Acute myocardial hypoxia increases BNP gene expression

It is well established that cardiac failure increases cardiac B-type natriuretic peptide (BNP) expression due to myocardial stretching. However, patients with ischemic heart disease also display increased plasma BNP and proBNP concentrations despite preserved cardiac function. In this study, we examined whether acute myocardial hypoxia increases cardiac BNP expression. Surgical reduction of the blood flow to an area of the anterior ventricular wall in pigs reduced the myocardial oxygen tension from 46 +/- 4 to 13 +/- 5 mmHg. The tissue contents of VEGF and BNP mRNA increased 1.8-fold and 3.5-fold, respectively (n=10, P<0.005) in hypoxic compared with normoxic ventricular myocardium after 2.2 +/- 0.2 h; the magnitude of the increase in BNP mRNA expression was positively correlated with that of VEGF in hypoxic myocardium (r=0.66, P<0.05). In support of a hypoxia-induced increase of BNP gene transcription, the content of a premature BNP mRNA was increased in hypoxic myocardium (4.8-fold, P<0.005) and in freshly harvested ventricular myocytes when kept in culture flasks and oxygen-deprived for 3 h (2.2-fold, P=0.002). ProBNP peptide accumulated in the medium of freshly harvested ventricular myocyte cultures but was undetectable in ventricular myocardium, indicating rapid release of the newly synthesized proBNP peptide. Accordingly, the plasma proBNP concentration increased after 2 h of myocardial hypoxia (P=0.028). Cumulatively, the data suggest that acute hypoxia stimulates cardiac BNP expression.

Risk of hospitalisation associated with infection with SARS-CoV-2 omicron variant versus delta variant in Denmark: an observational cohort study

BACKGROUND

Estimates of the severity of the SARS-CoV-2 omicron variant (B.1.1.529) are crucial to assess the public health impact associated with its rapid global dissemination. We estimated the risk of SARS-CoV-2-related hospitalisations after infection with omicron compared with the delta variant (B.1.617.2) in Denmark, a country with high mRNA vaccination coverage and extensive free-of-charge PCR testing capacity.

METHODS

In this observational cohort study, we included all RT-PCR-confirmed cases of SARS-CoV-2 infection in Denmark, with samples taken between Nov 21 (date of first omicron-positive sample) and Dec 19, 2021. Individuals were identified in the national COVID-19 surveillance system database, which included results of a variant-specific RT-PCR that detected omicron cases, and data on SARS-CoV-2-related hospitalisations (primary outcome of the study). We calculated the risk ratio (RR) of hospitalisation after infection with omicron compared with delta, overall and stratified by vaccination status, in a Poisson regression model with robust SEs, adjusted a priori for reinfection status, sex, age, region, comorbidities, and time period.

FINDINGS

Between Nov 21 and Dec 19, 2021, among the 188 980 individuals with SARS-CoV-2 infection, 38 669 (20·5%) had the omicron variant. SARS-CoV-2-related hospitalisations and omicron cases increased during the study period. Overall, 124 313 (65·8%) of 188 980 individuals were vaccinated, and vaccination was associated with a lower risk of hospitalisation (adjusted RR 0·24, 95% CI 0·22-0·26) compared with cases with no doses or only one dose of vaccine. Compared with delta infection, omicron infection was associated with an adjusted RR of hospitalisation of 0·64 (95% CI 0·56-0·75; 222 [0·6%] of 38 669 omicron cases admitted to hospital vs 2213 [1·5%] of 150 311 delta cases). For a similar comparison by vaccination status, the RR of hospitalisation was 0·57 (0·44-0·75) among cases with no or only one dose of vaccine, 0·71 (0·60-0·86) among those who received two doses, and 0·50 (0·32-0·76) among those who received three doses.

INTERPRETATION

We found a significantly lower risk of hospitalisation with omicron infection compared with delta infection among both vaccinated and unvaccinated individuals, suggesting an inherent reduced severity of omicron. Our results could guide modelling of the effect of the ongoing global omicron wave and thus health-care system preparedness.

FUNDING

None.

Household transmission of SARS-CoV-2 Omicron variant of concern subvariants BA.1 and BA.2 in Denmark

SARS coronavirus 2 (SARS-CoV-2) continues to evolve and new variants emerge. Using nationwide Danish data, we estimate the transmission dynamics of SARS-CoV-2 Omicron subvariants BA.1 and BA.2 within households. Among 22,678 primary cases, we identified 17,319 secondary infections among 50,588 household contacts during a 1-7 day follow-up. The secondary attack rate (SAR) was 29% and 39% in households infected with Omicron BA.1 and BA.2, respectively. BA.2 was associated with increased susceptibility of infection for unvaccinated household contacts (Odds Ratio (OR) 1.99; 95%-CI 1.72-2.31), fully vaccinated contacts (OR 2.26; 95%-CI 1.95-2.62) and booster-vaccinated contacts (OR 2.65; 95%-CI 2.29-3.08), compared to BA.1. We also found increased infectiousness from unvaccinated primary cases infected with BA.2 compared to BA.1 (OR 2.47; 95%-CI 2.15-2.84), but not for fully vaccinated (OR 0.66; 95%-CI 0.57-0.78) or booster-vaccinated primary cases (OR 0.69; 95%-CI 0.59-0.82). Omicron BA.2 is inherently more transmissible than BA.1. Its immune-evasive properties also reduce the protective effect of vaccination against infection, but do not increase infectiousness of breakthrough infections from vaccinated individuals.

Household transmission of SARS-CoV-2 Omicron variant of concern subvariants BA.1 and BA.2 in Denmark

SARS coronavirus 2 (SARS-CoV-2) continues to evolve and new variants emerge. Using nationwide Danish data, we estimate the transmission dynamics of SARS-CoV-2 Omicron subvariants BA.1 and BA.2 within households. Among 22,678 primary cases, we identified 17,319 secondary infections among 50,588 household contacts during a 1-7 day follow-up. The secondary attack rate (SAR) was 29% and 39% in households infected with Omicron BA.1 and BA.2, respectively. BA.2 was associated with increased susceptibility of infection for unvaccinated household contacts (Odds Ratio (OR) 1.99; 95%-CI 1.72-2.31), fully vaccinated contacts (OR 2.26; 95%-CI 1.95-2.62) and booster-vaccinated contacts (OR 2.65; 95%-CI 2.29-3.08), compared to BA.1. We also found increased infectiousness from unvaccinated primary cases infected with BA.2 compared to BA.1 (OR 2.47; 95%-CI 2.15-2.84), but not for fully vaccinated (OR 0.66; 95%-CI 0.57-0.78) or booster-vaccinated primary cases (OR 0.69; 95%-CI 0.59-0.82). Omicron BA.2 is inherently more transmissible than BA.1. Its immune-evasive properties also reduce the protective effect of vaccination against infection, but do not increase infectiousness of breakthrough infections from vaccinated individuals.

Household transmission of the SARS-CoV-2 Omicron variant in Denmark

In late 2021, the Omicron SARS-CoV-2 variant overtook the previously dominant Delta variant, but the extent to which this transition was driven by immune evasion or a change in the inherent transmissibility is currently unclear. We estimate SARS-CoV-2 transmission within Danish households during December 2021. Among 26,675 households (8,568 with the Omicron VOC), we identified 14,140 secondary infections within a 1-7-day follow-up period. The secondary attack rate was 29% and 21% in households infected with Omicron and Delta, respectively. For Omicron, the odds of infection were 1.10 (95%-CI: 1.00-1.21) times higher for unvaccinated, 2.38 (95%-CI: 2.23-2.54) times higher for fully vaccinated and 3.20 (95%-CI: 2.67-3.83) times higher for booster-vaccinated contacts compared to Delta. We conclude that the transition from Delta to Omicron VOC was primarily driven by immune evasiveness and to a lesser extent an inherent increase in the basic transmissibility of the Omicron variant.

Erythropoietin in patients with aneurysmal subarachnoid haemorrhage: a double blind randomised clinical trial

BACKGROUND

Erythropoietin (EPO) is neuroprotective in experimental models of stroke and subarachnoid haemorrhage (SAH) and possibly in patients with thromboembolic stroke. We studied the efficacy and safety of EPO in patients with SAH.

METHODS

A larger scale clinical trial was planned but preliminarily terminated because of a lower than expected inclusion rate. However, 73 patients were randomised to treatment with EPO (500 IU/kg/day for three days) or placebo. The primary endpoint was Glasgow Outcome Score at six months. We further studied surrogate measures of secondary ischaemia, i.e. transcranial Doppler (TCD) flow velocity, symptomatic vasospasm, cerebral metabolism (microdialysis) and jugular venous oximetry, biochemical markers of brain damage (S-100beta and neuron specific enolase) and blood-brain barrier integrity.

FINDINGS

The limited sample size precluded our primary hypotheses being verified and refuted. However, data from this study are important for any other study of SAH and as much raw data as possible are presented and can be included in future meta analyses. On admission the proportion of patients in a poor condition was higher in the EPO group compared with the placebo group but the difference was statistically insignificant. In the EPO-treated patients the CSF concentration of EPO increased 600-fold. Except for a higher extracelullar concentration of glycerol in the EPO group probably caused by the poorer clinical condition of these patients, there were no statistically significant group differences in the primary or secondary outcome measures. EPO was well tolerated.

CONCLUSIONS

Beneficial effects of EPO in patients with SAH cannot be excluded or concluded on the basis of this study and larger scale trials are warranted.

Fast track hysterectomy

OBJECTIVE

To identify factors limiting early discharge after laparoscopically assisted vaginal hysterectomy (LAVH) and abdominal hysterectomy, in a fast track setting with emphasis on information, treatment of pain, early mobilization, and early food intake.

STUDY DESIGN

A prospective, descriptive study of 32 unselected women allocated to either abdominal hysterectomy (n=16) or LAVH (n=16). The patients received the same information, care, and advice for the perioperative period except for an assumed 1-day hospital stay in the LAVH-group and 2 days in the abdominal group.

RESULTS

Patients were discharged median 1 day (1-3) after LAVH and 2 days (2-4) after abdominal hysterectomy. Work was resumed median 23 days after abdominal hysterectomy and 28 days after LAVH (P > 0.05).

CONCLUSIONS

The study questions the previously proposed advantages of shortened hospitalization and convalescence after LAVH compared with abdominal hysterectomy. Further studies with active rehabilitation are needed to demonstrate real differences between laparoscopic and open hysterectomy.

Co-dominant expression of the HLA-G gene and various forms of alternatively spliced HLA-G mRNA in human first trimester trophoblast

Genes may be silenced at the transcriptional level by 'genomic imprinting' in such a way that only one of the parental alleles is expressed. Imprinting may be tissue-specific and in some cases it seems also to be time-dependent during development. The phenomenon has been studied in pre- and post-implantation developmental processes. Animal studies of genomic imprinting of major histocompatibility complex (MHC) antigens in the placenta have shown discordant results. To address this issue in the human placenta, we examined the expression of the non-classical human leukocyte antigen (HLA) class I gene, HLA-G. Genomic imprinting of the HLA-G locus could have implications for the interaction in the feto-maternal relationship. Restriction Fragment Length Polymorphism (RFLP), allele-specific amplification and Single Strand Conformation Polymorphism (SSCP) analysis followed by DNA sequencing were performed on Reverse Transcription (RT) Polymerase Chain Reaction (PCR) products of HLA-G mRNA to examine the expression of maternal and paternal alleles. Our results demonstrate that HLA-G is co-dominantly expressed in first trimester trophoblast cells. A "new" non-synonymous base substitution in exon 4 was detected. We also investigated the different alternatively spliced forms of HLA-G mRNA in first trimester trophoblast and found the full-length transcript to be the far most abundant.

Increased transmissibility of SARS-CoV-2 lineage B.1.1.7 by age and viral load

New lineages of SARS-CoV-2 are of potential concern due to higher transmissibility, risk of severe outcomes, and/or escape from neutralizing antibodies. Lineage B.1.1.7 (the Alpha variant) became dominant in early 2021, but the association between transmissibility and risk factors, such as age of primary case and viral load remains poorly understood. Here, we used comprehensive administrative data from Denmark, comprising the full population (January 11 to February 7, 2021), to estimate household transmissibility. This study included 5,241 households with primary cases; 808 were infected with lineage B.1.1.7 and 4,433 with other lineages. Here, we report an attack rate of 38% in households with a primary case infected with B.1.1.7 and 27% in households with other lineages. Primary cases infected with B.1.1.7 had an increased transmissibility of 1.5-1.7 times that of primary cases infected with other lineages. The increased transmissibility of B.1.1.7 was multiplicative across age and viral load.

Molecular epidemiology of the SARS-CoV-2 variant Omicron BA.2 sub-lineage in Denmark, 29 November 2021 to 2 January 2022

Following emergence of the SARS-CoV-2 variant Omicron in November 2021, the dominant BA.1 sub-lineage was replaced by the BA.2 sub-lineage in Denmark. We analysed the first 2,623 BA.2 cases from 29 November 2021 to 2 January 2022. No epidemiological or clinical differences were found between individuals infected with BA.1 versus BA.2. Phylogenetic analyses showed a geographic east-to-west transmission of BA.2 from the Capital Region with clusters expanding after the Christmas holidays. Mutational analysis shows distinct differences between BA.1 and BA.2.

Genome investigations show host adaptation and transmission of LA-MRSA CC398 from pigs into Danish healthcare institutions

Over the last decade, an increasing number of infections with livestock-associated methicillin-resistant Staphylococcus aureus of clonal complex 398 (LA-MRSA CC398) in persons without contact to livestock has been registered in Denmark. These infections have been suggested to be the result of repeated spillover of random isolates from livestock into the community. However, other studies also found emerging sub-lineages spreading among humans. Based on genome-wide SNPs and genome-wide association studies (GWAS), we assessed the population structure and genomic content of Danish LA-MRSA CC398 isolates from healthcare-associated infections from 2014 to 2016 (n = 73) and compared these to isolates from pigs in Denmark from 2014 (n = 183). Phylogenetic analyses showed that most human isolates were closely related to and scattered among pig isolates showing that the majority of healthcare-associated infections are the result of repeated spillover from pig farms, even though cases of human-to-human transmission also were identified. GWAS revealed frequent loss of antimicrobial resistance genes and acquisition of human-specific virulence genes in the human isolates showing adaptation in response to changes in selective pressures in different host environments, which over time could lead to the emergence of LA-MRSA CC398 lineages more adapted to human colonization and transmission.

Electronic reporting of diagnostic laboratory test results from all healthcare sectors is a cornerstone of national preparedness and control of COVID-19 in Denmark

The COVID‐19 pandemic has led to an unprecedented demand for real‐time surveillance data in order to inform critical decision makers regarding the management of the pandemic. The aim of this review was to describe how the Danish national microbiology database, MiBa, served as a cornerstone for providing data to the real‐time surveillance system by linkage to other nationwide health registries. The surveillance system was established on an existing IT health infrastructure and a close network between clinical microbiologists, information technology experts, and public health officials. In 2020, testing capacity for SARS‐CoV‐2 was ramped up from none to over 10,000 weekly PCR tests per 100,000 population. The crude incidence data mirrored this increase in testing. Real‐time access to denominator data and patient registries enabled adjustments for fluctuations testing activity, providing robust data on crude SARS‐CoV‐2 incidence during the changing diagnostic and management strategies. The use of the same data for different purposes, for example, final laboratory reports, information to the public, contact tracing, public health, and science, has been a critical asset for the pandemic response. It has also raised issues concerning data protection and critical capacity of the underlying technical systems and key resources. However, even with these limitations, the setup has enabled decision makers to adopt timely interventions. The experiences from COVID‐19 may motivate a transformation from traditional indicator‐based public health surveillance to an all‐encompassing information system based on access to a comprehensive set of data sources, including diagnostic and reference microbiology.

Risk of hospitalisation associated with infection with SARS-CoV-2 lineage B.1.1.7 in Denmark: an observational cohort study

BACKGROUND

The more infectious SARS-CoV-2 lineage B.1.1.7 rapidly spread in Europe after December, 2020, and a concern that B.1.1.7 could cause more severe disease has been raised. Taking advantage of Denmark's high RT-PCR testing and whole genome sequencing capacities, we used national health register data to assess the risk of COVID-19 hospitalisation in individuals infected with B.1.1.7 compared with those with other SARS-CoV-2 lineages.

METHODS

We did an observational cohort study of all SARS-CoV-2-positive cases confirmed by RT-PCR in Denmark, sampled between Jan 1 and March 24, 2021, with 14 days of follow-up for COVID-19 hospitalisation. Cases were identified in the national COVID-19 surveillance system database, which includes data from the Danish Microbiology Database (RT-PCR test results), the Danish COVID-19 Genome Consortium, the National Patient Registry, the Civil Registration System, as well as other nationwide registers. Among all cases, COVID-19 hospitalisation was defined as first admission lasting longer than 12 h within 14 days of a sample with a positive RT-PCR result. The study population and main analysis were restricted to the proportion of cases with viral genome data. We calculated the risk ratio (RR) of admission according to infection with B.1.1.7 versus other co-existing lineages with a Poisson regression model with robust SEs, adjusted a priori for sex, age, calendar time, region, and comorbidities. The contribution of each covariate to confounding of the crude RR was evaluated afterwards by a stepwise forward inclusion.

FINDINGS

Between Jan 1 and March 24, 2021, 50 958 individuals with a positive SARS-CoV-2 test and at least 14 days of follow-up for hospitalisation were identified; 30 572 (60·0%) had genome data, of whom 10 544 (34·5%) were infected with B.1.1.7. 1944 (6·4%) individuals had a COVID-19 hospitalisation and of these, 571 (29·4%) had a B.1.1.7 infection and 1373 (70·6%) had an infection with other SARS-CoV-2 lineages. Although the overall number of hospitalisations decreased during the study period, the proportion of individuals infected with B.1.1.7 increased from 3·5% to 92·1% per week. B.1.1.7 was associated with a crude RR of hospital admission of 0·79 (95% CI 0·72-0·87; p<0·0001) and an adjusted RR of 1·42 (95% CI 1·25-1·60; p<0·0001). The adjusted RR was increased in all strata of age and calendar period-the two covariates with the largest contribution to confounding of the crude RR.

INTERPRETATION

Infection with SARS-CoV-2 lineage B.1.1.7 was associated with an increased risk of hospitalisation compared with that of other lineages in an analysis adjusted for covariates. The overall effect on hospitalisations in Denmark was lessened due to a strict lockdown, but our findings could support hospital preparedness and modelling of the projected impact of the epidemic in countries with uncontrolled spread of B.1.1.7.

FUNDING

None.

An ultrasound algorithm for identification of endometrial cancer

OBJECTIVE

To propose a scoring system to predict endometrial cancer using different ultrasound image characteristics at gray-scale, with and without enhancement by gel infusion, and Doppler transvaginal sonography (TVS) and to evaluate intra- and interobserver variability in assessment of these characteristics.

METHOD

Unenhanced TVS, Doppler examinations and gel infusion sonography (GIS) were performed prospectively in 174 consecutive postmenopausal women with endometrial thickness ≥ 5 mm. The reference standard in all women was hysteroscopy or hysterectomy with pathological evaluation of the malignancy. The presence of various ultrasound pattern characteristics indicative of endometrial malignancy and intra- and interobserver variability in their assessment were evaluated. Multivariate logistic regression was used to correlate image and clinical parameters to presence of endometrial cancer.

RESULTS

A simple Doppler flow score (which considered only presence of vascularity and not presence of single/double dominant vessel, multiple vessels, large vessels, color splash or densely packed vessels) had an area under the receiver-operating characteristics curve (AUC) of 0.83 in the prediction of endometrial cancer. Models including endometrial thickness, Doppler score and interrupted endomyometrial junction on unenhanced TVS predicted endometrial cancer with an AUC of 0.95 (95% CI, 0.92-0.99) and, with addition of irregular surface on GIS, the AUC was 0.97 (95% CI, 0.94-0.99). A risk of endometrial cancer (REC) scoring system based on body mass index, Doppler score, endometrial thickness and interrupted endomyometrial junction on unenhanced TVS and irregular surface at GIS performed very well at identifying endometrial cancer; at a REC-score of ≥ 4 the sensitivity for detection of endometrial cancer was 91% and specificity was 94%. Observers agreed in 82.3% of cases (kappa, 0.63 (0.48-0.78)) when subjective parameters were analyzed in stored videoclips.

CONCLUSION

Our observer-dependent proposed scoring system seems to perform well in the prediction of endometrial cancer and should be tested in future studies.

Platelet function after coronary artery bypass grafting: is there a procoagulant activity after off-pump compared with on-pump surgery?

OBJECTIVE

After off-pump coronary artery bypass (OPCAB) haemostasis might be better preserved compared with on-pump coronary artery bypass grafting (CABG). The aim of this study was to investigate whether this possibly better preserved haemostasis results in a procoagulant activity of the platelets.

DESIGN

Thirty patients were studied prospectively, 15 undergoing on-pump CABG and 15 undergoing OPCAB. Platelet function was evaluated four times within the first 24 h: preoperatively, postoperatively, 4 h and 1 day after surgery with a bedside whole blood clotting test.

RESULTS

A significant increase of platelet-activating-factor-induced platelet aggregation was observed postoperatively after OPCAB (p < 0.01). Only two patients did not reach preoperative values within 1 day postoperatively and four patients had a more than twofold increase. Platelet aggregation immediately after on-pump CABG was reduced to near half of preoperative values, but within 1 day postoperatively normal platelet aggregation was regained in half of the patients.

CONCLUSION

This study has mainly indicated that platelets after OPCAB were more easily activated in the early postoperative period. After CABG with cardiopulmonary bypass we found a temporary platelet dysfunction which seemed to be overcome within the first postoperative day.

Expression of cadherin and NCAM in human small cell lung cancer cell lines and xenografts

Tumour cell adhesion, detachment and aggregation seem to play an important part in tumour invasion and metastasis, and numerous cell adhesion molecules are expressed by tumour cells. Several families of cell-cell adhesion molecules have been described, of which two groups are particularly well characterised, the cadherin family and the Ig superfamily member, neural cell adhesion molecule (NCAM). We investigated expression of these two adhesion molecule families in small cell lung cancer (SCLC) cell lines and xenografts by immunoblotting. Nineteen tumours established from 15 patients with SCLC were examined. All tumours but one expressed both cadherin and NCAM. The tumours expressed one, two or rarely three cadherin bands, and different combinations of two major isoforms of NCAM with M(r)'s of approximately 190,000 and 135,000. Polysialylation of NCAM, a feature characteristic of NCAM during embryonic development, which may play a role in connection with tumour invasion and metastasis, was found in 14/18 NCAM expressing SCLC tumours. Individual tumours grown as cell lines and as nude mouse xenografts showed no qualitative differences in cadherin or NCAM expression.

Observed protection against SARS-CoV-2 reinfection following a primary infection: A Danish cohort study among unvaccinated using two years of nationwide PCR-test data

Background

The level of protection after a SARS-CoV-2 infection against reinfection and COVID-19 disease remains important with much of the world still unvaccinated.

Methods

Analysing nationwide, individually referable, Danish register data including RT-PCR-test results, we conducted a cohort study using Cox regression to compare SARS-CoV-2 infection rates before and after a primary infection among still unvaccinated individuals, adjusting for sex, age, comorbidity and residency region. Estimates of protection against infection were calculated as 1 minus the hazard ratio. Estimates of protection against symptomatic infections and infections leading to hospitalisation were also calculated. The prevalence of infections classified as symptomatic or asymptomatic was compared for primary infections and reinfections. The study also assessed protection against each of the main viral variants after a primary infection with an earlier variant by restricting follow-up time to distinct, mutually exclusive periods during which each variant dominated.

Findings

Until 1 July 2021 the estimated protection against reinfection was 83.4% (95%CI: 82.2-84.6%); but lower for the 65+ year-olds (72.2%; 95%CI: 53.2-81.0%). Moderately higher estimates were found for protection against symptomatic disease, 88.3% overall (95%CI: 85.9-90.3%). First-time cases who reported no symptoms were more likely to experience a reinfection (odds ratio: 1.48; 95%CI: 1.35-1.62). By autumn 2021, when infections were almost exclusively caused by the Delta variant, the estimated protection following a recent first infection was 91.3% (95%CI: 89.7-92.7%) compared to 71.4% (95%CI: 66.9-75.3%) after a first infection over a year earlier. With Omicron, a first infection with an earlier variant in the past 3-6 months gave an estimated 51.0% (95%CI: 50.1-52.0%) protection, whereas a first infection longer than 12 months earlier provided only 19.0% (95%CI: 17.2-20.5%) protection. Protection by an earlier variant-infection against hospitalisation due to a new infection was estimated at: 86.6% (95%CI: 46.3-96.7%) for Alpha, 97.2% (95%CI: 89.0-99.3%) for Delta, and 69.8% (95%CI: 51.5-81.2%) for the Omicron variant.

Interpretation

SARS-CoV-2 infection offered a high level of sustained protection against reinfection, comparable with that offered by vaccines, but decreased with the introduction of new main virus variants; dramatically so when Omicron appeared. Protection was lower among the elderly but appeared more pronounced following symptomatic compared to asymptomatic infections. The level of estimated protection against serious disease was somewhat higher than that against infection and possibly longer lasting. Decreases in protection against reinfection, seemed primarily to be driven by viral evolution.

Funding

None.

Effect of vaccination on household transmission of SARS-CoV-2 Delta variant of concern

Effective vaccines protect individuals by not only reducing the susceptibility to infection, but also reducing the infectiousness of breakthrough infections in vaccinated cases. To disentangle the vaccine effectiveness against susceptibility to infection (VES) and vaccine effectiveness against infectiousness (VEI), we took advantage of Danish national data comprising 24,693 households with a primary case of SARS-CoV-2 infection (Delta Variant of Concern, 2021) including 53,584 household contacts. In this setting, we estimated VES as 61% (95%-CI: 59-63), when the primary case was unvaccinated, and VEI as 31% (95%-CI: 26-36), when the household contact was unvaccinated. Furthermore, unvaccinated secondary cases with an infection exhibited a three-fold higher viral load compared to fully vaccinated secondary cases with a breakthrough infection. Our results demonstrate that vaccinations reduce susceptibility to infection as well as infectiousness, which should be considered by policy makers when seeking to understand the public health impact of vaccination against transmission of SARS-CoV-2.

International travel as source of a hospital outbreak with an unusual meticillin-resistant Staphylococcus aureus clonal complex 398, Denmark, 2016

In May 2016, an unusual outbreak with the Panton-Valentine leukocidin-positive human variant of meticillin-resistant Staphylococcus aureus (MRSA) clonal complex 398 occurred among mothers and infants in the maternity unit of a Danish hospital. MRSA sharing genotypic and phenotypic characteristics was confirmed in 36 cases, including 26 patients, nine household members and a healthcare worker (HCW) who had contact with all the patients. The national MRSA database contained 37 seemingly unlinked MRSA cases whose isolates shared the same genotypic and phenotypic characteristics as the outbreak strain. Whole genome sequencing showed that three of these isolates clustered together with the 36 outbreak isolates, suggesting spread outside the hospital. The HCW and 21 of 37 cases from the national MRSA database had links to south-eastern Asia, where the outbreak strain is endemic. These findings suggest that the HCW acquired the outbreak strain while travelling in south-eastern Asia and then introduced it into the hospital; from there, it spread within the patients’ households and into the community. Screening of travellers returning from countries with high levels of MRSA could be an important intervention to prevent spread of these bacteria into hospitals via patients or HCWs.

Secretory IgA response in oral immunotherapy. Investigation in birch pollinosis

A rationale for oral immunotherapy (OIT) might be founded on two potential mechanisms: induction of a mucosal secretory IgA response, or induction of systemic hyporesponsiveness (oral tolerance). Previous studies have shown clinically that there is a beneficial effect of OIT in birch pollinosis, in both children and adults. During OIT, birch pollen antigens in enterocoated capsules were given to 20 adults (participating in a double-blind, placebo-controlled trial) and 10 children, all suffering from birch pollinosis. Saliva and tears (only adults) samples were collected before, during, and after OIT. Each sample was assayed for both IgA antibodies against birch pollen antigens and total IgA by enzyme-linked immunosorbent assay. IgA antibody levels were also expressed in relation to total IgA concentrations, to correct for variations in secretion and flow rate between subjects and at different times. Changes in birch-specific secretory IgA antibodies in saliva and tears could not explain the beneficial effect of OIT in birch pollinosis. Further studies in this field are warranted.

Elevation of cyclic AMP levels in HL-60 cells accumulated in G1 or G2 by transmethylation inhibitors

Effects of the transmethylation inhibitors 3-deazaadenosine (c3Ado) and 3-deaza-(+/-)-aristeromycin (c3Ari) on cell cycle and cyclic AMP (cAMP) concentrations in human promyelocytic leukemia cells (HL-60) were studied by flow cytometry and radioimmunoassay techniques. Previously described cell cycle accumulations, after incubation with drugs (25 microM) for two cell doublings (36 hr), were localized to G1 and G2 after incubation with c3Ado and c3Ari, respectively. cAMP levels were elevated in cells treated with c3Ado (35%) and c3Ari (92%) for 36 hr. Addition of the phosphodiesterase (PDE) inhibitor theophylline, increased cAMP levels further, while cAMP responsiveness to the beta-adrenergic stimulator isoproterenol was attenuated after c3Ado and c3Ari incubation. Homocysteine thiolactone (Hcy) alone reduced cell growth slightly (5%) and increased cAMP levels (17%). Hcy increased the growth inhibitory effects of c3Ado, while no modulating effect was seen in combination with c3Ari, nor did Hcy counteract the effects on the cell cycle perturbations. The results suggest that c3Ado- and c3Ari-induced cell cycle accumulation is, at least in part, mediated through cAMP elevation, possibly due to PDE inhibition secondary to S-adenosyl-homocysteine hydrolase inhibition and S-adenosyl-homocysteine build-up.

Household transmission of SARS-CoV-2 Omicron variant of concern subvariants BA.1 and BA.2 in Denmark

SARS coronavirus 2 (SARS-CoV-2) continues to evolve and new variants emerge. Using nationwide Danish data, we estimate the transmission dynamics of SARS-CoV-2 Omicron subvariants BA.1 and BA.2 within households. Among 22,678 primary cases, we identified 17,319 secondary infections among 50,588 household contacts during a 1-7 day follow-up. The secondary attack rate (SAR) was 29% and 39% in households infected with Omicron BA.1 and BA.2, respectively. BA.2 was associated with increased susceptibility of infection for unvaccinated household contacts (Odds Ratio (OR) 1.99; 95%-CI 1.72-2.31), fully vaccinated contacts (OR 2.26; 95%-CI 1.95-2.62) and booster-vaccinated contacts (OR 2.65; 95%-CI 2.29-3.08), compared to BA.1. We also found increased infectiousness from unvaccinated primary cases infected with BA.2 compared to BA.1 (OR 2.47; 95%-CI 2.15-2.84), but not for fully vaccinated (OR 0.66; 95%-CI 0.57-0.78) or booster-vaccinated primary cases (OR 0.69; 95%-CI 0.59-0.82). Omicron BA.2 is inherently more transmissible than BA.1. Its immune-evasive properties also reduce the protective effect of vaccination against infection, but do not increase infectiousness of breakthrough infections from vaccinated individuals.

Risk of hospitalization and death within 2 years after methicillin-resistant Staphylococcus aureus (MRSA) diagnosis in persons colonized or infected with livestock and non-livestock-associated MRSA-A nationwide register-based cohort study

Livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) CC398 has emerged in humans throughout Europe and the USA during the last decade and is associated with the spread of LA-MRSA CC398 in production animals. In this study, we investigated the risk of subsequent hospitalization with an S. aureus-related diagnosis and death within the first 2 years after MRSA diagnosis. The study included 7,521 carriers of MRSA, an age-matched reference population of 376,041 individuals and 7,607 patients infected with MRSA. Hazard ratios (HR) for hospitalization with an S. aureus-related diagnosis were 4.09 (95% CI: 2.78-6.00) and for death 1.21 (95% CI: 0.80-1.83) in LA-MRSA CC398 carriers compared with the reference population. Comparing carriers of LA-MRSA CC398 and non-CC398 MRSA, HR for hospitalization was 0.61 (95% CI: 0.37-0.99) and death 0.25 (95% CI: 0.16-0.40), respectively. Patients initially diagnosed with LA-MRSA CC398 or non-CC398 MRSA infection differed from MRSA carriers in terms of older age, higher Charlson comorbidity index score and longer hospital stays. HR for subsequent hospitalization and death was similar regardless having infection with LA-MRSA CC398 or non-CC398 MRSA at the time of MRSA diagnosis. We established that MRSA CC398 carriers have a lower risk of hospitalization and death up to 2 years after MRSA diagnosis than non-CC398 MRSA carriers do. In contrast, MRSA carriage, regardless the MRSA strain is a burden in terms of hospitalization and death when compared to the background reference population. Further, we established that there are no differences in risk of subsequent hospitalization and death in patients initially diagnosed with MRSA CC398 or non-CC398 MRSA infection. We suggest that public health surveillance of MRSA clearly needs to distinguish between carriage and infection as well as strain type before any inference from number of cases to disease burden is made.