Adult and larval stages of Taenia solium cause 2 diseases in humans, i.e., taeniasis and cysticercosis, respectively. Diagnosis and treatment of taeniasis are the ultimate means to eliminate cysticercosis. A serological taeniasis diagnostic test has been developed for laboratory use. However, recombinant forms of the taeniasis diagnostic proteins are required to overcome the limited supply of native proteins and allow the development of a low-cost and field-applicable test with high sensitivity and specificity. Using 2-dimensional electrophoresis of T. solium excretory and secretory (TSES) products from hamster adult tapeworm in vitro cultures, we have identified 5 T. solium–specific protein spots, with molecular weights of 33 kDa (protein isoelectrofocusing point [pI]: 5.6, 5.3, 5.1) and 38 kDa (pI: 4.6, 4.5). Protein sequencing and molecular cloning of these proteins showed that although endowed with different pIs, the proteins with the same molecular weights shared the same protein backbone, named TSES...

The global spread of the highly pathogenic avian influenza (HPAI) A(H5N1) virus poses a serious pandemic threat, necessitating the swift development of effective vaccines. The success of messenger RNA (mRNA) vaccine technology in the COVID-19 pandemic, marked by its rapid development and scalability, demonstrates its potential for addressing other infectious threats, such as HPAI A(H5N1). We therefore evaluated mRNA vaccine candidates targeting panzootic influenza A(H5) clade 2.3.4.4b viruses, which have been shown to infect a range of mammalian species, including most recently being detected in dairy cattle. Ferrets were immunized with mRNA vaccines encoding either hemagglutinin alone or hemagglutinin and neuraminidase, derived from a 2.3.4.4b prototype vaccine virus recommended by the World Health Organization. Kinetics of the immune responses, as well as protection against a lethal challenge dose of A(H5N1) virus, were assessed. Two doses of mRNA vaccination elicited robust neutralizing antibody titers against a 2022 avian isolate and a 2024 human isolate. Further, mRNA vaccination conferred protection from lethal challenge, whereas all unvaccinated ferrets succumbed to infection. It also reduced viral titers in the upper and lower respiratory tracts of infected ferrets. These results underscore the effectiveness of mRNA vaccines against HPAI A(H5N1), showcasing their potential as a vaccine platform for future influenza pandemics.

Uncertainty about the importance of influenza transmission by airborne droplet nuclei generates controversy for infection control. Human challenge-transmission studies have been supported as the most promising approach to fill this knowledge gap. Healthy, seronegative volunteer ‘Donors’ (n = 52) were randomly selected for intranasal challenge with influenza A/Wisconsin/67/2005 (H3N2). ‘Recipients’ randomized to Intervention (IR, n = 40) or Control (CR, n = 35) groups were exposed to Donors for four days. IRs wore face shields and hand sanitized frequently to limit large droplet and contact transmission. One transmitted infection was confirmed by serology in a CR, yielding a secondary attack rate of 2.9% among CR, 0% in IR (p = 0.47 for group difference), and 1.3% overall, significantly less than 16% (p<0.001) expected based on a proof-of-concept study secondary attack rate and considering that there were twice as many Donors and days of exposure. The main difference between these studies was mechanical building ventilation in the follow-on study, suggesting a possible role for aerosols. Understanding the relative importance of influenza modes of transmission informs strategic use of preventive measures to reduce influenza risk in high-risk settings such as hospitals and is important for pandemic preparedness. Given the increasing evidence from epidemiological modelling, exhaled viral aerosol, and aerobiological survival studies supporting a role for airborne transmission and the potential benefit of respirators (and other precautions designed to prevent inhalation of aerosols) versus surgical masks (mainly effective for reducing exposure to large droplets) to protect healthcare workers, more studies are needed to evaluate the extent of risk posed airborne versus contact and large droplet spray transmission modes. New human challenge-transmission studies should be carefully designed to overcome limitations encountered in the current study. The low secondary attack rate reported herein also suggests that the current challenge-transmission model may no longer be a more promising approach to resolving questions about transmission modes than community-based studies employing environmental monitoring and newer, state-of-the-art deep sequencing-based molecular epidemiological methods.

A(H3N2) influenza vaccine effectiveness (VE) was low during the 2016–19 seasons and varied by age. We analyzed neutralizing antibody responses to egg- and cell-propagated A(H3N2) vaccine and circulating viruses following vaccination in 375 individuals (aged 7 months to 82 years) across all vaccine-eligible age groups in 3 influenza seasons. Antibody responses to cell- versus egg-propagated vaccine viruses were significantly reduced due to the egg-adapted changes T160K, D225G, and L194P in the vaccine hemagglutinins. Vaccine egg adaptation had a differential impact on antibody responses across the different age groups. Immunologically naive children immunized with egg-adapted vaccines mostly mounted antibodies targeting egg-adapted epitopes, whereas those previously primed with infection produced broader responses even when vaccinated with egg-based vaccines. In the elderly, repeated boosts of vaccine egg-adapted epitopes significantly reduced antibody responses to the WT cell–grown viruses. Analysis with reverse genetic viruses suggested that the response to each egg-adapted substitution varied by age. No differences in antibody responses were observed between male and female vaccinees. Here, the combination of age-specific responses to vaccine egg-adapted substitutions, diverse host immune priming histories, and virus antigenic drift affected antibody responses following vaccination and may have led to the low and variable VE against A(H3N2) viruses across different age groups.

Highly pathogenic avian influenza (HPAI) A(H5Nx) viruses continue to pose a pandemic threat. US national vaccine stockpiles are a cornerstone of the influenza pandemic preparedness plans. However, continual genetic and antigenic divergence of A(H5Nx) viruses requires the development of effective vaccination strategies using stockpiled vaccines and adjuvants for pandemic preparedness. Human sera collected from healthy adults who received either homologous (2 doses of a AS03_A-adjuvanted A/turkey/Turkey/1/2005, A/Turkey), or heterologous (primed with AS03_A-adjuvanted A/Indonesia/5/2005, A/Indo, followed by A/Turkey boost) prime-boost vaccination regimens were analyzed by hemagglutination inhibition and microneutralization assays against 8 wild-type HPAI A(H5Nx) viruses from 6 genetic clades. Molecular, structural and antigenic features of the A(H5Nx) viruses that could influence the cross-clade antibody responses were also explored. Compared with homologous prime-boost vaccinations, priming with a clade 2.1.3.2 antigen (A/Indo) followed by one booster dose of a clade 2.2.1 antigen (A/Turkey) administered 18 months apart did not compromise the antibody responses to the booster vaccine (A/Turkey), it also broadened the cross-clade antibody responses to several antigenically drifted variants from 6 heterologous clades, including an antigenically distant A(H5N8) virus (A/gyrfalcon/Washington/410886/2014, clade 2.3.4.4) that caused recent outbreaks in US poultry. The magnitude and breadth of the cross-clade antibody responses against emerging HPAI A(H5Nx) viruses are associated with genetic, structural and antigenic differences from the vaccine viruses and enhanced by the inclusion of an adjuvant. Heterologous prime-boost vaccination with AS03_A adjuvanted vaccine offers a vaccination strategy to use existing stockpiled vaccines for pandemic preparedness against new emerging HPAI A(H5Nx) viruses.