) booster formulation against symptomatic SARS-CoV-2 infection was examined using data from the Increasing Community Access to Testing (ICATT) national SARS-CoV-2 testing program.* During September 14-November 11, 2022, a total of 360,626 nucleic acid amplification tests (NAATs) performed at 9,995 retail pharmacies for adults aged ≥18 years, who reported symptoms consistent with COVID-19 at the time of testing and no immunocompromising conditions, were included in the analysis. Relative vaccine effectiveness (rVE) of a bivalent booster dose compared with that of ≥2 monovalent vaccine doses among persons for whom 2-3 months and ≥8 months had elapsed since last monovalent dose was 30% and 56% among persons aged 18-49 years, 31% and 48% among persons aged 50-64 years, and 28% and 43% among persons aged ≥65 years, respectively. Bivalent mRNA booster doses provide additional protection against symptomatic SARS-CoV-2 in immunocompetent persons who previously received monovalent vaccine only, with relative benefits increasing with time since receipt of the most recent monovalent vaccine dose. Staying up to date with COVID-19 vaccination, including getting a bivalent booster dose when eligible, is critical to maximizing protection against COVID-19 (1).

Development of a Multiplex Bead Assay To Detect Immunoglobulin G Antibodies to Babesia duncani in Human Serum.

Babesia duncani is the causative agent of babesiosis in the western United States. The indirect fluorescent antibody (IFA) assay is the diagnostic test of choice for detection of B. duncani-specific antibodies. However, this test requires parasitized red blood cells harvested from infected hamsters, and test results are often difficult to interpret. To simplify serological testing for B. duncani, a proteomics approach was employed to identify candidate immunodiagnostic antigens. Several proteins were identified by electrospray ionization mass spectrometric analysis, and four recombinant protein constructs were expressed and used in a multiplex bead assay (MBA) to detect B. duncani-specific antibodies. Two antigens, AAY83295.1 and AAY83296.1, performed well with high sensitivities and specificities. AAY83295.1 had a higher sensitivity (100%) but lower specificity (89%) than AAY83296.1, which had a sensitivity of 90% and a specificity of 96%. Combining these two antigens did not improve the performance of the assay. This MBA could be useful for diagnosis, serosurveillance, and blood donor screening for B. duncani infection.

Safety, Tolerability, and Immunogenicity of Plasmodium falciparum Sporozoite Vaccine Administered by Direct Venous Inoculation to Infants and Young Children: Findings From an Age De-escalation, Dose-Escalation, Double-blind, Randomized Controlled Study in Western Kenya.

BACKGROUND: The whole Plasmodium falciparum sporozoite (PfSPZ) vaccine is being evaluated for malaria prevention. The vaccine is administered intravenously for maximal efficacy. Direct venous inoculation (DVI) with PfSPZ vaccine has been safe, tolerable, and feasible in adults, but safety data for children and infants are limited. METHODS: We conducted an age de-escalation, dose-escalation randomized controlled trial in Siaya County, western Kenya. Children and infants (aged 5-9 years, 13-59 months, and 5-12 months) were enrolled into 13 age-dose cohorts of 12 participants and randomized 2:1 to vaccine or normal saline placebo in escalating doses: 1.35 × 105, 2.7 × 105, 4.5 × 105, 9.0 × 105, and 1.8 × 106 PfSPZ, with the 2 highest doses given twice, 8 weeks apart. Solicited adverse events (AEs) were monitored for 8 days after vaccination, unsolicited AEs for 29 days, and serious AEs throughout the study. Blood taken prevaccination and 1 week postvaccination was tested for immunoglobulin G antibodies to P. falciparum circumsporozoite protein (PfCSP) using enzyme-linked immunosorbent assay. RESULTS: Rates of AEs were similar in vaccinees and controls for solicited (35.7% vs 41.5%) and unsolicited (83.9% vs 92.5%) AEs, respectively. No related grade 3 AEs, serious AEs, or grade 3 laboratory abnormalities occurred. Most (79.0%) vaccinations were administered by a single DVI. Among those in the 9.0 × 105 and 1.8 × 106 PfSPZ groups, 36 of 45 (80.0%) vaccinees and 4 of 21 (19.0%) placebo controls developed antibodies to PfCSP (P < .001). CONCLUSIONS: PfSPZ vaccine in doses as high as 1.8 × 106 can be administered to infants and children by DVI, and was safe, well tolerated, and immunogenic. CLINICAL TRIALS REGISTRATION: NCT02687373.

Update: Characteristics of Health Care Personnel with COVID-19 - United States, February 12-July 16, 2020.

As of September 21, 2020, the coronavirus disease 2019 (COVID-19) pandemic had resulted in 6,786,352 cases and 199,024 deaths in the United States.* Health care personnel (HCP) are essential workers at risk for exposure to patients or infectious materials (1). The impact of COVID-19 on U.S. HCP was first described using national case surveillance data in April 2020 (2). Since then, the number of reported HCP with COVID-19 has increased tenfold. This update describes demographic characteristics, underlying medical conditions, hospitalizations, and intensive care unit (ICU) admissions, stratified by vital status, among 100,570 HCP with COVID-19 reported to CDC during February 12-July 16, 2020. HCP occupation type and job setting are newly reported. HCP status was available for 571,708 (22%) of 2,633,585 cases reported to CDC. Most HCP with COVID-19 were female (79%), aged 16-44 years (57%), not hospitalized (92%), and lacked all 10 underlying medical conditions specified on the case report form† (56%). Of HCP with COVID-19, 641 died. Compared with nonfatal COVID-19 HCP cases, a higher percentage of fatal cases occurred in males (38% versus 22%), persons aged ≥65 years (44% versus 4%), non-Hispanic Asians (Asians) (20% versus 9%), non-Hispanic Blacks (Blacks) (32% versus 25%), and persons with any of the 10 underlying medical conditions specified on the case report form (92% versus 41%). From a subset of jurisdictions reporting occupation type or job setting for HCP with COVID-19, nurses were the most frequently identified single occupation type (30%), and nursing and residential care facilities were the most common job setting (67%). Ensuring access to personal protective equipment (PPE) and training, and practices such as universal use of face masks at work, wearing masks in the community, and observing social distancing remain critical strategies to protect HCP and those they serve.

Low prevalence of viable Toxoplasma gondii in fresh, unfrozen American pasture-raised pork and lamb from retail meat stores in the United States.

In a national survey of fresh, unfrozen, American pasture-raised lamb and pork, the prevalence of viable Toxoplasma gondii was determined in 1500 samples selected by random multistage sampling (750 pork, 750 lamb) obtained from 250 retail meat stores from 10 major geographic areas in the USA. Each sample consisted of a minimum of 500g of meat purchased from the retail meat case. To detect viable T. gondii, 50g meat samples of each of 1500 samples were bioassayed in mice. Viable T. gondii was isolated from 2 of 750 lamb samples (unweighted: 0.19%, 0.00-0.46%; weighted: 0.04%, 0.00-0.11%) and 1 of 750 pork samples (unweighted: 0.12%, 0.00-0.37%; weighted: 0.18%, 0.00-0.53%) samples. Overall, the prevalence of viable T. gondii in these retail meats was very low. Nevertheless, consumers, especially pregnant women, should be aware that they can acquire T. gondii infection from ingestion of undercooked meat. Cooking meat to an internal temperature of 66°C kills T. gondii.