Provided are an H5 avian influenza vaccine strain which differentiates infected from vaccinated animals, a preparation method therefor, and an application. The vaccine strain uses an NA protein of influenza B as a label, and has application value and public health significance for the prevention, control and decontamination of H5 avian influenza.

Disclosed herein are compositions and methods related to mutant viruses, and in particular, mutant influenza viruses. The mutant viruses disclosed herein include a mutant BM2 sequence, and are useful in immunogenic compositions, e.g., as vaccines. Also disclosed herein are methods, compositions and cells for propagating the viral mutants, and methods, devices and compositions related to vaccination.

An H7 avian influenza vaccine strain which differentiates infected from vaccinated animals, a preparation method therefor, and an application. The highly pathogenic H7 avian influenza not only brings about huge economic losses to the livestock industry, but also seriously threatens public health safety. Conventional H7 avian influenza whole virus inactivated vaccines do have advantages such as being reliable in terms of effect, low in terms of cost and wide in terms of application range, but cannot serologically differentiate infected from vaccinated animals. The present invention uses NA of influenza B as a label to establish a method for constructing an H7 avian influenza vaccine strain which differentiates infection from vaccination, and may be used for the prevention, control and decontamination of the H7 avian influenza.

Provided is an application of a label gene sequence in the preparation of an H9 avian influenza vaccine strain which differentiates influenza A virus infection from vaccination, the label gene sequence containing a DNA sequence for coding an influenza B virus NA protein extracellular region amino acid sequence. Also provided are an H9 avian influenza vaccine strain which differentiates influenza A virus infection from vaccination, a preparation method therefor, and an application.

Disclosed herein are compositions and methods related to mutant viruses, and in particular, mutant influenza viruses. The mutant viruses disclosed herein include mutant M2 sequences, mutant BM2 sequences, and are useful in immunogenic compositions, e.g., as a quadrivalent vaccines. Also disclosed herein are methods, compositions and cells for propagating the viral mutants, and methods, devices and compositions related to vaccination.

Live attenuated viruses for protection against the novel coronavirus, designated as Sars-CoV-2 by the World Health Organization (WHO) are provided. The live attenuated chimeric virus strains are based on a live attenuated influenza B virus (LAIVB), used a master backbone, which includes deletion of the viral virulence element, the NS1 (non-structural protein 1) (DeLNS1-B), engineered to express one or more antigens of the Sars-CoV-2 (herein, CoV2Ag). The chimeric virus strain is referred to generally herein, as DelNS1-B-Sars-CoV-2-CoV2Ag. The DelNS1-B-Sars-CoV-2-CoV2Ag strain preferably shows spontaneous cold adaption with preference to grow at 30-33° C. The DelNS1-B-Sars-CoV-2-CoV2Ag strain can be used to protect a subject in need thereof, against a challenge of Sars-CoV-2. DelNS1-B-Sars-CoV-2-CoV2Ag is an important strategy for making highly attenuated and immunogenic live attenuated vaccines with the ability to induce protective immunity against Sars-CoV-2.

The invention provides a composition useful to prepare high titer influenza B viruses, e.g., in the absence of helper virus, which includes internal genes from an influenza B virus vaccine strain or isolate, e.g., one that is safe in humans, for instance, one that does not result in significant disease, that confer enhanced growth in cells in culture, such as MDCK cells, or in eggs.

The invention provides a composition useful to prepare high titer influenza B viruses, e.g., in the absence of helper virus, which includes internal genes from an influenza B virus vaccine strain or isolate, e.g., one that is safe in humans, for instance, one that does not result in significant disease, that confer enhanced growth in cells in culture, such as MDCK cells, or in eggs.

The invention provides a composition useful to prepare high titer influenza B viruses, e.g., in the absence of helper virus, which includes internal genes from an influenza B virus vaccine strain or isolate, e.g., one that is safe in humans, for instance, one that does not result in significant disease, that confer enhanced growth in cells in culture, such as MDCK cells, or in eggs.

Disclosed herein are compositions and methods related to mutant viruses, and in particular, mutant influenza viruses. The mutant viruses disclosed herein include mutant M2 sequences, mutant BM2 sequences, and are useful in immunogenic compositions, e.g., as a quadrivalent vaccines. Also disclosed herein are methods, compositions and cells for propagating the viral mutants, and methods, devices and compositions related to vaccination.