SARS-CoV-2 Seropositivity in Nursing Home Staff and Residents during the First SARS-CoV-2 Wave in Flanders, Belgium.

(1) Background: early in the COVID-19 pandemic, reverse transcription polymerase chain reaction (RT-PCR) testing was limited. Assessing seroprevalence helps understand prevalence and reinfection risk. However, such data are lacking for the first epidemic wave in Belgian nursing homes. Therefore, we assessed SARS-CoV-2 seroprevalence and cumulative RT-PCR positivity in Belgian nursing homes and evaluated reinfection risk. (2) Methods: we performed a cross-sectional study in nine nursing homes in April and May 2020. Odds ratios (ORs) were calculated to compare the odds of (re)infection between seropositive and seronegative participants. (3) Results: seroprevalence was 21% (95% CI: 18-23): 22% (95% CI: 18-25) in residents and 20% (95% CI: 17-24) in staff. By 20 May 2020, cumulative RT-PCR positivity was 16% (95% CI: 13-21) in residents and 8% (95% CI: 6-12) in staff. ORs for (re)infection in seropositive (compared to seronegative) residents and staff were 0.22 (95% CI: 0.06-0.72) and 3.15 (95% CI: 1.56-6.63), respectively. (4) Conclusion: during the first wave, RT-PCR test programmes underestimated the number of COVID-19 cases. The reinfection rate in residents was 3%, indicating protection, while it was 21% in staff, potentially due to less cautious health behaviour. Future outbreaks should use both RT-PCR and serological testing for complementary insights into transmission dynamics.

Kinetics of Viral Shedding for Outbreak Surveillance of Emerging Infectious Diseases: Modeling Approach to SARS-CoV-2 Alpha and Omicron Infection.

BACKGROUND: Previous studies have highlighted the importance of viral shedding using cycle threshold (Ct) values obtained via reverse transcription polymerase chain reaction to understand the epidemic trajectories of SARS-CoV-2 infections. However, it is rare to elucidate the transition kinetics of Ct values from the asymptomatic or presymptomatic phase to the symptomatic phase before recovery using individual repeated Ct values. OBJECTIVE: This study proposes a novel Ct-enshrined compartment model to provide a series of quantitative measures for delineating the full trajectories of the dynamics of viral load from infection until recovery. METHODS: This Ct-enshrined compartment model was constructed by leveraging Ct-classified states within and between presymptomatic and symptomatic compartments before recovery or death among people with infections. A series of recovery indices were developed to assess the net kinetic movement of Ct-up toward and Ct-down off recovery. The model was applied to (1) a small-scale community-acquired Alpha variant outbreak under the "zero-COVID-19" policy without vaccines in May 2021 and (2) a large-scale community-acquired Omicron variant outbreak with high booster vaccination rates following the lifting of the "zero-COVID-19" policy in April 2022 in Taiwan. The model used Bayesian Markov chain Monte Carlo methods with the Metropolis-Hastings algorithm for parameter estimation. Sensitivity analyses were conducted by varying Ct cutoff values to assess the robustness of the model. RESULTS: The kinetic indicators revealed a marked difference in viral shedding dynamics between the Alpha and Omicron variants. The Alpha variant exhibited slower viral shedding and lower recovery rates, but the Omicron variant demonstrated swifter viral shedding and higher recovery rates. Specifically, the Alpha variant showed gradual Ct-up transitions and moderate recovery rates, yielding a presymptomatic recovery index slightly higher than 1 (1.10), whereas the Omicron variant had remarkable Ct-up transitions and significantly higher asymptomatic recovery rates, resulting in a presymptomatic recovery index much higher than 1 (152.5). Sensitivity analysis confirmed the robustness of the chosen Ct values of 18 and 25 across different recovery phases. Regarding the impact of vaccination, individuals without booster vaccination had a 19% higher presymptomatic incidence rate compared to those with booster vaccination. Breakthrough infections in boosted individuals initially showed similar Ct-up transition rates but higher rates in later stages compared to nonboosted individuals. Overall, booster vaccination improved recovery rates, particularly during the symptomatic phase, although recovery rates for persistent asymptomatic infection were similar regardless of vaccination status once the Ct level exceeded 25. CONCLUSIONS: The study provides new insights into dynamic Ct transitions, with the notable finding that Ct-up transitions toward recovery outpaced Ct-down and symptom-surfacing transitions during the presymptomatic phase. The Ct-up against Ct-down transition varies with variants and vaccination status. The proposed Ct-enshrined compartment model is useful for the surveillance of emerging infectious diseases in the future to prevent community-acquired outbreaks.

SARS-CoV-2 co-detection with other respiratory pathogens-descriptive epidemiological study.

BACKGROUND: Co-detection of respiratory pathogens with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is poorly understood. This descriptive epidemiological study aimed to determine the effect of the interaction of different respiratory pathogens on clinical variables. METHODS: We retrospectively reviewed the results of comprehensive multiplex polymerase chain reaction (PCR) testing from November 2020 to March 2023 to estimate respiratory pathogen co-detection rates in Shinjuku, Tokyo. We evaluated the interactions of respiratory pathogens, particularly SARS-CoV-2, between observed and expected co-detection. We estimated the trend of co-detection with SARS-CoV-2 in terms of age and sex and applied a multiple logistic regression model adjusted for age, testing period, and sex to identify influencing factors between co-detection and single detection for each pathogen. RESULTS: Among 57,746 patients who underwent multiplex PCR testing, 10,516 (18.2%) had positive for at least one of the 22 pathogens. Additionally, 881 (1.5%) patients were confirmed to have a co-detection. SARS-CoV-2 exhibited negative interactions with adenovirus, coronavirus, human metapneumovirus, parainfluenza virus, respiratory syncytial virus, and rhino/enterovirus. SARS-CoV-2 co-detection with other pathogens occurred most frequently in patients of the youngest age group (0-4 years). A multiple logistic regression model indicated that younger age was the most influential factor for SARS-CoV-2 co-detection with other respiratory pathogens. CONCLUSION: The study highlights the prevalence of SARS-CoV-2 co-detection with other respiratory pathogens in younger age groups, necessitating further exploration of the clinical implications and severity of SARS-CoV-2 co-detection.

Association of Prior COVID-19 Infection with Risk of Breakthrough Infection Following Vaccination: A Cohort Study in Isfahan, Iran.

Background: Many people worldwide have developed a combination of natural and vaccine-induced immunity to COVID-19. This study investigated whether exposure to SARS-CoV-2 before full vaccination promotes protection against a breakthrough infection. Methods: We studied a total of 2,902,545 people in the Isfahan COVID-19 Registry. All the participants had received two doses of either Sinopharm BIBP, ChAdOx1-nCoV-19, Gam-COVID-Vac, or BIV1-CovIran vaccines. A cohort study examined the association between prior COVID-19 infection and the risk of a breakthrough infection for each vaccine. Cohorts in each pair were matched by gender, age group, calendar week of the first dose, the interval between the first and second doses, and the proportion of healthcare workers. The probable virus variant for the previous infections was also considered. Each individual's follow-up started 14 days after their second vaccine dose until either the end of the study censoring date, occurrence of a COVID-19 infection, or death. The breakthrough infection risk was compared between each cohort pair by using the hazard ratio (HR) and incidence rate ratio (IRR). Results: Total breakthrough HRs (95% confidence interval) (previously infected over infection-naïve matched cohort) were 0.36 (0.23-0.55), 0.35 (0.32-0.40), 0.37 (0.30-0.46), and 0.43 (0.32-0.56) for the BIV1-CovIran, Sinopharm BIBP, Gam-COVID-Vac, and ChAdOx1-nCoV-19 vaccine groups, respectively. The breakthrough infection IRRs were approximately similar to the total HRs mentioned above. Conclusion: Prior SARS-CoV-2 infection conferred additive immunity against breakthrough after vaccination, no matter which vaccine brand was injected. Such a result could guide health authorities to codify low-cost high-benefit vaccination protocols and protect the community's well-being.

SARS-CoV-2 Dynamics in the Premier League Testing Program, United Kingdom.

During 2020-2022, players and staff in the English Premier League in the United Kingdom were tested regularly for SARS-CoV-2 with the aim of creating a biosecure bubble for each team. We found that prevalence and reinfection estimates were consistent with those from other studies and with community infection trends.

A novel molecular assay conducted on the BD Max system to facilitate reflex testing for vanA and vanB in clinical isolates of enterococci.

Infections caused by vancomycin-resistant enterococci (VRE) are common. Real-time PCR assays targeting vanA and vanB facilitate screening of patients in healthcare settings to limit the risk of dissemination, especially amongst those at high-risk of infection or with limited treatment options. Such assays are commonly performed as reflex testing procedures where they augment phenotypic techniques and shorten turnaround time to benefit timely clinical management. 'Random access' and 'sample-to-result' real-time PCR platforms are suited for this application as they are of low complexity and less technically demanding. Modelled on these attributes, we configured a real-time PCR assay (VRE BD) for detection of vanA/B in clinical isolates of enterococci, adapted for the BD Max System (Becton Dickinson). We applied an unconventional approach by testing suspensions of microorganisms in water to circumvent the traditional pre-analytical genomic extraction process. Our objective of this study was to assess the performance of this assay for detection of VRE in cultures by validating against a traditional real-time PCR assay based on the LightCycler 2.0 platform (Roche, VRE RO). A high level of analytical sensitivity and specificity (≥99.0%) for both genes was obtained when testing suspensions derived from blood agar. Results for suspensions obtained from chromID VRE (Edwards Group) showed a similar level of performance for vanA detection (100%), but not for the vanB target (≥90.9%) where a lesser number of isolates were available for testing. However, our results for VRE detection in isolates from these media were repeatable and reproducible, and equated to positive and negative predictive values of ≥95.2% and ≥97.8%, respectively. Furthermore, the VRE BD assay was also able to accurately detect VRE in clinical and spiked BacT/ALERT (bioMérieux) blood cultures. Thus, the technical simplicity, short turnaround time and robustness of this high performing assay for VRE is suitable for reflex testing. In addition, the format developed for the BD Max platform has potential application for reflex testing other molecular targets of clinical importance.

Swab Testing to Optimize Pneumonia treatment with empiric Vancomycin (STOP-Vanc): study protocol for a randomized controlled trial.

Background: Vancomycin, an antibiotic with activity against Methicillin-resistant Staphylococcus aureus (MRSA), is frequently included in empiric treatment for community-acquired pneumonia (CAP) despite the fact that MRSA is rarely implicated in CAP. Conducting polymerase chain reaction (PCR) testing on nasal swabs to identify the presence of MRSA colonization has been proposed as an antimicrobial stewardship intervention to reduce the use of vancomycin. Observational studies have shown reductions in vancomycin use after implementation of MRSA colonization testing, and this approach has been adopted by CAP guidelines. However, the ability of this intervention to safely reduce vancomycin use has yet to be tested in a randomized controlled trial. Methods: STOP-Vanc is a pragmatic, prospective, single center, non-blinded randomized trial. Adult patients with suspicion for CAP who are receiving vancomycin and admitted to the Medical Intensive Care Unit at Vanderbilt University Medical Center will be screened for eligibility. Eligible patients will be enrolled and randomized in a 1:1 ratio to either receive MRSA nasal swab PCR testing in addition to usual care (intervention group), or usual care alone (control group). PCR testing results will be transmitted through the electronic health record to the treating clinicians. Primary providers of intervention group patients with negative swab results will also receive a page providing clinical guidance recommending discontinuation of vancomycin. The primary outcome will be vancomycin-free hours alive, defined as the number of hours alive and free of the use of vancomycin within the first seven days following trial enrollment estimated using a proportional odds ratio model. Secondary outcomes include 30-day all-cause mortality and time alive off vancomycin. Discussion: STOP-Vanc will provide the first randomized controlled trial data regarding the use of MRSA nasal swab PCR testing to guide antibiotic de-escalation. This study will provide important information regarding the effect of MRSA PCR testing and antimicrobial stewardship guidance on clinical outcomes in an intensive care unit setting. Trial registration: This trial was registered on ClinicalTrials.gov on February 22, 2024. (ClinicalTrials.gov identifier: NCT06272994).

Ignatzschineria indica Bacteremia Initially Misdiagnosed in a Patient With a Maggot-Infested Wound.

Gram-negative bacteremia in hospitalized patients often leads to prolonged hospital stays, increased healthcare costs, and mortality rates. Simultaneously, the presence of comorbidities like chronic wounds increases the risk of severe infection and complicated hospital courses involving amputation, broad-spectrum antibiotic use, and repeat hospital admissions, after discharge. This case presents a 72-year-old male with a past medical history significant for chronic lower extremity cellulitis with multiple prior hospitalizations. On admission, the patient had a chief complaint of progressively worsening left lower extremity pain along with nausea, vomiting, and diarrhea. CT imaging of the left lower extremity suggested severe cellulitis without signs of osteomyelitis. Blood cultures initially suggested Corynebacterium jeikeium, but were sent to an outside facility due to ambiguity of results. The outside facility identified the pathogen as Ignatzschineria indica. After confirming the results, antibiotics were appropriately de-escalated to oral levofloxacin. The patient continued to show clinical improvement and was discharged with follow-up appointments scheduled for infectious disease and bi-weekly visits to wound care. Considering the increasing prevalence of chronic wounds in the United States, awareness and recognition of emerging pathogens are crucial for the timely diagnosis, treatment, and management of these complex patients. Our case adds to the growing body of reports on the management of I. indica bacteremia resulting from maggot-infested wounds.

Comparative Evaluation of Mogibacterium timidum in the Subgingival Plaque of Periodontally Healthy and Chronic Periodontitis Patients: A Real-Time Polymerase Chain Reaction (PCR) Study.

BACKGROUND: Mogibacterium timidum is a new genus of anaerobic bacteria discovered in the year 2000. It is one of the most common bacteria present in the host microbial flora of dental plaque. The levels of M. timidum are supposedly higher in inflammatory conditions. AIMS AND OBJECTIVES: This study aimed to quantify the levels of M. timidum species in the subgingival plaque samples of healthy patients and patients with chronic periodontitis. MATERIALS AND METHODS: A total of 24 samples of the subgingival plaque, 12 healthy samples and 12 samples of chronic periodontitis patients, were collected in a buffer solution using a sterile Gracey curette. These samples were then sent to a laboratory for real-time polymerase chain reaction (PCR) testing. RESULTS: M. timidum was found in higher quantities in plaque samples taken from chronic periodontitis patients when compared to healthy patients. CONCLUSION: M. timidum can be said to be associated with chronic periodontitis condition. Further studies are required to know the exact nature of the pathogen.

Moleculargenetic and in Addition Partly Discrepant Infection Serological Malaria Testing in Two Blood Donors.

Introduction: According to the guidelines (GL) valid in Germany, persons born or raised in a malaria-endemic area or had continuously stayed in a malaria-endemic area for more than 6 months may only be admitted donating blood if, among other things, validated and quality-assured laboratory diagnostics show that there is no evidence of infectivity. In a statement of the Working Group "Blood" of the Federal Ministry of Health (WGB), a reduction of the deferral period from 4 to 3 years and an antibody test after the deferral period are recommended. Methods: In accordance with the GL, nucleic acid testing (NAT) by means of PCR is carried out at our institution after a retention period of 4 years. In addition to the validated molecular biological testing, an infection serological examination was performed. Case Presentation: In the present cases, Plasmodia genome was detected in the respective single PCR in two blood donors originating from malaria-endemic areas after the expiry of the deferral period. However, one donor tested negative for antibodies against Plasmodia. Discussion/Conclusion: This observation is discussed in the context of a recommendation of the WGB. The question is addressed whether PCR testing is dispensable or whether a combination of infection serological testing and NAT should be favored.

Next-generation microbiological testing in intraabdominal infections with PCR technology.

PURPOSE: Intraabdominal infections (IAI) are increasing worldwide and are a major contributor to morbidity and mortality. Among IAI, the number of multi-drug resistant organisms (MDRO) is increasing globally. We tested the Unyvero A50® for intraabdominal infections, compared the detected microorganisms and antibiotic resistance, and compared the results with those of routine microbiology. METHODS: We prospectively compared samples obtained from surgical patients using PCR-based Unyvero IAI cartridges against routine microbiology for the detection of microorganisms. Additionally, we identified clinical parameters that correlated with the microbiological findings. Data were analyzed using the t-test and Mann-Whitney U test. RESULTS: Sixty-two samples were analyzed. The PCR system identified more microorganisms, mostly Bacteroides species, Escherichia coli, and Enterococcus spp. For bacterial resistance, the PCR system results were fully concordant with those of routine microbiology, resulting in a sensitivity, specificity, and positive and negative predictive value (PPV, NPV) of 100%. The sensitivity, specificity, PPV, and NPV for the detection of microorganisms were 74%, 58%, 60%, and 72%, respectively. CRP levels were significantly higher in patients with detectable microorganisms. We identified more microorganisms and bacterial resistance in hospital-acquired intra-abdominal infections by using the PCR system. DISCUSSION: IAI warrants early identification of the microorganisms involved and their resistance to allow for adequate antibiotic therapy. PCR systems enable physicians to rapidly adjust their antibiotic treatment. Conventional microbiological culture and testing remain essential for determining the minimal growth inhibition concentrations for antibiotic therapy.

Retrospective case study of respiratory viral panel PCR testing in primary care.

Respiratory illnesses are some of the most common reasons for visits to primary and urgent care yet their treatment is rarely guided by laboratory testing. A retrospective case review was performed on the use of an reverse transcription polymerase chain reaction (RT-PCR) respiratory viral panel (RVP) in a primary-care setting to assess its impact, particularly on antibiotic prescribing. Routine sick visits where an RVP was used were reviewed to compare presentations and outcomes. In this small study, positive RVP tests help reduce unnecessary antibiotic prescriptions by nearly one-third. Although currently expensive, RVPs are a valuable tool for the assessment of respiratory illnesses distinguishing between those that require antibiotics and those with potential public health implications, such as COVID-19.

PCR testing for herpesviruses in aqueous humor samples from patients with and without clinical corneal endothelial graft rejection.

To compare prevalence of positive PCR tests for herpesviruses between patients with and without a history of clinical corneal endothelial allograft rejection (AGR). Retrospective cross-sectional study with two-group comparison. A total of 307 aqueous humor (AH) samples from 235 Patients and 244 eyes who underwent penetrating keratoplasty or Descemet membrane endothelial keratoplasty or had a diagnostic AH aspiration due to clinical AGR between 2019 and 2023 were tested for DNA of herpes simplex virus (HSV), varicella-zoster virus (VZV), cytomegalovirus (CMV), and Epstein-Barr virus (EBV). PCR test results were compared between the two groups (with/without AGR). Another sub-analysis examined the results of patients without a history of herpetic keratitis. A total of 8% of eyes with clinical AGR (9/108) had a positive PCR result for one of the herpesviruses (HSV:3, CMV:3, EBV:2, VZV:1). All patients in the group without AGR had negative PCR results for all previous viruses (0/136). The difference was statistically significant (p < 0.001). The sub-analysis of eyes without a history of herpetic keratitis also revealed significantly more positive herpes PCR results (7/87) in eyes with AGR than in eyes without AGR (0/42, p = 0.005). Clinical AGR after keratoplasty shows a significant correlation to viral replication. Herpetic infection and AGR could occur simultaneously and act synergistically. Timely differentiation between active herpetic infection and/or AGR is pivotal for proper treatment and graft preservation.

Self-administered versus clinician-performed BinaxNOW COVID rapid test: a comparison of accuracy.

We conducted a single-center study at a free community testing site in Baltimore City to assess the accuracy of self-performed rapid antigen tests (RATs) for COVID-19. Self-administered BinaxNOW RATs were compared with clinician-performed RATs and against a reference lab molecular testing as the gold standard. Of the 953 participants, 14.9% were positive for SARS- CoV-2 as determined by RT-PCR. The sensitivity and specificity were similar for both self- and clinician-performed RATs (sensitivity: 83.9% vs 88.2%, P = 0.40; specificity: 99.8% vs 99.6%, P = 0.6). Subgroup comparisons based on age and race yielded similar results. Notably, 5.2% (95% CI: 1.5% to 9.5%) of positive results were potentially missed due to participant misinterpretation of the self-test card. However, the false-positive rate for RATs was reassuringly comparable in accuracy to clinician-administered tests. These findings hold significant implications for physicians prescribing treatment based on patient-reported, self-administered positive test results. Our study provides robust evidence supporting the reliability and utility of patient-performed RATs, underscoring their comparable accuracy to clinician-performed RATs, and endorsing their continued use in managing COVID-19. Further studies using other rapid antigen test brands are warranted.IMPORTANCEAccurate and accessible COVID-19 testing is crucial for effective disease control and management. A recent single-center study conducted in Baltimore City examined the reliability of self-performed rapid antigen tests (RATs) for COVID-19. The study found that self-administered RATs yielded similar sensitivity and specificity to clinician-performed tests, demonstrating their comparable accuracy. These findings hold significant implications for physicians relying on patient-reported positive test results for treatment decisions. The study provides robust evidence supporting the reliability and utility of patient-performed RATs, endorsing their continued use in managing COVID-19. Furthermore, the study highlights the need for further research using different rapid antigen test brands to enhance generalizability. Ensuring affordable and widespread access to self-tests is crucial, particularly in preparation for future respiratory virus seasons and potential waves of reinfection of SARS-CoV-2 variants such as the Omicron variant.

Recurrent and complicated urinary tract infections in women: Utility of advanced testing to enhance care.

BACKGROUND: The United States currently faces a public health crisis with regarding to antibiotic-resistant bacteria, and new urinary tract infection (UTI) diagnostics are needed. Women with recurrent UTI (rUTI) and complicated UTI (cUTI) are at particular risk given their complexity and the paucity of adequate testing modalities. The standard urine culture (SUC) is the cornerstone for diagnosis, but it has many shortcomings. These pitfalls lead to dissatisfaction and frustration among women afflicted with rUTI and cUTI, as well as overuse of antibiotics. One innovation is PCR UTI testing, which has been shown to outperform SUC among symptomatic women. AIMS: This article discusses UTI PCR testing, as well as a possible role in clinical practice. MATERIALS AND METHODS: Published literature was reviewed and summarized. RESULTS: Management of rUTI and cUTI is complex, and providers should have all diagnostics available to facilitate providing optimal care. Urine PCR testing faces reimbursement issues despite fulfilling clinical indication parameters as described by insurance companies. DISCUSSION: The role of UTI PCR testing remains unclear. Reimbursement issues have led to underuse and limited real-world outcomes reinforcing benefit. CONCLUSION: This study proposes an algorithm for PCR testing among women with rUTI and cUTI.

The epidemiology of pediatric outpatient acute respiratory tract infections in the US: a multi-facility analysis of multiplex PCR testing from 2018 to 2023.

IMPORTANCE: Post-pandemic, it is essential to understand the epidemiology of pediatric acute respiratory tract infections (ARTIs). Our multi-facility study elucidates the outpatient epidemiology of pediatric ARTI using highly multiplexed PCR testing, providing critical insights into the evolving landscape of the etiological agents with a particular focus on the years following the emergence of SARS-CoV-2. Utilizing data from two different multiplex PCR panels, our research provides a comprehensive analysis of respiratory pathogen positivity from 2018 to 2023. Our findings indicate that over half of the annual test results identified at least one pathogen, primarily of viral origin. Intriguingly, despite the surge in testing during the COVID-19 pandemic, pathogen detection rates remain similar to the pre-pandemic era. These data hold significant implications for directing antimicrobial stewardship strategies, curbing unnecessary antibiotic use in pediatric respiratory diseases, and the value of multiplex PCR testing in the outpatient setting among pediatrics.

Implementing PCR testing in general practice-a qualitative study using normalization process theory.

BACKGROUND: The COVID-19 pandemic brought attention to a need for rapid testing of large populations. Experiences from community-based testing settings show that there can be workload difficulties, logistical challenges and socioeconomic downsides to large scale Polymerase Chain Reaction (PCR) testing. Alternative testing arenas have therefore been considered. Rapid point-of-care (POC) PCR test methods have since been developed and could have potential to surveille viral respiratory infections. It is, however, unknown if PCR testing can be successfully implemented routinely in general practice. The aim of this study was to assess factors that enable and inhibit the implementation of point-of-care PCR testing for acute respiratory tract infection in general practice. METHODS: Fourteen general practices in the east Zealand area in Denmark were included in the study and given access to POC PCR testing equipment during a flu season. The participating clinics were initially trained in the use of a POC PCR testing device and then spent 6 weeks testing it. We conducted qualitative interviews with general practitioners (GPs) and their staff, before and after the testing period, specifically focusing on their clinical decision-making and internal collaboration in relation to POC PCR testing. We used normalization process theory to design the interview guides and to analyze the data. RESULTS: Professionals reported no clinical need for a POC PCR testing device in a non-pandemic clinical setting. Results were delivered faster, but this was only timesaving for the patient and not the GP, who had to perform more tasks. CONCLUSION: In its current form, the added diagnostic value of using POC PCR testing in general practice was not sufficient for the professionals to justify the increased work connected to the usage of the diagnostic procedure in daily practice. TRIAL REGISTRATION: n/a.

Use of Danish National Somatic Cell Count Data to Assess the Need for Dry-Off Treatment in Holstein Dairy Cattle.

In Denmark, PCR testing of dairy cattle is commonly used to select animals for the antibacterial treatment of intramammary infection (IMI) during the dry-off period. IMI is associated with a high somatic cell count (SCC), routinely recorded for milk quality control for most commercial dairy herds. This study aimed to compare SCC curves over the lactation among dairy cows with positive vs. negative PCR test results for four major IMI pathogens. Data from 133,877 PCR-tested Holstein cows from 1364 Danish conventional dairy herds were used to fit a nonlinear mixed-effects model using a modified four-parameter Wilmink function. We stratified the data into first, second, third or fourth and later parity and fitted Wilmink curves to all SCC observations between 6 and 305 days in milk. The PCR tests were taken before dry-off at the end of the lactation to investigate which animals qualified for selective dry cow therapy. A PCR Ct-value of 37 and below was used to determine if an animal was PCR positive for any of the following IMI pathogens: Staphylococcus aureus, Streptococcus agalactiae, Str. dysgalactiae and Str. uberis. Our findings showed that mean SCC curve fits were higher for PCR-positive animals in all four parity groups and across lactations. The use of SCC data fitted to the entire lactation for multiple lactations enabled quantification of overall differences in SCC curves between cattle with and without detected IMI, adjusted for parity group and stage of lactation. These findings are relevant to the use of SCC to support treatment decisions.

Analysis of the effect of PCR testing and antigen testing on controlling the transmission for Omicron based on different scenarios.

After the policy adjustment, China no longer carries out COVID-19 PCR testing for all people, and antigen testing has become the main way to detect and manage infectious sources. We developed a dynamic model to evaluate and compare the effects between PCR and antigen testing for controlling the pandemic. Due to the increase of contact degree, the peak reduction effect of PCR testing in population is lower than that of antigen testing. Even if it was only 20% of people isolated at home after antigen testing, the peak of the epidemic could be reduced by 9.46%. If the proportion of antigen testing is further increased to 80%, the peak of the pandemic can be reduced by 31.41%. Antigen testing performed better effects in school (reduction proportion 29.27%) and community (29.34%) than in workplace (27.75%). Therefore, we recommend that antigen testing in the population should be encouraged during the pandemic, and home isolation of infected persons should be advocated, especially in crowded places. To improve the availability of antigen, the testing proportion should be further enhanced.