Evaluation of Thermal Support during Anesthesia Induction on Body Temperature in C57BL/6 and Nude Mice.

Heat supplementation during surgery is a common practice; however, thermal support is not commonly used during anesthesia induction. Mice lose body temperature quickly, and air movement can exacerbate this, potentially putting mice at a thermal deficit before surgery. Whether the method of warming during induction affects overall heat loss during anesthesia is unknown. We hypothesized that the method of heating would affect body temperature (Tb) during anesthesia induction, maintenance, recovery, and once placed back on the rack. Mice (C57BL/6NHsd-6M/6F [C57BL/6]; Hsd:Athymic Nude-Foxn1nu [Nude]; N = 24;12M/12F) were assigned to a treatment in a factorial design: thermal chamber (TC; ambient temperature [Ta] = 28.8°C); heating pad (HP; induction chamber placed on an electric heating pad;Ta = 28.4°C); and control (Ctrl; Ta = 21.6°C). During induction, one mouse at a time was anesthetized with isoflurane over a 3min period and then maintained under anesthesia for 10min on a hot water heating pad (33 °C). Then isoflurane was stopped and time to ambulation was recorded. Tb and activity were tracked in the home cage on the rack before and after anesthesia. During induction, Ctrl mice lost significantly more heat (-2.8 °C) than did TC (+0.2 °C) and HP mice (+0.1 °C) but TC and HP were not different. During anesthesia maintenance, Ctrl mice regained 1 °C, but their Tb was still lower than that of the treated groups. Nude mice consistently had a lower Tb than C57BL/6 mice, regardless of treatment or anesthesia phase. C57BL/6 Ctrl mice took longer to ambulate than either HP or TC mice, but the method of heating did not differentially affect Nude mice. In general, C57BL/6 as compared with Nude and females as compared with males were comparatively more active and had higher Tb during certain times of day, regardless of the heating methods. Overall, our findings support the provision of heat during anesthesia induction, regardless of method, to reduce overall Tb loss during a short anesthesia event.

ChAdOx1 nCoV-19 (AZD1222) vaccine candidate significantly reduces SARS-CoV-2 shedding in ferrets.

Vaccines against SARS-CoV-2 are likely to be critical in the management of the ongoing pandemic. A number of candidates are in Phase III human clinical trials, including ChAdOx1 nCoV-19 (AZD1222), a replication-deficient chimpanzee adenovirus-vectored vaccine candidate. In preclinical trials, the efficacy of ChAdOx1 nCoV-19 against SARS-CoV-2 challenge was evaluated in a ferret model of infection. Groups of ferrets received either prime-only or prime-boost administration of ChAdOx1 nCoV-19 via the intramuscular or intranasal route. All ChAdOx1 nCoV-19 administration combinations resulted in significant reductions in viral loads in nasal-wash and oral swab samples. No vaccine-associated adverse events were observed associated with the ChAdOx1 nCoV-19 candidate, with the data from this study suggesting it could be an effective and safe vaccine against COVID-19. Our study also indicates the potential for intranasal administration as a way to further improve the efficacy of this leading vaccine candidate.