SARS-CoV-2 cellular and humoral responses in vaccine-naive individuals during the first two waves of COVID-19 infections in the southern region of The Netherlands: a cross-sectional population-based study.

With the emergence of highly transmissible variants of concern, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) still poses a global threat of coronavirus disease 2019 (COVID-19) resurgence. Cellular responses to novel variants are more robustly maintained than humoral responses, and therefore, cellular responses are of interest in assessing immune protection against severe disease in the population. We aimed to assess cellular responses to SARS-CoV-2 at the population level. IFNγ (interferon γ) responses to wild-type SARS-CoV-2 were analyzed using an ELISpot assay in vaccine-naive individuals with different humoral responses: Ig (IgM and/or IgG) seronegative (n = 90) and seropositive (n = 181) with low (<300 U/mL) or high (≥300 U/mL) humoral responses to the spike receptor binding domain (anti-S-RBD). Among the seropositive participants, 71.3% (129/181) were IFNγ ELISpot positive, compared to 15.6% (14/90) among the seronegative participants. Common COVID-19 symptoms such as fever and ageusia were associated with IFNγ ELISpot positivity in seropositive participants, whereas no participant characteristics were associated with IFNγ ELISpot positivity in seronegative participants. Fever and/or dyspnea and anti-S-RBD levels were associated with higher IFNγ responses. Symptoms of more severe disease and higher anti-S-RBD responses were associated with higher IFNγ responses. A significant proportion (15.6%) of seronegative participants had a positive IFNγ ELISpot. Assessment of cellular responses may improve estimates of the immune response to SARS-CoV-2 in the general population. IMPORTANCE: Data on adaptive cellular immunity are of interest to define immune protection against severe acute respiratory syndrome coronavirus 2 in a population, which is important for decision-making on booster-vaccination strategies. This study provides data on associations between participant characteristics and cellular immune responses in vaccine-naive individuals with different humoral responses.

COVID-19 pandemic response in the Meuse-Rhine Euroregion: methods, participation and recommendations of a longitudinal cross-border study.

BACKGROUND: Comparative data collection in transborder areas can contribute to informed decision making processes when dealing with borderless health threats such as pandemics, and thus help minimize the negative health effects for its citizens. To examine the pandemic response over time and the impact of infectious disease control in a cross-border setting, a prospective longitudinal study was conducted in the border area between Germany, Belgium and the Netherlands. In the spring of 2021, a random sample of 26,925 adult citizens selected from governmental registries was invited to collect a blood sample at home for SARS-CoV-2 antibody testing and to fill in an online questionnaire on attitudes and behaviour towards infection prevention measures, cross-border mobility, social network and support, COVID-19 self-reported infection(s) and symptoms, vaccination, general self-reported health and socio-demographics. In autumn 2021, participants were invited for a follow-up round. An online tool was developed to coordinate fieldwork procedures, real-time monitoring of participation and consultation of antibody test results. Furthermore, a helpdesk in all three languages for participants' support was set up. RESULTS: In the first round, 6,006 citizens in the Meuse-Rhine Euroregion participated. 15.3% of the invited citizens on the Belgian side of the border participated. In the Netherlands and Germany this was respectively 27% and 23.7%. In the follow-up round 4,286 (71.4%) citizens participated for the second time. The participation rate was highest in the age group 50-69 years and lowest in > 80 in all sub regions of the Meuse-Rhine Euroregion. More women participated than men. Overall, more blood samples were returned than completed questionnaires. In total, 3,344 citizens in the Meuse-Rhine Euroregion completed all components of participation in both rounds. CONCLUSIONS: The collection of comparative data can help better assess the pandemic response and the impact of infectious disease control in a cross-border area. Recommendations for a longitudinal cross-border study include a centralized online environment, mapping out potential challenges related to national regulations in the preparation phase and organizing regional coordination centres to create more familiarity and trust towards the involved organisations.

Antibodies against SARS-CoV-2 after natural infection in healthcare workers and clinical characteristics as putative antibody production prediction.

Introduction: There is a need for detailed data on early antibody responses against SARS-CoV-2 as this may contribute to the prediction of the clinical course of COVID-19 and the optimization of convalescent plasma treatment. This study aims to gain insight into developing antibodies to SARS-CoV-2 in health care workers (HCWs) infected in the first wave of the SARS-CoV-2 pandemic in the Netherlands. Materials and methods: In this retrospective analysis, sera from PCR-confirmed COVID-19 positive HCWs are included at the time of the initial PCR (T = 0, n = 95) and at least 21 days after the initial serum (T ≥ 21, n = 133). This study assesses correlations between qualitative total Ig, IgM, IgA, IgG, and quantitative anti-S-RBD antibody responses and participant characteristics. Results: Higher Ct values were associated with higher antibody positivity rates for total Ig (OR 1.261 (95% CI 1.095-1.452)), IgM (OR 1.373 (95% CI 1.125-1.675)), and IgA (OR 1.222 (95% CI 1.013-1.475)). Gender was predictive of IgM and IgA antibody positivity rates at T = 0 (OR 0.018 (95% CI 0.001-0.268)) and (OR 0.070 (95% CI 0.008-0.646)). At T ≥ 21, a substantial proportion of HCWs developed IgM (103/133; 77.4%) and total Ig (128/133; 96.2%) antibodies. IgA and IgG seroconversions were observed in only 51.1% (67/131) and 55.7% (73/131) of HCWs. Anti-S-RBD responses were higher when the interval between onset of symptoms and sampling was longer. Conclusion: The findings of this study give insight into early antibody responses and may have implications for the selection of convalescent plasma donors and the further development of monoclonal antibody treatment.

Direct assessment of possible mutations in the 23S rRNA gene encoding macrolide resistance in Chlamydia trachomatis.

Reports of potential treatment failure have raised particular concerns regarding the efficacy of the single dose azithromycin regimen in the treatment of urogenital and anorectal Chlamydia trachomatis (CT) infections. Several factors have been suggested, including heterotypic resistance. Antimicrobial susceptibility testing in CT requires cell culture with serial dilutions of antibiotics, which is laborious and for which there is no standardized testing methodology. One method to partly overcome these difficulties would be to use a genotypic resistance assay, however most current available assays do still require prior CT culture. In order to facilitate the assessment of genotypic resistance directly from clinical samples, without the need for prior culture, the aim of this study was to develop a CT specific PCR assay for the assessment of resistance associated mutations (RAMs) in the 23S rRNA gene, and to evaluate a sample of clinical cases in which CT PCR's remained positive during follow-up despite azithromycin treatment. Neither the in silico analysis nor the analytical specificity testing demonstrated clinically relevant cross-reactivity with other bacterial species. These results in conjunction with the analytical sensitivity demonstrating consistent CT 23S rRNA gene detection in the range of 10e3 IFU/mL, exemplify the assay's apt performance. Although no known macrolide RAMs were detected in the clinical cases, the described assay allows future culture independent macrolide RAM surveillance in CT, and increases accessibility for other laboratories to engage in screening.

Controlling a human parainfluenza virus-3 outbreak in a haematology ward in a tertiary hospital: the importance of screening strategy and molecular diagnostics in relation to clinical symptoms.

BACKGROUND: The human parainfluenza virus 3 (HPIV-3) outbreak at the haemato-oncology ward of the Maastricht University Medical Centre in the summer of 2016. AIM: To describe an effective strategy to control the largest reported HPIV-3 outbreak at an adult haematology-oncology ward in the Netherlands by implementing infection control measures and molecular epidemiology investigation. METHODS: Clinical, patient and diagnostic data were both pro- and retrospectively collected. HPIV-3 real-time polymerase chain reaction (HPIV-3 RT-PCR) was validated using oropharyngeal rinse samples. Screening of all new and admitted patients was implemented to identify asymptomatic infection or prolonged shedding of HPIV-3 allowing cohort isolation. FINDINGS: The HPIV-3 outbreak occurred between 9 July and 28 September 2016 and affected 53 patients. HPIV-3 RT-PCR on oropharyngeal rinse samples demonstrated an up to 10-fold higher sensitivity compared with pharyngeal swabs. Monitoring showed that at first positive PCR, 20 patients (38%) were asymptomatic (of which 11 remained asymptomatic) and the average duration of shedding was 14 days (range 1-58). Asymptomatic patients had lower viral load, shorter period of viral shedding (≤14 days) and were mostly immune-competent oncology patients. The outbreak was under control five weeks after implementation of screening of asymptomatic patients. CONCLUSION: Implementation of a sensitive screening method identified both symptomatic and asymptomatic patients which had lower viral loads and allowed early cohort isolation. This is especially important in a ward that combines patients with varying immune status, because both immunocompromised and immune-competent patients are likely to spread the HPIV-3 virus, either through prolonged shedding or through asymptomatic course of disease.

Despite Excellent Test Characteristics of the cobas 4800 CT/NG Assay, Detection of Oropharyngeal Chlamydia trachomatis and Neisseria gonorrhoeae Remains Challenging.

Oropharyngeal Chlamydia trachomatis (CT) infections and, especially, Neisseria gonorrhoeae (NG) infections are common, but few commercial nucleic acid amplification tests (NAATs) specify extragenital samples for intended use. The test characteristics of the cobas 4800 CT/NG assay were evaluated for oropharyngeal swabs. The technical validation included analysis of the specificity, sensitivity, dynamic range, linearity, efficiency, and precision. The probability of detection curve combined with historical data enabled the estimation of potentially missed diagnoses. A clinical evaluation was performed on a subset of 2,798 clinical samples available from routine diagnostics. Results of the cobas 4800 were compared with those from in-house C. trachomatis/N. gonorrhoeae PCR assays. Discrepant samples were tested with resolver assays, and these results were considered decisive. No cross-reactivity was seen in the analytical specificity analysis. High linearity (R2 ≥ 0.983), efficiency (89% to 99%), and precision (cycle threshold [CT ] value of 0.1 to 0.9) were seen for both C. trachomatis and N. gonorrhoeae The limit of detection in oropharyngeal samples was 3.2 × 102 inclusion-forming units (IFU)/ml for C. trachomatis and 6.7 × 102 CFU/ml for N. gonorrhoeae Estimates on potentially missed diagnoses were up to 7.2% for C. trachomatis and up to 24.7% for N. gonorrhoeae Clinical sensitivity and specificity were evaluated with 25 C. trachomatis-positive, 86 N. gonorrhoeae-positive, and 264 negative samples, resulting in 100% and 99.6% for C. trachomatis and 100% and 96.7% for N. gonorrhoeae, respectively. The findings in this study demonstrate the utility of the cobas 4800 CT/NG assay for oropharyngeal samples. Despite its being a highly accurate test, the range of reported CT values, especially for N. gonorrhoeae, suggests relatively low oropharyngeal loads. Hence, consistent detection over the full range of oropharyngeal loads could be impaired.

Pilot implementation of a home-care programme with chlamydia, gonorrhoea, hepatitis B, and syphilis self-sampling in HIV-positive men who have sex with men.

BACKGROUND: Not all men who have sex with men (MSM) at risk for sexually transmitted infections (STIs) and human immunodeficiency virus (HIV) infection currently receive sexual healthcare. To increase the coverage of high-quality HIV/STI care for MSM, we developed a home-care programme, as extended STI clinic care. This programme included home sampling for testing, combined with treatment and sexual health counselling. Here, we pilot implemented the programme in a hospital setting (HIV-positive MSM) to determine the factors for the successful implementation of STI home sampling strategies. METHODS: Healthcare providers from the HIV hospital treatment centre (Maastricht) were invited to offer free STI sampling kits (syphilis, hepatitis B, [extra]genital chlamydia and gonorrhoea laboratory testing) to their HIV-positive MSM patients (March to May 2018). To evaluate implementation of the program, quantitative and qualitative data were collected to assess adoption (HIV care providers offered sampling kits to MSM), participation (MSM accepted the sampling kits) and sampling-kit return, STI diagnoses, and implementation experiences. RESULTS: Adoption was 85.3% (110/129), participation was 58.2% (64/110), and sampling-kit return was 43.8% (28/64). Of the tested MSM, 64.3% (18/28) did not recently (< 3 months) undergo a STI test; during the programme, 17.9% (5/28) were diagnosed with an STI. Of tested MSM, 64.3% (18/28) was vaccinated against hepatitis B. MSM reported that the sampling kits were easily and conveniently used. Care providers (hospital and STI clinic) considered the programme acceptable and feasible, with some logistical challenges. All (100%) self-taken chlamydia and gonorrhoea samples were adequate for testing, and 82.1% (23/28) of MSM provided sufficient self-taken blood samples for syphilis screening. However, full syphilis diagnostic work-up required for MSM with a history of syphilis (18/28) was not possible in 44.4% (8/18) of MSM because of insufficient blood sampled. CONCLUSION: The home sampling programme increased STI test uptake and was acceptable and feasible for MSM and their care providers. Return of sampling kits should be further improved. The home-care programme is a promising extension of regular STI care to deliver comprehensive STI care to the home setting for MSM. Yet, in an HIV-positive population, syphilis diagnosis may be challenging when using self-taken blood samples.

Is there a higher risk of a complicated course of hepatitis A in kidney transplant patients?

BACKGROUND: We describe a patient who was planned to receive a kidney transplant from his wife. Both were infected with Hepatitis A virus (HAV) two weeks prior to the planned transplantation. Due to prolonged shedding of HAV (up until 126 days) we decided to postpone the kidney transplant in order to prevent long term complications. OBJECTIVES: The main question in this case was is there a higher risk of a complicated course of HAV-infection after kidney transplantation? We discuss the need for upscale of preventative measures of HAV infections in solid organ transplant candidates. STUDY DESIGN: We performed a literature study on risks of a complicated course of HAV in solid organ transplant recipients and performed a seroprevalence study on anti-HAV in a cohort of 106 hemodialysis patients. RESULTS: Little is known whether HAV infection in solid organ transplant patients causes a more aggressive course of diseases. However, HAV infections in these populations are associated with increased risk of liver failure. CONCLUSIONS: This case highlights the need of scaling up preventative measures against HAV infections in solid organ transplant candidates.

Safety and immunogenicity of HBAI20 Hepatitis B vaccine in healthy naïve and nonresponding adults.

Approximately 5% of the healthy adult population respond inadequately to the commercial recombinant hepatitis B vaccines. As the recombinant vaccines all have an aluminium-based adjuvant, we tried to enhance the immune response by adding a cytokine-based adjuvant. This new adjuvant AI20, containing 20 µg recombinant human IL-2 attached to 20 µg aluminium hydroxide, was added to HBVaxPro©-10 µg (HBAI20). In a double-blind randomized controlled trial (RCT), 24 naïve subjects were randomized to receive either HBAI20 or commercial HBVaxPro©-10 µg vaccine. In an open-label study, 10 nonresponders received HBAI20 vaccine. All participants received 3 vaccinations (0, 1 and 6 months). In the RCT, the occurrence of any adverse events or severe events was similar between the trial arms. At month 7, all naïve participants were seroprotected; moreover, 92% in the HBAI20 group had protective antibodies 10 days after the second vaccination vs 58% in the HBVaxPro©-10 µg group, P = .16. In the open-label study, no serious adverse events were noted. The HBAI20 vaccine was able to elicit protective anti-HBs titres in 90% of nonresponders, 1 month after the third vaccination. According to these results, the new HBAI20 vaccine seems safe, well-tolerated and may promote more rapid protection against hepatitis B infection.

A multicentre verification study of the QuantiFERON®-TB Gold Plus assay.

OBJECTIVES: The aim of this verification study was to compare the QuantiFERON®-TB Gold Plus (QFT-Plus) to the QuantiFERON®-TB Gold In Tube (QFT-GIT). The new QFT-Plus test contains an extra antigen tube which, according to the manufacturer additionally elicits a CD8+ T-cell response above the CD4+ T-cell response. We assessed the value of this tube in detecting recent latent tuberculosis infections. METHODS: Between May 2015 and December 2016, 1031 subjects underwent QFT-Plus and QFT-GIT test. Overall agreement between both tests and performance for different test indications and/or immune states was assessed. A difference of >0.6 IU/mL interferon-γ release between the two antigen tubes of the QFT-Plus assay was considered a true difference and used as estimation for CD8+ T-cell response. RESULTS: Analysis of the QuantiFERON tests resulted in an overall agreement between assays of 95%. Subjects considered to be recently exposed to tuberculosis had significantly more often a true difference in interferon-γ release compared to all other subjects (p = 0.029). CONCLUSION: Results of QFT-Plus are highly comparable to QFT-GIT. Although there is an indication that a true difference in interferon-γ release between the antigen tubes is associated with recent latent tuberculosis infection, the QFT-Plus could not be used to exclude recent exposure.

Chlamydia trachomatis antibody detection in home-collected blood samples for use in epidemiological studies.

Capillary blood collected in serum tubes was subjected to centrifugation delay while stored at room temperature. Chlamydia trachomatis (CT) IgG concentrations in aliquoted serum of these blood samples remained stable for seven days after collection. CT IgG concentrations can reliably be measured in mailed blood samples in epidemiological studies.

Diagnosis of viral gastroenteritis in children: interpretation of real-time PCR results and relation to clinical symptoms.

Molecular methods such as real-time polymerase chain reaction (PCR) are rapidly replacing traditional tests to detect fecal viral pathogens in childhood diarrhea. This technique has now increased the analytical sensitivity so drastically that positive results are found in asymptomatic children, leading to complex interpretation of real-time PCR results and difficult distinction between asymptomatic shedding and etiological cause of disease. We performed a review of the literature including pediatric studies using real-time PCR and a minimal inclusion period of one year to exclude bias by seasonality. We searched for studies on rotavirus, norovirus, adenovirus, astrovirus, and sapovirus, known to be the most common viruses to cause gastroenteritis in the pediatric population. For these viruses, we summarized the detection rates in hospitalized and community-based children with clinical symptoms of gastroenteritis, as well as subjects with asymptomatic viral shedding. Moreover, insight is given into the different viral sero- and genotypes causing pediatric gastroenteritis. We also discuss the scoring systems for severity of disease and their clinical value. A few published proposals have been made to improve the clinical interpretation of real-time PCR results, which we recapitulate and discuss in this review. We propose using the semi-quantitative measure of real-time PCR, as a surrogate for viral load, in relation to the severity score to distinguish asymptomatic viral shedding from clinically relevant disease. Overall, this review provides a better understanding of the scope of childhood gastroenteritis, discusses a method to enhance the interpretation of real-time PCR results, and proposes conditions for future research to enhance clinical implementation.

Pelvic abscess caused by Arcanobacterium haemolyticum mimicking a soft tissue tumour.

Arcanobacterium haemolyticum has usually been isolated in cases of pharyngitis and wound infections. Rarely it has been reported to cause deep tissue infections. Here, a case of a 71-year-old-male, who developed a pelvic abscess due to A. haemolyticum that initially was thought to be a malignant tumour, is described.

Evaluation of a chromogenic agar (MRSASelect) for the detection of meticillin-resistant Staphylococcus aureus with clinical samples in The Netherlands.

A novel chromogenic medium for the detection of meticillin-resistant Staphylococcus aureus (MRSA), MRSASelect (Bio-Rad), was evaluated with clinical samples in a public health laboratory in The Netherlands. In total, 3000 samples were tested in the period January to March 2005, including 972 nose, 972 throat, 968 perineum, and 88 wound or urine samples. Presumptive MRSA colonies appeared pink/mauve on the MRSASelect medium. The performance of MRSASelect medium was compared with the routine screening method. Evaluation of the colony morphology showed that all confirmed MRSA isolates grew as pink/mauve colonies. None of the white colonies were MRSA strains. The number of false-positive pink/mauve colonies increased after prolonged incubation from 20 to 48 h. The specificity decreased from 92 % after 20 h incubation to 89 % after 48 h incubation. In total 70 MRSA strains were isolated, 55 of which were detected by the MRSASelect medium and 55 were detected by the routine screening method. Sensitivity was 78.6 % for both test procedures, and specificities were 99.5 and 100 %, respectively for the MRSASelect medium and the routine screening method. The addition of an enrichment broth to the MRSASelect medium increased the number of MRSA strains detected by 12 %. In total, 18 patients were MRSA positive, 4 of these were detected by the MRSASelect medium only and 1 was detected by the routine screening method only. Sensitivity on patient level was 94.4 and 77.8 % for the MRSASelect medium and the routine screening method, respectively, while specificities were 99.7 and 99.0 %.

[Further increase of quinolone resistance of gonococci in the Netherlands and proposal for a new surveillance]. / Verdere toename in chinolonresistentie van gonokokken in Nederland en voorstel voor hernieuwde surveillance.

Previous publications have indicated that between 2002 and 2003 in the Netherlands, the antimicrobial resistance in gonococci increased. Repeat measurements in 2004 and 2005 suggest a further increase in resistance ofgonococci, to quinolones in particular, from 7% in 2002 to 26% in 2005. National surveillance of gonococcal antimicrobial resistance is important for public health. In 2006 a further survey will be implemented, in which resistance data and epidemiological information on the patients are combined and collected in a project called 'Gonococcal resistance to antimicrobials surveillance' (GRAS).

[Resistance of gonococci in the Netherlands; results of a survey of medical microbiology laboratories]. / Resistentie van gonokokken in Nederland; resultaten van een enquête bij medisch-microbiologische laboratoria.

OBJECTIVE: To collect information about the incidence ofgonorrhoea and gonococcal resistance in the Netherlands. METHOD: A questionnaire was sent to 39 medical microbiology laboratories to obtain information on current diagnostics and the susceptibility testing method, and on the number of positive results and the susceptibility pattern of gonococcal isolates in 2002 and 2003 (up to and including November). RESULTS: 32 laboratories participated in this survey. 13 laboratories used culture alone and 19 laboratories used culture and/or a molecular test. Gonorrhoea was diagnosed 2,666 times in 2002 and 2,190 times in 2003, with an incidence of 33.5 and 27.0 per 100,000 inhabitants, respectively. The rate of resistance to beta-lactam antibiotics (penicillin and amoxicillin) was 12.2% and 10.7% in 2002 and 2003, respectively, and the rates of resistance to tetracycline were 18.5% and 20.6%. An increase in the resistance to quinolones was observed from 6.6% in 2002 to 9.5% in 2003. Resistance to cephalosporins was low (0.5% in 2002 and 1.2% in 2003). Furthermore, regional differences in susceptibility were found within the Netherlands. CONCLUSION: The observed gonococcal incidence and resistance form the basis for a gonorrhoea prevention and treatment programme in the Netherlands.