Safety, tolerability, and immunogenicity of a CpG/Alum adjuvanted SARS-CoV-2 recombinant protein vaccine (ZR202-CoV) in healthy adults: Preliminary report of a phase 1, randomized, double-blind, placebo-controlled, dose-escalation trial.

This was a phase 1 dose-escalation study of ZR202-CoV, a recombinant protein vaccine candidate containing a pre-fusion format of the spike (S)-protein (S-trimer) combined with the dual-adjuvant system of Alum/CpG. A total of 230 participants were screened and 72 healthy adults aged 18-59 years were enrolled and randomized to receive two doses at a 28-day interval of three different ZR202-CoV formulations or normal saline. We assessed the safety for 28 days after each vaccination and collected blood samples for immunogenicity evaluation. All formulations of ZR202-CoV were well-tolerated, with no observed solicited adverse events ≥ Grade 3 within 7 days after vaccination. No unsolicited adverse events ≥ Grade 3, or serious adverse events related to vaccination occurred as determined by the investigator. After the first dose, detectable immune responses were observed in all subjects. All subjects that received ZR202-CoV seroconverted at 14 days after the second dose by S-binding IgG antibody, pseudovirus and live-virus based neutralizing antibody assays. S-binding response (GMCs: 2708.7 ~ 4050.0 BAU/mL) and neutralizing activity by pseudovirus (GMCs: 363.1 ~ 627.0 IU/mL) and live virus SARS-CoV-2 (GMT: 101.7 ~ 175.0) peaked at 14 days after the second dose of ZR202-CoV. The magnitudes of immune responses compared favorably with COVID-19 vaccines with reported protective efficacy.

[Research advances in population dynamics of Orchidaceae].

In the study of population dynamics of Orchidaceae, demographic analysis can make us better understand the spatiotemporal variation of plant individuals, the core of the population dynamics study. Nevertheless, many orchid species have an epiphytic or lithophytic habit, which predisposes them to a discrete or patchy distribution. In this case, metapopulation study is a good method to judge the protective scale of the population by analyzing the extent of gene flow among patches. In addition, long-term observation is needed to obtain reliable information on the life history and population dynamics of Orchidaceae, and to understand the relationships between the spatiotemporal variation and functioning of orchid population in certain environmental conditions. As for the short-term study, it's essential for a better understanding of the relationships between the structurally dependent plants and the communities in which they are fund. This paper reviewed the research advances in the population dynamics of Orchidaceae from the viewpoints of the population ecology and ecological characteristics of Orchidaceae.