Lipid nanoparticles

A lipid nanoparticle (LNP) for use in mRNA vaccination, said LNP comprising:

• about 45-65 mol % of an ionizable lipid;
• about 4-15 mol % of a phospholipid;
• a sterol;
• a PEG lipid;
• and
• one or more mRNA molecules;
• characterized in that said LNP comprises less than about 1 mol % of said PEG lipid;
• preferably about and between 0.5-0.9 mol % of said PEG lipid.

A lipid nanoparticle (LNP) comprising:

• about 45-65 mol % of an ionizable lipid;
• about 4-15 mol % of a phospholipid;
• a sterol;
• a PEG lipid;
• and
• one or more nucleic acid molecules;
• characterized in that said PEG lipid is a C18-PEG2000 lipid;
• and in that said LNP comprises less than about 1 mol % of said PEG lipid;
• preferably about and between 0.5-09 mol % of said PEG lipid.

A lipid nanoparticle comprising:

• above 60 mol % of said ionizable lipid;
• about 8 mol % of said phospholipid;
• about 0.5-0.9 mol % of said PEG lipid;
• and
• balanced by the amount of said sterol.

A lipid nanoparticle comprising:

• about 64 mol % of said ionizable lipid;
• about 8 mol % of said phospholipid;
• about 0.5-0.9 mol % of said PEG lipid;
• and
• balanced by the amount of said sterol.

A lipid nanoparticle comprising:

• about 64 mol % of said ionizable lipid;
• about 8 mol % of said phospholipid;
• about 0.5 mol % of said PEG lipid;
• and
• balanced by the amount of said sterol.