Forskare: För- och nackdelar hos vaccinkandidaterna

An RNA vaccine or mRNA (messenger RNA) vaccine is a new type of vaccine that inserts fragments of viral mRNA into human cells, which are reprogrammed to produce pathogen antigens (e.g. viral protein spikes or cancer antigens), which then stimulate an adaptive immune response against the pathogen. The mRNA molecule is usually held in a drug delivery vehicle, such as lipid nanoparticles, to protect the fragile mRNA strands, and aid their absorption into the human cells. The advantages of RNA vaccines over traditional protein vaccines include production speed and cost, and the induction of cellular immunity as well as humoral immunity. The fragility of the mRNA molecule requires cold chain distribution and low temperature storage, and may impair the effective efficacy due to inadequate dosage.Up until November 2020, no mRNA vaccine, drug, or technology platform, had ever been approved for use in humans, and before 2020, mRNA was only considered a theoretical or experimental candidate for human use. As of November 2020, there were two novel mRNA vaccines awaiting emergency use authorization as COVID-19 vaccines (having completed the 8-week required period post final human trials) – MRNA-1273 from Moderna, and BNT162b2 from a BioNTech/Pfizer partnership. Global regulators had to balance a lack of medium to longer-term data on potential side-effects from novel mRNA COVID-19 vaccines, with the urgent need to address the global coronavirus pandemic, for which the faster production capability of mRNA vaccines is valuable.

An adenovirus vaccine is a vaccine against adenovirus infection.It was used by the United States military from 1971 to 1999, but was discontinued when the only manufacturer stopped production. This vaccine elicited immunity to adenovirus serotypes 4 and 7, the serotypes most often associated with acute respiratory disease. On March 16, 2011, the U.S. Food and Drug Administration approved an adenovirus vaccine manufactured by Teva Pharmaceuticals under contract to the U.S. Army. This vaccine is essentially the same as the one used from 1971 to 1999. On October 24, 2011, the military services began administering the new adenovirus vaccine to recruits during basic training.The vaccine is orally administered and consists of live (not attenuated) virus. The tablets are coated, so that the virus passes the stomach and infects the intestines, where the immune response is raised.It should not be confused with the strategy of using adenovirus as a viral vector to develop vaccines for other pathogens, or as a general gene carrier.