Abstract: There are provided herein, inter alia, complexes, compositions and methods for a vaccine for COVID-19. The cell-penetrating complexes provided herein may include a nucleic acid non-covalently bound to a cationic amphipathic polymer, the cationic amphipathic polymer including a pH-sensitive immolation domain. The cell-penetrating complexes provided herein are, inter alia, useful in vaccines, wherein the vaccine includes a ribonucleic acid including a sequence encoding a viral protein, a nucleic acid adjuvant and a cationic amphipathic polymer provided herein including embodiments thereof.