Immunization with inactivated whole virus particle influenza virus vaccines improves the humoral response landscape in cynomolgus macaques.

Although antibody-inducing split virus vaccines (SV) are currently the most effective way to combat seasonal influenza, their efficacy can be modest, especially in immunologically-naïve individuals. We investigated immune responses towards inactivated whole influenza virus particle vaccine (WPV) formulations, predicated to be more immunogenic, in a non-human primate model, as an important step towards clinical testing in humans. Comprehensive analyses were used to capture 46 immune parameters to profile how WPV-induced responses differed to those elicited by antigenically-similar SV formulations. Naïve cynomolgus macaques vaccinated with either monovalent or quadrivalent WPV consistently induced stronger antibody responses and hemagglutination inhibition (HI) antibody titres against vaccine-matched viruses compared to SV formulations, while acute reactogenic effects were similar. Responses in WPV-primed animals were further increased by boosting with the same formulation, conversely to modest responses after priming and boosting with SV. 28-parameter multiplex bead array defined key antibody features and showed that while both WPV and SV induced elevated IgG responses against A/H1N1 nucleoprotein, only WPV increased IgG responses against A/H1N1 hemagglutinin (HA) and HA-Stem, and higher IgA responses to A/H1N1-HA after each vaccine dose. Antibodies to A/H1N1-HA and HA-Stem that could engage FcγR2a and FcγR3a were also present at higher levels after one dose of WPV compared to SV and remained elevated after the second dose. Furthermore, WPV-enhanced antibody responses were associated with higher frequencies of HA-specific B-cells and IFN-γ-producing CD4+ T-cell responses. Our data additionally demonstrate stronger boosting of HI titres by WPV following prior infection and support WPV administered as a priming dose irrespective of the follow up vaccine for the second dose. Our findings thus show that compared to SV vaccination, WPV-induced humoral responses are significantly increased in scope and magnitude, advocating WPV vaccination regimens for priming immunologically-naïve individuals and also in the event of a pandemic outbreak.

Fabrication of a highly protective 3D-printed mask and evaluation of its viral filtration efficiency using a human head mannequin.

Facemasks are one of the most effective and low-cost prophylactics for COVID-19. In the spring 2020, when a severe shortage of facemasks occurred worldwide, various types of 3D-printed masks were designed and proposed. However, the protective effects conferred by most of these masks were not experimentally evaluated. Here, we provide a new simple design of 3D-printed mask and evaluate its protective effect in a viral filtration test using a human head mannequin. The developed mask can be constructed with a low-cost 3D printer, with an approximate production cost of US $4. This mask has three parts: the main part, wearing parts, and a piece of non-woven fabric filter. The volume of the filter, which needs to be changed daily, was reduced to approximately 1/10 of that of commercially available surgical masks used in this study. The developed mask is fabricated from polylactic acid, a biodegradable plastic, and its surface contour contacting the face may be adjusted after softening the material with hot water at 60-80°C. The viral filtration efficiency of the developed mask was found to be over 80%. This performance is better than that of commercially available facemasks, such as surgical masks and cloth masks, and equal to those of KN95 and KF94.