Lessons learned from the first 50 COVID-19 critical care transfer missions conducted by a civilian UK Helicopter Emergency Medical Service team.

BACKGROUND: The COVID-19 pandemic has placed exceptional demand on Intensive Care Units, necessitating the critical care transfer of patients on a regional and national scale. Performing these transfers required specialist expertise and involved moving patients over significant distances. Air Ambulance Kent Surrey Sussex created a designated critical care transfer team and was one of the first civilian air ambulances in the United Kingdom to move ventilated COVID-19 patients by air. We describe the practical set up of such a service and the key lessons learned from the first 50 transfers. METHODS: Retrospective review of air critical care transfer service set up and case review of first 50 transfers. RESULTS: We describe key elements of the critical care transfer service, including coordination and activation; case interrogation; workforce; training; equipment; aircraft modifications; human factors and clinical governance. A total of 50 missions are described between 18 December 2020 and 1 February 2021. 94% of the transfer missions were conducted by road. The mean age of these patients was 58 years (29-83). 30 (60%) were male and 20 (40%) were female. The mean total mission cycle (time of referral until the time team declared free at receiving hospital) was 264 min (range 149-440 min). The mean time spent at the referring hospital prior to leaving for the receiving unit was 72 min (31-158). The mean transfer transit time between referring and receiving units was 72 min (9-182). CONCLUSION: Critically ill COVID-19 patients have highly complex medical needs during transport. Critical care transfer of COVID-19-positive patients by civilian HEMS services, including air transfer, can be achieved safely with specific planning, protocols and precautions. Regional planning of COVID-19 critical care transfers is required to optimise the time available of critical care transfer teams.

Plasmodium vivax DBP binding to Aotus nancymaae erythrocytes is Duffy antigen dependent.

Plasmodium vivax is the second leading cause of malaria worldwide. Invasion of human erythrocytes by P. vivax merozoites is dependent upon the interaction between the parasite Duffy binding protein (PvDBP) and the erythrocyte Duffy antigen receptor. Therefore, disruption of this vital interaction is an attractive target for therapeutic intervention. Although Aotus nancymaae is a commonly used primate model for human P. vivax infections, it has not been confirmed that the interaction between Ao. nancymaae erythrocytes and P. vivax is Duffy antigen dependent. Our results indicate that normal Ao. nancymaae erythrocytes readily bind to PvDBPII and that this binding is completely abolished with chymotrypsin treatment of the erythrocytes. Furthermore, the results of our inhibition assays show a dose-dependent decrease in binding with increasing amounts of anti-PvDBPII polyclonal rabbit sera or anti-Fy6 monoclonal antibody. These data indicate that the interaction between Ao. nancymaae erythrocytes and P. vivax DBPII is Duffy antigen dependent, validating this model system for in vivo studies of anti-PvDBP inhibition.

Naturally acquired inhibitory antibodies to Plasmodium vivax Duffy binding protein are short-lived and allele-specific following a single malaria infection.

The Duffy binding protein of Plasmodium vivax (DBP) is a critical adhesion ligand that participates in merozoite invasion of human Duffy-positive erythrocytes. A small outbreak of P. vivax malaria, in a village located in a non-malarious area of Brazil, offered us an opportunity to investigate the DBP immune responses among individuals who had their first and brief exposure to malaria. Thirty-three individuals participated in the five cross-sectional surveys, 15 with confirmed P. vivax infection while residing in the outbreak area (cases) and 18 who had not experienced malaria (non-cases). In the present study, we found that only 20% (three of 15) of the individuals who experienced their first P. vivax infection developed an antibody response to DBP; a secondary boosting can be achieved with a recurrent P. vivax infection. DNA sequences from primary/recurrent P. vivax samples identified a single dbp allele among the samples from the outbreak area. To investigate inhibitory antibodies to the ligand domain of the DBP (cysteine-rich region II, DBP(II)), we performed in vitro assays with mammalian cells expressing DBP(II) sequences which were homologous or not to those from the outbreak isolate. In non-immune individuals, the results of a 12-month follow-up period provided evidence that naturally acquired inhibitory antibodies to DBP(II) are short-lived and biased towards a specific allele.

Numbers of adults with diagnosed HIV infection 1996-2005--adjusted totals and extrapolations for England, Wales and Northern Ireland.

Using data from the annual surveys of individuals receiving HIV related treatment or other care from 1996 to 2000, trends in prevalent numbers of diagnosed HIV infections have been extrapolated to the years 2001-05. Results show that the adjusted prevalent number for 1996 was 14,205 and that this has increased by 62% by the end of 2000, and will have increased by 139% by the end of 2005. The drivers for this increase have been the sustained rise in diagnoses in infections heterosexually acquired in sub-Saharan Africa and the continuing numbers of new diagnoses in men who have sex with men.

National assessment of prevalent diagnosed HIV infections.

HIV infection is associated with high treatment and care costs and subject to large differences in prevalence between health districts. Equitable distribution of resources requires information provided by an annual national survey of prevalent diagnosed HIV infections (SOPHID). This measures HIV caseloads by health district of residence throughout England, Wales, and Northern Ireland and is used to inform local public health professionals and to improve allocation of government funding for HIV prevention and care. Survey totals are adjusted by underreporting and non-attendance factors to produce a more accurate assessment of the total caseloads. On average the combined adjustments increase the reported caseload by 14.7% annually. Adjusted prevalence estimates ranged from 14,164 in 1995 to 18,460 in 1998, an increase of 30%.