SARS-CoV-2 evolution during prolonged infection in immunocompromised patients

Prolonged infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in immunocompromised patients provides an opportunity for viral evolution, potentially leading to the generation of new pathogenic variants. To investigate the pathways of viral evolution, we carried out a study on five patients experiencing prolonged SARS-CoV-2 infection (quantitative polymerase chain reaction-positive for 79-203 days) who were immunocompromised due to treatment for lymphoma or solid organ transplantation. For each timepoint analyzed, we generated at least two independent viral genome sequences to assess the heterogeneity and control for sequencing error. Four of the five patients likely had prolonged infection; the fifth apparently experienced a reinfection. The rates of accumulation of substitutions in the viral genome per day were higher in hospitalized patients with prolonged infection than those estimated for the community background. The spike coding region accumulated a significantly greater number of unique mutations than other viral coding regions, and the mutation density was higher. Two patients were treated with monoclonal antibodies (bebtelovimab and sotrovimab); by the next sampled timepoint, each virus population showed substitutions associated with monoclonal antibody resistance as the dominant forms (spike K444N and spike E340D). All patients received remdesivir, but remdesivir-resistant substitutions were not detected. These data thus help elucidate the trends of emergence, evolution, and selection of mutational variants within long-term infected immunocompromised individuals.

IMPORTANCE

SARS-CoV-2 is responsible for a global pandemic, driven in part by the emergence of new viral variants. Where do these new variants come from? One model is that long-term viral persistence in infected individuals allows for viral evolution in response to host pressures, resulting in viruses more likely to replicate efficiently in humans. In this study, we characterize replication in several hospitalized and long-term infected individuals, documenting efficient pathways of viral evolution.

A comparison of multivalent and bivalent vaccination strategies for the control of virulent ovine footrot

Virulent footrot is a significant economic and animal welfare concern. The disease can be treated, controlled, and eliminated with vaccine, but selecting the appropriate vaccination strategy can be challenging. There are two main strategies: outbreak (serogroup)-specific univalent or bivalent vaccination, or use of a multivalent vaccine containing up to nine of the most common serogroups. The objective of this study was to compare these approaches in sheep flocks infected with multiple Dichelobacter nodosus serogroups. In the first phase, we undertook an immunogenicity trial in which we compared four pre-commercial multivalent recombinant fimbrial vaccines containing six (A, B, C, G, H, I) or nine (A, B, C, D, E, F, G, H, I) serogroups, and compared them to commercial bivalent vaccines. Two multivalent vaccines stimulated significantly higher antibody responses than two other multivalent vaccines but the number of serogroups included in the multivalent vaccine formulations did not have a significant effect. In the first phase, we also compared inter-vaccination intervals of two- and three-months between sequential bivalent vaccines, and found that a two-month interval was sufficient to avoid antigenic competition. In the second phase, the most immunogenic multivalent vaccine (nine serogroups) was compared to sequential bivalent vaccines and monthly foot-bathing in a field trial in four commercial Merino flocks. The duration of protection afforded by the multivalent vaccine was likely to be less than that of the bivalent vaccines, as the antibody titres stimulated were lower and less persistent.

A study of urgent and emergency referrals from NHS Direct within England

OBJECTIVES

The presented study aimed to explore referral patterns of National Health Service (NHS) Direct to determine how patients engage with telephone-based healthcare and how telephone-based healthcare can manage urgent and emergency care.

SETTING

NHS Direct, England, UK PARTICIPANTS: NHS Direct anonymised call data (N=1,415,472) were extracted over a representative 1-year period, during the combined month periods of July 2010, October 2010, January 2011 and April 2011. Urgent and emergency calls (N=269,558; 19.0%) were analysed by call factors and patient characteristics alongside symptom classification. Categorical data were analysed using the χ(2) test of independence with cross-tabulations used to test within-group differences.

PRIMARY AND SECONDARY OUTCOME MEASURES

Urgent and emergency referrals to 999; accident and emergency or to see a general practitioner urgently, which are expressed as call rate per 100 persons per annum. Outcomes related to symptom variations by patient characteristics (age, gender, ethnicity and deprivation) alongside differences by patient characteristics of call factors (date and time of day).

RESULTS

Urgent and emergency referrals varied by a range of factors relating to call, patient and symptom characteristics. For young children (0-4), symptoms related to 'crying' and 'colds and flu' and 'body temperature change' represented the significantly highest referrals to 'urgent and emergency' health services symptoms relating to 'mental health' alongside 'pain' and 'sensation disorders' represented the highest referrals to urgent and emergency health services for adults aged 40+ years.

CONCLUSIONS

This study has highlighted characteristics of 'higher likelihood' referrals to urgent and emergency care through the delivery of a national nurse-led telephone healthcare service. This research can help facilitate an understanding of how patients engage with both in and out of hours care and the role of telephone-based healthcare within the care pathway.

Young people's use of NHS Direct: a national study of symptoms and outcome of calls for children aged 0-15

OBJECTIVES

National Health Service (NHS) Direct provides 24/7 expert telephone-based healthcare information and advice to the public in England. However, limited research has explored the reasons to why calls are made on behalf of young people, as such this study aimed to examine call rate (CR) patterns in younger people to enable a better understanding of the needs of this population in England.

SETTING

NHS Direct, England, UK.

PARTICIPANTS AND METHODS

CRs (expressed as calls/100 persons/annum) were calculated for all calls (N=358 503) made to NHS Direct by, or on behalf of, children aged 0-15 during the combined four '1-month' periods within a year (July 2010, October 2010, January 2011 and April 2011). χ² Analysis was used to determine the differences between symptom, outcome and date/time of call.

RESULTS

For infants aged <1, highest CRs were found for 'crying' for male (n=14, 440, CR=13.61) and female (n=13 654, CR=13.46) babies, which is used as a universal assessment applied to all babies. High CRs were also found for symptoms relating to 'skin/hair/nails' and 'colds/flu/sickness' for all age groups, whereby NHS Direct was able to support patients to self-manage and provide health information for these symptoms for 59.7% and 51.4% of all cases, respectively. Variations in CRs were found for time and age, with highest peaks found for children aged 4-15 in the 15:00-23:00 period and in children aged <1 in the 7:00-15:00 period.

CONCLUSIONS

This is the first study to examine the symptoms and outcome of calls made to NHS Direct for and on behalf of young children. The findings revealed how NHS Direct has supported a range of symptoms through the provision of health information and self-care support which provides important information about service planning and support for similar telephone-based services.

Resection of colorectal liver metastases in the elderly: does age matter?

AIM

Despite the incidence of colorectal cancer increasing with age the proportion of patients undergoing surgery for colorectal liver metastases decreases dramatically in the elderly. Is this referral or selection bias justified?

METHOD

A prospective database of resection for colorectal liver metastases at a single centre was retrospectively analysed to compare the outcome in patients aged ≥75 years (group E) with those aged <75 years (group Y). Data were analysed using the Kaplan-Meier method with Cox regression modelling.

RESULTS

Of 1443 resections, 151 (10.5%) in group E were compared with 1292 (89.5%) in group Y. The two groups were matched apart from higher American Society of Anesthesiology scores (P=0.001) and less use of chemotherapy (P=0.01) in the elderly. Perioperative morbidity and 90-day mortality were higher in the elderly compared with the younger group (32.5%vs 21.2%, P=0.02, and 7.3%vs 1.3%, P=0.001). In the last 5 years, mortality in the elderly improved and was no longer significantly different from that of the younger patients [n=2/76 (2.6%) vs n=9/559 (1.6%); P=0.063]. The 5-year survival was similar in groups E and Y for cancer-specific (41.4%vs 41.6%, P=0.917), overall (37.0%vs 38.2%) and median (44.1 months vs 43.6 months, P=0.697) survival respectively.

CONCLUSION

In the elderly liver resection for metastatic disease can be performed with acceptable mortality and morbidity with as good a prospect of survival as for younger patients.

Perioperative fluid management: prospective audit

BACKGROUND

Postoperative fluid management is a core surgical skill but there are few data regarding current fluid management practice and the incidence of potential fluid-related complications in general surgical units. We conducted a prospective audit of postoperative fluid management and fluid-related complications in a consecutive cohort of patients undergoing midline laparotomy.

METHODS

Over a 6-month period, the peri-operative fluid management of 106 consecutive patients was prospectively audited. Serum electrolyte data, fluid balance data, co-morbidities, operative and anaesthetic variables and quantities of fluid and electrolytes prescribed were recorded. The development of fluid-related and other complications was noted.

RESULTS

There were no correlations between routinely available fluid balance parameters and the quantities of fluid and electrolytes prescribed, suggesting that doctors do not consult fluid balance data when prescribing. Fifty-seven patients (54%) developed at least one fluid-related complication. These patients received significantly greater volumes of fluid and sodium each day postoperatively. They had higher rates of other non-fluid-related complications and death. They had a longer hospital stay. In a multivariate model, mean daily fluid load predicted the development of fluid-related complications.

CONCLUSION

Fluid prescription practice in general surgical units is sub-optimal, resulting in avoidable iatrogenic complications. Involvement of senior staff, education and possibly the introduction of prescribing protocols may improve the situation.

Neutrophil-lymphocyte ratio as a prognostic factor in colorectal cancer

BACKGROUND AND OBJECTIVES

Simple methods to identify colorectal cancer patients at risk of recurrence are needed. This study aimed to determine if neutrophil-to-lymphocyte ratio (NLR) predicts survival in colorectal cancer patients.

METHODS

Two-hundred thirty patients diagnosed with colorectal cancer over a two-year period were identified from a prospectively maintained colorectal cancer database. NLR was calculated from pre-operative full blood counts. In the case of patients who did not undergo surgery, the full blood count from their out-patient visit was used. Known prognostic factors were recorded. Overall and cancer-specific survival were calculated.

RESULTS

Pre-operative NLR greater than 5 correlated with overall and cancer-specific survival in univariate analyses. NLR was not independent of Dukes stage.

CONCLUSIONS

Pre-operative NLR may represent a simple method of identifying colorectal cancer patients with a poor prognosis pre-operatively.

Neutrophil-lymphocyte ratio as a prognostic factor in colorectal cancer

BACKGROUND AND OBJECTIVES

Simple methods to identify colorectal cancer patients at risk of recurrence are needed. This study aimed to determine if neutrophil-to-lymphocyte ratio (NLR) predicts survival in colorectal cancer patients.

METHODS

Two-hundred thirty patients diagnosed with colorectal cancer over a two-year period were identified from a prospectively maintained colorectal cancer database. NLR was calculated from pre-operative full blood counts. In the case of patients who did not undergo surgery, the full blood count from their out-patient visit was used. Known prognostic factors were recorded. Overall and cancer-specific survival were calculated.

RESULTS

Pre-operative NLR greater than 5 correlated with overall and cancer-specific survival in univariate analyses. NLR was not independent of Dukes stage.

CONCLUSIONS

Pre-operative NLR may represent a simple method of identifying colorectal cancer patients with a poor prognosis pre-operatively.

Fatty acid compositions of gonadal material and diets of the sea urchin, Psammechinus miliaris: trophic and nutritional implications

The fatty acid compositions of gonadal material was examined for the sea urchin Psammechinus miliaris (Gmelin) held in aquaria and fed either salmon feed pellets or the macroalga, Laminaria saccharina for 18 months. Gonadal material was also examined from P. miliaris collected from four field sites, including commercial scallop lines encrusted with the mussel, Mytilus edulis, sea cages stocked with Atlantic salmon Salmo salar and two intertidal sea-loch sites, characterised by either a fine mud or a macroalgal substratum. The fatty acid compositions of known and potential dietary material was examined. The proportions of certain fatty acids in the gonads of P. miliaris were significantly affected by diet type and location. Docosahexaenoic acid (DHA) 22:6 n-3 was significantly higher in the gonads of the sea urchins fed salmon feed in aquaria and collected from the salmon cages and scallop lines than in the gonads of the sea urchins fed L. saccharina in aquaria and collected from the intertidal sea loch sites. The salmon feed and the mussel tissue also contained a high proportion of this fatty acid. Stearidonic acid 18:4 n-3 and arachidonic acid 20:4 n-6, however, were found in significantly higher proportions than DHA in the gonads of the sea urchins fed L. saccharina and collected from the two intertidal sea-loch sites. L. saccharina was also found to contain high proportions of stearidonic and arachidonic acid. The gonads of the sea urchins collected from the intertidal site, characterised by a mud substratum, and from the scallop lines were found to contain a lower 18:1 n-9/18:1 n-7 ratio and a higher proportion of branched and odd-chained fatty acids, signifying a high dietary bacterial input, than the sea urchins held in the aquaria and collected from the salmon cage. 20:2 and 22:2 non-methylene-interrupted dienoic fatty acids (NMIDs) were found in P. miliaris fed diets lacking these fatty acids suggesting de novo biosynthesis. These results, therefore, suggest that the proportions/ratios of certain fatty acids in the gonads of P. miliaris could be used to give an indication of the predominant diet type of this species in the wild.

Free beta-chorionic gonadotropin: a cross-reactivity study of two immunometric assays used in prenatal maternal serum screening for Down's syndrome

We have evaluated the cross-reactivity characteristics of two distinct immunometric assays for the measurement of free beta-human chorionic gonadotropin (free beta). These maternal serum assays have been used in the initial studies which evaluated free beta as a marker in the prenatal detection of Down's syndrome. It has been suggested that free beta assays are subject to substantial potential for cross-reactivity. To confirm that free beta was the analyte responsible for enhanced detection efficiency both non-competitive and competitive cross-reactivity evaluations were undertaken. These studies demonstrated acceptably small cross-reactivity to other glycoprotein hormones or their beta components. We conclude that properly designed free beta assays will provide specific analyte measurement and improved detection efficiency in Down's syndrome screening.

Maternal serum Down syndrome screening: free beta-protein is a more effective marker than human chorionic gonadotropin

The use of quantitative human chorionic gonadotropin measurement in obstetrics has a long and successful history. Prior studies on the utility of human chorionic gonadotropin in Down syndrome screening have utilized assays that measure the intact human chorionic gonadotropin molecule. This study targeted a distinct marker, the human chorionic gonadotropin free beta-protein, which is present in second-trimester maternal serum at much lower concentrations than is intact human chorionic gonadotropin. Our study of 29 cases of trisomy 21 and 450 control samples shows 80% detection efficiency with maternal serum alpha-fetoprotein, the free beta-protein, and maternal age in pregnancies under 17 weeks' gestation. We conclude that the combination of maternal serum alpha-fetoprotein and the human chorionic gonadotropin free beta-protein will be useful in the prenatal detection of trisomy 21.

Maternal serum alpha-fetoprotein (MSAFP) patient-specific risk reporting: its use and misuse

Fundamental to maternal serum alpha-fetoprotein screening is the clinical utility of the laboratory report. It follows that the scientific form of expression in that report is vital. Professional societies concur that patient-specific risk reporting is the preferred form. However, some intermediate steps being taken to calculate patient-specific risks are invalid because of the erroneous assumption that multiples of the median (MoMs) represent an interlaboratory common currency. The numerous methods by which MoMs may be calculated belie the foregoing assumption.

Maternal serum Down syndrome screening: unconjugated estriol is not useful

Study of 41 known Down syndrome cases and 441 matched controls did not confirm earlier reports that low unconjugated estriol levels can be used to detect fetal Down syndrome. Hence the obstetric community should exercise caution in using unconjugated estriol levels as a marker in prenatal Down syndrome screening.

Maternal serum alpha-fetoprotein screening. III. Pitfalls in evaluating black gravid women

Maternal serum alpha-fetoprotein levels are higher in black women. Misinterpretation of maternal serum alpha-fetoprotein screening results can subject black gravid women to unnecessary invasive diagnostic procedures and their calculable risks. Screening errors for black women can result from the use of normative data bases established with maternal serum samples drawn from other racial groups or the use of such data bases in conjunction with a published correction factor. Because the incidence of open neural tube defects is lower for blacks than for others, excessive false positive results for blacks (estimated to be 8817 to 28,215 cases annually) would be a pernicious misapplication of maternal serum alpha-fetoprotein screening. We address the problem outlined above and recommend independently developed, valid, normative data bases.