Author Correction: Human volunteer study of the decontamination of chemically contaminated hair and the consequences for systemic exposure

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Evaluating the impact of decontamination interventions performed in sequence for mass casualty chemical incidents

The Initial Operational Response (IOR) to chemical incidents is a suite of rapid strategies including evacuation, disrobe and improvised and interim decontamination. IOR and Specialist Operational Response (SOR) decontamination protocols involving mass decontamination units would be conducted in sequence by UK emergency services following a chemical incident, to allow for safe onward transfer of casualties. As part of a series of human volunteer studies, we examined the effectiveness of IOR and SOR decontamination procedures alone and in sequence. Specifically, we evaluated the additional contribution of SOR, when following improvised and interim decontamination. Two simulants, methyl salicylate (MeS) with vegetable oil and benzyl salicylate (BeS), were applied to participants’ skin. Participants underwent improvised dry, improvised wet, interim wet, specialist decontamination and a no decontamination control. Skin analysis and UV photography indicated significantly lower levels of both simulants remaining following decontamination compared to controls. There were no significant differences in MeS levels recovered between decontamination conditions. Analysis of BeS, a more persistent simulant than MeS, showed that recovery from skin was significantly reduced following combined IOR with SOR than IOR alone. These results show modest additional benefits of decontamination interventions conducted in sequence, particularly for persistent chemicals, supporting current UK operational procedures.

Airway Hygiene in Children and Adults for Lowering Respiratory Droplet Exposure in Clean and Dirty Air

Respiratory illness threatens the learning potential of hundreds of millions of children around the world. We find in a human volunteer study involving three sites and 253 volunteers that respiratory droplets — of the size and nature to potentially contain COVID-19, influenza, allergens and other contaminants — diminish in number on exhalation by up to 99% via the “airway hygiene” administration of a nasal saline rich in calcium. Exhaled particles were significantly higher and efficacy of airway hygiene greatest at the site (Bangalore India) with highest fine particle ambient air burden. We argue for the use of airway hygiene for pandemic and post-pandemic global learning.

Human volunteer study of the decontamination of chemically contaminated hair and the consequences for systemic exposure

The decontamination of exposed persons is a priority following the release of toxic chemicals. Efficacious decontamination reduces the risk of harm to those directly affected and prevents the uncontrolled spread of contamination. Human studies examining the effectiveness of emergency decontamination procedures have primarily focused on decontaminating skin, with few examining the decontamination of hair and scalp. We report the outcome of two studies designed to evaluate the efficacy of current United Kingdom (UK) improvised, interim and specialist mass casualty decontamination protocols when conducted in sequence. Decontamination efficacy was evaluated using two chemical simulants, methyl salicylate (MeS) and benzyl salicylate (BeS) applied to and recovered from the hair of volunteers. Twenty-four-hour urinary MeS and BeS were measured as a surrogate for systemic bioavailability. Current UK decontamination methods performed in sequence were partially effective at removing MeS and BeS from hair and underlying scalp. BeS and MeS levels in urine indicated that decontamination had no significant effect on systemic exposure raising important considerations with respect to the speed of decontamination. The decontamination of hair may therefore be challenging for first responders, requiring careful management of exposed persons following decontamination. Further work to extend these studies is required with a broader range of chemical simulants, a larger group of volunteers and at different intervention times.

Evaluating Putative Repellent ‘Push’ and Attractive ‘Pull’ Components for Manipulating the Odour-orientation of Host-seeking Malaria Vectors in the Peri-domestic Space

Background Novel malaria vector control approaches aim to combine tools to work in synergy for maximum protection. This study aimed to evaluate novel and re-evaluate existing, putative repellent ‘push’ and attractive ‘pull’ components for manipulating the odour-orientation of malaria vectors in the peri-domestic space. Methods Anopheles arabiensis outdoor human landing catches and trap comparisons were implemented in large semi-field systems to (1) test the efficacy of citriodiol or transfluthrin-treated fabric strips positioned in house eave gaps as push components for preventing bites; (2) understand the efficacy of an MB5-baited Suna-trap in attracting vectors in the presence of a human being; (3) assess 2-butanone as a CO2 replacement for trapping; and (4) determine the protection provided by a full push-pull set up. The air-concentrations of the chemical constituents of the push-pull mosquito control tool were quantified.Results Microencapsulated citriodiol eave strips did not provide any outdoor protection against host-seeking An. arabiensis. Transfluthrin-treated strips significantly reduced the odds of a mosquito landing on the human volunteer (OR 0.17; 95% CI 0.12-0.23). This impact was lower (OR 0.59; 95% CI 0.52-0.66) during the push-pull experiment which was associated with low night-time temperatures likely affecting the transfluthrin vaporisation. The MB5-baited Suna trap supplemented with CO2 attracted only a third of the released mosquitoes in the absence of a human being, however, with a human volunteer in the same system, the trap caught less than 1% of all released mosquitoes. The volunteer consistently attracted over two-thirds of all mosquitoes released. This was the case in the absence (‘pull’ only) and in the presence of a spatial repellent (‘push-pull’), indicating that in its current configuration the tested ‘pull’ does not provide a valuable addition to a spatial repellent. The chemical 2-butanone was ineffective in replacing CO2. Transfluthrin was detectable in the air space but with a strong linear reduction in concentrations over 5 metres from release. The MB5 constituent chemicals were only irregularly detected, potentially suggesting insufficient release and concentration in the air for attraction.Conclusion This step-by-step evaluation of the selected ‘push’ and ‘pull’ components led to a better understanding of their ability to affect host-seeking behaviours of the malaria vector Anopheles arabiensis in the peri-domestic space and helps to gauge the impact such tools would have when used in the field for monitoring or control.

Evaluating the effectiveness of a lower extremity venous phantom on developing ultrasound examination skills and confidence

Introduction The aims of this study were: (1) Determine the effect on student ultrasound scanning skills using a lower extremity venous ultrasound phantom in addition to standard teaching methods of didactic lecture and scanning live volunteers and (2) Determine the effect of using a lower extremity venous ultrasound phantom in addition to standard teaching methods of didactic lecture and scanning live volunteers on student confidence levels in performing the lower extremity venous ultrasound examination. Methods Participants were first year diagnostic medical sonography students with minimal scanning experience ( n = 11), which were randomized into two groups. Group 1 ( n = 5) received the standard didactic lecture and attended a scan lab assessment where they performed a lower extremity venous examination on a human volunteer. Group 2 ( n = 6) received the standard didactic lecture, performed three scheduled scanning sessions on an anatomic lower extremity venous phantom with flow and then attended the same scan lab assessment as Group 1, where they performed a lower extremity venous examination on a human volunteer. Results Scan lab assessments on day 4 of the study demonstrated a significant difference in scanning performance ( p = 0.019) between the two groups. Post scan lab assessment confidence scores also demonstrated a significant difference between how participants in each group scored their confidence levels ( p = 0.0260), especially in the ability to image calf veins. Conclusions This study suggests anatomical phantoms can be used to develop scanning skills and build confidence in ultrasound imaging of the lower extremity venous structures.