COVID-19 in non-hospitalised adults caused by either SARS-CoV-2 sub-variants Omicron BA.1, BA.2, BA.4/5 or Delta associates with similar illness duration, symptom severity and viral kinetics, irrespective of vaccination history

BACKGROUND

SARS-CoV-2 variant Omicron rapidly evolved over 2022, causing three waves of infection due to sub-variants BA.1, BA.2 and BA.4/5. We sought to characterise symptoms and viral loads over the course of COVID-19 infection with these sub-variants in otherwise-healthy, vaccinated, non-hospitalised adults, and compared data to infections with the preceding Delta variant of concern (VOC).

METHODS

In a prospective, observational cohort study, healthy vaccinated UK adults who reported a positive polymerase chain reaction (PCR) or lateral flow test, self-swabbed on alternate weekdays until day 10. We compared participant-reported symptoms and viral load trajectories between infections caused by VOCs Delta and Omicron (sub-variants BA.1, BA.2 or BA.4/5), and tested for relationships between vaccine dose, symptoms and PCR cycle threshold (Ct) as a proxy for viral load using Chi-squared (χ2) and Wilcoxon tests.

RESULTS

563 infection episodes were reported among 491 participants. Across infection episodes, there was little variation in symptom burden (4 [IQR 3-5] symptoms) and duration (8 [IQR 6-11] days). Whilst symptom profiles differed among infections caused by Delta compared to Omicron sub-variants, symptom profiles were similar between Omicron sub-variants. Anosmia was reported more frequently in Delta infections after 2 doses compared with Omicron sub-variant infections after 3 doses, for example: 42% (25/60) of participants with Delta infection compared to 9% (6/67) with Omicron BA.4/5 (χ2 P < 0.001; OR 7.3 [95% CI 2.7-19.4]). Fever was less common with Delta (20/60 participants; 33%) than Omicron BA.4/5 (39/67; 58%; χ2 P = 0.008; OR 0.4 [CI 0.2-0.7]). Amongst infections with an Omicron sub-variants, symptoms of coryza, fatigue, cough and myalgia predominated. Viral load trajectories and peaks did not differ between Delta, and Omicron, irrespective of symptom severity (including asymptomatic participants), VOC or vaccination status. PCR Ct values were negatively associated with time since vaccination in participants infected with BA.1 (β = -0.05 (CI -0.10-0.01); P = 0.031); however, this trend was not observed in BA.2 or BA.4/5 infections.

CONCLUSION

Our study emphasises both the changing symptom profile of COVID-19 infections in the Omicron era, and ongoing transmission risk of Omicron sub-variants in vaccinated adults.

TRIAL REGISTRATION

NCT04750356.

Cost effective use of satellite packs in neonates: importance of birth weight

BACKGROUND

Blood banks split an adult packed red cell bag (usually 250 ml) into 30 ml bags, making a total of eight neonatal "satellite" packs per donor. These packs are then "allocated"/"committed" to be used to serially transfuse a newborn.

AIM

To study transfusion requirements of premature infants in relation to their birth weight and thereby attempt to rationalise the method of dispensing satellite blood packs.

METHOD

Data on the distribution of neonatal transfusions with respect to weight were obtained retrospectively from unit A (51 infants, 168 transfusions) and unit B (46 infants, 151 transfusions). These data were used to model the effect of different policies on donor exposure and number of unused packs.

RESULTS

Infants weighing less than 1000 g at birth have significantly higher transfusion requirements than those weighing 1000 g or more (p = 0.001 (unit A), p = 0.004 (unit B)). Our model predicted a significant reduction in donor exposure if eight packs/infant were allocated to those weighing < 1000 g, and a significant cut in the number of unused packs if four satellite packs/infant were allocated to those weighing > or = 1000 g.

CONCLUSIONS

It would be safer and cost effective to allocate eight packs/infant to those with birth weights < 1000 g and four packs/infant to those with birth weights > or = 1000 g.

Randomized study of nasal continuous positive airway pressure in the preterm infant with respiratory distress syndrome

AIM

To evaluate whether very preterm babies can be extubated successfully to nasal continuous positive airway pressure (nCPAP) within one hour of birth after receiving one dose of surfactant in the treatment of respiratory distress syndrome (RDS).

METHODS

Forty-two infants of 25 to 28(+6) wk of gestation were intubated at birth and given one dose of surfactant. They were then randomized within one hour of birth to either continue with conventional ventilation or to be extubated to nCPAP.

RESULTS

Eight out of 21 (38%) babies randomized to nCPAP did not require subsequent reventilation. (Ventilation rates of 62% vs 100%, p = 0.0034). The smallest baby successfully extubated weighed 745 g. There were also significantly fewer infants intubated in the nCPAP group at 72 h of age (47% vs 81%, p = 0.025). There was no significant difference between the two groups in the number of babies that died, developed chronic lung disease or severe intraventricular haemorrhage.

CONCLUSION

A significant number of very preterm babies with RDS can be extubated to nCPAP after receiving one dose of surfactant. nCPAP is a potentially useful modality of respiratory support even in very premature infants.

Creutzfeldt-Jakob disease. The story so far

CJD continues to be an increasing problem for perioperative practitioners to be aware of. Maureen Dyke reviews the implications for perioperative practice.

Alison Bell Memorial Award. Latex sensitivity and allergy: fact and fiction

Health care workers (HCW) have a higher incidence of latex sensitivity than car maintenance workers! The wearing of latex gloves over several years increases the risk of developing latex allergy! All glove related skin reactions are due to latex! People with spina bifida have a high incidence of latex sensitivity! There is a relationship between allergies to natural latex rubber and avocados, chestnuts and bananas! We should all stop using latex products! Powdered gloves are as safe as unpowdered ones, as long as they are rinsed well!

Malignant hyperthermia

Malignant hyperthermia, although an uncommon condition, has dramatic consequences when it occurs. The exact cause of MH is unknown but it is triggered by agents such as suxamethonium and volatile anaesthetic agents, especially Halothane. The condition can occur at anytime during the perioperative period and practitioners need to be vigilant towards its signs and symptoms as well as fully aware of the need for prompt action should it occur. The management of MH also includes identifying those at risk and taking measures to minimise these risks during anaesthesia.

Why not wear gloves?

"This is Cornwall, we don't need to worry about Universal Precautions here"! It was this comment, by a consultant anaesthetist last year, which prompted the introduction of this health promotion project to encourage the practice of glove wearing amongst all the anaesthetic staff. Information was sought on their current practice, reasons for choice and attitudes towards change. As a result of their comments, a campaign was organised, implemented and, in due course, evaluated.